and the second woman to command a space shuttle mission, after Eileen Collins. Melroy was pilot of the Discovery space shuttle mission to expand the International Space Station (ISS) in October 2000; this expansion opened the door for future assembly missions and prepared the station for its first resident crew. In October 2002, she also piloted the Atlantis flight to the ISS, where a truss was installed; it took three space walks to outfit and activate the new component, and Melroy acted as internal spacewalk choreographer during the mission; this mission was also the first to use a camera on the External Tank, providing a live view of the launch to flight controllers and NASA TV viewers. In October 2007, Melroy served as the mission commander on STS-120; during the mission, the Harmony node was delivered to the ISS (which opened up the capability for future international laboratories to be added to the station), an emergency seven-hour spacewalk was performed to repair a torn solar array, and Expedition 16 Commander Peggy Whitson joined Melroy to make space history as the first simultaneous female commanders of the shuttle and space station. Melroy was selected as an astronaut in 1994 and left NASA in 2009. During her career, she logged over 38 days in space.
In 2014, the National Conference for College Women Student Leaders honoured Melroy with a Woman of Distinction award, which recognizes women who have made a difference for others.