Apollo Guidance ComputerThe Apollo Guidance Computer (AGC) was a digital computer produced for the Apollo program that was installed on board each Apollo command module (CM) and Apollo Lunar Module (LM). The AGC provided computation and electronic interfaces for guidance, navigation, and control of the spacecraft. The AGC was the first computer based on silicon integrated circuits. The computer's performance was comparable to the first generation of home computers from the late 1970s, such as the Apple II, TRS-80, and Commodore PET.
Rocket engineA rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordance with Newton's third law. Most rocket engines use the combustion of reactive chemicals to supply the necessary energy, but non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Vehicles propelled by rocket engines are commonly called rockets.
Liquid-propellant rocketA liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid propellants. Gaseous propellants may also be used but are not common because of their low density and difficulty with common pumping methods. Liquids are desirable because they have a reasonably high density and high specific impulse (Isp). This allows the volume of the propellant tanks to be relatively low.
Apollo command and service moduleThe Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship, which carried a crew of three astronauts and the second Apollo spacecraft, the Apollo Lunar Module, to lunar orbit, and brought the astronauts back to Earth.
Trans-lunar injectionA trans-lunar injection (TLI) is a propulsive maneuver used to set a spacecraft on a trajectory that will cause it to arrive at the Moon. The first space probe to attempt TLI was the Soviet Union's Luna 1 on January 2, 1959 which was designed to impact the Moon. The burn however didn't go exactly as planned and the spacecraft missed the Moon by more than three times its radius and was sent into a heliocentric orbit. Luna 2 performed the same maneuver more accurately on September 12, 1959 and crashed into the Moon two days later.
Moon landingA Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon. This includes both crewed and robotic missions. The first human-made object to touch the Moon was the Soviet Union's Luna 2, on 13 September 1959. The United States' Apollo 11 was the first crewed mission to land on the Moon, on 20 July 1969. There were six crewed U.S. landings between 1969 and 1972, and numerous uncrewed landings, with no soft landings happening between 22 August 1976 and 14 December 2013.
Multistage rocketA multistage rocket or step rocket is a launch vehicle that uses two or more rocket stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or attached next to each other. Two-stage rockets are quite common, but rockets with as many as five separate stages have been successfully launched.
