Expedition 21 was the 21st long-duration mission to the International Space Station (ISS).

The expedition began on 11 October 2009, with Frank de Winne becoming the first ESA astronaut to command a space mission.

Soyuz TMA-16 brought the final members of Expedition 21 to the ISS, along with space tourist Guy Laliberté.

Nicole P. Stott was the last ISS expedition crew member to fly on the Space Shuttle.

This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.