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If Santa Claus is to visit the millions of boys and girls expecting presents on Christmas morning, he would need the help of space technology. Spacecraft orbit the Earth at speeds of more than 17,000 miles per hour while cargo airplanes only travel through the atmosphere at hundreds of miles per hour. The artist has chosen the fastest way for Santa to deliver presents. The mistake is not putting rockets, a cabin, communications and other systems needed by Santa to operate in space. Click on features of Santa's sleigh and reindeer to find how a spacecraft sleigh should be designed.

Spacecraft Sleigh

People who design spacecraft and rockets start their designs by choosing the types of systems needed to accomplish the mission of the spaceship or rocket. They list the things the vehicle must do. They call this list the "requirements" or the "specifications" of the spaceship.

When Santa designed his sleigh, he chose systems which would enable him to deliver gifts to deserving children. Since his sleigh had to operate on snow, he chose two skis instead of wheels for transport. Sleighs, cars, and spaceships need engines so Santa selected reindeer to pull his sleigh over the snow. The size of the engine required is determined by the number of reindeers Santa chose. The more reindeers, the faster and farther the sleigh can travel. To travel farther and faster in space, rocket designers choose larger engines clustered together in greater numbers.

Many systems Santa selected for his sleigh are similar to systems space designers select for rockets and spacecraft. Santa's sleigh carries cargo in a sack that Santa carries over his shoulder. The shuttle carries cargo in the payload bay. When Santa arrives at a child's home, he opens his sack, reaches inside, selects a gift and puts it under the Christmas tree. When the shuttle reaches orbit, the payload bay doors open, a mechanical arm called the "manipulator" reaches into the cargo bay and pulls out a satellite and puts or "deploys" it in space. Whether you design a sleigh or a spaceship, choosing the systems and requirements is the most important step in the design.


1. List the systems you would need for a car to drive on the Moon. Draw a picture of your lunar car and list the systems with arrows pointing to them.

2. If Santa's sleigh operates in space as shown in the picture, what important space systems did Santa forget to include?

Space Cargo

We know Santa's mission on Christmas Eve is to bring gifts of toys to boys and girls throughout the Earth. The astronauts' space shuttle has a mission to put satellites in orbit which often help boys and girls throughout the world. Some satellites warn us of hurricanes. Others help ships and planes find their way to a destination.

Santa has a huge sack to carry or "stow" his toys on board his sleigh. Like Santa's toy sack, the shuttle has a cargo bay designed to stow satellites and other space experiments for placement in Earth orbit. Putting a satellite in orbit is called deployment.

Santa uses his hands and arms to reach into his sack and retrieve a toy for a deserving child. The shuttle has an arm called the Remote Manipulator System or RMS to reach into the cargo bay for a satellite. The RMS removes the satellite from the shuttle and places it outside the shuttle.

The RMS is a type of robot. A robot is an electrical and mechanical devise which acts like a human. The RMS is a robot which acts like Santa's hand and arm by gripping an object and placing it in a desired place.

If Santa's sleigh carried a robot which looks and acted like Santa, no spacesuit would be needed because robots do not breathe. The RMS replaces the actions of astronauts. The RMS does not need oxygen. For some actions this is an advantage over having an astronaut do the job. In the case of Santa, a robot would be able to do the job of operating in space. But robots are not warm and loving like Santa is to boys and girls who visit him during the Christmas season in stores and shopping centers around the world.


1. What jobs might a robot do better than a human in space?

2. What jobs might a human do better than a robot in space?

Santa's Moon Sleigh

To design a space sleigh, it is helpful to examine the design of the craft which took astronauts to the Moon. It was called the command and service module. It had a rocket engine in its rear which thrust the vehicle on its journey to the Moon. The front cone shaped portion of the craft was called the command module because from it the astronauts commanded and controlled the operation of the spacecraft.

Behind the command module was the service module which provided services to the astronauts. Among the services were oxygen, electrical power, water, and control jets to steer the command and service module on its journey in space. The artist failed to include the steering jets. The vehicle shown could not be operated in space because these jets were left out in the drawing. After answering the questions below, click on different parts of Santa and his sleigh to learn more about systems needed to operated in space.


1. Why do you think the command module has a cone shape?

2. Since no steering jets are shown, what other way could the command and service module be steered?

Spaceship Engines

Santa's reindeer are the engines which pull his sleigh across the ice and snow of the North Pole. The three shuttle main engines and the two solid rockets boosters are the engines which push the shuttle and its cargo into space. Each system does its intended work quite well, but neither can be interchanged for the other. Reindeers can't do the job of rocket engines in space.

Spacecraft and reindeer have many things in common. If we compared a spaceship to a reindeer, most of the systems required for space operations exist in a reindeer. For example, all spaceships have a structure or framework on which the engines, electronics, and other systems are attached. A reindeer's structure is called in biology, the skeleton. While the spaceship skeleton has struts of aluminum or graphite, the reindeer's skeleton structure has bones.

Besides the structure of spaceships, electronics must be included to operate the engines, the steering systems and other controls. This is done by an on board computer. The computer's electronic instructions are transmitted to the engine and other systems by wires. Again, similar systems exist in the biology of reindeer. The reindeer's brain and nervous system serves the same purpose as the spaceship's computer, controls, and wires.

Actually, practically, every system a reindeer has, also exists in spaceships. There is a stomach which holds food before for digestion and convertion to energy to fuel a reindeer's work. A fuel tank in a rocket hold its food which will be converted to energy for propulsion from the rocket's thrust chamber.

The list of comparisons goes on and on when we consider the reindeer's eyes compared to a spaceship's radar and radio, the reindeer's hoofs and legs compared to the lunar lander's four legs and landing pods, and many other similar systems required by reindeer and spacecraft.


1. The first scientists to study flight, examined the systems a bird needed to fly. What systems does a bird have that are like an airplane?

2. There are insects that operate like rockets. An insect called the bombardier beetle has a combustion chamber at its rear. The insect causes self generated gas to explode and spew from the chamber to defend itself from enemies. How could the study of biology help scientists design spacecraft?

Spacecraft Landing

The ski type runners for Santa's sleigh work well on Earth for sliding over snow and water but they would be little help in space or on rough and rugged surfaces on Earth.

Spacecraft land on wheels, water, or on landing pods. An example of a spacecraft which lands on wheels in the NASA shuttle. The early NASA manned spacecraft programs known as Mercury and Gemini had craft which descended from orbit using heat shields and parachutes to slow the final descent into the ocean. The first spacecraft to land on the Moon had four legs with four landing pod-like feet at the bottom of each leg. The landing craft's descent engine fired in a retro or reverse direction to slowly drop the lunar lander to the Moon's surface.

If the landing surface is smooth and sandy, Santa's sleigh runners would work fine. In fact, some space vehicles designed to land on flat surfaces of Mars use ski-like runners for landing.


1. Why didn't Neil Armstrong's lunar landing vehicle have runners like Santa uses?

2. If the NASA shuttle landed on water, how would you redesign its landing system? Draw your redesign on a picture of the shuttle landing.

Space Satellites and Probes

The satellite beside Santa's sleigh might be there to receive messages from Santa's workshop at the North Pole. Satellites are used for radio and television communication on Earth. By pointing a TV transmitter at the satellite, a television signal can be reflected off the satellite's antenna to a distant location on Earth thousands of miles from the Earth transmitter's location. Three satellites placed at selected orbits of 22,300 miles above the Earth can cover the entire Earth with a television signal.

When a rocket places a scientific instrument in an Earth orbit, the instrument is called an Earth satellite. When a rocket carries a scientific instrument on a journey to another planet, the instrument is a space probe. The instrument is probing for new knowledge of the distant planets of the Solar System.


1. Which type of scientific instrument would be used to find the following information? An Earth satellite or space probe?
a. what the weather will be like tomorrow
b. a view of the Olympic games held in a foreign country
c. a volcano erupting on Io, a satellite of Jupiter
d. the amount of ozone in the Earth's atmosphere
e. the amount of hydrogen in Jupiter's atmosphere

2. Why does NASA send probes to the planets instead of men? Discuss the advantages and disadvantages.

Santa's Spacesuit

Santa's red and fluffy suit might be ideal to keep him warm at the North Pole, but Santa would not be very comfortable in space wearing his suit. Compare Santa's spacesuit to those worn by astronauts. First, Santa has no space helmet or oxygen pack for breathing in space. Without oxygen, Santa, could not survive in space. This is certainly an error. Next, astronauts' suits have specially designed cooling features. Their underwear has small tubes which circulate cooling fluid over their entire body. Multilayers of insulating specially designed fabric serve as the suit's material. While Santa's suit has cotton and wool, astronauts have insulated suits to protect their bodies from the extreme hot and cold temperatures of space.


1. Draw a picture of a suit Santa could use in space. Include a helmet, oxygen pack, as well as Santa's familiar hat and red color. Should Santa shave before putting on his helmet?

2. Do Santa's reindeer need suits also? Explain. If they do need a suit, design a reindeer spacesuit and helmet.