Laser Angioplasty

The DymerTM 200+ excimer angioplasty system vaporizes blockages in coronary arteries without damaging arterial walls

Physicians have a powerful new weapon in the war against heart disease, thanks to space technology. A laser system first used for satellite-based atmospheric studies has been reapplied to treat atherosclerosis, the buildup of fatty deposits - called plaque - in the arteries. These deposits can lead to heart disease, the number one cause of death in the United States.

Developed by Advanced Interventional Systems, Inc. (AIS), Irvine, California, the DymerTM 200+ excimer laser angioplasty system vaporizes blockages in coronary arteries without damaging arterial walls. In January 1992, the system received Food and Drug Administration approval for treatment of coronary disease.

Laser angioplasty is less expensive and, because it is minimally invasive, less risky than a coronary bypass, which replaces clogged blood vessels. Further, lasers can help a broader range of patients than the current bypass alternative, balloon angioplasty (see next page), in which a flexible catheter with a tiny balloon at its tip is threaded into the blocked artery and inflated to widen the path for blood flow.

The AIS system employs excimer laser technology pioneered at NASA's Jet Propulsion Laboratory (JPL) for remote sensing of the ozone layer. While other types of lasers such as CO2 and nd:YAG have surgical applications, they are too hot for delicate coronary surgery and could damage tissue, cause blood vessel spasms, or create blood clots. The excimer is a "cool" laser that uses ultraviolet light energy to operate at 65° C, a temperature human tissue can tolerate.

The Dymer 200+ laser angioplasty system is safer than coronary bypass operations and offers wider utility than balloon angioplasty.

The laser light is carried through fiber optic bundles within a flexible catheter designed to navigate the complex coronary anatomy. The Dymer 200+ incorporates NASA- developed switching technology to produce a uniform laser beam that can be controlled and pulsed in as little as 200 billionths of a second to maintain a low working temperature.

Since clinical tests began in 1988, over 2000 coronary angioplasty procedures have been performed with the system at 30 hospitals nationwide. It can be used to treat peripheral vascular disease and may have applications in neurosurgery and orthopedics.

Cardiac Imaging System

Computer- created "movies" of the heart help doctors to spot life-threatening blockages

Balloon angioplasty is a non-surgical procedure for clearing fatty deposits in the coronary arteries that block blood flow and cause heart attacks. The procedure involves threading a thin hollow tube called a catheter directly into a clogged artery. A cardiologist guides the catheter with the aid of an imaging system that shows on a monitor the heart's regions and the catheter as it moves. When the catheter penetrates a blocked segment, a small balloon at the tip of the catheter is inflated, pushing aside the fatty plaque and clearing the artery.

Although not available to all patients with narrowed arteries, the use of balloon angioplasty has expanded dramatically over the past decade‹from 12,000 procedures worldwide in 1982 to an anticipated 560,000 in the U.S. alone this year. This growth has fueled demand for higher quality imaging systems to improve accuracy and the odds for success.

The Digital Cardiac Imaging (DCI) System answers this demand by incorporating image processing technology first developed for NASA's Earth remote sensing satellites. Designed by Philips Medical Systems International, The Netherlands, and marketed in the U.S. by Philips Medical Systems North America Company, Shelton, Connecticut, the DCI offers much sharper real-time images. It is the most widely used digital cardiac imaging system, according to the manufacturer, with more than 300 units in operation worldwide, including over 100 in the U.S.

The Philips system gives the cardiologist direct control of "roadmapping," in which freeze-frame images of a blood vessel section aid in guiding the catheter. Using a cordless control unit such as a remote TV channel selector, the cardiologist can manipulate images to make immediate assessments, compare live x-ray and road map images by placing them side-by-.side on monitor .screens, or compare pre- and post-procedure conditions. The additional information allows the doctor to get into and out of the heart more quickly, minimizing trauma.

The image processing technology employed by the DCI originated some 15 years ago at International Imaging Systems (I2S), Milpitas, California. 12S pioneered optical, analog, and digital image processing equipment for NASA's Earth resources survey spacecraft, exemplified by the Landsat satellite family. In the early 1980s, 12S responded to emerging interest within the medical industry for such applications as ultrasound, computer-aided tomography (CT), and magnetic resonance imaging (MRI) body scanners. I2S supplied medical equipment firms with image processing hardware and software identical to that used by NASA. Subsequently, I2S broadened its market and developed application-specific products for its industrial clients, including a high-performance processor for Philips Medical's DCI system.

Advanced Pacemaker

A state-of-the-art implantable pacemaker closely matches the natural rhythm of the heart

Communications technology that bridges the gap between Earth stations and orbiting satellites also enables doctors to communicate with pacemakers implanted in the human body.

At top is Synchrony*, a state-of-the-art implantable pacemaker that closely matches the natural rhythm of the heart. Below is the companion element of the Synchrony Pacemaker System, the Programmer Analyzer APS-II, which allows a doctor to reprogram and fine-tune the pacemaker to each user's special requirements without surgery.

Bi-directional telemetry, a type of two-way communications developed by NASA, provides the means to both instruct and query the pacemaker. For example, the doctor can send signals to the pacemaker to alter its rate and also receive signals from the implanted device regarding the status of its interaction with the heart. This way, the doctor can adjust the device to best suit a patient's needs, which may change over time.

Developed by Siemens-Pacesetter Inc., Sylmar, California, the Synchrony Pacemaker System won Food and Drug Administration approval for general marketing in August 1989 after clinical trials involving more than 750 implants in 90 hospitals.

Synchrony features a unique sensor that allows the pacemaker to respond to body movements. During increased activity, it accelerates the heart rate, boosting the supply of oxygen to the body. This opens up to pacemaker patients a wide range of activities‹jogging, dancing, swimming,‹from which they were previously barred.

The Programmer Analyzer APS-II has 28 pacing functions and thousands of programming combinations to accommodate diverse lifestyles. The microprocessor unit records and stores pertinent patient data for up to a year.

Implantable Heart Aid

Miniaturized space technology detects a broad range of spontaneous heart arrhythmias

Sudden cardiac death (SCD) strikes nearly half a million Americans each year. Eighty percent die before medical help arrives and those who survive face a two-year recurrence rate that may be a as high as 55 percent. For many potential victims, however, the Automatic Implantable Cardioverter Defibrillator, or AICD* (shown at right) offers new hope: it can reduce the two-year SCD mortality rate to less than three percent.

The AICD incorporates spacebased miniaturized electronics to detect a broad range of spontaneous heart arrhythmias, including those caused by ventricular fibrillation, during which the heart loses its ability to pump blood, causing death or brain damage in minutes. The AICD works by shocking the heart via electrodes that have been surgically placed in and on the heart. Comprising a pulse generator and two sensors that continuously monitor heart activity, the AICD automatically delivers electrical countershocks to restore rhythmic heartbeat as necessary. It works in the same way as defibrillators used by emergency squads and hospitals, but offers the advantage of being permanently available to patients with high risk of experiencing SCD.

The AICD pulse generator was developed in the early 197Os by Intec Systems Inc. and Medrad Inc., Pittsburgh, PA, in conjunction with researchers at Sinai Hospital, Baltimore, Maryland. NASA funded development of an AICD recording system and an independent design review of the system, both conducted by the Applied Physics Laboratory of Johns Hopkins University, Howard County, Maryland. The first model was successfully implanted in a dog in 1976 and, after 12 years and more than $4 million in research, the device was implanted in a 57-year-old woman at Johns Hopkins Hospital on February 4, 198O. Clinical studies ensued and a grant from NASA enabled Intec Systems and the Applied Physics Laboratory to pursue development of more advanced models.

The AICD is manufactured by Cardiac Pacemakers, Inc., St. Paul, Minnesota, a subsidiary of Eli Lilly and Company, which purchased Intec Systems in 1985. CPI was the first company to receive FDA approval for an implantable defibrillator and continues to work to make this lifesaving technology available to a greater number of patients.

Implantable and External Pumps

Offering diabetics automatic, precise control of blood sugar levels

Insulin-dependent diabetics have been aided by the use of space technology in the development of both external and implantable insulin delivery systems. A computerized pump can serve as an electronic artificial pancreas that infuses insulin at a pre-programmed rate, allowing for more precise control of blood sugar levels, without which complications such as blindness and kidney disease may result, while freeing the diabetic from the burden of daily insulin injections.

The Programmable Implantable Medication System (PIMS) resulted from efforts begun in the 197Os at NASA's Goddard Space Flight Center to transfer aerospace technology to the medical field. Created by the Applied Physics Laboratory of Johns Hopkins University in cooperation with Goddard and MiniMed Technologies, a California-based manufacturer of medical equipment, the PIMS is surgically implanted in the diabetic's abdomen to continuously deliver insulin.

The implant consists of a refillable drug reservoir, a pumping mechanism, a catheter leading from the pump to the diabetic's intestines, a microcomputer, and a lithium battery‹all encased in a titanium shell 3.2 inches in diameter and three quarters of an inch thick. The pump's tiny dimensions are the product of years of work to miniaturize components for satellite use.

(Photo Caption) The MiniMed 504 Insulin Infusion Pump, on aid to diabetics.

(Photo Caption) Clipped to a patient's clothing, the minipump delivers insulin continuously at a preprogrammed rate adjusted to the individual, allowing the insulin-dependent diabetic to lead a more normal life.

NASA technology also helped create the pumping mechanism, which is based on a design for the biological laboratory of the Mars Viking space probe. The device delivers insulin into the abdominal cavity in short bursts or "pulses," which conserves battery power. When an insulin refill is needed‹about four times a year‹it can be injected without surgery by a special hypodermic needle.

Both patient and physician can adjust the insulin delivery rate via digital telemetry‹a technique developed by NASA to communicate with spacecraft from Earth. By holding a small radio transmitter over the implant and dialing one of ten preprogrammed codes, the diabetic can change the infusion rate or ask for a supplemental dose of insulin before meals or when blood sugar levels are elevated. Another code allows the physician to access information from the pump's stored memory, reprogram insulin delivery, and generate computer records of the pump's performance.

A device similar to the PIMS, but worn externally, is the MiniMed* 5O4 Insulin Infusion Pump. Also based on NASA technology, the MiniMed SO4 can be clipped to a belt or other part of the user's clothing and worn around the clock. About the size of a credit card and weighing just 3.8 ounces, it houses a microprocessor, a long-life battery, and a syringe reservoir filled with insulin. The syringe is connected to an infusion set that consists of a thin, flexible plastic tube about 3O inches long with a needle at its end. The patient inserts the needle subcutaneously, usually in the abdomen. Insulin is infused at rates determined by the patient's needs and programmed into the microprocessor.

Temperature Pill

The sensor reads the patient's internal temperature and telemeters the information to a receiving coil outside the body

Illustrated below is an ingestible thermometer capable of accurately measuring and relaying deep internal body temperatures. Developed by the Johns Hopkins University Applied Physics information to Laboratory in collaboration with NASA's Goddard Space Flight Center, the Ingestible Thermal Monitoring System (marketed under the trade name CorTemp by Human Technologies, Inc. of St. Petersburg, Florida) enables improved patient care in hospitals and offers opportunities in medical experimentation.

The three-quarter-inch silicone capsule contains a telemetry system, a microbattery, and a quartz crystal temperature sensor. The sensor reads the internal temperature and telemeters the information to a receiving coil outside the body. From there it is relayed to a computer. The ITMS monitors continuously during the 24 to 78 hours it takes the capsuleto travel through the digestive system. The pill can record a patient's temperature every 3O seconds and can be programmed to sound an alarm if the temperature exceeds preset limits.

Researchers developed the ITMS for treatment of such emergency conditions as dangerously low (hypothermia) and dangerously high (hyperthermia) body temperatures. Extremely accurate readings are vital in treating such cases. While the average thermometer is accurate to one-tenth of a degree Centigrade, ITMS is off no more than one hundredth of a degree, and provides the only means of gauging deep body temperature.

Although the concept for the temperature pill dates back to the 195Os, until recently technology could not produce parts small enough for an ingestible capsule, while meeting reliability, accuracy, and cost objectives. The ITMS achieves these performance goals by adopting space-based technologies such as miniaturized integrated circuits and telemetry techniques originally developed for transmission of coded signals to Earth from orbiting satellites.

The system has applications in fertility monitoring, incubator monitoring, and some aspects of surgery, critical care, obstetrics, metabolic disease treatment, gerontology (aging), and food processing research. APL is working on an advanced four-channel capsule that will simultaneously monitor temperature, heart rate, inner body pressure, and acidity.

Infrared Thermometer

Aural thermometer gauges body temperature in two seconds or less

Adopting infrared sensor technology developed for space missions,the Diatek Corporation of San Diego, Calif., produced an aural thermometer that gauges body temperature in two seconds or less. Accurate to within two-tenths of a degree, the Model 7OOO thermometer measures heat emitted from the patient's tympanic membrane, or eardrum.

The technique could save considerable time for nurses, who take many temperatures in the course of a hospital shift. In the U.S. alone, some two billion clinical temperature readings are taken annually, about half of them in acute care hospital facilities. The national shortage of nursing personnel spurred Diatek to pursue development of a faster thermometer. The company's researchers turned to infrared optical technology because it offered quick operation and extreme accuracy. The Model 7OOO optical sensor was designed by Diatek engineers and refined with help from NASA's Jet Propulsion Laboratory, which has 3O years experience using infrared sensors to remotely measure the temperatures of planets and stars.

To take a temperature, the nurse inserts the plastic-covered probe into the opening of the patient's ear canal and presses a button to activate the sensor. The probe detects infrared radiation emitted from the eardrum and a microprocessor converts it to the corresponding body temperature, which is displayed on a liquid crystal screen. The aural device enhances the comfort of critically ill, incapacitated, or newborn patients, and makes frequent temperature taking less bothersome Further, it reduces the risk of cross-infection because it avoids contact with mucous membranes and employs disposable probe covers.

The thermometer weighs only eight ounces and can be operated with one hand. It is targeted for acute-care hospitals ancl alternative health care sites such as nursing homes, blood banks, and cancer and burn centers. Diatek expects 6O percent of all clinical thermometers to use infrared sensors by 1997.

(Photo Caption) A nurse takes a patient's temperature with the Diatek Model 7000 aural thermomenter, which employs infrared technology to obtain a near-instantaneous reading.

Thermal Video

A noninvasive means of observing physiological problems

Since the time of Hippocrates, physicians have known that temperature variations hold important clues for diagnosing disease. A localized hot spot on the skin's surface might indicate unseen inflammation, while a cold spot could be symptomatic of poor blood circulation. In the past, however, there was no way to accurately measure fluctuating heat emissions. Now, through the rapidly advancing technology of infrared thermography, physicians have a tool to detect the slight temperature differences that warn of pathology.

Thermographic devices convert invisible infrared (IR) radiation into voltage signals that can be displayed on a monitor. The first IR sensors were developed for military purposes such as missile guidance. Hughes Aircraft Company pioneered the civil application of IR heat sensors as part of a NASA-sponsored research project.

More recently, medical use of thermography has rapidly gained acceptance as a noninvasive means of observing physiological problems. Whereas an x-ray indicates structural anomalies, thermography can pointout functional anomalies. For instance, a thermogram showing an asymmetrical temperature pattern on the body surface serves as a visual indicator of pain, while mapping of dermatones (areas of skin supplied by a specific spinal nerve) enables accurate measurement of nerve dysfunction. Sensory nerve impairment in the lower back is indicated by a temperature difference, from one extremity to the other, of only 1 degree C.

Thermography is proving to be a valuable screening tool in diagnosis. It can provide information that obviates the need to do more invasive tests that might be painful or hazardous. Thermal imaging also can verify a patient's progress through therapy and rehabilitation, and it is finding special utility in determining the extent of sports injuries.

One of the leading purveyors of thermographic equipment is FLIR Systems of Portland, Oregon. The company purchased Hughes' line of Probeye* thermal video systems in 199O and now markets a wide range of infrared systems and accessories, principally for industrial uses such as inspection of electronic components, profiling for nonrestrictive testing, quality inspection, preventive maintenance. and routine monitoring of production processes and energy losses.

(Photo Caption) The Probeye thermal video system serves as a none invasive diagnostic tool. Here, the patient's posture allows the scanner to sense heat differences in the lower back and thereby assess sensory nerve impairment.

(Photo Caption) This thermographic image reveals that the first two fingers of the right hand emit less heat at the skin surface, indicating subnormal blood circulation.

Body Imaging

Apollo research spawned new medical and diagnostic tools

The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-196Os for use in the Apollo Lunar Landing Program. Designed to computer-enhance pictures of the moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools.

DSP is employed in advanced body imaging techniques including computer-aided tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice in the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves to create images, rather than x-rays. The resultant MRI and CT images are often complementary. In most cases, MRI is useful for viewing soft tissue but not bone, while CT images are good for bone but not always for soft tissue discrimination.

Physicians and engineers in the Department of Radiology at the University of Michigan Hospitals, Ann Arbor, Michigan, are developing a method for combining the best features of MRI and CT scans to increase the accuracy of discriminating one type of body tissue from another. one of their research tools is a computer program originally developed to distinguish Earth surface features in Landsat image processing. Called HICAP, the program can be used to distinguish between healthy and diseased tissue in body images.

At top is a CT image of a slice of human liver with many lesions. It was analyzed and processed by HICAP to produce the image at bottom, in which the false-color red areas represent regions of a normal liver. Consecutive liver slices can be processed in this manner to produce a three-dimensional view of the liver.

HICAP was supplied to the Department of Radiology by NASA's Computer Software Management and Information Center (COSMIC*). Located at the University of Georgia, COSMIC makes available to the private sector government-developed computer programs that have commercial applications.

Skin Damage Assessment

High-resolution color images of human tissue aid burn treatment

The critical factor in the diagnosis and treatment of serious burns is accurate measurement of burn depth. The application of NASA ultrasound technology, originally developed to detect microscopic flaws in aircraft and spacecraft materials, has provided an advanced instrument that enables immediate assessment of burn damage. This knowledge improves patient treatment and may even save lives in serious burn cases.

The customary treatment for a severe burn is to allow natural sloughing of necrotic or dead tissue and then to close the resulting wounds with skin grafts. Effective treatment, therefore, depends upon early recognition of the extent of the dead tissue and its removal, by chemical or surgical means, to minimize risk of infection and hasten healing.

In 1983, NASA's Langley Research Center initiated a project to address this need for precise determination of burn depth. The project was spearheaded by physicists with Langley's Nondestructive Measurement Science Branch, which conducts research on ultrasonic and other techniques for evaluating quality and fatigue of aerospace materials. Also participating in the project were the Medical College of Virginia (MCV), Richmond, Virginia; the University of Aberdeen, Scotland; and the NASA Technology Applications Team, Research Triangle Institute (RTI), North Carolina.

(Photo Caption) Dr. Anthony Marmarou of the Medical College of Virginia uses the Supra Scanner to measure the depth of a patient's burn, a key factor in diagnosis and treatment.

Langley developed a prototype instrument capable of determining the level where bumed tissue ends and healthy tissue begins. This is possible because, when skin is burned, the protein collagen that makes up some 4O percent of skin becomes more dense. The Langley technique involved directing ultrasonic waves at the burned area: the difference in density between damaged and healthy tissue causes sound waves to reflect at the point of interface.

After successful completion of preliminary clinical tests by MCV, NASA's RTI technology team negotiated an agreement with Jack Cantwell Inc. (now Topox, Inc., Chadds Ford, Pa.) to commercialize the technology. Following clinical tests of the commercial version, known as the Supra Scanner, it was granted FDA approval in December 199O.

The Supra Scanner combines a scanning transducer and computer in a single instrument that can be used at a patient's bedside. The patented system produces high-resolution color images of up to 14 millimeters of human tissue, generates cross-sectional images of the skin, and provides data on skin surface and subsurface features.

The Supra Scanner also is applicable in diagnosis of skin cancer and lymphatic disorders, and in plastic surgery.

Gait Analysis System

A diagnostic tool for patients who experience difficulty walking

Data collected by orbiting satellites is relayed to Earth using telemetry, in which coded signals are sent by radio and then decoded on the ground. Telemetry is employed in collecting weather, air pollution, and water quality data and, in a specialized form known as biotelemetry, for such applications as monitoring astronaut vital functions from the ground.

One important Earth spinoff of biotelemetry is a diagnostic tool for patients who experience difficulty walking due to birth defects, disease, or injury. Such disorders affect the nervous system, causing muscular spasticity and loss of coordination. The impact on individual muscles varies widely and is difficult to determine solely by physical examination. Through a process called electromyography‹the recording of electrical activity in the muscles‹physicians can identify the affected muscles and prescribe treatment.

A space-derived invention known as the Gait Analysis Telemetry System provides valuable assistance in electromyographic analyses. The system, a cooperative development of NASA, the Children's Hospital at Stanford, Palo Alto, California, and L&M Electronics Inc., Daly City, Califomia, registers detailed information on a patient's leg muscle action during walking tests. Miniature sensor/transmitters, each about the size of a half dollar, are affixed directly over the muscle group being studied. Each transmitter has its own tiny lithium battery and a pair of sensing electrodes. The muscle activity sensed‹called an EMG, for electromyogram‹is sent to a computer for analysis and display.

Because it is wireless, the system has a big advantage over other EMG monitoring systems, which involve wires that connect leg sensors with a receiver/recorder. Wires may hamper a patient's walking and distort the recorded gait pattern.

Numerous hospitals use the system to conduct walking tests of children afflicted with cerebral palsy, muscular dystrophy, congenital disorders, or injuries. The telemetry records, measures, and analyzes muscle activity in the limbs and spine, yielding computer-generated pictures of gait pattems. These help physicians determine the potential of corrective surgery, evaluate various types of braces, or decide whether physical therapy can improve a child's mobility. The system also is employed in a research program at the Department of Veterans Affairs' Rehabilitation Research and Development Center, Palo Alto, Califomia, to investigate the possibility of restoring locomotion to patients with spinal cord injuries and severe gait disorders.

(Photo Caption) The Motion Analysis Loboratory of thildren's Hospital at Stanford uses o spote-derived biotelemetry system in tests of walking impaired children. The resulting data is used to determine the degree and locomotion of abnormal muscle activity and in prescribing treatment.

(Photo Caption) At left, leg sensars send signals to a computer that develops pictures of gait patterns for use by physicians and therapists.

Programmable Remapper

It manipulates images so that the portions that would normally fall outside are mapped onto the usable field of vision

At right is the Programmable Remapper, a novel digital image processing machine that has important potential for alleviating retinitis pigmentosa, maculopathy, and other vision impairments.

The Remapper candetermine how to best use the functional parts of a patient's retina. It manipulates images so that the portions that would normally fall outside are mapped onto the usable field of vision. If, for example, a person's central vision has deteriorated but peripheral vision is still intact, images are remapped or "pushed out" to the still-functioning peripheral field of vision.

The Remapper is an offshoot of a NASA program aimed at developing an image processor to simplify, speed up, and improve the accuracy of pattem recognition in video imagery. The processor is needed to solve problems associated with automated spacecraft tracking/docking and autonomous planetary landings. The original specifications were drawn up by the Tracking and Communications Division of Johnson Space Center (JSC), and the design accomplished jointly by JSC and Texas Instruments Inc., Dallas, Texas.

During its development, the Remapper's potential for application to human low vision problems quickly became apparent and NASA's Technology Utilization office provided funds to conduct vision- related research. Commercially available from Texas Instruments as a tool for optometric research, the Remapper is being adapted for use as a prosthesis for people suffering from certain forms of low vision.

It works at video rates; what is seen on the monitor screen is what is actually seen by the subject, with no computer analysis necessary. Thus, the system is a good candidate for prosthesis use if researchers can sufficiently reduce its size and cost to make it practical and portable. Worn on a belt or elsewhere, the Remapper would warp the image to correspond to the patient's vision characteristics and the viewing task. The patient would then view the warped image on a small video display in front of one or both eyes.

Computer Reader for the Blind

Optacon has provided a new level of independence

More than 20 years ago, Telesensory, Mountain View, Califomia, produced a spinoff technology that enabled the blind and deaf-blind to read‹not just braille transcriptions but anything in print. In 1989, the company introduced an even more exciting aid for the blind, a second-generation spinoff that not only provides access to printed words, but also to the electronic information available on most personal computers. The original device, called optacon, is a combination of optical and electronic technology and incorporates research performed at Stanford Research Institute under the sponsorship of NASA's Ames Research Center. The user passes a mini-camera over a printed page with his left hand; a control unit processes the camera's picture, translates it into a vibrating image of the words the camera is viewing, and the user senses the tactile image with his other hand. optacon, which can be used with virtually any alphabet or language, has provided a new level of independence for thousands of blind people in more than 7O countries.

(Photo Caption) Optocon II permits a blind woman to perceive print and graphical images by providing to the images that she can read by touch.

Optacon II, a dramatically enhanced version, is a joint product of TeleSensory and Canon Inc., Tokyo, Japan, which introduced the original optacon to Japan in 1974. It employs the same basic technique of converting printed information into a tactile image, but connects directly to an IBM or Macintosh computer. This opens up a new range of job opportunities to the blind. optacon II comprises a handheld camera with a silicon integrated circuit of lOO light-sensitive transistors; a microprocessor control unit that processes information from the camera; and a tactile array, driven by the control unit, consisting of lOO vibrating rods. The camera's "retina" sends the shape of what it is viewing to the control unit and the corresponding rods in the tactile array vibrate. Moving the camera with one hand, the operator perceives the vibrating image with the index finger of the other hand. optacon II is not limited to reading printed words; it can convert any graphic image viewed by the camera.

Vision Trainer

Improving vision defects by teaching a patient to control the eye's focusing muscle

Optometrist Dr. Joseph N. Trachtman invented a vision training system that could help the estimated 150 million Americans who are either nearsighted or farsighted to see better without glasses. Called the Accommotrac* Vision Trainer, it is based on vision studies by NASA's Ames Research Center and a special optometer developed for Ames by Stanford Research Institute.

Dr. Trachtman's vision trainer is designed to improve vision defects by teaching a patient to control the ciliary body, the focusing muscle of the eye. The key is biofeedback, a technique whereby a patient leams to control a bodily process or function of which he is not normally aware. Biofeedback can be used, for example, to enable a person to voluntarily control blood pressure and heart rate.

For vision training, the patient dons a headset and enters a darkened room. As he looks into the optical part of the system, harmless infrared light is directed into his eye and its focusing status measured 4O times a second. As the patient opens and closes the eye, an audible tone tells him how well he is controlling the focusing muscle. A nearsighted person, for example, would want the tone to go higher, indicating that he is relaxing the muscle and thereby improving his vision. The inability of the eye muscle to relax causes the blurry vision experienced by many nearsighted people.

(Photo Caption) Dr. Sanford Cohen, an optometrist, uses the Accommotrac Vision Trainer to teach a patient how to improve her vision by controlling and relaxing the eye's focusing muscl.

It takes a lot of practice and motivation, but through a series of one-hour sessions, a patient gradually learns to control relaxation or contraction (for farsightedness) of the eye muscle by auditory feedback. Not all patients can throw away their corrective lenses, but a high percentage achieve an improvement such as halting or reversing their need for ever-stronger lens prescriptions.

The Accommotrac Vision Trainer has also proven effective in treating eye movement problems such as strabismus (cross eyes) and amblyopia (lazy eye). Professional athletes have used the system to improve peripheral visual awareness and, thereby, athletic performance.

The origin of Dr. Trachtman's invention dates back more than 2O years, to when Ames contracted with Stanford Research Institute for studies of pilots' visual accommodation, the ability of the eye to adapt to distinct vision at different distances. Stanford researchers developed an optometer to measure visual accommodation. While running experiments with the optometer on pilots, they discovered that humans could learn to control eye focusing. Adding auditory biofeedback created an effective learning system and a way to overcome an aviation phenomenon known as "empty field myopia," the potentially dangerous tendency of pilots to absently focus on the windscreen instead of scanning the sky for hazards.

Ocular Screening System

Visiscreen-100 provides the means for wide-scale detection of vision problems

In the United States today, thousands of young children have eye defects which, if not detected and treated in the early stages, could result in permanent blindness. Until recently, there was no nationwide ocular screening program for the young, due to the lack of a fast, reliable, and economical method. Now, however, a NASA-patented invention called Visiscreen-lOO provides the means for wide-scale detection of vision problems.

Visiscreen was developed jointly by NASA's Marshall Space Flight Center and Dr. Howard Kerr, President of Medical Sciences Corporation (MSC), the exclusive manufacturer. The portable 2.4-meter apparatus has a hood at one end to hold the subject's head. At the other end is a photorefractor consisting of a 35-mm camera with a telephoto lens and an electronic flash unit.

When the subject is photographed, the light from the flash is sent into the retina and then reflected back to the camera lens. The camera captures the reflective properties of the inner and outer parts of both eyes in a color photograph that MSC technicians analyze using a set of computerized algorithms. Each eye is examined for refractive error and obstruction in the cornea or lens, while alignment problems are detected by the simultaneous imaging of both eyes. If problems are discovered, they are verified by an ophthalmologist.

Because it requires minimal cooperation, the system can be used for infants, preschoolers, and noncommunicative children. Visiscreen offers greater sensitivity than the traditional eye chart. In a test of 1657 Alabama children, only 111 failed the chart test, but the Visiscreen system found 5O7 abnormalities that were verified later by ophthalmologists. The system identifies amblyopia (progressive dimming of vision), also known as "lazy eye," in time for treatment.

(Photo Caption) The Visiscreen-l00 Photorefractor Ocular Screening System offers a simple, reliable, fast, inexpensive method for detecting eye problems in children.

(Photo Caption) Dr. Keith Morgan, a pediatric ophthalmologist, displays an example of a defect detected by Visiscreen-100. Note the difference in the child's plupils: the right eye shows a red disk characteristic of a normal retinal reflex; the left shows a dark coloration in the retinal reflex; the left shows a dark coloration in the retina indicating a defect later diagnosed as a cataract.

Speech Aids

The Speech Teacher* provides visual cues for speech improvement

A deaf person learning to speak requires assistance to modulate the tone and volume of his speaking voice. Recognizing this need, Joseph A. Resnick, president of Dynamed Audio Inc., Natrona Heights, Pennsylvania, invented the Resnick Speech Teacher* to provide visual cues for speech improvement.

Many deaf people, for example, tend to speak in unusually high- pitched tones. When the subject speaks into the Speech Teacher, it electronically processes the speech. Indicator lights on the device's panel corresponding to the subject's speech are compared with a display representing the optimum speech tone. The subject then tries to adjust his speech to match the model.

(Photo Caption) Joseph A. Resnick, president of Dynamed Audio Inc., demonstrates his Speech Teacher. The device uses visual cues to help deaf and hearing-impaired people improve their speech.

(Photo Caption) The Resnick Tone Emitter 1, which can be implanted in a denture, can take the place of a person's natural larynx. The miniature electronic device emits a tone that is shaped into words by the tongue, teeth, lips, and palate.

The Speech Teacher is available in a desk model, intended for use by clinicians, as well as a wrist-mounted version to wear in everyday social situations. The Speech Teacher is one of several devices invented by Resnick in which a NASA Regional Technology Transfer Center (RTTC) has played a part. NASA's six RTTCs nationwide perform computer search and retrieval services for industrial clients such as Resnick, who begins his technology development with a visit to the RTTC at the University of Pittsburgh.

Among other inventions for which the Pittsburgh RTTC provided assistance is the Resnick Tone Emitter ITM, a miniature electronic device for people who have lost their natural larynx to injury, cancer, or other diseases. Built into a denture, the device‹like a human voice box‹produces a tone that can be shaped into words by the tongue, teeth, lips, and palate. The system includes a microchip, microcircuitry, a power switch, a speaker covered with an impervious membrane, and a rechargeable battery. These components are so small that they fit like fillings into three or more artificial teeth within a partial or full denture.

Cool Suit

The system can eliminate 40-60 percent of stored body heat

Young Stevie Roper could only watch from the sidelines while other children played schoolyard games. Victim to a rare skin disease called hypohydrotic ectodermal dysplasia (HED), Stevie was born without the sweat glands needed to eliminate excess body heat. As a result, any physical exertion or exposure to warm temperatures could induce heat stroke.

Years ago, during a visit to his aunt, Sara Moody, Stevie became overheated while riding in a non-air-conditioned car. He was saved by a quick-thinking cousin who spotted a lawn hose, stopped the car, and doused him with cold water.

The incident prompted Ms. Moody to seek the help of NASA's Langley Research Center, which put her in touch with Life Support Systems Inc. (LSSI) of Mountain View, California. A manufacturer of personal cooling gear, LSSI fabricated a child-size version of its Mark VII Microclimate Cooling Suit. The outfit consists of a helmet liner and vest that fit comfortably beneath the boy's clothes. An antifreeze solution cooled by a portable, battery-powered refrigeration unit is pumped through tubes to the garments. The system can eliminate 4O-6O percent of Stevie's stored body heat while lowering his heart rate by 5O-8O beats per minute.

(Photo Caption) Born without sweat glands, Stevie Roper lives a closer-to-norma life by wearing a space-derived cool suit. Coolant circulates through tubes in the vest and headpiece to prevent overheating.

(Photo Caption) The lack of sweat glands in Krystal Sharrett's feet had caused serious sores ond threatened amputation. Presented a cool suit in April 1989, Toby improved dramatically and by June the sores had completely healed.

(Photo Caption) Gary Rodne of Life Support Systems, Inc. displays a HED cool suit‹headcap and torso vest‹that is a child-size version of the company's MicroClimate line of protective garments for workers whose jobs subject them to heat stress.

The Mark VII suit originated in a 196Os NASA program that produced a channeled cooling suit for astronauts. While now used mainly in industrial settings that require heavy protective clothing, such as nuclear power plants and steel mills, the suit also has found numerous military applications. other uses include relieving cockpit heat stress for race car drivers and cooling firefighters. In 1988, LSSI released the ThermoAire Splint*, based on the same technology, to replace ice packs and elastic bandages for sports injuries.

Following media coverage of Stevie's story, LSSI began receiving requests from around the world for suits to help people with HED and other diseases and conditions‹including multiple sclerosis, cystic fibrosis, severe bums, and some forms of cancer‹that can make a person prone to overheating. The suits can be custom-made for particular body parts or problems, and have enabled many people to participate in sports and other strenuous activities from which they were previously barred.

Advanced Wheelchair

They constructed the chair using aerospace composite materials

For those who must rely on wheelchairs for mobility, more than one million in the U.S. alone, clearly the ideal chair would be lightweight and easy to maneuver. However, most commercially-available wheelchairs are heavy and awkward, break down frequently, and don't last very long. Recognizing these problems, the Department of Veterans Affairs and the National Institute of Handicapped Research have sponsored several wheelchair research projects.

Most projects have focused on improving parts rather than on developing an entirely new chair. One cooperative effort, however, undertook full-scale development‹from analysis of requirements to prototype fabrication and evaluation‹of an advanced wheelchair based on aerospace technology. NASA's Langley Research Center teamed with the University of Virginia (UVA) Rehabilitation Engineering Center, Charlottesville, Virginia to develop the prototype shown below. NASA funded Langley's part of the program, while UVA received support from the National Institute of Handicapped Research. Also participating in the program was the NASA-sponsored Research Triangle Institute (RTI) Application Team, Research Triangle Park, North Carolina.

The Langley/UVA engineers first employed aerospace computerized structural analysis techniques to arrive at the optimum design. Then they constructed a prototype using aerospace composite materials, which are generally lighter but stronger than metals. The resulting chair weighs only 25 pounds but has the same strength and weight-bearing capability as a 5O-pound stainless steel wheelchair. It can be collapsed for auto stowage, and features a solid seat, wheel guards, dynamic brakes, shaped hand rims, and a footrest with smooth contours to aid in opening doors. The RTI Application Team is discussing commercial production of the advanced wheelchair with several interested manufacturers.

Vehicle Controller

Lunar Rover technology enables quadriplegics

In 1972, a paraplegic named Tom Wertz saw Apollo astronauts driving the Lunar Rover with just one hand - using a T-bar. After test-driving a rover himself, he realized that if such technology could be adapted to automobiles, it would help handicapped people become more independent. NASA and the Department of Veterans Affairs agreed, and contracted with Johnson Engineering, Boulder, Colorado to implement Wertz' idea. Roughly ten years after Wertz witnessed Apollo's lunar exploration, Johnson installed a prototype Unistik* vehicle control in a Ford van.

Johnson designed a two-axis joystick that controls the vehicle's steering wheel, brake, and accelerator pedal. It allows the driver to control the vehicle through small, low-force hand motions, from any position.

The Unistik Controller was designed for C-5 quadriplegics, such as Wertz, who have spinal cord lesions at the fifth cervical vertebra. People with such severe injuries have very limited use of their upper extremities; they are able to move their hand only a few inches to either side. The joystick is ideal because it has a very low control resistance.

Unistik driving is simple. Moving the stick forward accelerates the vehicle, to the rear slows it down, and left or right tums the steering wheel in the proper direction. Moving the joystick to the two o'clock position, for example, will yield an accelerating turn to the right. Another joystick controls tum signals and headlights. A push of a button deactivates the Unistik, returning the van to normal operation. Thus, both handicapped and able-bodied people can use the same vehicle.

Unistik also provides a platform for the evaluation of intelligent vehicle systems. The computer that controls its driving functions can receive input through a human-operated joystick, or from radar, laser, radio, and other sensor technologies. Unistik thereby enables research that will help all of us drive more safely on tomorrow's highways.

Human Tissue Stimulator

The HTS can send electrical pulses tbrough wire leads to targeted nerve centers or to particular areas of the brain

Chronic pain and involuntary motion disorders can be treated by electrical stimulation from a device implanted in the body. Called the Human Tissue Stimulator (HTS), the device was developed by Pacesetter Systems Inc., Sylmar, Califomia, in cooperation with the Applied Physics Laboratory of Johns Hopkins University, Howard County, Maryland, and with the sponsorship of NASA's Goddard Space Flight Center.

The HTS is based on Goddard-developed technology employed in NASA's Astronomy Satellite-3. It incorporates the same nickel cadmium battery, telemetry, and command systems used in the satellite, but reduced to microminiature proportions so that the implantable element is the size of a deck of cards (shown above, lower left-hand corner of photo). In contrast to earlier stimulating devices‹which require cumbersome, extemally-carried power packs or have very limited lifetimes‹ the HTS is totally implantable.

The HTS includes a tiny re-chargeable battery, an antenna, and electronics to receive and process commands. It reports on its own condition via telemetry, a wireless process wherein instrument data is converted to electrical signals and sent to a receiver where the signals are translated into usable information.

Once implanted, the HTS can send electrical pulses through wire leads to targeted nerve centers or to particular areas of the brain. A control console (shown above) allows a physician to monitor and program the HTS, for example to alter the character and strength of the electrical impulses to address particular conditions such as intractable pain. The implant's nickel cadmium battery can be recharged through the skin, eliminating the need for frequent surgical replacement.

The benefits of the HTS can be swift and remarkable. The first implant, in 1983, involved a female patient who had severe involuntary movement disorders associated with multiple schlerosis. Several hours after surgery, the stimulator was applied to a part of the thalamus, a small region of the brain. The patient's tremors vanished‹even though moments earlier she had been unable to guide a cup of coffee to her lips.

Another implant was used to treat a man who for several years had suffered excruciating pain in his left arm, caused by a wrist injury in a fall. Implanted under his left amm, the HTS was connected by wire leads to electrodes on the brachial plexus, a group of nerves that link the spinal cord with the injured arm. When the stimulator was activated, the patient reported immediate relief from the pain.

Although the initial implants were successful, extensive testing is required before the HTS can be made available for general use. Within the next few years, Pacesetter Systems expects to produce commercial programmable neural stimulators based on the HTS.

Blood Analyzer

A versatile, economical assembly for rapid separation of specific blood proteins in very small quantities

After a person's blood is drawn for a routine blood test, a biochemist must sort out its complex mixture of particles and organic molecules. A widely-used method of determining the presence and amount of specific blood constituents is electrophoresis, which employs an electrical current to separate fluid componetns and prevent interference from other compounds in the solution.

In the mid-196Os, NASA's Ames Research Center sponsored development of an automated electrophoresis device for the weightless environment of space. Designed for use on a monkey- carrying spacecraft to provide information on blood behavior in zero gravity, it never reached flight status. In 1972, a modified system was planned for use in the Skylab space station to study possible changes in astronauts' blood during long-term weightlessness. Although it did not fly in space, it was used in simulated weightlessness studies at Ames. Because the project had produced considerable advanced technology, the device was revived once more in the mid-197Os, this time as a technology utilization project aimed at producing an automated system for Earth use.

(Photo Caption) A researcher at Vanderbilt University, Nashville, Tennessee, uses the Sartophor system to study protein function

Ames contracted with the device's original developer, Dr. Benjamin W. Grunbaum of the University of California at Berkeley, for what later became known as the Grunbaum System for Electrophoresis. It is a versatile, economical assembly for rapid separation of specific blood proteins in very small quantities, permitting their subsequent identification and quantification. The system can handle lO to 2O samples simultaneously.

Grunbaum's innovation became a commercial product in 1982, produced under NASA license by Sartorius Filters Inc., Hayward, California. Known commercially as the Sartophor* System for Electrophoresis, it is both a research instrument and a diagnostic aid, with many applications in medicine, law enforcement science, pathology, biochemistry, and other biological sciences. Capable of analyzing a range of substances other than blood, it can also be used in the food, agriculture, cosmetic, and pharmaceutical industries.

(Photo Caption) The Sartophor System for Electrophoresis is both a research instrument and a diagnostic tool.

(Photo Caption) The Sartophor System for Electrophoresis is both a research instrument and a diagnostic tool.

Microbe Detector

A device that incorporates space technology to signficantly reduce body fluid analysis time

The traditional method of testing for disease-producing microorganisms, or pathogens, to involves three steps. First, specimens of body fluid‹urine or sputum, for example‹are prepared in cultures. Then, the cultures are incubated for two to four days, after which time microbiologists study the cell growth to determine the presence of and identify pathogens.

Speeding up this process can reduce hospital stays by allowing quicker identification and earlier treatment of infection. Merieux Vitek Inc. (formerly Vitek Systems, a subsidiary of McDonnell Douglas), Hazelwood, Missouri, manufactures a device that incorporates space technology to significantly reduce body fluid analysis time. The technology dates back to McDonnell Douglas' Microbial Load Monitor (MLM), developed for NASA's Voyager interplanetary exploration program to detect bacterial contamination aboard the spacecraft. The company later studied an enhanced MLM capable of detecting and identifying bacterial infections among an astronaut crew. Recognizing the MLM's commercial potential, McDonnell Douglas converted the technology into a time-saving system for medical analysis called the AutoMicrobic System (AMS).

Instead of the petri dish customarily used to prepare cultures, AMS employs test kits‹disposable, plastic cards approximately the size of a playing card, with each card containing from 16 to 3O wells that each hold a different chemical substance. There are two types of cards: identification cards and susceptibility cards. A body fluid sample is injected into the identification card and organisms in the sample react with the chemicals in the wells. Mounted in trays, the cards are placed in the AMS' incubator/ reader module. Scanning each well once an hour, the system "reads" the reactions taking place, compares them with information in the computer, and identifies the organism‹or gives a negative report when no organism is present. This data is reported on a display screen and printout.

Once an organism is identified, the body sample goes into the susceptibility card‹whose wells contain a number of different antibiotics. This card is similarly inserted into the system for computer examination, to determine which antibiotic is most effective against the organism. The entire process takes from four to 13 hours, compared with two to four days for culture preparations. AMS can handle up to 24O specimens at one time.

(Photo Caption) The AutoMitrobic System for identification and analysis of bacterial infections in humon body fluids uses disposable test kits instead of the traditional petri dish to prepare cultures.

In addition to enabling microbiology laboratories to fumish guidelines for antimicrobial treatment within one day of specimen collection, the AMS also minimizes human error, reduces technician time, and increases lab output. Beyond its medical uses, the AMS can serve in food processing and other industry laboratories for such applications as detection and identification of organisms during incoming, in-process, and finished goods inspections; identification of biological indicators in sterilization processes; and in-plant environmental testing.

Space Technology for Firefighting

Lightweight air cylinders patterned on technology originally developed for rocket motor casings

Firefighters, like astronauts, often brave dangerous, hostile environments protected mainly by the technology on their backs. In fact, a variety of technologies first developed for space exploration beneficial for fire fighting and prevention. Spinoffs include a portable firefighting module, protective clothing for workers in hazardous environments, fire-retardant paints and foams, fireblocking coatings for outdoor structures, and flame-resistant fabrics. Perhaps the farthest-reaching is the breathing apparatus worn by firefighters throughout the U.S. for protection from smoke inhalation injury.

In 1971, in response to concerns expressed by many of the nation's fire chiefs, NASA began the first concerted effort to improve firefighter breathing systems, which had not changed appreciably since the 194Os. The traditional breathing system was heavy, cumbersome, and so physically taxing that it often induced extreme fatigue. Many firefighters decided not to use the equipment, electing to brave the smoke rather than risk collapse from heat and exhaustion. As a result, smoke inhalation injuries increased.

(Photo Caption) Researchers at Johnson Space Center incorporated materials and technology from the space program into the design of a lighter, less bulky breathing apparatus for firefighters.

In concert with the National Bureau of Standards' Fire Technology Division, NASA established a public interest project directed by Johnson Space Center (JSC). JSC embarked on a four-year design and development effort that applied technology from the portable life support systems Apollo astronauts used on the moon. A committee of fire chiefs and city managers helped JSC establish the system specifications, and such organizations as the National Fire Protection Association periodically reviewed the program. Martin Marietta Corporation and Structural Composites Industries, Inc. were awarded contracts to build lightweight air cylinders patterned on technology originally developed for rocket motor casings, while Scott Aviation received the contract to build the remaining components. The resultant breathing system weighed approximately 2O pounds, one-third less than past systems, and improved wearer mobility. It consisted of a face mask, frame and hamess, a waming device, and an air bottle. The basic air cylinder offered the same 3O-minute operating time as its predecessor, but was lighter and slimmer by virtue of using aluminum/composite materials and doubling pressurization to 45OO pounds per square inch. Inverting the air cylinder shifted the valve to the underside, reducing risk of damage from falling debris. The frame and harness were easier to put on and take off, and the system's weight shifted from shoulders to hips, greatly improving wearer comfort. Further, the new face mask offered better visibility and closer fit, and the beep of the air depletion warning device could be heard only by the wearer, reducing confusion in the hectic environment of a fire scene. JSC conducted extensive testing of the improved system, which was followed by a series of field tests in 1974-75 by the fire departments of New York (the nation's largest), Houston, and Los Angeles. After completion of the tests, the New York City Fire Department became one of the first Qre services to adopt the new technology. Use of the lightweight apparatus spread quickly across the country. The result: a drastic reduction in the number of inhalation injuries to firefighters, according to the U.S. Fire Administration. Though they have made many design modifications and refinements, manufacturers of breathing apparatus to this day still incorporate in some way the original NASA technology.

(Photo Caption) At the NYFD Randall's Island Training facility, firefighters undergo "mask confidence training," carrying out such fire operations as probing building interiors and squeezing through tight confines. Their NASA-developed breathing system features a reduced profile to improve mobility.

(Photo Caption) Protected by a "hazmat" suit, a New York City firefighter disposes of hazardous material, while below, one firefighter helps another to adjusthis breathing system.

Food Processing Control

Pillsbury developed the Hazard Analysis and Critical Control Point concept, designed to prevent food safety problems

When NASA started planning for manned space travel in 1959, the myriad challenges of sustaining life in space included a seemingly mundane but vitally important problem: How and what do you feed an astronaut? There were two main concerns: safety problems preventing food crumbs from contaminating the spacecraft's atmosphere or floating into sensitive instruments, and assuring complete freedom from potentially catastrophic disease-producing bacteria, viruses, and toxins. To solve these problems, NASA enlisted the help of the Pillsbury Company, Minneapolis, Minnesota. Over the next decade, Pillsbury designed some of the first space foods and produced astronaut meals for the Mercury, Gemini, and Apollo manned spaceflight programs.

Pillsbury quickly solved the first problem by coating bite-size foods to prevent crumbling. Assurance against bacterial contamination proved a more difficult task. Investigators found that standard quality control methods could not bring such guarantees. Answering the challenge, Pillsbury developed the Hazard Analysis and Critical Control Point (HACCP) concept, potentially one of the farthest-reaching space spinoffs. HACCP is designed to prevent food safety problems rather than to catch them after they have occurred. The first step, hazard analysis, is a systematic study of a product, its ingredients, processing conditions, handling, storage, packaging, distribution, and directions for consumer use to identify sensitive areas that might prove hazardous. Hazard analysis provides a basis for blueprinting the Critical Control Points (CCPs) to be monitored. CCPs are points in the chain from raw materials to finished product where loss of control could result in unacceptable food safety risks.

(Photo Caption) Examples of food and drink products carried aboard early manned spacecraft. Measures developed by Pillsbury to assure astronaut protection from food poisoning evolved into a comprehensive food safety system.

Consider, for example, the production of cooked and vacuum- packed turkey breast. CCPs could include cooking, chilling, rehydrating, pasteurizing, chilling again, and storing. Once determined, criteria can be set that must be met for each CCP. In the example, the cooking CCP under current regulations would require the turkey to be cooked to a 16O degree F internal temperature. Plant personnel would be required to check and record the cooking temperature regularly; the inspector would check the plant's records for authenticity and accuracy, verifying that the thermometer measured the temperature accurately and periodically double-checking the product's intemal temperature. This illustrates the simplicity of HACCP. Yet, when the CCPs are determined, monitored, and verified on an ongoing basis, the result is a sophisticated process control system highly unlikely to produce an unsafe or otherwise contaminated product.

Pillsbury used the HACCP system to manufacture the food that went to the moon aboard Apollo spacecraft. Within two years of the first lunar landing in 1969, Pillsbury plants were following HACCP in production of food for Earth-bound consumers. Pillsbury's subsequent training courses for Food and Drug Administration (FDA) personnel led to the incorporation of HACCP in the FDA's Low Acid Canned Foods Regulations, set down in the mid-197Os to ensure the safety of all canned food products in the U.S.

The U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS), the public health agency responsible for inspecting meat and poultry, is conducting an extensive study to determine how HACCP can best be employed in its meat and poultry inspection program. In another government project, the FDA and the National Marine Fisheries Service of the National oceanic and Atmospheric Administration are planning an HACCP-based voluntary inspection service for seafood.

(Photo Caption) At left and below is a sampling of Pills bury consumer products manufactured under a spinoff system for improved food processing control.

(Photo Caption) A food inspector inspects the internal temperature of sausages to ensure the product is safe to eat.

Radiation-Blocking lenses

Suntiger eyeglass lenses bar 99 percent of the potentially harmful wavelengths

Taking a tip from nature and technology from NASA, Suntiger Inc. Biomedical optics, North Hollywood, Califomia, produced a line of sunlight-filtering glasses that protect human vision by blocking blue, violet, and ultraviolet light which, research has shown, can cause eye disorders such as cataracts and senile macular degeneration. The Suntiger PST* (Polarized Selective Transmission) lenses (shown at right) bar 99 percent of the potentially harmful wavelengths.

Suntiger lenses are similar in principle to the natural filters in the eyes of hawks and eagles. They block out the intense glints of reflected sunlight that cause areas of the retina to receive high doses of light, or glare, and improve night vision and visual acuity through smog or fog. The lenses are available in various tints for sunglasses, visors, ski goggles, and prescription eyeglasses. Introduced in the early 198Os, the PST lens is a "spinoff from a spinoff," a secondary product that emerged from research focused on fabricating welding curtains to protect people exposed to welding arcs from blue and ultraviolet radiation. James B. Stephens and the late Charles G. Miller, both employed at the Jet Propulsion Laboratoly, spent three years of their own time applying JPL problem-solving techniques to development of a dye formula for a welding curtain. Success led to further research by Stephens and others in the field of protective glasses.

Suntiger has advanced the technology to encompass many new applications, among them industrial inspection glasses to protect plant workers from impact and splash hazards as well as harmful levels of ultraviolet and blue light. Suntiger also has designed safety lenses for dentists who use ultraviolet curing systems. Yet another advance is the Fluorotech* lens specifically developed to block the hazardous radiation peaks emitted by fluorescent lights and unfiltered CRT screens, which have roused complaints of eye irritation and headaches.

Safety Grooving

Reduces accidents on wet runways and highways

Below right, a machine equipped with diamond blades is cutting grooves in the concrete holding pen of a cattle ranch. Concrete floors, regularly employed for sanitary purposes in pens and feeding areas, wear smooth and become slippery with time, hazarding injury or death to valuable cattle should they slip and fall. Ranchers worldwide have found grooving an effective remedy. This unusual use of safety grooving exemplifies an expanding list of applications for a technique developed more than two decades ago.

Safety grooving to improve human and animal footing on slick or smooth surfaces is another "spinoff from a spinoff." The technique was pioneered in the early 196Os at NASA's Langley Research Center to reduce aircraft accidents on wet runways. Investigators sought to curb tire hydroplaning, a condition that occurs during rainstomms when tires roll or slide along water-covered pavement. The tires are lifted away from the surface by the action of water pressure and ride on a thin and treacherous film of water. Grooves, cut transversely across the runway, create channels through which excess water is forced, thereby reducing the skid hazard and improving an airplane's ability to brake.

After demonstrating the technique's effectiveness, Langley assisted the Federal Aviation Administration in testing various groove configurations. This led to the first runway grooving at a U.S. commercial airport, National Airport in Washington, D.C., in 1967. Since then hundreds of airports have been safety-grooved in the U.S., Canada, Europe, and Asia.

Langley scientists also brought the technique to the attention of highway safety engineers. Grooving is now widely used on highways (below left) to reduce skidding, decrease stopping distances, and improve a vehicle's comering ability on curves. A report by the Califomia Division of Highways, which conducted before-and-after grooving studies at 14 locations, showed a wet-weather accident reduction of approximately 85 percent after grooving.

The success of safety grooving on runways and highways has spurred a growing industry and a wide range of innovative applications. Grooving has improved pedestrian safety on sidewalks, railroad station platfomms, and swimming pool decks, and in playgrounds, parking lots, service stations, and car washes. Indoor uses include working areas in refineries, factories, warehouses, meat packing facilities, and food processing plants.

Lightning Protection

Research has enhanced understanding of lightning's effects

In the complex evolution of aerospace technology, advances that solve one problem may exacerbate another, in turn steering researchers toward further advances. Two recent innovations in aircraft design provide good examples: the use of composite materials to gain strength while reducing weight, and implementing digital electronic systems to improve efficiency in flight and engine control. Both technologies tend to make aircraft more susceptible to lightning damage. Research at NASA and elsewhere, undertaken to address the new dangers, has both enhanced understanding of lightning's effects and produced countermeasures to allow safe use of these technologies.

NASA's Langley Research Center played a leading role in lightning investigations with its seven-year (198O-1986) Storm Hazards Research Program, undertaken at Congressional direction to determine the threat of thunderstorms to commercial aviation. Serving as a supporting contractor to the program was Lightning Technologies, Inc., Pittsfield, Massachusetts, a small engineering and testing firm that designs and verifies protection against lightning and other electrical hazards. Lightning Technologies is a spinoff company founded in 1977 by J. Anderson Plumer, formerly an employee of General Electric Company's High Voltage Laboratory, a NASA contractor. Plumer is an example of a "personnel spinoff," wherein NASA technology is transferred to the private sector by the job shift of a scientist or engineer formerly engaged in NASA research.

(Photo Caption) Research at Lightning Technologies includes evaluation of a simulated strike on an F-106 model similar to the one used in the NASA program.

The project used a specially-equipped, protected F-lO6B research airplane that sought out thunderstorms in the hope of being struck by lightning. Data gathered from more than 8OO strikes advanced knowledge of lightning hazards and contributed to protective technology. Lightning Technologies assisted NASA in planning the program, improving and verifying the lightning protection data.

The researchers learned that multiple-burst lightning injects many randomly-occurring electric currents into the airplane. This creates magnetic fields that can induce errors, faulty commands, or other upsets in a plane's electronic systems. This finding led the FAA to require, beginning in 1987, that aircraft electronics systems performing flight-critical functions be protected from damage or upset due to multiple-burst lightning. The standards apply to all new planes with the technologically advanced systems as well as older planes that have such systems installed.

The NASA research also determined that lightning strikes can hit almost any spot on an airplane surface, not just‹as previously believed‹the plane's extremities, such as wings and propeller tips. This alerted aircraft designers to the compounded hazards of employing composite materials, which are less conductive and therefore more vulnerable to lightning damage than the aluminum alloys they replace.

Lightning Technologies has used its NASA-acquired experience and technology to develop protective measures for both electronic systems and composite structures. These include better electrical bonding and shielding techniques for wiring, and methods of increasing system immunity to lightning with improved computer software and surge-suppression devices.

X-Ray Imaging System

Low-intensity imaging has yielded three generations of practical spinoffs

NASA's Goddard Space Flight Center is a leader in the development ofimaging technology for x-ray astronomy, the study of celestial bodies by measuring the x-rays they emit. The center's work in low intensity imaging has yielded three generations of spinoffs with practical payoffs in reducing radiation levels and enhancing public safety. Goddard itself produced the first: a small, portable, isotopic, low-radiation x-ray instrument known as the Low Intensity X-ray Imaging Scope, designed for medical emergencies such as on-site examination of injuries at an accident scene or a sporting event.

Subsequently, NASA licensed the technology to several companies, among them HealthMate, which developed the FluoroScan* Imaging System (above right), a high-resolution, low-radiation device for medical applications, that enables continuous real-time viewing of stationary or moving objects. The company replaced the isotopic penetrating source with a variable-power x-ray tube and made other enhancements while retaining the small size, light weight, and maneuverability of Goddard's system.

Because it emits minimal radiation, the Food and Drug Administration allows use of the FluoroScan without the lead aprons, film badges, or lead-lined walls required with other x-ray systems. FluoroScan occupies only two square feet of space, weighs about 2O pounds, and can be plugged into an electrical outlet or operated from a rechargeable battery. Approximately 5OO hospitals have replaced their high-intensity imaging systems with the FluoroScan, according to the manufacturer.

The system is particularly useful for examination of fractures, dislocations, and foreign objects, and in the placement of catheters. In surgery, its real-time imaging capability enables continuous monitoring; for example, an orthopedic surgeon can set a fracture while simultaneously viewing the insertion of pins. In attending newborns, especially those requiring intensive care, it offers the dual benefits of lower radiation for tiny patients and higher resolution of the area being viewed. In veterinary medicine, FluoroScan permits animals to be examined without sedation as it does not require a still patient to produce a quality image.

The latest application of the Goddard technology is the InnerView Realtime X-ray Imaging System, a direct spinoff of FluoroScan produced by National Imaging Systems, a division of HealthMate, Inc. InnerView offers low cost and safety for industrial x-ray applications such as airport and building security (inspection of luggage, containers, boxes, etc.), nondestructive testing, quality control inspection, and production inspection.

Electro-Expulsive Aircraft Deicer

The Electro-Expulsive Separation System uses one-thousandth the power of existing electro-thermal deicers

Ice buildup on aircraft wings can cause accidents and engine damage. A dynamic new deicing system developed at NASA promises to improve flight safety while offering bonuses in airplane performance and cost savings. The deicer, dubbed the Electro-Expulsive Separation System (EESS), earned its inventor, Ames Research Center engineer Leonard A. Haslim, the 1988 NASA Inventor of the Year award.

EESS uses one-thousandth the power of existing electro-thermal deicers and weighs one-tenth as much. It can be used on aircraft wings, as well as helicopter rotors and jet engine inlet ducts, and can be installed on new aircraft or easily retrofitted to planes already in service.

EESS consists of an elastic, rubber-like boot on the wing's leading edge. The boot is embedded with flexible, conducting copper ribbons separated by slits. Capacitors in an onboard power supply discharge a strong direct current pulse into the ribbons, creating an electromagnetic field that forces adjacent conductors violently apart. The conductors flex into the slits, causing the boot surface to jump and pulverize ice build-up on the wing.

(Photo Caption) The photo at right shows a wind tunnel test of the Electro-Expulsive Separation System (EESS) on an ice covered aircraft wing segment. A millisecond after the EESS is activated, most of the ice is gone, pulverized and ejected by electromagnetic force. At left is EESS inventor Leonard A. Haslim.

The technique overcomes many of the limitations of other deicers. Jet transport aircraft, for example, frequently use systems that bleed hot air from the engines to melt wing ice. The bleed, however, reduces engine thrust and increases fuel consumption. Further, the melted ice may refreeze on other aircraft parts. EESS adds no boots, another common remedy, operate slowly and will not break ice until it becomes one-quarter to one-half inch thick; when it does, big chunks may damage engines or airfoils. EESS, on the other hand, instantly ejects ice of any thickness from mere frost to an inch-thick glaze, vaporizing the ice so that no shard is large enough to damage the plane. EESS also is smaller and easier to maintain and repair in the field than conventional systems.

The invention has captured the attention of the military, airline operators, aircraft manufacturers, and public safety agencies. In November 1988, following a series of successful evaluation tests, including wind tunnel and flight testing at Lewis Research Center, NASA awarded a patent license to Dataproducts New England, Inc. (DNE), Wallingford, Connecticut. The license granted DNE exclusive rights to market EESS for large turbine-powered airplanes. NASA may award other licenses for small turbine-powered aircraft and for propeller-driven craft.

Although developed as an aircraft system, EESS has application elsewhere. Big ships also can accumulate large ice accretions that degrade performance. A deicing system for ships would be a boon to the nation's fishing fleets, particularly those operating off the coast of Alaska, where harsh icing conditions are common. If applied to the treacherous ice on road bridges, EESS could replace chemical ice removal methods that cause structural and surface damage. The electro-expulsion technique may extend beyond ice removal, providing a mold release for the bakery and plastics industries, a self-pumping fluid tube for hydraulic systems, or even a synthetic artery to improve blood flow to the heart.

Collision Avoidance System

Intended to complement ground-based air traffic control, TCAS II alerts pilots to the presence of other aircraft in their vicinity

In the mid-195Os, when increasing air traffic congested skies over the U.S., government and aviation industry groups began searching for an airborne system to warn pilots of collision threats. It wasn't until the 198Os, however, that advancing technology permitted development of the Traffic Alert and Collision Avoidance System (TCAS II). Intended to complement ground-based air traffic control, TCAS II alerts pilots to the presence of other aircraft in their vicinity, identifies and tracks air space "intruders" whose course and speed make threats, and recommends immediate action to avoid collision. Display warnings are backed by automatic voice messages delivered through a cockpit speaker.

In the upper right screen, an intruder has come close enough to trigger a "traffic advisory." The intruder's display symbol changes from a white diamond (non-threat) to a yellow circle (potential threat) and the pilot hears the vocal advisory "traffic, traffic."

In the middle screen, the intruder has moved even closer to become a definite collision threat. TCAS II issues a "resolution advisory," changing the intruder's symbol to red. The cockpit speaker announces the required evasive action: "descend, descend, descend." To find out how rapidly to descend, the pilot consults the vertical speed indicator on his display, on which TCAS II has colored a portion of the dial red and green. The pilot must maneuver the airplane so that the needle moves out of the red area and into the green target area.

The screen at lower left shows the maneuver was successful. TCAS II indicates, by changing the intruder's symbol back to a yellow circle, that the crisis has passed and the voice message confirms "clear of conflict."

NASA's Ames Research Center played a key role in the airlines' in-service evaluation of TCAS II, teaming with the Federal Aviation Administration (FAA) to study the associated human-performance factors. Using ground-based flight simulators flown by airline crews, Ames researchers verified that pilots could use TCAS II correctly within the allowable five-second response time, and that the system reduced the severity of simulated traffic conflicts. The NASA program enhanced the TCAS II displays to increase both the speed and accuracy of pilots' responses and validated a set of pilot performance parameters coded in the system's logic for effective collision-evading maneuvers. Ames' work also contributed to development of airline pilot training procedures.

In 1989, the FAA ruled that TCAS would be required on all passenger aircraft, including planes operated by U.S. Flag airlines and those of foreign registry serving U.S. cities. Commercial aircraft with more than 3O seats must have a TCAS II installed and operating by the end of 1993; passenger aircraft with l0 to 3O seats must be equipped with one by 1995.

Self-Righting life Raft

Saving over 500 lives in the last decade

Shown at right is a novel survival craft called the Givens Buoy Life Raft, designed and manufactured by inventor Jim Givens (below).

The rafts have demonstrated the ability to protect lives during extremely adverse weather conditions, saving over 5OO lives in the last decade. Often safer than the boats that carry them, the rafts have even transported people safely through the eyes of hurricanes.

The raft consists of a canopied topside and an underwater hemispheric ballast chamber. A "flapper valve" admits large amounts of water to the chamber, providing ballast to keep the raft's center of gravity constant. The stabilization system compensates for changes in wave angle and for weight-shifting as raft occupants board and move about, and assures the raft won't blow away in high winds. The raft cannot overturn even if all the occupants shift to one side. Should an exceptionally strong wave overturn the raft, it will somersault and right itself automatically.

The Givens raft is based in part on NASA technology. During the Apollo program, astronauts left their Command Modules after ocean landings to wait in inflatable rafts for helicopter pickup. NASA found that flat-bottom rafts tended to overturn under the force of the helicopter's downwash. So Johnson Space Center developed a new method of raft stabilization for which NASA secured a patent. Working independently, Jim Givens produced a similar system. He patented his invention and obtained an exclusive license to use the NASA. technology.

Produced in various sizes, the Givens Buoy Life Raft offers capacities ranging from six to 2O people. It is housed in a canister for compact stowage. When the raft is needed, a pull on a line triggers automatic inflation, which snaps the canister's bands. In just 12 seconds, the dual buoyancy chambers inflate, the canopy covers the raft's topside, and it's ready for use.

Landsat legacy

Landsat has provided resource management benefits to thousands of government and private sector users worldwide

For two decades, the Landsat resources survey satellites have orbited Earth, recording information about the planet's surface conditions. The crafts' spaceborne sensors detect various types of radiation emitted or reflected from surface objects. The data generated by this NASA-developed system is computer-processed into images and tapes used by researchers to differentiate between a broad range of Earth features and monitor processes over time. The data can be interpreted to distinguish, for example, between two types of vegetation, between densely populated urban areas and lightly populated farmland, or between clear and polluted water.

Now operated commercially by the Earth observation Satellite Company, Landsat has provided resource management benefits to thousands of govemment and private sector users worldwide. The remote sensing data serves in such areas as agricultural inventory, oil and mineral prospecting, weather forecasting, charting sources of fresh water, wildlife preservation, air and water pollution monitoring, delineating urban growth pattems, improving map accuracy, and studying floods to reduce the potential for devastation.

(Photo Caption) This multilayer magnetic data image was generated by an I2S system for use in geophysical research.

(Photo Caption) This three dimensional image of a hurricane produced by I2S includes an overlay showing latitude and longitude of storm features.

Landsat also has fostered a small but flourishing industry devoted to commercial applications of remote sensing technology. Some of this industry's companies manufacture sensor systems for aircraft or spacecraft scanning, others produce hardware or software for image processing, while still others offer specialized services related to analysis and interpretation of remotely sensed data.

Representative of these spinoff companies is Intemational Imaging Systems (I2S), Milpitas, Califomia, a manufacturer of equipment and software for image processing applications. In 1975, with advice and support from NASA, I2S developed its initial equipment to process Landsat data for Earth resources management. Since then, I2S has continued to work under contract with six NASA centers, and has sold nearly a thousand systems in 42 countries for processing Landsat data.

Through continuing research, I2S has expanded both its product line and range of applications. Research hospitals are employing I2S systems to develop software for presenting cross-sectional and three-dimensional body images useful in diagnostics, while the U.S. Bureau of Engraving uses a high- resolution scanner and an I2S system for quality control of paper money printing. A major lumber company uses I2S equipment to check log grades prior to mill operations, and Lockheed Missiles and Spacem Company uses it for quality assurance of the space shuttle heat-shielding tiles.

Weather Information Processing

METPRO is a complete meteorological data acquisition and processing system

The key to surviving a typhoon is getting a head start. When Typhoon Sarah, packing winds of 125 miles per hour, hit the east coast of Taiwan on September 11, 1989, the vital forewarning was provided with the help of the new METPRO Weather Satellite Reception and Processing Ground Station. METPRO collected data from a meteorological satellite positioned over the Equator near Australia and converted it into images showing the size, center, and path of the storm as it approached Taiwan. As a result, the island's Central Weather Bureau was able to issue timely advisories to its inhabitants. Produced by General Sciences Corporation (GSC), Laurel, Maryland, the METPRO system is a complete meteorological data acquisition and processing system. It collects raw data from remote ground-based observation systems, radio broadcasts, and satellites, then generates weather maps for use in both forecasting and research.

(Photo Caption) Drs. Lily and Jeffrey Ghen, founders of General Sciences Corporation, consult with a programmer regarding the METPRO image of Typhoon Sarah shown on the monitor.

METPRO is a direct descendant of a research system GSC developed for Goddard Space Flight Center's Laboratory of Atmospheric Sciences. Called METPAK, it was designed to analyze weather satellite data. Later, GSC produced an enhanced version of METPAK that could process weather observations from radar surface, and satellite sensors, as well as oceanographic data. This version served as the basis for the commercial METPRO system, introduced in 1989. In addition to Taiwan, the system currently is used in Korea and Thailand.

(Photo Caption) An example of another METPRO product: a sea surface temperature map of the waters off the coasts of south Ghino and Korea, created by processing data from the TIROS satellite's Advanced Very High Resolution Radiometer

Document Monitor

Imaging technology is helping to preserve some of America's most treasured documents

NASA imaging technology, first used to create pictures of the planets and moons in our solar system, is helping to preserve some of America's most treasured documents‹including the U.S. Constitution, the treasured Declaration of Independence, documents and the Bill of Rights‹for future generations.

A hardware/software system based on NASA technology and known as the Charters of Freedom Monitoring System periodically assesses the documents' physical condition, allowing National Archives conservators to take early and swift action to halt deterioration. Although protected in helium-filled glass casings, these documents still can be damaged by light, vibration, and humidity; their parchment pages may stretch or split and the ink may fade, flake, or wear off.

The effort began in 1982 when the National Archives asked NASA's Jet Propulsion Laboratory (JPL) to develop a systematic method of assessing the condition of historic documents. JPL conducted studies of space imaging technology, in particular a highly-sensitive charge-coupled device (CCD) employed in the Galileo Jupiter explorer and the Hubble Space Telescope. JPL, in turn, asked the Perkin-Elmer Corporation, Norwalk, Connecticut, optical systems prime contractor for Hubble, to apply its expertise to the development of a precise photometer and then to integrate it into a complete document monitoring system. Perkin-Elmer started work in 1984 and installed the system at the National Archives in 1987.

The monitoring system employs a CCD detector as the electronic "film" for its scanning camera, which can only "see" one narrow line at a time. A linear motion system developed by the Anorad Corporation moves the camera over the document line by line to acquire a series of images, each representing a one-square-inch area. The photometer can detect changes in contrast, shape, or other indicators of degradation with five to ten times the sensitivity of the human eye. Images are captured at precise intervals and compared to previous ones, with special attention to changes in readability due to ink flaking or fading, changes in document dimensions resulting from shrinkage, and enlargement of existing tears and holes.

The National Archives is exploring other uses for the electronic camera, including methods of measuring the effects of conversion treatments on historical documents and authentication of artwork.

(Photo Caption) A segment of the U.S. constitution is shown in this false color image generated by the Charters of Freedom Monitoring System. Red areas indicate ink flaking that probably occurred before the document was encased in its protective shield.

(Photo Caption) The Charters of Freedom Monitoring System is designed for early detection of damage to documents in the National Archives.

Corrosion-Resistant Coating

IC531 has demonstrated exceptional performance in single-coat applications

The Statue of Liberty and the Golden Gate Bridge have in common both their status as important U.S. landmarks and their coastal locations, where they face constant exposure to the corrosive forces of salt spray, wind, and fog. Both are protected by an innovative coating developed by NASA in the early 197Os to reduce maintenance costs at its principal space launch base, Kennedy Space Center (KSC), located on Florida's Atlantic Coast.

Goddard Space Flight Center initiated a research program to provide the KSC launch structures long-term resistance to salt corrosion while also protecting them from hot rocket exhaust and the thermal shock created by rapid temperature changec during the first seconds of a launch. The effort yielded breakthrough silicate chemistry and a new coating that dries in about 3O minutes and gives long-term protection in a single application. Easy to mix and apply, the zinc-rich formula offers cost advantages in materials, labor hours per application, and fewer applications over a given time span.

To encourage private sector use of the coating technology, NASA licensed it to Shane Associates, Inc., Wynnewood, Pennsylvania, in 1981. The following year, Inorganic Coatings, Inc. (IC), Malvern, Pennsylvania, signed an agreement with Shane to become the sole manufacturer and sales agent of the compound, dubbed IC 531.

In ten years of commercial use, IC 531 has demonstrated exceptional performance in single-coat applications and as a primer in multi-coat systems where it is combined with epoxy, acrylic, and other topcoat formulations. Because IC 531 is water-based, it is nontoxic, nonflammable, and generates no volatile organic compounds or hazardous chemical, waste.

(Photo Caption) The coating was applied to a girder panel on the Columbia River Bridge in Astoria., Oregon.

IC S31 came to public attention in 1984 when, after a seven-month study of various coatings, it was selected by the National Parks Service and the Statue of Liberty Foundation to coat the iron skeleton of the Statue of Liberty during its renovation. It also was chosen as the protective system for Panama Canal rehabilitation. More recently, the coating was applied to the interior structure of an enormous Buddha, roughly the size of Miss Liberty, at Po Lin Temple on Hong Kong's Lantau Island. other applications include offshore drilling rigs; laboratory salt spray chambers; bridges such as California's Golden Gate and Oregon's Astoria River; and antenna installations in California, Hawaii, and the Canton Island in the South Pacific.

(Photo Caption) Obscured by scaffolding, the Statue of Liberty is shown undergoing extensive renovation and refurbishment after discovery of deterioration. Corrosion-resistant IC 531 was applied to the interior structure to prolong the statue's life.

Air/Wastewater Purification Systems

Aquaculture‹ the use of aquatic plants to remove pollutants from wastewater

The occupants of future interplanetary spacecraft, space stations, and space colonies will be protected from the airlessness and extreme temperatures of space by an artificial atmosphere within an airtight vessel. No craft, however, could carry enough oxygen and water to support a large crew for months, let alone years. The initial supply of oxygen and water will have to be cleansed, detoxified, and used again and again.

For the past two decades, scientists at the Environmental Research Laboratory of NASA's Stennis Space Center (SSC) have been investigating natural biological processes for air and water purification. Their long-range goal is development of a bioregenerative life support system for long-duration spacecraft, but their research has already yielded methods for purifying air and water on Earth.

Efforts at SSC began with aquaculture, the use of aquatic plants to remove pollutants from wastewater at relatively little cost. The water hyacinth, a free-floating fresh-water plant, was found to thrive on sewage, absorbing astonishing amounts of pollutant.

Hyacinths also can be harvested for use as a fuel, fertilizer, or protein additive to cattle feed. Subsequently, a number of U.S. towns adopted hyacinth-based aquaculture as their primary way to treat wastewater.

(Photo Caption) Exterior and interior views of the Bio-Home at Stennis Space Center, where NASA researcers are exploring the capabilities of plants to absorbe gases and reduce pollution in long duration spacecraft or in superinsulated homes and offices.

Hyacinths, however, are warm climate plants and have limited potential for space use. The SSC team developed a more effective techniquev for in-space water reclamation and toxic chemical removal: the artificial marsh filtering system. It employs a combination of sewage-digesting microbes living in a rock bed and pollutant-absorbing plants such as bulrushes, reeds, and canna lilies. Both cold- and salt-tolerant, the marshes can be used in northern climates and have been adopted successfully by several communities.

Branching off from aquaculture, SSC began exploring the use of foliage plants for air filtration and purification. Although intended for space use, the resulting systems had obvious application to air pollution reduction in superinsulated homes and offices.

While energy-efficient, sealed buildings have less exchange of fresh outdoor air for stale indoor air, increasing concentrations of toxic chemicals. These typically consist of emissions from such building constituents as synthetic wallboard, fibers, and glues; cleaning products; insecticides; and gas or woodburning appliances. Researchers evaluated the ability of certain plants to remove the three most common pollutants in tightly insulated buildings: formaldehyde, benzene, and carbon monoxide. They found that philodendrons, golden pothos, the common spider plant, and Chinese evergreens were particularly effective.

(Photo Caption) A research at Stennis' Environmental Research Laboratory conducs an absorption test. A plant is placed in a sealed chamber into which a gas is injected and then the amount of gas absorbed by the plant is measured.

(Photo Caption) The Bio-Safe system being assembled here employs a layer of charcoal to help the plant absorb contaminants. The system includes an air pump that pulls in room air, routes it through the charcoal and the plant's roots where the pollutants are trapped and digested, and then sends the cleansed air back into the room.

Further studies indicated that a carbon plant filter system, in which a bed of charcoal helps plant roots absorb pollutants, can remove high levels of toxic chemicals and tobacco smoke. Two companies began marketing such filtering systems as commercial products in 1988:

Bio-Safe, Inc., New Braunfels, Texas, designed a system consisting of a pot, a plant (such as a philodendron), charcoal, and an air pump or fan installed near the plant's root system. The pump draws air into the plant-microbe system, pulling it through the charcoal and over the plant roots. Pollutants are trapped by the charcoal and digested by the roots or broken down by microorganisms living in the roots. The pump then directs purified air back into the room.

The Applied Indoor Resource Company, Tampa, Florida, developed the Bio-Pure system, which includes a foliage filter plant in a planter and, beneath the plant, a layer of patented soil medium‹called Dandy Dirt‹ with charcoal, legumes, and mosses serving as filtering agents. A mechanical blower moves air through the filtering system for cleansing by microorganisms.

(Photo Caption) Not a floral display but a practical wastewater treatment facility - a field of floating water hyacinths that absorb and digest pollutants in wastewater. The technology stems from NASA studies of water reclamation systems for long-duration spacecraft.

Plant Research

Hydroponics uses liquid nutrient solutions instead of soil to support plant growth

Future pioneers setting up bases on the moon, Mars, and elsewhere in the solar system will enter environments without food, air, or water to support human life. In hopes of allowing such bases a degree of self-sufficiency, NASA is conducting research to develop modules that will recycle human and industrial waste and provide the essential ingredients for growing plants. The plants, in turn, will provide food, oxygen, and water and eliminate the need to supply resources from outside the bases. One such module, the Controlled Ecological Life Support System (CELSS), is under development at NASA's Kennedy Space Center (KSC). In a novel govemment/industry research partnership, scientists at Walt Disney World's EPCOT Center in Lake Buena Vista, Florida, are joining in the CELSS project. EPCoT's participants are members of an agricultural research team at The Land, an entertainment, research, and educational facility sponsored by Kraft General Foods.

The cooperative effort, both a research program and.a technology demonstration, offers the.public an unusual opportunity to see high technology at work. Commercial spinoffs are a potential bonus: the CELSS work may generate information useful in hydroponic vegetable production on Earth. Hydroponics uses liquid nutrient solutions instead of soil to support plant growth. The KSC Walt Disney project is under way in a greenhouse near the end of The Land's boat ride (bottom), on which visitors travel through five greenhouses displaying more than 3O crops from around the world. Within the experimental greenhouse, plants are grown on A- frame structures (top) that make it possible to spray the roots from the inside with nutrient solution. The Land researchers are testing software and hardware subsystems to control conditions on these special growth racks. other studies will look at how microbial contaminants such as fungi and bacteria affect plant growth, and determine which plants can be grown together in a hydroponic environment without interfering with each other's growth patterns. This information is critical to developing a reliable CELSS.

Gas Analyzer

A way to separate gases into components, identify them, and measure their concentrations

Hazardous gas leaks, posing grave threats to human health, can elude detection until too late. Often colorless and odorless, these gases can be dangerous even in minute concentrations. At bottom is a miniaturized chromatography system derived from space technology that provides a convenient way to separate gases into components, identify them, and measure their concentrations.

The system is contained in an instrument called the M2OO, a second- generation NASA spinoff developed by Microsensor Technology, Inc. (MTI), Fremont, Califomia, featuring dual gas chromatographs. Chromatographs are used to monitor work areas for gas leaks or volatile chemical spills, identify gases produced during energy explorations, and monitor stack gases for compliance with pollution laws. Police use them for breath alcohol analysis and arson investigations, while doctors apply them to respiratory and anesthesiology analysis.

The M2OO traces its origin to work performed in the early 197Os by NASA's Ames Research Center, which sought to develop a gas analyzer for the Viking Landers, two unmanned spacecraft that explored Mars. Ames wanted an extremely sensitive gas chromatograph for detection of possible life forms and analysis of Martian soil and atmosphere. The landers' tight quarters required that the chromatograph be very small and lightweight, unlike the bulky models then in use. Ames designed a miniature chromatograph and contracted with Stanford University for the hardware.

Although the unit was not developed in time for use aboard the Viking Landers, the technology attracted the interest of the National Institute for occupational Safety and Health (NIOSH). Seeking a portable device to detect gas leaks in industrial environments, NIOSH funded further development of the Ames/Stanford chromatograph. Subsequently, three of the Stanford researchers left to form MTI and produce a portable gas analyzer for the commercial market. They introduced the original version, called Michromonitor M5OO, in 1982 and the M2OO. in 1988.

The M2OO incorporates innovative micromachining technology that enabled MTI to fabricate a gas chromatograph on a silicon wafer and to overcome design limitations previously inhibiting production of a high-speed, high-resolution chromatograph. Intended for use in the plant, field, or laboratory, the M2OO weighs only 12 pounds and completes most analyses in less than 3O seconds. It can analyze a wide range of mixtures and measure concentrations as small as one part per million.

(Photo Caption) U.S. Coast Guard workers employ the portable chromatography system to identify unknown subtances in public areas that might be hazardous.


The first commercial products manufactured in orbit

The plastic beads at right represent the first commercial products manufactured in orbit, part of a production run of millions made during space shuttle flights in the early 198Os. These tiny spheres are of identical diameter, perfect because they were produced in the absence of gravity. The microspheres' precise dimensions permit their use as reference standards for extremely accurate calibration of instruments in research and industrial laboratories. They are sold for applications in environmental control, medical research, and manufacturing.

In a representative application, TSI, Inc., St. Paul, Minnesota, uses the spheres to calibrate an Aerodynamic Particle Sizer designated the APS 33B. TSI purchased the microspheres from the National Institute of Standards and Technology, which had certified their exact size. Designed to count and weigh submicron-size particles, the APS 33B can be applied in evaluating air pollution control devices, meteorological research, testing filters, inhalation toxicology, and other fields where analysis of small airbome particles is needed.

The APS 33B sensor operates on the basic physics principle that a particle's "true aerodynamic size" can be determined by measuring its speed through a known flow field. Aerodynamic size is important in all of the applications previously listed because particles of equal aerodynamic diameter share similar characteristics. For example, they have similar chances of penetrating a filter and similar airborne lifetimes. As a medical consideration, they tend to deposit in similar parts of the human respiratory system.

The APS 33B draws particles through a flow nozzle, producing a precisely-controlled, accelerating high- speed jet of air. The velocity within the flow field remains constant; therefore, when particles accelerate at varying rates, it is due to size difference. Small particles accelerate more rapidly, large ones more slowly. The system measures the time it takes a particle to pass between two laser beam markers; computer analysis of the time interval yields the particle's velocity and thereby its aerodynamic size.

Power Factor Controller

The Power Factor Controller matches voltage to actual need, sauing energy

The electricity fed by power companies to outlets in homes and businesses arrives at a fixed voltage‹the level needed by AC motors to handle their heaviest loads. The motors, however, use power unevenly: sometimes they do run high, but sometimes they idle, and most of the time they run somewhere in between. In the mid-197Os, NASA's Marshall Space Flight Center began investigating ways to curb the power wastage that occurs when motors operate at less than full load but still receive full load power. Cumulative power wastage, considering the millions of electric motors in service, is enormous.

Marshall engineer Frank Nola invented a device called the Power Factor Controller (PFC) that matches voltage to actual need. Plugged into a motor, the PFC continuously determines motor load by sensing shifts between the voltage and current flow. When it detects a light load, it cuts the voltage to the minimum required, which in turn reduces needless current flow and heat loss. Early laboratory tests showed that the PFC could trim power usage by six to eight percent under normal motor load conditions, and by as much as 65 percent when the motor was idling.

(Photo Caption) A motor control center incorporating PF0 technology was designed by Intellinet Oorporation for Baltimore's Fort Howard Veterans Administration Hospital to protect kidney dialysis and other critical systems from power outages.

With such tremendous energy saving potential, the PFC quickly became one of NASA's most widely-adopted technologies. More than 15O companies sought and were granted licenses for commercial use of the invention. Scores of commercial products incorporating the PFC have been applied to machines ranging from household refrigerators to industrial drilling machines.

Controlling voltage lowers engine heat, thus extending the useful life of electrical insulation and bearing lubricants. one of the resultant spinoffs, a motor starter from Intellinet Corporation, Baltimore, Maryland, controls the voltage applied at startup so that the motor accelerates gradually and smoothly. This protects the motor, gears, and belts from mechanical stresses caused by cold starts.

(Photo Caption) The Electra-Miser* is one of hundreds of products that incorporate the Power Factor Controller Concept.

(Photo Caption) Shown here in close up, the Electra-MiserTM is designed to cut power up to 40 percent in typewriters, washing maahines, refrigerators, and similar equipment.

Stirling Engine

The Stirling powerplant has the potential for high reliability and long life

The free-piston Stirling engine, a strong candidate to fulfill space power needs in the late 199Os and into the next century, also holds promise for reliable and efficient power generation to support a variety of Earth applications. The power plant is currently under development at the Lewis Research Center as part of NASA's Civil Space Technology Initiative.

Invented in 1962, the Stirling is an integrated unit consisting of a free-piston engine to convert heat into linear motion and an altemator to convert the linear motion into electric power. It has the potential for high reliability and long life‹features critical for space use‹because it has few moving parts, can use noncontacting gas bearings, and can be hermetically sealed.

These characteristics also make the Stirling attractive for use on Earth. Potential spinoff applications include hybrid electric vehicles, domestic and military generator sets, and remote electric power generation. When run in reverse, the Stirling can be used for cooling applications such as cryocoolers, domestic and commercial refrigeration systems, and heat pumps.

Industrial research teams, in cooperation with the U.S. Department of Energy, are completing designs of solar power systems featuring the free-piston Stirling convertor. Two current systems are capable of converting the sun's heat into approximately 25 kW of electricity, which can then be supplied to a utility grid. Researchers anticipate the use of dish Stirling systems for remote power applications worldwide, and the technology may be incorporated into a line of solar thermal products.

(Photo Caption) The Cummins Engine Company Solar/Stirling Converter turns the sun's heat into approximately 25 kW of electricity.

Solar Energy

A viable alternative energy source in areas where no conventional source exists

When sunlight strikes certain materials, such as silicon, electrons are set in motion. These mobile electrons can be drawn off as electricity. This basic principle of photovoltaic conversion, or PV, is used to provide power to nearly all man-made satellites.

NASA pioneered PV power for spacecraft and has supported U.S. Department of Energy programs to expand terrestrial applications. NASA's Jet Propulsion Laboratory (JPL) is the group primarily responsible for developing advanced PV technology while cutting its costs.

Although PV power is still too expensive for widespread use on Earth, it has proven a viable alternative energy source in areas where no conventional source exists, such as remote automated weather stations, sea-based navigational buoys, forest stations, and third world villages. PV arrays are routinely used at remote communications installations to operate large microwave repeaters, TV and radio repeaters, rural telephones, and small telemetry systems that monitor environmental conditions. Siemens Solar Industries, Camarillo, Califomia, has PV installations on five continents. They power agricultural water pumping systems, provide electricity for isolated villages and medical clinics, and power railroad signals and air/sea navigational aids. The company also has introduced solar-powered outdoor lighting for the consumer market.

(Photo Caption) Installed in 1991, this PV array in Mont Soleil, Switzerland, provides 500 kW of voltage support to the area's utility grid.

In the last decade, Siemens Solar has been developing large-scale PV power generation for utilities. A JPL contractor since the early development of Earth-use solar arrays, Siemens has produced and implemented some of the world's largest PV systems. The company recently began work on the first commercial PV power plant for utility grid support in Kerman, California, and will participate in a rural electrification project to install lOOO PV-powered residential lighting systems in the interior region of northeast Brazil.

Heat Pipes for the Alaska Pipeline

Keeping the ground continually frozen reduces the risk of pipeline damage

On June 2O, 1977, the Alyeska Pipeline Service Company shipped the first barrel of crude oil down the newly- constructed trans- Alaska pipeline. As the company celebrated its fifteenth anniversary this summer, the nine billionth barrel of oil arrived safely at Alyeska's Valdez Marine Terminal.

(Photo Caption) NASA heat pipe technology plays a vital role in protecting Alaska's environment from possible pipeline oil spills.

Four feet in diameter and 8OO miles long, the pipeline carries oil across three mountain ranges, floodplains, hundreds of rivers and streams, and, perhaps most challenging, the vast Alaskan permafrost. This permafrost soil alternately freezes and thaws as temperatures rise and fall with the seasons, and the ground shifts and swells unpredictably. Winter frost-heaves uplift the soil in much the same way as rainwater freezing below a highway creates potholes, but with far greater force. In summer, thawing frost causes the soil to settle unevenly. Only keeping the ground continually frozen can prevent these seasonal ground shifts and protect against the natural forces that might otherwise weaken supporting structures, rupture the pipeline, and spill large amounts of oil over the land.

Recognizing this, engineers at McDonnell Douglas incorporated into the pipeline's structure NASA technology commonly used to cool electronic equipment on spacecraft. The vertical supports holding up the line are heat pipes that keep the arctic ground frozen, minimizing the risk of pipeline damage. In building the pipeline, the Alyeska Pipeline Service Company used roughly 76,OOO McDonnell Douglas heat pipes, varying in size from two to three inches in diameter and from 31 to 66 feet long, to ensure safe transport of the oil.

Riblets for Stars & Stripes

The hull's underside was coated with a "riblet" skin that helped the craft slide through the sea more smoothly.

On February 4, 1987, skipper Dennis Conner and his ten-man crew guided the Stars & Stripes racing yacht past the finish line at Fremantle, Australia to recapture sailing's most coveted prize, the America's Cup. Representing the San Diego Yacht Club, Conner and Stars & Stripes scored a 4-O sweep in the best-of-seven finals over Australia's Kookaburra IIL Factors contributing to the yacht's outstanding performance in a variety of wind and wave conditions included boat design, tactics, sail selection, and a key piece of NASA technology.

In a Fremantle press conference, Stars & Stripes design coordinator John Marshall disclosed the boat's "secret weapon": the hull's underside was coated with a "riblet" skin that helped the craft slide through the sea more smoothly. Riblets originated at Langley Research Center as part of NASA's continuing efforts to improve aircraft fuel efficiency. In aeronautical research, they are minute grooves on an aircraft's surface that reduce skin friction by smoothing the turbulent airllow next to the skin. V-shaped and angled in the direction of the airflow, the grooves are no deeper than a scratch but have a pronounced effect on air turbulence.

The first riblets were machined on flat aluminum sheets and tested in a Langley wind tunnel. When engineers of the 3M Company, St. Paul, Minnesota learned of the tests, they suggested molding the riblets into a light weight plastic film with an adhesive backing. The film could be pressed into place on an airplane, eliminating the need for welding and allowing relatively inexpensive retrofitting to existing planes. Langley accepted 3M's offer to produce riblet tapes for research and used them in 1986 tests on a Learjet. In flight tests, the film riblets demonstrated a drag reduction capability of about eight percent, similar to the results of wind tunnel tests using metal sheets.

The technology also helps reduce hull friction for vessels moving through water, which increases speed. The Boeing Company, 3M, and the Flight Research Institute of Seattle, Washington collaborated on the development and first water tests of riblet film in 1984. Among several boats fitted with riblet tapes was a U.S. rowing shell that competed in the 1984 Summer Olympics at Los Angeles in the four-oar-with-coxswain category. The shell's crew won a silver medal, the first U.S. medal in the event in many years.

More important than its contributions to racing is the technology's potential benefits to air transportation. Langley's long-range reduction capability to 15-16 percent would translate into a five percent reduction in fuel costs, a savings in the hundreds of millions annually for U.S. commercial airlines. Riblets also could be used in oil, gas, and water transmission lines, and on submarines and jet engine turbine blades.

ICEMAT Ice Making System

Reduces rink setup time while easing transport

The touring troupes of Intemational Ice Shows, Palos Heights, Illinois, perform on portable ice rinks at amusement parks, sports arenas, dinner theaters, shopping malls, and even the White House. The key to rink portability, fast freezing, and ice consistency is a mat of flexible tubing called ICEMAT~. The tubing is an offshoot of a solar heating system developed by Calmac Manufacturing Corporation, Englewood, New Jersey, under contract to NASA's Marshall Space Flight Center, as part of a Department of Energy solar energy research program.

Most solar collectors distribute heat via a network of metal pipes through which sun-heated water flows. Calmac president Calvin McCracken devised an innovative energy absorber using flexible tubing rather than pipes. The tubing is made of a synthetic, rubber-like material called EPDM. Delivered in rolls four and a half inches wide, it can be cut to any length and zipped together, which allows tailoring of a solar collector to any size or shape. The tubing is easily spliced for repairs and resistant to cracking due to ozone attack or the stress of repeated expansion and contraction.

Called SUNMAT~, the flexible tube system originally was designed as a solar collector for home, pool, or hot water heating. It also can be used as a radiant floor heating unit in homes or offices and can help prevent buildup of snow and ice on outdoor driveways, patios, and parking lots.

(Photo Caption) An International Ice Shows troupe performs on a temporary rink built atop a theater stage by means of a spinoff icemaking system derived from NASA solar heating research.

Calmac sold the SUNMAT line to the Besicorp Group, Ellenville, New York, which markets the system in two variations: SUNMAT for solar energy collection and SolaRoll for radiant heating applications. Calmac, meanwhile, developed the ICEMAT system, based in part on the Marshall/DoE work, now produced under license by ITI' Marlow Division, Midland Park, New Jersey. Like SUNMAT, ICEMAT is a mat of tubing used to distribute a working fluid, but instead of hot water the fluid is an antifreeze, such as glycol, refrigerated to a temperature of zero degrees Fahrenheit. The rink builder lays a floor of plastic tubing, covers it with water, then pumps chilled glycol through the tubes. It works in a way similar to a home refrigerator: the cold glycol draws warmth from the water, thereby freezing it. Using ICEMAT, International Ice Shows offers rental ice rinks‹ portable indoor and outdoor units ranging in size from a large room to a hockey rink. ICEMAT's advantages include rink setup in less than half the time it would take if metal pipes were used; corrosion- and temperature- resistant tubing; and, perhaps most important, ease of transport. The tubing comes in compact spools containing hundreds of linear feet, as opposed to lengths of rigid metal tubing. This is a big factor when you consider that a 2OO-foot rink requires more than 32 miles of tubing.

Cordless Products

Cordless tools and appliances based on technology from the Apollo era

One of the most successful commercial spinoffs of space- based technology is a line of cordless products dating back to the Apollo era. Among the tasks required of Apollo astronauts was to gather rock and soil samples from the moon's surface and below it. For the latter, they needed a special drill. The drill had to cut through the sometimes hard lunar surface layer, extract core samples from a depth of up to ten feet, and, like everything else that went to the moon, it had to be lightweight and compact. Further, it had to have its own power source. Although the tool could have operated on power from the Lunar Module, the astronauts' home and operating base, scientific requirements dictated sampling at diverse locations, sometimes far from the base.

The drill's development was entrusted to the Black & Decker Corporation, Towson, Maryland, which responded with a successful battery-powered, permanent-magnet motor device. In the course of the drill's development, Black & Decker used a unique computer program to optimize the design of the drill's motor and ensure minimal power consumption. That computer program, along with the general knowledge and experience gained in developing the drill, provided a strong technology base for the development of battery-powered implements.

Black & Decker has continued to refine this technology and now produces a line of consumer and professional cordless tools and appliances. These include the Dustbuster*, a handheld vacuum cleaner for the home or auto, and cordless, rechargeable drills, shrub trimmers, and grass shears. Worldwide sales of Black & Decker's cordless, rechargeable products are approximately $4OO million annually.

(Photo Caption) Among Black & Decker's cordless products are the Dustbuster miniature vacuum. at left. and a handheld drill applicable in construction tasks (above)

Metallized Materials

Through space use, a once commercially-obscure product has become a booming commodity

Metallization is the coating of a material with a fine mist of vaporized metal to create a foil-like effect. It's not a space-age invendon; in fact, the concept dates back to the 19th century. Metallization is, however, a prime example of how space use of an existing product or process sometimes triggers a chain reaction: the space need creates a market, the new market inspires further development, which expands the range of applications. Eventually, the once commercially-obscure product becomes a booming commodity. In the case of metallization, space use helped transform a small-scale manufacturing operation producing decorative metallized plastics into a flourishing industry marketing materials for scores of applications.

It started in the early days of the space program when NASA was experimenting with large balloon- satellites as orbital relay stations to reflect communications signals from one Earth location to another. The material for the balloon skin had to be highly reflective to ³bounce" the radio signals. It also had to inflate in orbit to a diameter roughly equivalent to the height of a ten-story building, but be exceptionally thin and lightweight to fold into a beachball-size canister for launch from Earth. The solution was a new type of plastic film coated with a superfine mist of vacuum- vaporized aluminum.

NASA subsequendy used the material as a reflective insulator to protect astronauts from solar radiation and sensitive spacecraft instruments from extreme temperatures. The widening field of applications spurred R&D by manufacturers to improve vacuum metallizing techniques. This, in turn, led to development of diverse commercial products, including insulated outdoor garments, life rafts, reflective blankets, wall coverings, window shades, food packaging, candy wrappings, and photographic reflectors.

Metallized Products, Inc. (MPI), Winchester, Massachusetts, was one of the companies that worked with NASA on dhe original space materials. MPI continues to supply metallized materials for space use and has developed lines of industrial and consumer-oriented metallized film, fabric, paper, and foam. one of the most successful MPI products is TXG laminate, once employed by NASA as a reflective canopy for visual and radar detection of the rafts in which returning Apollo astronauts awaited pickup by ships or helicopters. TXG not only is superreflective, but nonporous, waterproof, and rot-proof. Subsequently, Winslow Company Marine Products, osprey, Florida, obtained a license for commercial production of the survival raft. In cooperation with MPI, Winslow improved the strength and thermal characteristics of TXG so that its survival rafts would provide maximum protection from heat, cold, wind, and rain.

A reflective kite of gold TXG produced by Solar Reflections, Inc., Fort Lauderdale, Florida, serves as a highly conspicuous distress indicator in an emergency. The sos Signal Kite can be flown as high as 2OO feet to enhance radar and visual detectability. It provides campers, hikers, and mountain climbers with a lightweight, easily portable emergency signaling device, and boaters with a convenient substitute for bulky dish devices. Made of metallized nylon, the kite spans six feet but weight only six ounces.

Connecticut Advanced Products, Glastonbury, Connecticut, has adopted lXG for its Thermoguard heat shields, custom-tailored reflective curtains that cover the windshield and windows of parked aircraft to protect avionics equipment from heat buildup and ultraviolet radiation. In a similar application, the Starshade~ from Star Technology Corporation, Carbondale, Colorado, is a multilayered automatic shade system for large windows in commercial or residential buildings.

Among MPI's own products are various protective fabrics that retain up to 8O percent of the user's body heat, helping to keep a person warm for hours in cold weather crises or to prevent post-accident shock. All are remarkably compact. The Space* Emergency Bag, for instance, opens into a three-by-seven-foot personal tent/blanket and then folds into a three-ounce package the side of a deck of playing cards.

(Photo Caption) Thermoguard heat shields, windshields, and window curtains custom-tailored by Connecticut Advanced Products from TXG metallized fabric reflect the sun¹s rays and protect long-parked aircraft from heat buildup and ultraviolet radiation that could damage its sensitive and expensive avionics equipment.

(Photo Caption) Fishing boat captain Kurt Barlow deploys an SOS Signal Kite, a highly-reflective distress signal made of metallize nylon that can be elevated to 200 feet for best visibility. Barlow also is wearing a reflective cap for protection from the sun.

(Photo Caption) Among the Applications of reflective TXG is the Emergency Blanket manufactured by Metallized Products, here used by a ski patrol to protect a skier shaken by a fall. The blanket, which folds into a package no bigger than a deck of cards (bottom left), retains up to 80 percent of the user¹s body heat.

(Photo Caption) The Winslow Radar Feflector Life Raft features a canopy made of TXG that reflects the sun¹s ray¹s like a mirror, enabling radar or satellite sensors to spot it, and also provides thermal insulation to occupants.

Memory Metals

Shape memory effect devices can be made to expand when cooled or contract when heated

Certain metal alloys are able to change from one shape to another in response to temperature variations. This ³shape memory effect," or SME, is caused by a transformation in the alloy's crystal structure. SME devices can be made to expand when cooled or contract when heated; they have either one-way or two-way "memories." A one-way SME alloy can be deformed and then resume its original shape when heated to a specific temperature. Two-way alloys hold their original shape at one temperature and another shape at a different temperature.

Interest in SME, a 196Os technology, was rekindled by NASA in the 198Os. Arnong the companies awarded NASA contracts for advanced SME investigations was Memry Technologies, Inc., Norwalk, Connecticut. Since 198S, the company has worked on SME alloys for composite structures and space station applications, producing alloys over a wide range of transforrnation temperatures in sheet, wire, rod, and tube form.

Adapting its SME expertise acquired under NASA contract, Memry Technologies has applied two-way SME alloys to comrnercial safety products known as MEMRYSAFE* and FIRECHEK*. MEMRYSAFE products protect against scalding in the home by instantly restricting the flow of water in the shower, bath, and sink before scalding temperatures are reached. A related product, ULTRAVALVETM, is a computer- controlled shower and bath valve (shown above) that allows the user to preselect a preferred bathing temperature. The temperature is maintained by an automatic electronic control and confirmed by a digital readout.

FIRECHEK, a fire control safety valve for semiconductor industrial process lines containing hazardous gases or fluids, detects unsafe temperatures and automatically shuts off the pneumatic pressure operating the control valve. The SME element accomplishes detection and actuation simultaneously and requires no outside power source.

Another firm - Marchon* Eyewear, Inc., Melville, New York‹has applied NASA's memory metal technology to a "smart" eyeglass frame (shown at left) that remembers its shape and wearer's fit. Frames made with Flexon* can snap back to their original shape after being wrapped around a finger, bent in half, or twisted like a pretzel. Flexon works at room temperature and does not need heat to retum to its original shape.

Marchon's advancement on the NASA technology, a boon to the more than 115 million U.S. eyeglass wearers, is a patented "memory encoding process" that gives the special titanium alloy used in the frames its flexible memory. Flexon frames are marketed under two brands: Autoflex~ by Marchon and Accuflex* by an affiliated company, Marconin* S.p.A.

Stratch-Resistant Sunglass Coating

Scratch-resistant lenses lasted, with normal wear, ten times longer than the most widely- used plastic optical lenses

For decades, ground and polished glass had been the preferred lens in the eyeglass industry. That changed in 1972, when the Food and Drug Administration issued a regulation that all sunglass and prescription lenses must be shatter-resistant The one disadvantage to glass is its brittleness, so eyeglass manufacturers turned to plastics. Plastic lenses offered resistance to shattering, lower manufacturing costs, excellent optics, and far better absorption of ultraviolet radiation. In addition, they were lightweight and easier to shape to facial contours. The one disadvantage was that, unlike glass, plastics were highly susceptible to scratching.

Foster Grant Corporation, Leominster, Massachusetts, devoted a decade of research to the search for a coating that would give plastic lenses glass-like scratch resistance without compromising any of plastic's attributes. The answer was a highly abrasion-resistant coating and deposition process developed at NASA's Ames Research Center by researcher Dr. Ted Wydeven (at top). Initially intended to protect the plastic surfaces of aerospace equipment in harsh environments, the coating increases lens hardness and, thereby, scratch resistance.

Foster Grant acquired an exclusive license for the process from NASA and began manufacturing sunglasses. Their scratchresistant lenses lasted, with normal wear, ten times longer than the most widely- used plastic optical lenses, surpassing even glass (shown at left). Today, the majority of sunglass, corrective, and safety lenses sold in the United States are made of plastic.

In 1991, Fosta-Tek assumed the license for the NASA process from Foster Grant and currently uses it on eyewear, industrial face shields, and flat-sheet plastic for industrial applications. The coating is one of the most pervasive space technology spinoffs.

Heart Rate Monitor

An insulated device made of a thin dielectric film

In the mid-197Os, looking ahead to the era of long-duration space missions, NASA saw a need for a new type of sensing electrode for astronaut health monitoring. The conventional conducting electrode, which made contact with the skin through a paste electrolyte, had disadvantages for long-term use. The paste can irritate skin, for example, and it eventually dries, causing data distortion. other electrodes that directly contact the skin without paste pose problems of "motion artifact," in which the subject's movements cause electrode movement and signal-distorting noise.

Under a NASA grant, researchers at Texas Technical University designed a new type of electrocardiographic electrode, an insulated device made of a thin dielectric film. The dry, reusable electrode works upon contact with the skin and is not affected by heat, cold, or light, nor by perspiration or rough or oily skin. Further, the film prevents motion artifact during exercise.

NASA patented and then licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber and founder of Heart Rate, Inc., Costa Mesa, CA. Charnitski incorporated the technology into advanced personal heart monitors and exercise machines for the physical fitness, medical, and home markets.

At bottom left is Heart Rate's Home Model VersaClimber lO8H, a stepping/full-body climbing exercise machine designed to make use of all the major skeletal muscle groups during aerobic and strength conditioning. The VersaClimber is available in a multiple-user health club model and therapy models with built-in seats for cardiac rehabilitation and orthopedically-impaired patients. Additional models are designed for professional sports teams, schools, hotels, firefighters, and the military services. The Versa-Climber's display module, shown at left, provides such information as calorie burn rate, exercise time, climbing speed, and distance climbed.

On the home version, an infrared heart beat transmitter is worn under exercise clothing. The transmitted heart rate is used as a speedometer to control the intensity of the exercise. The ability to accurately read heart rate and set work intensity levels offers advantages to a full range of users from the cardiac rehab patient to the highly-trained professional athlete.

Athletic Shoes

The Compression Chamber midsole was* subjected to stresses equivalent to 400 miles of running and showed no visible signs of wear or structural fatigue

Athletic shoe manufacturers spend millions annually searching for innovations that will give them an edge in a lucrative and extremely competitive industry. One company, AVIA Group Intemational, Inc., Portland, Oregon, a subsidiary of Reebok International, Ltd., applied space technology in a major shoe advancement known as the AVIA Compression Chamber* midsole, introduced to the market in october 199O.

In the late 198Os, AVIA began a project to eliminate the unwanted compression or breakdown that causes loss of cushioning in athletic shoes. The company contracted with Alexander L. "Al" Gross of Lunar Tech, Inc., Aspen, Colorado, to design an advanced shoe that would retain its shock absorption, stability, and flexibility properties over a longer lifetime.

Al Gross, an aerospace engineer who has won several awards for his work in space suit design, turned to NASA technology. His basic approach to the shoe design was to eliminate foam materials from the midsole because they are subject to cushioning loss from the repeated vertical force of body weight and as a result become rigid.

A task force led by Gross chose a rigid/flexible" system similar to that in a space suit. Being pressurized, the space suit is rigid but permits astronaut mobility with the "convolute system," a series of bellows in the joint areas that expand and contract with every motion. By layering or combining materials and varying the shape, size, and number of bellows, space suit designers can vary joint flexibility.

For the AVIA shoe project, the task force created an external pressurized shell with horizontal bellows for cushioning and vertical columns for stability. By varying the shape, number, and thicknesses of shell materials and the styling lines within the shell, the designers were able to "tune" the stiffness and cushioning properties of the midsole.

Creating a stress-free environment to ensure durability demanded a single part without weld lines or cement seams. To meet that requirement, AVIA and Gross adopted another NASA technology‹a stress- free "blow molding" process originally employed to get superior impact resistance for the Apollo lunar helmet and visor. Blow molding, never before used in the footwear industry, allows AVIA to reconfigure the Compression Chamber for different sports.

In durability tests at Penn State Center, the Compression Chamber midsole was subjected to stresses equivalent to 4OO miles of running and showed no visible signs of wear or structural fatigue. The midsole, AVIA officials say, is the ''first step" towards a completely foamless, non-fatiguing midsole that will not wear out.

(Photo Caption) National Basketball Association star Clyde Drexler puts AVIA Compression Chamber shoes through a workout. The shoe, designed to retain its performance properties over a longer life span, is an adaptation of NASA space suit technology.

Water Filter/Conditioner

Technology developed to purify space shuttle water

At right is the General Ionics Model IQ Bacteriostatic Water Softener, a home product that not only softens municipally treated water but also inhibits the growth of bacteria within the filtering unit. It was developed by Ionics, Inc., Bridgeville, Pennsylvania, manufacturer of water treatment equipment for municipal, industrial, and consumer use.

The IQ's ability to arrest bacterial growth is based on NASA silver ion technology developed to purify water aboard the space shuttle. In space use, an electrolytic water filter generates silver ions in concentration~ of SO to lOO parts per billion into the water flow. The silver serves as an effective bactericide/deodorizer.

The NASA innovation has been applied in several water purification products, among them a line of home and portable water filters developed by Ray Ward, president of Ambassador Marketing, National City, Califomia. Ward was assisted in his equipment design by Ionics, which helped him make the most efficient use of silver-impregnated carbon. Activated carbon helps remove objectionable tastes and odors caused by the addition of chlorine and other chemicals to municipal water supplies.

Ionics vice president Walter J. Poulens later leamed that some European countries were considering a ban on water softeners that breed bacteria. It occurred to Poulens that the silver ion technology he had worked on with Ward might provide the key element to a water softener that also arrests bacterial growth.

Ionics used the NASA technology as a springboard for development of a silver carbon so dense that it would remain on top of the water-softening resin bed where, company research indicated, the greatest bacterial growth occurs. After extensive testing, the Environmental Protection Agency evaluated the IQ's silver carbon process and confimmed its ability to effectively inhibit bacterial growth.

Pool Purification

Space-based system yeilds pool and spa water that exceeds EPA standards for drinking water

Shown at right is a Florida pond cluttered with algae. At far right is the same pond 48 hours after treatment by the Caribbean Clear Automatic Pool Purifier, which utilizes NASA technology developed to sterilize the water supply on long-duration spacecraft. The absence of algae and the very clear water, evidenced by the clouds reflected on the pond's mirror-like surface, demonstrate the system's efficacy.

In the 196Os and early 197Os, Johnson Space Center conducted a research program to develop a small, lightweight water purifier for Apollo spacecraft requiring minimal power and no astronaut monitoring. The program produced an electrolytic silver ion generator only slightly larger than a cigarette pack and weighing only nine ounces. Units mounted at various locations in a spacecraft's potable water supply and wastewater system would dispense silver ion concentrations of lOO to 3OO parts per billion, sufficient to eliminate bacteria in the water within hours.

Caribbean Clear, Inc., a Leesville, South Carolina manufacturer of electronic products, used this invention as the basis for its Automatic Pool Purifier, an alternative to conventional pool cleaning chemicals. Caribbean Clear's main customers are swimming pool owners who want to eliminate chlorine and bromine. The purifiers in the Caribbean Clear product are the same silver ions used in the Apollo system to kill bacteria, with copper ions added to kill algae. They yield pool and spa water that exceeds the Environmental Protection Agency's standards for drinking water.

At right is a residential swimming pool with a built-in hot tub, both serviced by the Automatic Pool Purifier. The system is effective in both units despite the difference in temperature. Shown below is the key element of the system: two silver-copper alloy electrodes that generate silver and copper ions when an electric current is passed through them. The rest of the system includes a microcomputer that monitors water condition, temperature, and electrode wear; and a controller that automatically introduces the correct amount of ions into the water.

According to Caribbean Clear, purifying a pool widh its system costs less dhan treating the same pool with chlorine and algaecides. It requires only a once-weekly test to measure the level of copper ions in the pool; a twist of a knob in dhe control unit increases or decreases output as required.

The system is available in the U.S. and 42 other countries. The company makes models for purifying everything from residential hot tubs to a six-million-gallon commercial pool. In addition to private pool owners, Caribbean Clear numbers among its customers the U.S. Navy; Holiday Inn, Marriott, and Sheraton hotels; YMCA facilities; and many healdh clubs. The system also can be employed to kill algae and bacteria in fish ponds, fountains, and cooling towers.

Heat Pipes

A low-cost, high-efficiency alternative to complex dehumidification systems used in supermarkets

To keep food fresh and prevent frost formation in freezer cases, require high-capacity air conditioning and dehumidifying. Any innovation that improves air conditioning efficiency can result in significant cost and energy savings for the supermarket industry. The Phoenix 2OOO rooftop refrigeration/air conditioning system at right, manufactured by Phoenix Refrigeration Systems, Inc. (PRS), Conyers, Georgia, incorporates heat pipes derived from NASA technology to both control humidity and conserve energy.

The addition of heat pipes to the Phoenix 2OOO stemmed from PRS' participation in an ongoing, large-scale field test evaluating the heat pipe as a low-cost, high-efficiency alternative to the complex and expensive mechanical dehumidification systems used in many supermarkets. Georgia Power Company, which is spearheading the program, is joined by the Alabama Power Company, Florida Power Corporation, Mississippi Power Company, and Wisconsin Electric Power Company, along with a number of supermarket chains. The sponsors will share results with supermarkets, equipment designers, and manufacturers.

Originally developed by NASA for temperature control of sensitive electronic systems used in space, the heat pipe is a simple but highly effective heat transfer system. The individual heat pipe is a sealed tube containing a small amount of liquid refrigerant. The tube is inclined so that the refrigerant can flow to the lower end by gravity.

The low end is an evaporator, the high end a condenser. When the refrigerant flows to the low end, it evaporates and absorbs heat in the process. The low-density vapor then rises to the other end, where it releases heat and condenses into a liquid to repeat the cycle. The system thereby alternately cools and heats without significant use of energy or any moving parts. Applied successfully in such diverse places as libraries and candy storage facilities, heat pipes also have proven effective for moisture control in indoor spa and pool buildings and in homes in humid climates.

Georgia Power kicked off the performance verification program in July 1989 with an installation at a Winn Dixie supermarket in Lithonia, Georgia. PRS supplied a standard rooftop refrigeration/air conditioning system modified to include a 144-tube heat pipe system. The pipes ease the load on the air conditioner while providing effective humidity control. The project has since expanded to include supermarkets in Wisconsin, Florida, Virginia, Texas, New York, and Maryland. An interim report on findings at the Winn Dixie indicated that the system performed well and did indeed reduce energy consumption. Additional data will be gathered to precisely quantify the energy savings and impact of the heat pipes on supermarket air conditioning systems.

Virtual Reality

Environment-hopping may one day be as commonplace as a dnve in the family car

Imagine having the power to instantly change your environment; to be transported at will to the surface of the moon or, with a wave of your hand, to be transformed into a single molecule speeding through the human circulatory system. Though it sounds like science fiction, environment-hopping may one day be as commonplace as a drive in the family car, thanks to an exciting new technology called virtual reality (VR).

Virtual reality combines three-dimensional graphics and sound to create highly-realistic simulations. In the mid-198Os, NASA's Ames Research Center developed for life sciences research one of the first practical VR systems‹the Virtual Interface Environment Workstation (VIEW), a head-mounted stereoscopic display that allows the operator to virtually "step into" a scene and interact with it. The display can be an artificial computer-generated environment or a real environment relayed from remote video cameras.

VIEW's headset contains two small television screens, one for each eye so the image appears three-dimensional. A sensor mounted on the headset tracks head position and orientation, enabling the computer to shift the image in correlation with the wearer's head movements. Headphones provide three-dimensional audio, enhancing the illusion of being inside the display. Ames is developing a library of software for different scenes and the operator can select a menu option using voice or gesture commands. one example of a practical application: a design engineer can virtually become part of a rocket engine's fuel flow and travel with the flow, noting places where it slows, speeds up, or becomes turbulent; he can leam much more about the system design than by relying only on two-dimensional simulation.

The operator can interact with the display and control the action by wearing a DataGloveTM that converts hand gestures and positions into computer-readable form. Developed for Ames by VPL Research, Inc., Redwood City, Califomia, the Iycra glove is lined with fiber optic cables and sensors that detect finger movements and transmit the infommation to a host computer; a computer-created image of the hand will move exactly as the operator is moving his gloved hand. With appropriate software, the operator can use the glove to grasp a virtual object, for example, moving a chair within a simulated room; the computer will dutifully move the chair in the TV display. Moreover, the operator can "feel" the chair through tiny vibrators in the glove's fingertips.

The DataGlove can be used to control conventional computer screens, replacing mice and joysticks. "It provides a natural, intuitive way to interact with your computer," says Ann Lasko, VPL's director of product design. Mattel, Inc. has introduced a plastic glove based on VPL's technology as an accessory for Nintendo video games. The "Power Glove" lets players manipulate onscreen graphics.

(Photo Caption) A NASA scientist tests a virtual reality headset. She sees a computer generated 3D scene or a real environment remotely relayed by video cameras. The stereo imagery suggests that she is actually part of the scene.

(Photo Caption) The DataGlove allows a computer user to handle onscreen images as if they are real three dimensional objects. Sensors lining the glove communicate hand movements to a graphics computer.

The VPL glove also offers applications in telerobotics and biomedicine. New York University researchers use the device to remotely control a dexterous robot hand, while Greenleaf Medical Systems of Palo Alto, California employs the glove in a system that measures how much the joints of the human hand can bend, helping doctors to accurately determine hand impairments. Greenleaf recently hooked up a speech synthesizer to the DataGlove to demonstrate the capability for turning hand gestures into audible words. They hope to develop a low- cost system that would translate sign language into speech.

Taking the technology a step further, VPL developed the DataSuitTM, a sensor-equipped full body garment that reports to the computer the motions, bends, gestures, and spatial orientations of the wearer, enabling full body interaction with the virtual world. The DataSuit's first commercial application is an unusual one: it is worn by film actors to give fluid, realistic motion to animated characters in computer-generated movie special effects.

After the DataSuit, VPL created its own version of the eyewear in NASA's VIEW system, called the EyePhoneTM. The company offers a complete/ package, the RB2 Virtual Environment, that includes a DataGlove; the EyePhone, a design control workstation, and associated software, cables, and connections for $45,OOO. With the computers, made by Silicon Graphics, the system costs $2OO,OOO for a single user, $4OO,OOO for two users. The price has severely limited use of the technology, but VR enthusiasts are counting on a continuance of the dramatic drop in computer costs that made personal computers widely available to similarly broaden VR applications.

With improvements over the next few years, VPL anticipates such new uses for the RB2 system as allowing an architect's clients to inspect and perhaps alter a building's design before the structure is built by virtually walking through a graphic replication of it; similarly, the system makes it possible to tour dynamic models of communication networks, large databases, and traffic control systems. VR permits three-dimensional scientific visualization, particularly useful in chemistry, geology, and aerodynamics. As a training tool, it would enable medical students to operate on virtual patients in a simulated hospital. VR could revolutionize education, for it allows virtual time travel; a student can virtually be a pharaoh in ancient Egypt, a tyrannosaurus hobnobbing with other dinosaurs, or an astronaut exploring a vast canyon on Mars. And entertainment? Says VPL: "We leave that to your imagination." VR is "composable as a work of art and as unlimited and harmless as a dream," states company literature. "When VR becomes widely available, it will not be seen as a medium used within a physical reality, but rather as an additional reality. VR opens up a new continent of ideas and possibilities."

(Photo Caption) An EyePhone wearer sees a 3D image of his hand while the same image is displayed on the monitor.

(Photo Caption) A VR user goes for a "virtual" bike ride across terrains computer-generated in the headset.

Digital Image Processing

Aided by NASA, digital imaging technology began to spin offin new directions

Before the Apollo 11 lunar landing and Neil Armstrong's historic moon walk, NASA flew a series of unmanned spacecraft called Ranger designed to make a comprehensive photographic reconnaissance of Earth's moon. Although the first six Ranger spacecraft were unsuccessful, Rangers 7, 8, and 9, flown in 1964-65, achieved their objectives and returned some 17,OOO high-resolution images.

Ranger's camera systems, though the best available at the time, were subject to many distortions‹ lopsided, stretched, too dark, too light images‹and to contamination by the noise of the craft's electronic equipment. These problems could have been corrected by conventional photographic techniques, but Jet Propulsion Laboratory (JPL) engineer Dr. Robert Nathan had a better idea: convert Ranger's analog signals to digital signals and use a computer to enhance the images. Accordingly, he began developing the first operational digital image processing software. There also was a need for hardware to record both analog video and digital images on film. No suitabl commercial hardware existed, so JPL's Fred Billingsley designed a system called the Video Film Converter (VFC). Built for JPL by Link General Precision, the VFC was used in the 197Os for image playback of the striking pictures retumed by the planetary missions of the unmanned Mariner spacecraft.

(Photo Caption) When the Voyager spacecraft passed near Jupiter, its thermal mapping data revealed a heat source on the surface of the moon Io. Advanced image processing techniques developed by 3M Comtol enabled analysts to assemble this picture of the heat source and its "halo," a volcanic eruption spewing matter several miles.

Over the years, there has been a steady stream of advances in digital image processing, spurred by the advent of ever-more sophisticated spacecraft transmitting immense volumes of image data from distances farther and farther from Earth. When the sheer mass of incoming data threatened to overwhelm computer capacity, JPL developed a method of performing simultaneous‹rather than step-by-step‹image processing operations through the application of VLSI (Very Large Scale Integrated) circuitry. This "pipeline filter," first used to process Voyager 2's Uranus images in 1986, enhances images up to 2OO times faster than previous systems.

Aided by the efforts of JPL and other NASA centers, digital imaging technology began to spin off in new directions: the medical field, the new art of Earth resources survey by remote sensing, enhancement of motion pictures, industrial quality control, and a variety of other uses.

In the 196Os, JPL's Drs. Robert Nathan, Robert Selzer, and Kenneth Castleman pioneered use of digital processing techniques to enhance electron microscope, x-ray, and light microscope images. This work sparked experimental medical applications by other organizations and emergence of a growing industry providing image processing systems for health care. Among medical applications are computed tomography (CAT) scanning, diagnostic radiography, brain or cardiac angiography, sonar body imaging, surgery monitoring, and nuclear magnetic resonance, a relatively new body scanning technique.

(Photo Caption) Shown here is Perceptive Systems' PSIC0M 327, a general purpose image processing system for medical, scientific, and industrial applications.

NASA also provided the initial technology base for application of image processing to remote sensing of the Earth and its resources. The exceptional utility of this technology stems from the ability of advanced sensors aboard satellites and aircraft to detect radiations‹light and heat waves‹emanating from Earth objects. Since each object has its own "signature," it is possible to distinguish between surface features and to generate computer-processed imagery identifying specific features important to resource managers. This capability offers applications in such areas as crop forecasting, rangeland and forest management, land use planning, mineral and petroleum exploration, mapmaking, water quality evaluation, and disaster assessment. The primary users of the technology have been federal, state, and local govemments, but it is making its way into commercial operations‹for example, resource exploration companies looking for oil, gas, and mineral sources and timber production fimms seeking more efficient treeland management.

Many of the companies working in digital image processing are direct offspring of NASA's work. An example is 3M Comtal, Pasadena, Califomia, which traces its lineage to image processing research conducted for National Space Technology Laboratories‹later renamed the Stennis Space Center‹in the 196Os. 3M Comtal's equipment processed the amazing views of Viking on Mars and the Voyager transmissions from Jupiter; today the company remains a leader in the field.

In other cases, individual products rather than whole companies have been derived from the NASA technology. For example, Unisys Defense Systems, Camarillo, Califomia, developed image processing software called SDCIPSTM that has been applied in such diverse areas as military command and control, document image processing, geographic infommation systems, and U.S. Postal Service video encoding research. Capable of such operations as digital filtering, contrast enhancement, and surface illumination and contouring, SDCIPS is a spinoff of techniques developed by JPL for medical image processing.

(Photo Caption) The satellite view of a hurricane at top gave meteorologists information about the storm's size, strength, and direction. But temperatures within the storm, obtained by processing infrared photography data to create the color-coded image in the lower photo, provided a clearer understanding of the storm.

(Photo Caption) Visionlab II from 3M Comtal provides image processing technology for use with personal computers.

(Photo Caption) A spinoff software package called SDCIPS combined satellite radar data with digital terrain data through a color-space transformation to produce this compositeaimage in which the circular area highlights topographic contours.

Structural Analysis

stress analysis; defining high stress points and vibrational characteristics of sheet metal components in car and truck bodies; and static analyses of suspension components.

Another industrial user of NASTRAN is DeVlieg-Sundstrand, Belvidere, Illinois, a manufacturer of machine tools that produce parts for other machines. These machine tools must be able to maintain a certain rigidity during temperature and load changes associated with the manufacturing process; their rigidity determines their accuracy and prevents production errors in the machine parts. NASTRAN is applied in the design process to predict rigidity.

Texas Instruments (Tl), Temple, Texas, uses the program to design impact and non-impact printers. Dot matrix impact printers form characters by means of a series of actuator mechanisms that fire needles at an ink ribbon to transfer ink dots to paper. Each mechanism has a tiny magnetic core and an actuator coil, an armature, and a print needle. The printhead is a circular arrangement of a large group of such assemblies; in operation, the printhead moves across the paper to produce characters.

Generation of a magnetic field causes the armature to propel the needle toward the ribbon. To optimize the design of the printhead, it is necessary to maximize the magnetic force propelling the armature, which requires extremely accurate calculations of the magnetic field. Tl used NASTRAN for that purpose and was able to develop the optimum geometry for a new printhead entirely by NASTRAN simulation.

TI's Central Research Laboratories also employed NASTRAN in designing a deformable mirror device (DMD) that has several applications in non- impact printing, where it can replace the laser and the rotating mirror of conventional laser printers. Tl was unable to accurately predict the DMD's behavior, which was dependent upon the electric field and mechanical properties. Researchers employed NASTRAN to model the DMD and, with the combined results of various analyses, were able to predict the voltages required for operation and indicate ways in which efficiency might be increased.

(Photo Caption) DeVlieg-Sundstrand uses the machining center at left to manufatture machine tools that produce parts for other machines. The company uses NASTRAN (see images below) to predict how a tool will maintain its rigidity during the temperature and load changes associated with the manufacturing process.

NASTRAN is available to industry through.NASA's Computer Software Management and Information Center (COSMIC). Located at the University of Georgia, CoSMIC maintains a library of computer programs from NASA and other government agencies and offers them for sale at a fraction of the cost of developing a new program.

(Photo Caption) The Honda Acura Legend Coupe was designed with the aid of NASTRAN.

Data Acquisition Systems

KineticSystems created a fiber optic highway that provided data transmission between the simulators and the host computers at a rate of 24 million bits per second

KineticSystems Corporation, Lockport, Illinois, produces high- speed CAMAC Automated Measurement and Control) data systems for scientific and industrial applications. Some of the company's most advanced products resulted from a joint R&D program with NASA's Langley Research Center in the mid-198Os. The program sought to determine the feasibility of using CAMAC equipment to provide a distributed input/output system for Langley's Advanced Real Time Simulation (ARTS) system, which supports flight simulation research in such areas as automated control, navigation and guidance, air combat, and workload analysis for pilots and astronauts.

It found CAMAC an ideal approach that would allow up to 32 high-performance simulators situated throughout the Langley complex to be controlled by centrally-located host computers. With Langley input, KineticSystems developed the hardware for ARTS. Much of the CAMAC equipment was off-the-shelf, but the project required development of an enhanced performance data highway and modules with higher resolution converters. KineticSystems created a fiber optic highway that provided data transmission between the simulators and the host computers at a rate of 24 million bits per second, enabling simulators in several locations to interact in real time. The company also developed a series of 16-bit analog to digital, digital to analog, and digital to synchro converter modules.

(Photo Caption) CAMAC chassis and sampling of data acquisition and control modules.

(Photo Caption) The CAMAC system monitors steelmaking operations.

The technology created in the ARTS project significantly boosted KineticSystems' technical capability and fostered a wide variety of new applications in both the public and private sectors, such as fusion research, power grid analysis, process automation, turbine testing, petroleum distribution, chemical processing, and steelmaking. As cooperative marketing partners, KineticSystems and Digital Equipment Corporation, Marlborough, Massachusetts, have delivered equipment derived from the ARTS work to hundreds of users in the U.S. and abroad.

Parallel Processing System

Simultaneous processing of image picture elements rather than step-by-step serial processing

In the late 197Os, NASA saw a need for greatly increased computing power to handle the voluminous information being transmitted to Earth by orbiting satellites such as the Landsat Earth-scanner, which was sending digital data to ground stations at the rate of 15 million bits per second.

To provide the capability to process very-high-resolution image data from spacecraft sensors, Goddard Space Flight Center commissioned development of a unique type of computer based on the concept of mparallel processing, which involves picture elements (pixels) rather than step-by-step serial processing. Designed and built by Goodyear Aerospace Corporation, the resulting prototype was known as the Massively Parallel Processor (MPP). It was delivered to Goddard in 1983 and was soon found to have utility in a far broader range of applications than just image processing.

In massively parallel processing, an entire image is processed at once, while in serial processing an image is processed one pixel at a time; the latter takes hours to analyze and classify an image, MPP about 2O seconds.

The MPP architecture‹known as SIMD for single instruction stream, multiple data stream‹offers enormous computational power at a lower cost than other architectures. The speed of the prototype was derived from a network of 16,384 simple processors, which allowed dividing up a task so that each processor performed the same operation on different pieces of data at the same time.

To measure and document the advantages and disadvantages of parallel processing, and to understand the capabilities and limitations of the MPP, NASA organized a working group of 4O scientists who were provided opportunities to test their computational algorithms on the MPP beginning in the fall of 1985.

A year later, sufficient results had been generated to warrant convening ‹at Goddard‹the first symposium on massively parallel scientific computation. The MPP investigators described a broad range of applications, including signal and image processing, Earth science, and computer science and graphics. The performance of many of these applications was found to be in the supercomputer range, and for certain tasks MPP was found to be faster than traditional vector supercomputers. Subsequently, Goddard funded the development of a second-generation MPP called the Blitzen Project to demonstrate that the size and weight of the MPP could be reduced enough to allow its use in spacecraft.

Based in part on technology developed in the two MPP projects, MasPar Computer Corporation, Sunnyvale, California, produced a new generation of massively parallel computing systems: the MasPar MP-1 product family, ranging from a unit with lO24 processors that can deliver 16OO MIPS (millions of instructions per second) and 82 MFLoPS (millions of floating operations per second) to one with 16,384 processors that can deliver 26,OOO MIPS and 13OO MFLOPS. MP-1 users, including NASA, are attacking computationally-intensive problems in such areas as image and signal processing, database management query systems, neural network algorithms, computational fluid dynamics, and seismic data reduction.

Portable Computer

GRiD Compass, the first true portable laptop computer

In November 1983, NASA flew a nine-day space shuttle mission that marked the space debut of a remarkable high-performance navigation monitoring computer dubbed SPOC, for Shuttle Portable Onboard Computer.

SPOC was an adaptation of the GRiD Compass (shown at right), the first true portable laptop computer, produced by GRiD Systems Corporation, Fremont, California. Hardware had to be modified and new software developed to meet space requirements, which led to changes in commercial models that benefited the company's competitive position.

Since the shuttle's main computers must handle a multitude of processing functions, NASA wanted a separate computer to provide reliable monitoring of the craft's orbital path and a visual display of its position at any time. Since weight and space are vital considerations in space operations, the computer had to be small and lightweight; nonetheless, it had to have graphic display capability, a large memory storage capacity, high processing speed, and sufficient ruggedness to withstand launch vibration. After evaluating a number of small computers, NASA selected GRiD Compass.

The principal modification needed was a fan to cool the computer; GRiD computers norrnally were cooled by convection, or heat transfer by circulation, but that process does not work in the weightless environment of space. NASA also wanted a larger electroluminescent screen and Velcro strips to keep SPOC from floating. The fan later was incorporated into the larger-screen models of the Compass II line; likewise, Velcro strips have been used on subsequent products, including the new PalmPADTM PC, the first wearable pen computer, shown in use above. Designed for data collection applications, the PalmPAD also features a rugged magnesium case for added protection‹an innovation first developed for the Compass line.

Shuttle operations required a sophisticated operating and control system, one of the major considerations in NASA's selection of the GRiD Compass. Nonetheless, NASA and GRiD software engineers spent many hours writing, testing, and rewriting source code. This process, the company reports, ultimately benefited GRiD and its commercial clients because it helped fine-tune the GRiD operating System and common code documentation. over the past decade, GRiD Systems' annual sales have grown from less than $1 million to over $25O million. The company's computers are still used by NASA; the GRiD Model 153O, a more powerful 386 SL-based laptop that replaced sPoC, helps space shuttle astronauts to keep track of the craft's position in orbit and enables them to control payload experiments, collect data, and instantly transmit research results to investigators on Earth.

Fabric Structures

Space suit material now part of American landscape

What to wear to the moon is the question that spurred the development of a strong and lightweight fabric that has since landscape become part of the American landscape.

During the Apollo program, NASA sought to improve upon the fabrics it had used in fashioning space suits for the Mercury and Gemini astronauts, and began its search for a durable, noncombustible material that was also thin, lightweight, and flexible. At the time, owens-Corning was developing a glass fiber yarn could be woven into a fabric. The fabric was then coated with Teflon* for added strength, durability, and hydrophobicity‹the ability to repel moisture. The material met NASA specifications and was used in space suits throughout the Apollo era.

The technology soon found additional applications. The health care market required flame-resistant draperies and the Fiberglass fabric was adapted for that use. A more recent application is in the construction field, where a heavier version of the fabric is used as a permanent covering for shopping centers nationwide, for sports stadiums such as the new Georgia Dome in Atlanta and the olympic Stadium in Rome, and for airport terminals in Denver, Colorado and Saudi Arabia.

Architects, engineers, and building owners are turning increasingly to fabric structures because of their aesthetic appeal, relatively low cost, low maintenance outlays, energy efficiency, and good space utilization. Typically, fabric structures are built in one of two ways. Either they're tension structures that are supported by a network of cables and pylons, or air-supported structures that consist of an outer membrane and an inner liner. The area between these two layers is inflated to maintain the pressure differential necessary for roof rigidity.

(Photo Caption) This air-supported stadium at B.C. Plate, Vancouver, British Columbia, is Canada's first covered stadium. It seats up to 60,000 and has a ten acre fabric roof that weighs only l/30th as much as a conventional roof of that size. Sixteen giant fans blow air into the balloon-like envelope between the roof's outer membrane and its inner liner maintaining the pressure differential necessary for roof rigidity.

The space-based fabric is marketed by Birdair, Inc., Amherst, NY. Its translucency value, which ranges from 4 to 18 percent, reduces lighting needs and its reflectivity lowers cooling costs. The Teflon coating reduces maintenance costs by increasing the fabric's resistance to moisture, temperature extremes, and deterioration. Pound for pound, the material is stronger than steel and weighs less than five ounces per square foot. These factors combine to lower initial costs and speed construction.

Flat Cable

The flat cable can be mounted on walls and floors instead of in them

In the never-ending quest to make aircraft and spacecraft more compact, NASA engineers have devised a multitude of ingenious space-saving, weight-shaving measures. one such measure is the use of extremely thin flat wire‹ known as flat conductor cable (FCC) ‹instead of the relatively thick and protrusive round cable. only as thick as a credit card, FCC dramatically reduces the space occupied by the many miles of power lines in aerospace vehicles.

NASA recognized that commercial buildings, which also have miles of wiring, would benefit by adopting FCC technology. In the late 196Os, NASA funded a program in which Marshall Space Flight Center developed prototypes for several FCC applications, including a baseboard- mounted system.

(Photo Caption) An undercarpet flat cable installation is shown in the foreground in this view of the Sun Refining and Marketing Company's office in Philadelphia. Flat conductor cable offers cost savings in simplified building construction, reduced installation time, and ease of alteration.

Since industry participation was essential to large-scale application of FCC, NASA sponsored formation of a consortium composed of a dozen firms engaged in electrical hardware and associated manufacturing activities. Using Marshall's early work as a departure point, the member companies pooled their resources to develop complete FCC systems which encompass not only the cable but the sheathing, connectors, tools, and other equipment needed to facilitate FCC use by designers and builders. Subsequently, the use of FCC covered by carpet tiles in commercial buildings gained approval from Underwriters Laboratory and was listed in the National Electrical Code established by the National Fire Protection Association.

The flat cable can be mounted on walls and floors instead of in them; it can be installed beneath a carpet or along a baseboard, its essential sheathing designed to look like decor rather than plumbing. This enables elimination of the traditional ducting, under floors and elsewhere, necessary to accommodate conventional wiring. And when electrification needs changing, as they frequently do in commercial buildings, the surface- mounted FCC system is readily accessible.

In short, FCC offers simplified building construction, reduced installation time, and ease of alteration, all of which translate into substantial cost savings. Because of these multiple advantages, FCC has gained wide acceptance among builders, interior designers, and building managers.

Bolt Stress Monitor

Precise measurement of stress on a tightened bolt is critical

Pictured at right is the Pulse Phase Locked Loop Bolt Stress Monitor, or P2L2, an important safety advance for the construction industry. Developed at NASA's Langley Research Center, the P2L2 uses sound waves to accurately determine whether a bolt is properly tightened. Precise measurement of stress on a tightened bolt is critical in building and maintaining such structures as pressure vessels, bridges, and power plants, where overtightened or undertightened bolts can fail and cause serious accidents or costly equipment breakdowns.

The most common and least costly method of gauging bolt stress is the torque wrench, which is inherently inaccurate; it does not account for the friction between nut and bolt, which has an influence on stress. At the other end of the spectrum, there are accurate stress measurement systems, but typically they are expensive and bulky.

The battely-powered P2L2 bridges the gap: it is inexpensive, lightweight, portable, and extremely accurate‹to within one percent‹because it is not subject to friction error. The microprocessor-based instrument transmits a sound wave pulse to the bolt being tightened and receives a return signal indicating changes in resonance due to stress, akin to the tone changes in a violin string as it is tightened. The monitor measures the changes in resonance and produces a digital reading of stress on the bolt.

NASA has used the invention for bolting applications ranging from space shuttle landing gear wheels to wind tunnel fan blades, and is now transfering the technology to commercial markets.

Last June, the Langley Center held a Bolt Tension Monitor Workshop for industry that generated significant private sector interest in licensing the P2L2 and resulted in Langley's selection of the StressTel Corporation, Scotts Valley, California, as its commercial partner for further development of the system. StressTel, a leading manufacturer of ultrasonic testing equipment, plans to incorporate the NASA technology in its new Bolt-Mike SMIITM, a portable bolting control system offering simple operation, self-calibration, and data upload and download capabilities.

Quality ControI System

D Sight reveals tiny flaws previously difficult or impossible to observe

Manufacturers across a wide range of industries are employing machine vision systems to improve quality standards in the fit and finish of their products. Most of these systems do not have the sensitivity, however, to detect all of the imperfections their users would like to catch and correct.

Diffracto Ltd., Windsor, Ontario, offers an innovative system called D Sight (TradeMark) that reveals tiny flaws previously difficult or impossible to observe. D Sight can be used to inspect both flat and curved surfaces to locate such imperfections as dents, dings, wrinkles, and blisters. It detects and magnifies defects measuring less than one thousandth of an inch.

Industry tests have shown that D Sight can identify 94 percent of the defects when inspecting stamped sheet metal, as compared with only 5O percent for traditional flaw detection methods such as visual inspection.

D Sight is a spinoff from the space shuttle program. Diffracto was licensed to develop commercial applications for the vision guidance system of the shuttle's remote manipulator arm. While experimenting with the vision system, Diffracto engineers noticed the phenomerlon of reflected light from the target material. This led to a research and development effort that produced the first commercial D Sight model.

The basic system consists of a solid-state camera equipped with a quartz halogen lamp, a retroreflective screen, and an image processing computer. The camera photographs the part being studied while the screen bounces light off the surface to highlight defects. The resulting image is computer-analyzed and the discovered defects projected onto a video monitor for comparison with a stored master image of an acceptable part. Also included is a hard copy printer that provides documented evidence of product quality and proof of inspection.

For the D Sight technique to work, the target surface must be reflective. Since some surfaces‹such as unpainted sheet metal‹are not reflective enough, Diffracto created a reflectivity enhancing process that involves wiping an oil- or water-based compound on the surface.

The company has sold units to Chrysler, Ford, General Motors, and other auto suppliers who employ D Sight to inspect body panels and windshields, and to check "first articles" for die-related defects. Plastics manufacturers use the system to determine what temperatures, pressures, and materials will produce the best quality surfaces. Moreover, several aircraft manufacturers have bought units to inspect aircraft composite skins.

Diffracto has installed more than 6O systems worldwide. In cooperation with the Canadian National Research Council's Institute for Aerospace Research, they have developed a portable unit to perform nondestructive tests on in-service aircraft. The DAIS (D Sight Aircraft Inspection System) enables fast detection of impact damage and other flaws that often go undetected with current visual methods.

(Caption)The upper photo shows a carr door viewed under normal light, while the lower photo shows the some door viewed with the D Sight system.

Nondestructive Testing Tool

X-rays can penetrate manufactured parts and structures to help pinpoint defects

Just as x-rays can scan the human body to aid doctors in diagnosing disease, they can penetrate manufactured parts and structures to help pinpoint defects. In both instances, the x-ray images are digitally processed using techniques that originated in NASA R&D programs of the 1960s.

This technology, called computed tomography (CT) or CATScan, is gaining acceptance by industry as a tool for nondestructive inspection. And NASA is once again leading the way: the Marshall Space Flight Center sponsored development of a versatile CT device‹dubbed the Advanced Computed Tomography Inspection System (ACTIS)‹that is finding a variety of nondestructive testing applications. Developed for Marshall by Bio-Imaging Research, Lincolnshire, Illinois, ACTIS can evaluate components ranging in diameter from four inches to four feet and materials ranging from steel to rubber. It provides results superior to conventional techniques in contrast sensitivity, spatial resolution, and visualization.

Marshall is using ACTIS to test rocket motor assemblies and other critical components. Boeing Aerospace & Electronics, Kent, Washington, purchased the first industrial model and has used it to learn more about materials and processes, particularly high-strength composite materials.

ACTIS can help diagnose design problems early in the product development cycle, saving time and expense. The system identified anomalies in the space shuttle main engine turbopumps at an early development phase, prompting changes in the casting process. It has been used by the U.S. Department of Energy to inspect sealed barrels of nuclear waste and by automobile manufacturers to inspect prototype steering wheels, engine blocks, and gear boxes. Studies indicate that it could grade lumber and assist in optimizing the lumber industry's cutting plans.

(Caption) In this CT image of a crosssection of a rocket motor gas generator, the bright yellow spots in the orange background (near the perimeter) are small voids that indicate anomalies.

(Caption) Applications of ACTIS at Boeing include nondestructive evaluation of aircraft components.

Pressure Measurement Systems

The basic system was able to make 1000 measurements a second, a hundredfold improvement

Pressure Systems, Inc. (PSI), Hampton, Virginia is a thriving company whose business evolved from a single spinoff development.

PSI began life in 1977, its "plant" a single room in the home of founder and president Douglas B. Juanarena, its sole product an innovative pressure sensing device developed at NASA's Langley Research Center. Today, PSI manufactures 2O products within four basic product lines and has annual sales exceeding $8 million, exports accounting for about 25 percent of its total business.

The PSI success story began in the early 197Os when Langley Research Center was looking for a way to obtain better accuracy and higher data rates in measuring airflow pressure at many points around a wind tunnel model. Mechanical systems then in use could only perform ten measurements a second. To get the hundreds of measurements needed in a typical test, it was necessary to conduct many repetitive tunnel runs. This bred inaccuracies because test conditions changed over the lengthy period required to make the measurements.

There was a corollary need to cut energy costs, which then were soaring as a result of the world energy crisis. Since wind tunnels consume enormous amounts of energy, it became imperative to find ways to shorten tunnel operating times without compromising data accuracy or quantity.

Langley found a solution to both problems in a new technology called electronically scanned pressure (ESP), developed by an engineering team that included Douglas Juanarena. The Langley ESP measurement system was based on miniature integrated circuit pressure-sensing transducers that communicated pressure data to a minicomputer; these sensors could be calibrated while in use, an innovation that greatly improved accuracy. High data rates were achieved by using one transducer for each pressure port in a wind tunnel, which would have been impractical with mechanical systems. Inherent errors in the transducers were automatically computer- corrected. The basic system was able to make lOOO measurements a second, a hundredfold improvement, and was small, relatively low-cost, and highly accurate and reliable.

Juanarena formed PSI in 1977 to exploit the NASA invention. A year later he left Langley, obtained a license for the technology, and introduced the first commercial product, the 78OB pressure measurement system, which quickly captured a large part of the pressure scanning market among U.S. government and industrial wind tunnel users. Subsequently, the French and West German governments standardized on PSI instrumentation for their wind tunnels. PSI systems also are used for pressure measurements in flight; at top an engineer is adjusting a wing-mounted unit that gathers data from a dozen sensors along the wing's leading edge.

Looking to the broader potential of ESP technology, PSI developed a pressure scanner for automating industrial processes where there is a need for making multiple pressure measurements quickly and with high accuracy. PSI continued to refine the technology and now produces ESP modules and accessories in 16, 32, and 48 channel configurations, with data rates up to 4OO,OOO measurements a second.

Laser Technology

The beams can be used to transmit communications signals; to drill, cut, or melt hard materials; or in medical applications

At right is a green microlaser introduced in 1988 by Amoco Laser Company, Naperville, Illinois. At bottom is Amoco's breakthrough infrared diode-pumped microlaser. Both are spinoffs of a laser concept developed at NASA's Jet Propulsion Laboratory (JPL) for optical communications over interplanetary distances.

Lasers emit a narrow and very intense beam of light or other radiation. The beams can be used, for example, to transmit communications signals; to drill, cut, or melt hard materials; or, in medical applications, to remove diseased body tissue.

Microlasers are revolutionary miniaturized all-solid-state lasers that cover a broad part of the wavelength spectrum and offer dramatically improved performance over traditional lasers. Amoco offers 2O microlaser products for an expanding range of applications that includes medical instrumentation and therapy, color separation equipment for graphics and printing, film reading and writing, projection TV, telecommunications, optical memory storage, plus a variety of industrial R&D/production uses such as micromaterials processing, spectroscopic and analytical measurement, and semiconductor processing. In addition to producing technology in-house, Amoco has acquired other patents relating to solid-state lasers pumped by tiny diodes. This includes the NASA technology in the infrared and green microlasers, which was developed at JPL by Donald L. Sipes, Jr. of the California Institute of Technology (CalTech). Subsequently, NASA waived the patent rights to CalTech, which lecensed the technology to Amoco Laser. According to Sipes, the patent centers on the discovery that a diverging, elliptically-shaped laser beam, such as that emitted by a laser diode, can be used to pump a solid- state laser very efficiently and also produce an extremely narrow, ideal beam.

Induction Heating Systems

Induction products enable fast spot and seam bonding of many plastics, composites, and metals

Over a decade ago, NASA's Langley Research Center began searching for a new way to join plastic and composite parts of space structures in orbit. These materials are difficult to join in the airliess environment of space by conventional methods. Adhensive bonding, for example, is not reliable in a vacuum, riveting techniques often deform the material, and mechanical fasteners require hole preparation and special tools.

Langley researchers decided the best approach was induction‹or magnetic‹heating, which causes little or no deformation and can be used with any type of thermoplastic material. They developed and patented a prototype system that offered advantages not only in space structure assembly but also in the automotive, appliance manufacturing, aerospace, and construction industries.

In 1981, Inductron Corporation, Grafton, Virginia, obtained an exclusive NASA license to commercialize the induction heating technology. The company produced a series of induction heating systems and associated equipment‹such as heating heads and joining tools‹ suited for aircraft, industrial, and military use. Inductron products enable spot and seam bonding of many plastics, composites, and metals in a fraction of the time required by standard methods, according to the company. Applications include battlefield repair of aircraft windscreens, skins, hydraulic lines, and rotor blades; rapid attachment of strain gauges; laboratory testing of adhesives; and manufacture and repair of composite assemblies.

Inductron markets several models of the Torobonder low-powered, portable induction bonding systems. Similar in size and weight (24-27 pounds), they differ primarily in output wattage. In the above leJ~ photo, an engineer is using a Torobonder to repair a damaged helicopter windshield.

Another Inductron development is the Toroid Joining Gun pictured above right, which is used to heat a variety of conductive materials. one version of the gun is used in the military and industry to heat metal heat-to-shrink couplings and fittings, typically for repair of hydraulic, air, or plumbing lines. The fittings are heated to a high temperature at which they shrink and bond to the line. Inductron's device offers advantages over earlier heat-to-shrink methods in that it has no open flame and is nonhazardous, generates focused and controllable heat, does not adversely affect surrounding objects such as wire harnesses or fuel lines, and has a long shelf life.

Shown at top right is yet another Inductron innovation, the Torobrazer, which provides a new way to braze and anneal sawblade joints using the induction heating process. Advantages include portability, low cost, low power, and ease of operation, even for inexperienced personnel.

In 199O, Inductron entered into an agreement with NASA to patent all induction-heating-related inventions in NASA's name, with Inductron granted exclusive rights to practice the technology.

High Pressure Waterstripping

Paint literally can be removed one layer at a time, at waterjet pressures of 24,000 psi, with no damage

Today's focus on environmental concerns brings with it ever-tightening restrictions on the use and disposal of chemical stripping agents. Offering a viable solution to this dilemma, Pratt & Whitney's USBI Co., a whooly owned subsidiary of United Technologies Corporation, Huntsville, Alabama, has successfully transferred its waterjet processing technology from the manned space program to aviation and other industries.

USBI and NASA began waterjet processing work in 1977 with the development of the Waterblast Research Cell at NASA's Marshall Space Flight Center. Under NASA's guidance, USBI developed automated high-pressure waterjet systems that were brought on- line in 1985 and 1986 at Kennedy Space Center (KSC) and that have resulted in a 96% reduction in man-hours. USBI currently operates NASA's high-pressure waterjet facility at KSC, removing the themmal protective coatings from the space shuttle's solid rocket boosters. Recognizing the technology's broad potential, USBI began developing spinoffs of the waterjet technology to address environmental challenges facing the commercial airline industry and U.S. govemment. Current stripping methods require use of many hazardous and toxic chemicals such as methylene chloride. USBI's Automated Robotic Maintenance System (ARMSTM) integrates the benefits of high- or ultra-high-pressure waterjetting with the precision of robotics to provide an efficient coating removal system whose only residuals are water and the coating itself. The water is then filtered and reused, reducing waste and leaving only the dry coating residue for disposal.

USBI's first waterjet spinoff is the U.S. Air Force's Large Aircraft Robotic Paint Stripping (LARPS) system, which will consist of high-pressure waterjet equipment coupled with a mobile robot that follows preprogrammed paths for stripping paint from big aircraft such as KC-135s and B-52s. Using special end effectors (robot hands) developed by USBI, the process is so precisely controlled that paint literally can be removed one layer at a time, at waterjet pressures of 24,OOO psi, with no damage to the aircraft skin. The technology is now available to the aircraft industry for engine maintenance. USBI already has begun installation of an Engine ARMSTM for Delta Airlines at its Hartsfield Intemational Airport facilities in Atlanta, Georgia. The system can strip tenacious plasma-sprayed coatings such as ceramics and magnesium zirconate using only water at ultra- high pressures up to 55,OOO psi. USBI has demonstrated that waterjet processing can reduce coating removal time for engine parts by as much as 9OO/O, while increasing service life compared to current chemical or mechanical methods.

Other applications include stripping of paint and coatings from helicopter blades, transmission housings, gearboxes, and other parts; and removal of paint from ships, submarines, and railway equipment. Economic benefits are derived from reduced processing time, virtual elimination of hazardous chemicals, and reduced waste disposal costs‹all while enhancing worker safety and protecting the environment. Due to the high level of interest from a wide range of industries, Pratt & Whitney currently is structuring a new division around the waterjet work begun by USBI that will be called Pratt & Whitney‹Waterjet Systems.

(Caption) The USBI-operoted waterjet system at Kennedy Space Center removes thermal protective toafings from the space shuttle's solid rocket booster.

Composites For lighter Structures

PMR-15 allows fabrication of high-quality fiber-reinforced composites

Pictured at right is the General Electric Company's F404, power plant for the Navy's F/A-18 fighter aircraft. The engines's outer duct is made not of metal but of a strong and light weight composite material - the first application of a fiber-reinforced composite as a primary structu~al member in a jet engine. Composites previously had been limited to applications where they encountered only low to moderate temperatures.

The duct material is a fabric woven of carbon fiber impregnated with a high-temperature polyimide resin. Called PMR-15, the resin was developed by Dr. Tito T. Serafini and other investigators at NASA's Lewis Research Center in response to a need for a resin that could withstand higher temperatures and thereby expand the range of composite applications. Epoxy resins, the type most widely used as composite matrix materials, have excellent mechanical properties and can be processed easily, but they are limited to applications where temperatures do not exceed 3SO degrees Fahrenheit. To produce a higher temperature polymer, researchers had to overcome extraordinary processing difficulties.

More than a decade ago, the Lewis team started research toward a polyimide resin that could withstand greater temperatures and be readily processed. After lengthly experimentation involving alteration of the chemical nature of the resin and methods of processing it, they successfully developed PMR-15, which offers good processing characteristics and allows fabrication of high-quality fiber-reinforced composites that can operate in an environment of 6OO degrees Fahrenheit.

But laboratory development of the polyimide was only a start; it then had to be converted to a manufacturing material for cost- effective production use. In 1979, General Electric's Aircraft Engine Business Group, looking for a lightweight, low-cost substitute for titanium in the F4O4 engine duct, became interested in PMR-15. There ensued a four-year processing technology effort, jointly funded by NASA and the Navy, followed by a Navy-sponsored project that resulted in a manufacturing process for use of the graphite polyimide composite.

Initially clothlike in appearance, the material is cut, layered, and shaped to a desired configuration, then cured in an autoclave, where the fibers and resin are molded under pressure into a component that looks metallic but weighs about 15 percent less than the predecessor titanium duct. Fabricated by GE Aircraft Engines (GEAE), the F4O4 composite duct was ground- and flight-tested in 1984-85 and introduced into production in 1988. A variety of PMR- 15 composite parts have been introduced into other GEAE products, including the FllO engine family.

PMR-15 was selected for the Space Technology Hall of Fame in 1991. The PMR formulation has been made available to commercial suppliers of composite materials, and is currently offered by various sources including Fiberite, Inc. and SP Systems (formerly Ferro Corporation). Composite fabrics and tapes based on PMR-15 are being produced for a rapidly growing range of applications.

Dry lubricant Coating

The coating binds instantly to any metal or resin substrate with a thickness of 20 millionths of an inch

The Mariner missions of the 196Os.and 197Os produced a wealth of information about Earth's neighboring planets‹Venus, Mars, and Mercury. The Mariner family of unmanned spacecraft incorporated a great deal of what was then considered leading-edge technology ‹advances in onboard power, scientific instrumentation, communications, and imaging/data transmission systems. Among these innovations was an unsung technology: a dry film lubricant developed for NASA by Stanford University. It offered markedly reduced friction and extended wearlife of mating parts operating in harsh interplanetary environments, where temperatures ranged from well below zero to 5OO degrees Fahrenheit.

The technology subsequently was acquired and refined by Micro Surface Corporation, Morris, Illinois, which markets the lubricant as the WS2 modified tungsten disulfide coating. A pressurized refrigerated air application process impinges a dry metallic WS2 coating without heat, curing, binders, or adhesives. The coating binds instantly to any metal or resin substrate with a thickness of 2O millionths of an inch.

In the aftermath of the Mariner missions, the dry lubricant found its way into industry use, but only by aerospace and defense contractors. In 1984, Micro Surface introduced WS2 to general use and it has since compiled an excellent track record in an ever-widening range of applications across the automotive, medical equipment, plastics, tool and die, and robotics industries. It has been employed, for example, to coat machine tools, industrial gears and bearings, electric motors, compressors, cryogenic pumps, and small firearms. WS2 can help improve product quality, extend equipment service life, and eliminate or reduce costly maintenance problems.

In the plastics industry, WS2 users have found that in operations such as blow molding, injection molding, and extrusions the coating increases production by reducing the drag between tool steel and resin. In the automotive field, it is used by Ford Motor Company, General Motors, and Chrysler Corporation to reduce friction and wear in auto bearings, transmissions, and engine internal parts.

(Caption) In the manufacture of plastic parts such as the ones shown here, companies coat injection molds to reduce sticking and increase production.

(Caption) Ed Fabiszak, gneral manager of Micro Surface Corporation, displays a tool for making plastic parts that has been coated with WS2, a dry lubricant originally developed for space use.

Micro Surface's growing list of WS2 customers reads like a Who's Who of American Industry. In addition to the U.S. automotive Big Three, a random selection includes American Can Corporation, Kimberly Clark Company, Dow Corning Corporation, Ethyl Corporation, General Electric Company, Phillips Petroleum, Whirlpool Corporation, and, of course, NASA.

Diamond Coatings

Diamond films offer tremendous potential in such advances as chemically-inert protective coatings and machine tools and parts that are ten times more wear-resistant

The hardest substance on Earth, diamond is resistant to wear, an outstanding thermal conductor and electric insulator, immune to attack from most chemicals, transparent, and relatively friction-free. These attributes would make diamond the ideal material for a wide range of industrial applications were it not for its extremely high cost.

A new technique, however, makes it possible to get the advantages of diamond in a number of applications without the cost penalty‹by coating and chemically bonding an inexpensive substrate (supporting material) with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous potential in such advances as chemically-inert protective coatings; machine tools and parts that are ten times more wear- resistant; and consumer products ranging from wristwatch crystals to eyeglasses. In the U.S., Japan, and Europe, growing diamond-coating industries are vying to get a foothold in a new market that is predicted to reach up to $1 billion in this decade and far beyond that in the 21st century.

Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc., Allentown, Pennsylvania. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate.

NASA's Lewis Research Center, interested in the aerospace potential of synthetic diamond coatings, has investigated a variety of ways to deposit DLCs on different types of substrates. Among the coating methods studied is a technique called direct ion beam deposition, in which an ion generator creates a stream of ions from a hydrocarbon gas source; the carbon ions impinge directly on the target substrate and "grow" into a thin DLC film. Lewis' research has generated patents related to a dual ion approach. This low-pressure, low- temperature technique allows coating plastics and other substrates that cannot tolerate extreme heat.

Lewis is providing technical assistance to Diamonex on a major step that would significantly expand the DLC market: scratch-resistant coatings for plastic prescription eyeglasses. The trick is to make the hard DLC coating thick enough to provide scratch resistance yet maintain optical clarity. Diamonex is working with a lens manufacturer to commercialize this technology.

The photos illustrate some of the applications of diamond coatings. Above are a magnetic data storage disk and several read/write head sliders that are coated to reduce friction and increase disk life. on the oppos~te page are some typical uses of non-optically-transparent DLC coatings: at top center is a speaker diaphragm that is coated to provide a higher frequency response from the speaker; moving clockwise in the photo are needles used in weaving cottoncloth, coated to reduce friction and snagging; at bottom is a diamond- coated ball for an artificial hip joint, whose wear resistance and durability is increased by coating; and at left are surgical needles coated to reduce patient recovery time by minimizing needle puncture damage. The photo below shows several optics applications: at top, prescription eyeglasses; at the three o'clock position, a polycarbonate blank for sunwear; at four o'clock, two coated polycarbonate lenses; at bottom, a lens with iridescent diamond coating for fashion; and at upper left, sunglasses.

Diamonex is developing and marketing‹under the trade name Diamond Aegis (TradeMark)‹a line of polycrystalline diamond-coated products that can be custom-tailored for optical, electronic, and engineering applications. The company's initial focus is on optical products. other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools, and bearings.

Ion Generators

An ion engine theoretically could accelerate a spacecraft to a velocity approaching the speed of light

In 1959-60, the first.electron bombardment thruster was developed by NASA Lewis Research Center engineer Dr. Harold R. Kaufman. This and later "Kaufman thrusters," as they came to be known, were designed for use in a spacecraft electric propulsion technique called ion propulsion.

Ions are atoms or molecules that have lost one or more of their electrons and therefore are electrically charged. one way of generating ions for propulsion is by electron bombardment of a gas in a discharge chamber, which causes atoms to lose electrons. The ions thus created are accelerated and ejected from the chamber as ion beams. Mixed with an equal number of electrons, the ion beam becomes a thrusting force similar in function to the hot gas exhaust of a chemical rocket, but with a major difference: where the chemical rocket creates high thrust for short periods, the ion propulsion system generates very low thrust for extremely long periods with high exhaust velocity.

As a primary space propulsion system, an ion engine theoretically could accelerate a spacecraft to a velocity approaching the speed of light for voyages beyond the solar system. It also offers utility as an auxiliary propulsion system for spacecraft stationkeeping and attitude control.

Dr. Kaufman's ion propulsion devices were used in some space projects beginning in the mid-196Os, but their potendal as a primary propulsion system lies in the future. The technology created for space use resulted, however, in development of a variety of industrial ion beam sources. other techniques for ion generation have been developed in the U.S. and abroad, but most broad- beam electron bombardment ion sources now in use trace their origins to Dr. Kaufman's work.

The main industrial applications of ion beam technology are in etching microcircuits for electronic systems and in deposition of thin films used, for example, as coatings on solar cells or optical equipment. Recently, there has been growing use of ion sources for modifying or controlling the properties of thin films (see article on page 11O). In this application, the target material is bombarded by an ion beam before, during, or after the film deposition process to improve certain properties of the end products, such as adhesion or corrosion resistance.

A company whose product line derives largely from Dr. Kaufman's work is Commonwealth Scientific Corporation (CSC), Alexandria, Virginia. Dr. Kaufman serves as a vice president of research and a member of the board; CSC's president is George R. Thompson, shown in the top photo on theprevious page. In the photo beneath that, an engineer is assembling a CSC ion source. At top is a closeup view of a CSC Mark II Gridless lon Source. The photos at left show a complete CSC etching deposition system and a closeup of the chamber.

Founded in 1966, CSC is a leader in engineering research for the ion beam industry and a top producer of ion beam equipment. The company's product line includes more than a dozen types of ion sources, power supplies for the sources, surface analysis equipment, and thin film coating equipment.

Magnetic Liquids

The ferrofluidic seal solved a persistent problem - contamination due to leaking seals

One of the earliest spinoffs to emerge from NASA research was a unique class of liquids possessing magnetic properties. Called ferrofluids, these synthetic fluids can be positioned and controlled by magnetic force - offering advantages in manufacture of electronic products, industrial processes, medical equipment, visual displays, automated machine tools, and many other applications.

The ferrofluid concept had its genesis at NASA's Lewis Research Center more than 30 year ago. Looking for a way to feed weightless fuel to the engine of an orbiting spacecraft, a Lewis scientist conceived the idea of magnietizing the fuel by dispersing within it finely ground iron oxide particles; the fuel could then be drawn into the engine by a magnetic source. NASA never appied the concept to at problem but it surfaced again in the mid-1960s - at Avco Space Systems Division - as a possible method of controlling a spacecraft's temperature. Again ferrofluids were bypassed in favor of another solution.

However, two Avco scientists - Dr. Ronald Moskowitz and Dr. Ronald Rosensweig - saw great commercial potential in ferrofluids, obtained a NASA license for the technology, and formed the Ferrofluids (Registered TradeMark) Corporation, Nashua, New Hampshire. They found an initial application in a zero-leakage, nonwearing seal for the rotating shaft of a system used to make semiconductor chips. The ferrofluidic seal solved a persistent problem - contamination due to leaking seals - and sparked widespread interest in the new technology. Use of ferrofluids in rotary shaft seals has increased rapidly and the majority of computer memory disk drives also employ magnetic fluid exclusion seals.

In the photo below left are fluid film bearings in a variety of sizes and configurations; examples of ferrofluid bearings used in disk drives are shown below right. Ferrofluids also are being applied in robotic, fiber optic, and laser systems. From a sales volume of $65,000 in its first year of operation, Ferrofluids has grown to a $60 million a year company operating in 25 countries.

Flexible Circuits

They are attractive in dynamic applications that involve continuous or periodic movement of the circuitry

Flexible circuitry is an arrangement of printed wiring used to interconnect the parts of an electronic system. First applied on military aircraft and missiles, where size, weight, and reliability are primary design considerations, the flexible circuitry can be molded to the shape of a chassis for marked reduction in bulk. Although flex circuits generally cost more than conventional connectors, they nonetheless offer savings in some applications because they are less expensive to install. They are attractive in dynamic applications that involve continuous or periodic movement of the circuitry; in such applications, where reliability must be maintained over millions of flexing cycles, flexible circuits have demonstrated outstanding performance.

Now used in a broad range of civil applications, flexible circuits are produced by combining three materials: an insulating plastic film; a metallic conductor, typically copper foil; and an adhesive to bind the insulator and the conductor into a laminated circuit. The adhesive is crucial to the circuit's performance and is selected with care, taking into consideration such factors as bond strength, temperature resistance, and the flexible lifetime of the printed circuit.

NASA's Langley Research Center developed an adhesive called LARC- TPI that is being used to produce laminates under an exclusive license by Rogers Corporation's Circuit Materials Division, Chandler, Arizona, one of the nation's largest manufacturers of flexible circuits. LARC-TPI belongs to a family of linear polyimides that generally are tough, flexible, and have excellent mechanical and electrical characteristics over a wide temperature range. Hence, they have been used‹and are being considered for broader us‹as structural adhesives for bonding parts of aircraft, missiles, and spacecraft subjected to high temperatures, for example, engine nacelles and cowls, or the friction-heated leading edge of a high- speed airplane.

The problem with linear polyimides is that they have been difficult to process. Special requirements for bonding components of a proposed space system led Langley Research Center to create an advanced structural adhesive by chemically altering the structure of the polyimide to improve its characteristics and eliminate processing problems. The resulting LARC-TPI can be processed at lower temperatures and has good moisture resistance‹both of which help prevent formation of voids‹and it has excellent adherence to a large number of plastics and metals.

(Caption) Rogers Corporation's flexible circuits are easy to install and useful in applications that involve continuous or periodic movement of the circuitry.

In its first commerical application, Rogers Corporation used LARC-TPI to bind the insulation film KaptonX to copper foil conductor material in the manufacture of flexible circuits. The product line of Rogers' Circuit Materials Division includes flexible circuits for such consumer products as electronic watches, cameras, TV games, calculators, and burglar alarms; industrial applications such as display panels, medical instruments, test instrumentation, and electrostatic copiers; computer jumpers, memories, terminals, and printers; aerospace systems such as missiles, transponders, and avionics; automotive applications such as dashboard clusters and fuel, engine, and pollution controls; and, in communications, CB radios, telephor.f receivers, pagers, and antennas.

Robot Hand

The Salisbury Hand can move objects about, twist them, and otherwise manipulate them by finger motion alone

Although manufacturers have long been interested in robotics technology as a means to automate industrial processes, technical limitations have slowed broad commercial use of robots. A major limitation has been the dexterity of the "hand," technically known as the end effector. Most of the current hands have shortcomings in grasping objects; they are limited in the range of configurations the hand can assume and must be fitted with special fingers for each object being handled. Robots also are limited in effecting precise position and force control. Attaining true robot dexterity requires improvements in robot mechanisms coupled with advancements in robot control techniques.

In 1982, NASA began developing a test bed for research on control and use of dexterous robot hands. In cooperation with Stanford University and the California Institute of Technology (CalTech), Jet Propulsion Laboratory (JPL) initiated work on an articulated hand capable of adapting its grasping posture to a wide variety of object shapes and of performing rapid, small motions required for delicate manipulation without need for moving the more massive arm joints. Initial specifications were drawn up by Carl Ruoff of JPL and Dr. Kenneth Salisbury of Stanford. Later, Salisbury developed the final design.

(Caption) Capable of grasping and manipulating a wide variety of shapes, the Salisbury Hand was developed ot the Jet Propulsion Laboratory and Stanford University.

The Stanford/JPL Hand, which has come to be known as the Salisbury Hand, has three human-like fingers, each with three joints. The rounded tips of the fingers are covered with a resilient material that provides friction for gripping. Like the fingers on a human hand, the robot fingers can provide more than three contact areas since more than one segment of each finger can touch an object. Thus, the robot hand can move objects about, twist them, and otherwise manipulate them by finger motion alone. Moreover, the hand can be adapted to different arms.

Salisbury continued his work on the robot hand at the Massachusetts Institute of Technology's Artificial Intelligence Laboratory, concentrating on advanced software for commanding finger motion and interpreting information from fingertip sensors. In response to requests from other research groups for copies of the hand, Salisbury formed Salisbury Robotics, Inc., Cambridge, Massachusetts, to reproduce the device. In addition to the prototype, still in use in Stanford's Robotic Project, and another unit at MIT, copies have been delivered to General Motors Research Laboratory, the National Institute of Standards and Technology, Sandia National Laboratories, and the University of Massachusetts at Amherst.

According to Salisbury, the invention has provided the basis for numerous dexterous hand research projects around the world and has proved to be a robust and flexible platform for a broad range of control and sensory investigations.

Clean Room Apparel

An ofshoot of NASA contamination control technology

A tiny speck of dust could trigger a malfunction in a sensitive spacecraft system, so NASA developed contamination control technology for assembly of flight equipment in hospital-like "clean rooms." one of several offshoots of that technology base is a line of contamination control garments used by hospitals, pharmaceutical and medical equipment manufacturers, aerospace and electronic plants, and other industrial facilities where extreme cleanliness is vital. They are produced and marketed by Baxter Healthcare Corporation, Industrial Division, Valencia, California under the trade name Micro-Clean (Registered Name) 212.

NASA spearheaded contaminatic. control technology in the 196Os, building an informational base with input from Marshall Space Flight Center, Johnson Space Center, Kennedy Space Center, Lewis Research Center, and Sandia National Laboratories. The agency conducted special courses for clean room technicians and supervisors and published a series of handbooks that represented the most comprehensive body of contamination control information available at that time.

American Hospital Supply Corporation (AHSC), Baxter Healthcare's predecessor company, used the NASA base as a departure point for research aimed at improving industrial contamination control techniques. In 198O, AHSC researchers studied the NASA handbooks, visited NASA centers, and investigated several contractor clean room operations, acquiring a wealth of data on contamination control and problem areas.

The project found that the greatest sources of clean room contamination were the people who worked in such facilities; they generated microscopic body particles that escaped through tiny "windows" in the woven garments they wore. This conclusion led to AHSC's development of the original Micro- Clean line of apparel, made of a non- woven material known as TyvekTM capable of filtering 99 percent of all particulate matter measuring half a micron (a millionth of a meter) and larger.

Baxter Healthcare has continued to improve the line through advanced technology. The key enhancement in the Micro-Clean 212 line is a proprietary polyimide coating applied to the base fabric (Tyvek) to seal and tie down any loose fibers, thereby minimizing fabric linting and particle generation from abrasion. Further, the company redesigned its coverall (shown at left) to minimize the stress points along the seams and make the garment virtually tearproof.

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