NASA’s Space Shuttle Program concluded in 2011 with three final missions to the International Space Station. Each mission carried supplies and equipment that will sustain the space station crews until NASA’s new Commercial Resupply Service providers take over this role.
Shuttle Discovery launched the STS-133 mission on Feb. 24, carrying the retrofitted, Italian-built multipurpose logistics module (MPLM) “Leonardo” to the space station. On May 16, Endeavour launched STS-134 and, along with supplies and equipment, brought the Alpha Magnetic Spectrometer-2 (AMS) to the space station. The AMS is a particle physics experiment module designed to search for unusual matter by measuring cosmic rays. STS-135 launched on July 8, making the space shuttles’ final delivery of supplies to the space station. Just before returning to Earth, STS-135 Commander Chris Ferguson presented the station’s crew with a U.S. flag flown on the first space shuttle mission, STS-1, in April 1981. The flag will remain displayed aboard the station until the next crew launched from the U.S. retrieves it for return to Earth so it can be carried by the first crew launched from the U.S. on a journey of exploration beyond low-Earth orbit.