Apollo 13 and its still attached Saturn V third stage (called the S-IVB) were thoroughly checked while in orbit. At 3:48 p.m., the astronauts sent their first telecast from space, a five-minute program which included a description of their view of the cloud-covered Eastern United States. S-IVB was re-ignited at 4:48 p.m. EST to give Apollo 13 its final boost toward the Moon. A check of systems after shutdown of the S-IVB showed that all were operating satisfactorily.
At 5:20 p.m. EST, Odyssey separated from the adapter that connected it with the S-IVB. Simultaneously, the four panels that made up the sides of the adapter fell away, exposing Aquarius, the Apollo 13 Lunar Module. The Lunar Module is designed principally for landing two men on the Moon, serving as a shelter and base during the short lunar expedition, and later returning the astronauts to the Command/Service Module, waiting in lunar orbit.
After separating Odyssey from the adapter, the astronauts moved out about 60 feet ahead of S-IVB. Then they turned Odyssey around and docked it nose-to-nose with Aquarius. They backed their craft and the attached Aquarius away from the S-IVB. By 6:14 p.m., they had freed Aquarius and turned their three-module spacecraft around to head for the Moon. Most of the transposition and docking maneuvers were telecast live to Earth in a 72-minute program that began about 5:30 p.m.
Also shown on TV was the maneuver that sent the S-IVB on a separate path to crash on the Moon as a scientific experiment, designed to add to knowledge about the make-up of the Moon. This turned out to be the only successful lunar experiment of Apollo 13.
The path of Apollo 13 was so true that a scheduled course adjustment was cancelled as unnecessary. No major mission event was scheduled until 8:54 p.m., Sunday, when a hybrid transfer was initiated. This rerouted the craft to sweep within 70 miles of the Moon rather than the approximately 115-mile altitude of the earlier course. The change was designed to put Aquarius in the right place at the right time for the desired lunar landing site. The hybrid transfer also meant that Apollo 13 could return to Earth only by another course adjustment. On the earlier course, called a free return trajectory, Apollo could swing around the Moon and return to Earth Without using any additional rocket power.
The hybrid transfer, conducted for all the world to see on TV, was so accurate that a scheduled subsequent maneuver was unnecessary.
Another major event on Sunday threw a usually cool and calm astronaut into a mild panic. In the rush to substitute for Mattingly, Swigert forgot to file his Federal Income Tax return.
"How do I apply for an extension ?" he asked. Amid laughter from Mission Control, he sought to explain: "Things kinda happened real fast down there and I need an extension. I'm really serious. Would you..."
Joe Kerwin, the capsule communicator, was unsympathetic: "You're breaking up the room down here."
Swigert continued: "... turn it in ?"
Later, Flight Director Glynn Lunney said that American citizens out of the country get a 60-day extension on filing. "I assume this applies," he added.
On Monday evening at 9:15 p.m. EST, Lovell and Haise entered the pressurized Aquarius for the first time. Among other things, Mission Control wanted them tocheck an Aquarius helium tank that had shown a slightly high pressure on the launch pad. Lovell found that the pressure in the tank was showing the kind of rise expected.
Haise remarked that "One of the nice things for a novice like myself is the ease of moving around in here."
The two spent about an hour inside of Aquarius, telecasting their activities to Earth. The show ended, and all was well.
Haise was still in Aquarius. Lovell was in the tunnel between Aquarius and Odyssey, clutching a camera and gingerly making his way among the wires. Swigert was in Odyssey. Suddenly, they were startled by a loud bang.
At first, Lovell and Swigert thought that Haise had released a valve, as planned, in Aquarius. But Haise, now back in the CM, and scanning the instrument panel, saw that one of the main electrical systems of Apollo 13 was deteriorating. Just before 10:10 p.m., Swigert radioed the words that drew mankind together in a common concern: "Hey, we've got a problem here."