Page 43 - Curriculum Visions Dynamic Book

propulsion system The motors or rockets and their tanks designed to give a launcher or space vehicle the thrust it needs.
trajectory The curved path followed by a projectile.
The Apollo project
The project to reach the Moon was called Apollo (after Apollo, the god of light).
It involved a very powerful launcher called Saturn V (see page 20). It was needed because the spacecraft it was to launch into a lunar trajectory weighed 50 tonnes.
The Apollo spacecraft, consisting of the command module (CM) and service module (SM) (together known as the CSM), as well as the lunar module (LM), had to
have sufficient rocket power to land and take off from the Moon’s surface as well as to send itself into another suitable trajectory for reentering the Earth’s atmosphere. To save the extra power required in getting a large spacecraft off the Moon’s surface, only the lunar module was used in the descent to the Moon. It was nicknamed “Eagle.” While the LM descended to the Moon, the CSM continued to orbit the Moon.
The command module was the spacecraft’s control centre. It was designed to be big enough to house three astronauts. It was cone-shaped, 3.7 metres high, 4 metres in diametre, and weighed about 4,500 kilograms.
The service module was fitted below the command module. It was 3.9 metres in diametre and 6.7 metres long. Its purpose was to house the propulsion system that would make any course corrections, would retrofire rockets to put the spacecraft into lunar orbit, and later would send the spacecraft out of lunar orbit and into a path that would return it to the Earth.
The lunar module was positioned between the service module and the Saturn V launch vehicle. It was the part of the spacecraft that would carry two astronauts on the short journey from the lunar orbit to the surface of the Moon. When their surface explorations were over, it would then return them to the command module. The lunar module was about 6.4 metres high and 3.4 metres in diametre, and weighed 13,600 kilograms.
 Apollo takeoff.
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