Apollo 13's total mission duration was six days, rounded to the nearest day.
The spacecraft launched on April 11, 1970, and splashed down in the Pacific Ocean on April 17. The precise elapsed time was about 142 hours 54 minutes, or 5 days, 22 hours, and 54 minutes, which rounds to six days.
Apollo 13 was intended to land in the Fra Mauro region, but an oxygen-tank explosion in the service module forced the crew to abandon the landing. Commander Jim Lovell, command module pilot Jack Swigert, and lunar module pilot Fred Haise used the lunar module Aquarius as a lifeboat.
The crew looped around the Moon before returning to Earth. Mission controllers conserved power, water, and oxygen through a series of improvised procedures. Because the mission lasted nearly six days rather than its planned lunar-landing profile, summaries may quote either the exact duration or the rounded figure.