Flight Engineer Sunita Williams made her first flight into space aboard the STS-116 mission to join Expedition Fourteen in progress. She replaced European Space Agency Astronaut Thomas Reiter as the third expedition crewmember on the station for her six-month mission. Williams remained in orbit with the Expedition Fifteen crew that arrived in April 2007. During her stay, she set a record for spacewalks by a female astronaut by conducting four excursions for a total of 29 hours and 17 minutes. Upon Williams' return with the STS-117 crew, she will have accumulated more time in space than any other woman.
During Space Shuttle Discovery's mission to the International Space Station, the STS-116 crew continued construction of the outpost adding the P5 spacer truss segment during the first of four spacewalks. The next two spacewalks rewired the station's power system, preparing it to support the station's final configuration and the arrival of additional science modules. A fourth spacewalk was added to allow the crew to retract solar arrays that had folded improperly.
Several Detailed Supplementary Objectives (DSOs) and Supplemental Medical Objectives (SMOs) were also flown during the STS-116 mission. DSOs and SMOs are space and life sciences investigations. Their purpose is to determine the extent of physiological deconditioning resulting from space flight, test countermeasures to those changes, and characterize the environment of the Space Shuttle and/or space station relative to crew health. Experiments performed during this mission were:
Space Shuttle Discovery returned to Kennedy Space Center in Florida on December 22nd bringing STS-116 to an end. This flight was the orbiter's 33rd mission and the 117th in the Shuttle program's history.