Spectators look at a self-made rocket model ascending during a show in front of the Peter and Pawel Fortress in St. Petersburg April 10, 2011. People marked the upcoming Day of Aviation and Cosmonautics and the 50th anniversary of Yuri Gagarin's historic first space flight celebrated on April 12. [Photo/Agencies]

A self-made rocket model, launched by students of the Siberian State Aerospace University, ascends near a monument of the Cosmos-3 rocket carrier which is 32.4 metres (105 feet) high, in the centre of Russia's Siberian city of Krasnoyarsk April 10, 2011. Students marked the upcoming Day of Aviation and Cosmonautics and the 50th anniversary of Yuri Gagarin's historic first space flight celebrated on April 12. The words on the rocket read: 'Space'. [Photo/Agencies]