Apollo 9 was the first mission to test a crewed lunar module in Earth orbit.
Launched on March 3, 1969, Apollo 9 carried James McDivitt, David Scott, and Rusty Schweickart. Its central goal was to demonstrate that the command module, service module, and lunar module could operate together before an actual lunar mission.
The crew practiced separating and docking the lunar module, nicknamed Spider, with the command module, Gumdrop. Schweickart also performed a spacewalk to test equipment and procedures intended for lunar surface operations. The lunar module’s ascent and descent stages were tested in space, including an independent flight away from the command module.
Apollo 7 had tested the Apollo command and service modules but did not carry a lunar module. Apollo 8 orbited the Moon without one, while Apollo 10 tested a lunar module in lunar orbit as a rehearsal for landing. Apollo 9 therefore provided the first complete crewed test of the landing spacecraft in Earth orbit.