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Space exploration
Exploring the moon


Human beings enter space

Immediately after the LM touched down, the astronauts performed a complete check to make sure that the landing had not damaged any equipment. Then they prepared to go outside. Armstrong and Aldrin had worn space suits during the landing. They transferred their air hoses from a cabin supply to their backpack units, then released the air from the cabin and opened a small hatch below their front windows. First Armstrong and then Aldrin crawled backward through the hatch. They descended a ladder mounted on one of the LM's legs to a wide pad at the base of the leg. A television camera mounted on the side of the LM sent blurred images of the astronauts back to Earth. Armstrong stepped off the pad onto the moon and said, "That's one small step for a man, one giant leap for mankind." Most of the huge TV audience did not hear Armstrong say the word a before man because of a gap in the transmission.

The astronauts had no trouble adjusting to the weak lunar gravity. They found rocks and soil samples and photographed their positions before picking them up. The astronauts also set up automatic science equipment on the moon. Meanwhile, from the orbiting CSM, Collins conducted various scientific observations and took photographs.

Returning to Earth. The LM's descent stage served as a launch pad for the ascent stage liftoff. To lighten the spacecraft, the crew left all extra equipment behind, including backpacks and cameras. The ascent stage rocketed into orbit, where it linked up with the waiting CSM. The astronauts transferred samples and film into the CSM, then cast off the LM ascent stage. The crew fired the on-board rocket again to push the CSM out of lunar orbit and set their course for Earth.

The CM splashed down in the Pacific Ocean on July 24. NASA immediately put the lunar material, the astronauts, and all equipment that had been exposed to the lunar environment into isolation. The purpose of the isolation, which lasted about 17 days for the astronauts, was to determine whether any germs or other harmful material had been brought from the moon. Nothing harmful was found.

The second flight to the moon was as successful as the first. The Apollo 12 LM made a precision landing on the lunar surface on Nov. 19, 1969. Astronauts Charles (Pete) Conrad, Jr., and Alan L. Bean walked to a landed space probe, Surveyor 3, and retrieved samples for study.

The flight of Apollo 13, which was supposed to result in the third lunar landing, almost ended in disaster. The flight, from April 11 to 17, 1970, became a mission to save the lives of three astronauts-James A. Lovell, Jr., Fred W. Haise, Jr., and John L. Swigert, Jr.

During the spacecraft's approach to the moon, one of the two oxygen tanks in the SM exploded. The blast also disabled the remaining tank. The tanks provided both breathing oxygen and fuel for the electrical power systems of the CM and the SM. Moments later, Swigert reported "OK, Houston, we've had a problem."

After the explosion, flight controllers at Mission Control in Houston quickly realized that the astronauts probably did not have enough oxygen and battery power to get them back to Earth. The flight controllers ordered the crew to power up the LM, which was still docked with the CSM. The crew then shut down the CSM, saving its power supply until power would be needed for descent to Earth. The LM had its own power and oxygen supplies, but it was not designed to support three astronauts. The astronauts used only minimal electric power during the 3-day return trip to Earth, and all three of them survived.

A NASA investigation later determined the cause of the tank explosion. Months before the launch, wires leading to a fan thermostat inside the tank had been tested at too high a voltage. As a result, the wire's insulation had burned off. When the fan was turned on during the flight, the wires short-circuited. The short caused a fire in the pure oxygen environment of the tank, resulting in the explosion. The blast blew off one side of the SM and broke the feed line to the other tank.

Contributor: James Oberg, M.S., Spaceflight Engineer; author, UFOs and Outer Space Mysteries.
Source : World Book 2005

Space exploration
What is space?
Getting into space and back
Living in space
Meeting basic needs in space
Communicating with Earth
The dawn of the space age
Space probes
Probes to Venus
Probes to Jupiter and beyond
Probes to comets
Human beings enter space
Apollo: Mission to the moon
Exploring the moon
Returning to Earth
The International Space Station
Space shuttles
Types of shuttle missions