Collins piloted two space shuttle missions, Discovery in February 1995 and Atlantis in May 1997, that involved rendezvous with the Russian space station Mir. She then led the Columbia mission launched in July 1999 to deploy the Chandra X-Ray Observatory, and in July–August 2005 commanded Discovery on the first space shuttle flight after the Columbia disaster of 2003. Collins was selected as an astronaut in 1990. She retired from NASA in May 2006, logging during her career over 872 hours in space.