Onufrienko was selected as a cosmonaut candidate in 1989. From September 1989 to January 1991, he underwent a course of general space training. Starting April 1991, he underwent training as a member of test cosmonauts group. Starting March 1994, he entered flight training to be the commander of the stand-by crew of the
Mir-18 expedition aboard the
Soyuz TM-21 spacecraft and the
Mir space station as part of the
Shuttle-Mir program.
Mir EO-21 From February 21 to September 2, 1996, Onufrienko served as commander of the Mir EO-21 expedition. The
Soyuz TM-23 spacecraft carrying Onufrienko with cosmonaut
Yury Usachov lifted off from the
Baikonur Cosmodrome on February 21, 1996, at 12:34:05 UTC. After two days of autonomous flight, the Soyuz spacecraft docked with the Mir space station's forward-facing port on February 23 at 14:20 UTC. One month later, he and Yuri Usachov were joined by
NASA astronaut
Shannon Lucid. During Mir-21 Onufrienko performed numerous research experiments including Protein crystal growth experiments experiments in materials science using high temperature melting oven "Optizon". The new module
Priroda, the seventh and final module of the Mir Space Station arrived on April 26, 1996. Its primary purpose was to conduct Earth resource experiments through
remote sensing and to develop and verify remote sensing methods. During Mir EO-21 supplies arrived with the
Progress M-31 spacecraft. Onufrienko and Yuri Usachov were joined by French astronaut
Claudie André-Deshays after the departure of Shannon Lucid. On September 2, 1996, Onufrienko, Usachev and Claudie André-Deshays returned to Earth on board the Soyuz TM-23 capsule. The spacecraft landed at 07:41:40 UTC 108 km south west of
Akmola (Tselinograd). Altogether, on board Soyuz TM-23 and Mir, Onufrienko logged 193 days in space.
Expedition 4 Onufrienko again served as commander on ISS
Expedition 4. Onufrienko returned to space on board
STS-108 mission. Launched on December 5, 2001, at 22:19:28 UTC from the
Kennedy Space Center,
Endeavour docked with the
International Space Station (ISS) on December 7, 2001, at 20:03 UTC. The primary objective of STS-108 was to deliver supplies to and help maintain the ISS. During a -month stay aboard the ISS, the 3 member Expedition 4 crew (Onufrienko and NASA astronauts
Daniel W. Bursch and
Carl E. Walz) performed flight tests of the station hardware, conducted internal and external maintenance tasks, and developed the capability of the station to support the addition of science experiments. The
Expedition 4 crew returned to Earth aboard
STS-111, with
Endeavour landing at
Edwards Air Force Base, California, on June 19, 2002. In completing this mission, Onufrienko logged an additional 196 days in space, for a total of 389 days of spaceflight.
Spacewalks Onufrienko has performed eight career spacewalks totaling 42 hours and 33 minutes. As of June 2010, he has secured the
11th position in the list of astronauts who have the most spacewalk time. Onufrienko performed six spacewalks during his stay on board the Mir Space Station and performed another two during his visit to the ISS. Onufrienko performed his first career spacewalk on 15 March 1996. He and cosmonaut Usachov started the spacewalk at 01:04 UTC. They installed the second Strela boom and prepared for Mir Cooperative Solar Array (MCSA) installation. The spacewalk lasted 5 hours and 51 minutes. On 20 May 1996 Onufrienko performed his second career spacewalk. The spacewalk started at 22:50 UTC and ended at 04:10 UTC clocking 5 hours and 20 minutes. During the spacewalk, the two cosmonauts removed the Mir cooperative solar array (MCSA) from its stowed position on the exterior of the docking module at the base of the
Kristall module. They used the Strela boom to reach and move the array to the
Kvant-1 module. The two spacewalkers also inflated an aluminum and nylon pup-up model of a Pepsi Cola can, which they then filmed against the backdrop of Earth. The
Pepsi Cola company paid for the procedure and planned to use the film in a television commercial. However, the commercial never aired—reportedly because Pepsi later changed the design of the can. Onufrienko performed his third career spacewalk on 24 May 1996. He and cosmonaut Usachov started the spacewalk at 22:50 UTC. They installed the MCSA on the
Kvant-1 module. The spacewalk lasted 5 hours and 34 minutes. On 30 May 1996, Onufrienko ventured outside the Mir Space Station to conduct his fourth career spacewalk. He and cosmonaut Usachov started the spacewalk at 18:20 UTC. They installed the modular optoelectrical multispectral scanner (MOMS) outside
Priroda and handrails on the
Kvant-2 module to facilitate moving around outside the station during future extravehicular activities. MOMS was used to study the Earth's atmosphere and environment. The spacewalk lasted 4 hours and 20 minutes. On 6 June 1996, Onufrienko performed his fifth career spacewalk. He and Usachov installed micrometeoroid detectors and replaced cassettes in the Swiss/Russian Komza experiment and installed the Particle Impact Experiment, the Mir Sample Return Experiment, and the SKK-11 cassette, which exposed construction materials to space conditions. The spacewalk lasted 5 hours and 59 minutes. ==See also==