Haise was lunar module pilot for Apollo 13, April 11-17, 1970. Apollo 13 was scheduled for a ten-day mission for the first landing in the hilly, upland Fra Mauro region of the moon. The original flight plan, however, was modified en route to the moon due to a failure of the service module cryogenic oxygen system which occurred at approximately 55 hours into the flight. Haise and fellow crewmen, James A. Lovell (spacecraft commander) and John L. Swigert (command module pilot), working closely with Houston ground controllers, converted their lunar module "Aquarius" into an effective lifeboat. Their emergency activation and operation of lunar module systems conserved both electrical power and water in sufficient supply to assure their safety and survival while in space and for the return to earth.