Apollo 9 was the first crewed flight of the Lunar Module — the spacecraft that would carry astronauts to the surface of the Moon. Launched on March 3, 1969, from Kennedy Space Center’s LC-39A atop a Saturn V rocket, it carried Commander James McDivitt, Command Module Pilot David Scott, and Lunar Module Pilot Rusty Schweickart on a 10-day Earth orbital mission to test every system needed for a lunar landing.

The mission’s defining moment came on flight day 5 when McDivitt and Schweickart separated the Lunar Module “Spider” from Scott’s Command Module “Gumdrop” and flew independently for over six hours. They fired the descent engine, jettisoned the descent stage, and ignited the ascent engine — simulating the exact rendezvous sequence planned for a Moon landing. It was the first time two crewed American spacecraft flew simultaneously, and the successful rendezvous and docking proved the LM could get astronauts off the lunar surface and back to the command module.

Schweickart also performed an EVA on flight day 4, stepping outside Spider to test the Portable Life Support System (PLSS) backpack and the lunar spacesuit in the vacuum of space. This was the same suit and backpack that would be worn on the Moon. Despite Schweickart experiencing motion sickness earlier in the mission, the EVA was a success and validated the equipment for lunar surface operations.

Apollo 9 splashed down on March 13, 1969, in the North Atlantic Ocean and was recovered by the USS Guadalcanal. The mission proved that all Apollo hardware worked together flawlessly in space, clearing the way for Apollo 10’s lunar dress rehearsal and Apollo 11’s historic Moon landing just four months later.