Apollo Lunar Module

The Apollo Lunar Module was a two-stage spacecraft that carried astronauts between lunar orbit and the Moon’s surface. Its descent stage landed on the Moon, while its ascent stage returned the crew to lunar orbit.

Descent stage: The lower stage of the Apollo Lunar Module, which powered the landing and remained on the lunar surface. Its engine slowed the spacecraft for landing, and its structure served as the ascent stage’s launch platform.
Apollo program: The NASA human spaceflight program that sent astronauts to the Moon between 1969 and 1972. The Lunar Module was developed specifically to carry out Apollo’s crewed lunar landings.
Apollo 11: The 1969 Apollo mission that first landed humans on the Moon. Its Lunar Module, Eagle, made the first crewed lunar landing.
Apollo command and service module: The Apollo spacecraft that carried astronauts between Earth and lunar orbit and returned them to Earth. Unlike the Lunar Module, it was built to survive atmospheric reentry and remain in lunar orbit.
Ascent stage: The crewed upper stage of the Apollo Lunar Module, which lifted off from the Moon and returned astronauts to lunar orbit. It separated from the descent stage and carried the crew back to the command module.
John Houbolt: A NASA engineer who advocated lunar-orbit rendezvous as the architecture for crewed Moon missions. His persistent advocacy helped establish the mission plan that required a dedicated lunar lander.
Apollo 12: The second crewed Apollo mission to land astronauts on the Moon, in November 1969. Its lander demonstrated a precision landing near the Surveyor 3 spacecraft.
Lunar Gateway: A planned crew-tended space station in lunar orbit intended to support future lunar exploration. It represents a different approach to lunar operations, using an orbital outpost rather than an Apollo-style lander alone.
Apollo Lunar Module Ascent Engine: The rocket engine that propelled the Apollo Lunar Module’s ascent stage from the Moon into lunar orbit. Its fixed-thrust engine had to deliver a reliable lunar liftoff without a backup engine.
Grumman Aircraft Engineering Corporation: The American aerospace company that designed and built the Apollo Lunar Module. Grumman developed the lander under contract to NASA and became closely associated with its nickname, the Lunar Excursion Module.

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