Apollo 13 was the seventh crewed mission in the Apollo space program and the third intended to land on the Moon. The craft was launched on April 11, 1970, from Kennedy Space Center, but the lunar landing was aborted after an oxygen tank in the service module (SM) exploded two days into the mission. The crew instead looped around the Moon, and returned safely to Earth on April 17, 1970, six days after launch. The mission was commanded by Jim Lovell with Jack Swigert as Command Module Pilot (CMP) and Fred Haise as Lunar Module Pilot (LMP). Swigert was a late replacement for the original CMP Ken Mattingly, who was grounded by the flight surgeon after exposure to German measles.
The explosion was caused by accidental ignition of damaged wire insulation inside an oxygen tank during a routine tank stirring operation. The accident resulted in a rapid loss of all oxygen in the service module, which was necessary for breathable air and for generating electrical power for the command module (CM). The command module's power had to be shut down to conserve its remaining resources for reentry, forcing the crew to transfer to the lunar module (LM) to power up its life support and navigational systems. These circumstances mandated an abort of the lunar landing and new procedures to bring the crew back to Earth alive.
Although the LM was designed to support two men on the lunar surface for two days, Mission Control in Houston drafted new procedures so it could support three men for four days. The crew experienced great hardship caused by limited power, loss of cabin heat, shortage of potable water, and the critical need to make makeshift repairs to the carbon dioxide removal system.
The flight passed the far side of the Moon at an altitude of 254 kilometers (137 nautical miles) above the lunar surface, and 400,171 km (248,655 mi) from Earth, a spaceflight record marking the farthest humans have traveled from Earth. The story of the Apollo 13 mission has been dramatized multiple times, most notably in the 1995 film Apollo 13.