High Quality Content by WIKIPEDIA articles! Soyuz TMA-21 ("Gagarin") was a Soyuz flight to the International Space Station (ISS). It transported three members of the Expedition 27 crew to the ISS, and docked at the station on April 6, 2011. TMA-21 is the 109th flight of a Soyuz spacecraft, the first of which launched in 1967. The Soyuz remained attached to the space station as a lifeboat, throughout the remainder of Expedition 27 and through the end of Expedition 28, and returned to Earth on September 16, 2011.