Apollo 13 used its Lunar Module as a lifeboat after an onboard accident.
Apollo 13 launched on April 11, 1970, intending to make the third crewed lunar landing. About two days into the flight, an oxygen tank in the Service Module exploded. The damage crippled the spacecraft’s electrical power, oxygen supply and propulsion systems, making the Command Module unsafe for the journey home.
Mission Control instructed astronauts Jim Lovell, Jack Swigert and Fred Haise to power down the Command Module and move into the Lunar Module Aquarius. The LM had been designed to support two people on the lunar surface for a limited stay, not three astronauts during a long emergency return. Engineers and controllers therefore improvised procedures to conserve power, water and oxygen.
The crew looped around the Moon on a free-return trajectory rather than entering lunar orbit, then transferred back into the Command Module shortly before reentry. Aquarius was jettisoned before splashdown on April 17. Apollo 13’s landing was aborted, but the lifeboat strategy brought all three astronauts safely home.