Michael Collins stayed in lunar orbit while Neil Armstrong and Buzz Aldrin walked on the Moon during Apollo 11.
Collins was the mission’s command module pilot. He remained alone aboard Columbia while Armstrong and Aldrin descended in the lunar module Eagle to the Sea of Tranquility on 20 July 1969. Collins had to maintain the command module’s systems, prepare for rendezvous, and remain ready to help recover the crew if the lunar module could not return.
Columbia passed behind the Moon during each orbit, temporarily cutting Collins off from radio contact with Earth. He completed about 30 lunar orbits and searched for Eagle as it sat on the surface. After Armstrong and Aldrin lifted off, Collins piloted the rendezvous and docking that reunited all three astronauts.
This division of duties was essential to Apollo’s lunar-orbit-rendezvous plan: two astronauts landed while one remained with the spacecraft needed for the journey home. Collins had already flown on Gemini 10 in 1966 and later became one of the 24 Apollo astronauts to reach lunar distance. He died in 2021 at age 90.