The Apollo Program (US)
The aim of the Apollo program was to land the first person on the Moon, but they also went beyond landing Americans on the Moon and returning them safely to Earth. They included;
- Establishing the technology to meet other national interests in space.
- Achieving preeminence in space for the United States.
- Carrying out a program of scientific exploration of the Moon.
- Developing man's capability to work in the lunar environment.
When the program was announced, in 1961, only two people had actually been in space. Scientists were faced with a daunting task to construct a rocket powerful enough to reach the Moon and a spacecraft that could travel there and back leading them to develop the Saturn V rocket especially for the Apollo missions.
Saturn V Rocket
The Saturn V was developed at NASA's Marshall Space Flight Center in Huntsville, Ala. It was one of three types of Saturn rockets NASA built. Two smaller rockets, the Saturn I (1) and IB (1b), were used to launch humans into Earth orbit. The Saturn V sent them beyond Earth orbit to the moon.
The Saturn V rocket was 111 meters (363 feet) tall, about the height of a 36-story-tall building, and 18 meters (60 feet) taller than the Statue of Liberty. Fully fuelled for liftoff, the Saturn V weighed 2.8 million kilograms. The rocket generated 34.5 million newtons of thrust at launch, creating more power than 85 Hoover Dams. A car that gets 30 miles to the gallon could drive around the world around 800 times with the amount of fuel the Saturn V used for a lunar landing mission. It could launch about 118,000 kilograms (130 tons) into Earth orbit and about 43,500 kilograms (50 tons) to the moon.
How did it work
Saturn V comprised of 3 stages, each stage would burn its engines until it was out of fuel and would then separate from the rocket. The engines on the next stage would fire, and the rocket would continue into space. The first stage had the most powerful engines, since it had the challenging task of lifting the fully fuelled rocket off the ground. The first stage lifted the rocket to an altitude of about 68 kilometres (42 miles). The second stage carried it from there almost into orbit. The third stage placed the Apollo spacecraft into Earth orbit and pushed it toward the moon. The first two stages fell into the ocean after separation. The third stage either stayed in space or hit the moon.
Significant missions
Apollo 1
On Jan. 27, 1967, NASA experienced its first space disaster - the deaths of three astronauts during a training excercise for the Apollo 1 mission; Virgil I. Grissom, Edward H. White II, and Roger B. Chaffee. After over five hours of delays and problems, a spark inside the spacecraft ignited flammable material and instantly engulfed the closed compartment in flames. By the time the hatch was pried away more than five minutes later, the crew had died from asphyxiation. The precise source of the spark and fire was never determined; neither were any individuals or specific organisations implicated in the fire. In retrospect, the actual cause was due to the combination of several conditions: an oxygen-rich atmosphere; flammable interior materials such as paper, the space suits, velcro, and other flight equipment; a vast array of exposed internal wiring, which presented many potential sources of electrical sparks; and the design and manufacture of the spacecraft. As a result of the fire, many changes were made to the design, manufacturing, test, and checkout procedures of the vehicles and the management of the entire Apollo Program.
'There will be risks, as there are in any experimental programme, and sooner or later, we're going to ... lose somebody' Gus Grissom
Apollo 8
Apollo 8 was launched on December 21, 1968, and was the first manned mission to achieve lunar orbit. The crew of this six-day mission, Frank Borman, James A. Lovell, Jr. and William A. Anders, conducted a complete test of the command service module flight profile for lunar missions. The command service module entered lunar orbit on December 24, 1968, and orbited the moon for ten revolutions (20 hours 7 minutes) before returning to the earth and a controlled reentry into the Pacific Ocean.
Apollo 10
Apollo 10 was a dress rehearsal for a lunar landing mission and was conducted in lunar orbit, but it excluded the actual landing. Launched on May 18, 1969, the spacecraft Charlie Brown (CSM) and Snoopy (LM) spent over two days and 31 revolutions in lunar orbit. The crew of Thomas P. Stafford, John W. Young, and Eugene Andrew Cernan conducted all propulsive maneuvers required for a lunar landing mission.
During lunar orbit, Stafford and Cernan descended in the LM to within 14 km (18 mi) of the lunar surface before completing the first lunar orbit rendezvous with the CSM. This eight-day mission was recovered in the Pacific Ocean and was completed less than two months prior to the planned launch of the first lunar landing mission.
Apollo 11
Apollo 11 was the first mission in which humans landed on the Moon, walked on the lunar surface and returned to Earth. On 20 July 1969 2 astronauts (Apollo commander Neil A.Armstrong and lunar module pilot Edwin E, 'Buzz' Aldrin JR.) landed in the Mare Tranquilitatis (the Sea of Tranquility) on the Moon in the lunar module, while the command and service module piloted by Michael Collins continued in lunar orbit. During their stay on the Moon the astronauts set up scientific experiemnts, took photographs, and collected lunar samples. The lunar module (Eagle) spent 21 hours 36 minutes on the lunar surface, and the crew spent 2 hours 31 minutes outside the module in a local area excursion on foot to a distance of approximately 50m from the module (base) The lunar module took off from the Moon on 21 July and the astronauts returned to Earth on 24 July. As a precautionary measure, the astronauts were quarantined for 14 days.
Apollo 13
Apollo 13 was launched on April 11, 1970, as the third planned lunar landing mission. The crew of James A. Lovell, Jr., John L. Swigert, Jr. and Fred Wallace Haise, Jr. flew the spacecraft Odyssey (CSM) and Aquarius (LM). Two days after launch, as Apollo 13 approached the moon to begin lunar operations, an explosion occurred that caused the service module of the CSM to lose its oxygen, electrical power, and other systems, including its capability to perform an abort maneuver for a direct return to the earth. The crew quickly moved to the LM which became their lifeboat in space. All of the systems in the command module of the CSM, which remained functional, were deactivated to preserve its capability to reenter the atmosphere upon return to the earth. The LM had no heatshield and therefore could not be used for earth reentry.
At the time of the explosion, the return time to the earth was over four days. Because the LM did not have enough oxygen or water for this length of time, it became necessary to use the LM lunar landing engine for a major propulsive maneuver in space to change the spacecraft's path and speed its return to the earth. Overcoming numerous life-threatening problems, including near freezing temperatures and excess carbon dioxide in the LM, Apollo 13 successfully reentered the earth's atmosphere for a landing in the Pacific Ocean on April 17, 1970, over five days after launch.
The cause of the explosion was traced to a chain of events resulting in the ignition of the insulation covering a wire inside one of the three liquid oxygen tanks in the CSM. It occurred when a fan (to which the wire was connected) was turned on to stir the liquid oxygen inside the tank.
Sources
http://www.astronomytoday.com/exploration/apollo.html
http://www.nasa.gov/mission_pages/apollo/missions/index.html#.Uwp190J_vns
http://www.nasa.gov/audience/foreducators/rocketry/home/what-was-the-saturn-v-58.html#.Uwp8QEJ_vns
