# Expedition 20

Expedition 20 was the 20th long-duration flight to the International Space Station. The expedition marked the first time a six-member crew inhabited the station. Because each Soyuz-TMA spacecraft could hold only three people, two separate launches were necessary: Soyuz TMA-14 launched on 26 March 2009, and Soyuz TMA-15 followed on 27 May 2009.
Soyuz TMA-15 launched from Baikonur Cosmodrome at 10:34 UTC on 27 May 2009. The vehicle docked with the station on 29 May 2009, officially changing the Soyuz TMA-14 crew from Expedition 19 to Expedition 20.
Gennady Padalka was the first commander of a six-member station crew, and the first commander of two consecutive expeditions (Expedition 19 and 20). Nicole Stott was the final expedition astronaut to be launched on the shuttle.
During the expedition, Koichi Wakata performed a special experiment wherein he did not change his underpants for one month, in order to test a specially-designed underwear without washing or changing; he reportedly did not develop body odor due to the effects of the special garment.
The station would not be permanently occupied by six crew members all year. For example, when the Expedition 20 crew (Roman Romanenko, Frank De Winne and Bob Thirsk) returned to Earth in November 2009, for a period of about two weeks only two crew members (Jeff Williams and Max Surayev) were aboard. This increased to five in early December, when Oleg Kotov, Timothy Creamer and Soichi Noguchi arrived on Soyuz TMA-17. It decreased to three when Williams and Surayev departed in March 2010, and finally returned to six in April 2010 with the arrival of Soyuz TMA-18, carrying Aleksandr Skvortsov, Mikhail Korniyenko and Tracy Caldwell Dyson.

## Crew

| Position | First Part (May to July 2009) | Second Part (July to August 2009) | Third Part (August to October 2009) |
| Commander | Gennady Padalka, RSA Third spaceflight | Gennady Padalka, RSA Third spaceflight | Gennady Padalka, RSA Third spaceflight |
| Flight Engineer 1 | Michael Barratt, NASA First spaceflight | Michael Barratt, NASA First spaceflight | Michael Barratt, NASA First spaceflight |
| Flight Engineer 2 | Frank De Winne, ESA First spaceflight | Frank De Winne, ESA First spaceflight | Frank De Winne, ESA First spaceflight |
| Flight Engineer 3 | Roman Romanenko, RSA First spaceflight | Roman Romanenko, RSA First spaceflight | Roman Romanenko, RSA First spaceflight |
| Flight Engineer 4 | Robert Thirsk, CSA Second and last spaceflight | Robert Thirsk, CSA Second and last spaceflight | Robert Thirsk, CSA Second and last spaceflight |
| Flight Engineer 5 | Koichi Wakata, JAXA Third spaceflight | Timothy Kopra, NASA First spaceflight | Nicole Stott, NASA First spaceflight |

## Backup crew

* Maksim Surayev, Commander
* Jeff Williams
* Timothy Creamer
* Catherine Coleman
* André Kuipers
* Dimitri Kondratyev
* Chris Hadfield

## Extra-vehicular activity

| Mission | Spacewalkers | Start (UTC) | End (UTC) | Duration |
| Expedition 20 EVA 1 ‡ | Gennady Padalka Michael R. Barratt | 5 June 2009 7:52 | 5 June 2009 12:46 | 4 hours, 54 minutes |
| Prepared the Zvezda service module transfer compartment for the arrival of the Poisk module, installed docking antenna for the module, photographed antenna for evaluation on the ground, and photographed the Strela-2 crane. ||||
| Expedition 20 EVA 2 | Gennady Padalka Michael R. Barratt | 10 June 2009 6:55 | 10 June 2009 7:07 | 12 minutes |
| Internal spacewalk in the depressurised Zvezda transfer compartment, to replace one of the Zvezda hatches with a docking cone, in preparation for the docking of the Poisk module later in 2009. Poisk docked automatically to the zenith port of Zvezda on 12 November 2009, and serves as an additional docking port for Russian vehicles. ||||
‡ denotes spacewalks performed from the Pirs docking compartment in Russian Orlan suits.
On 3 July 2009 expedition members undocked the Soyuz TMA-14 craft from the aft port of the Zvezda service module and piloted it over to the Pirs docking compartment. This was done to clear the way for the arrival of a Progress supply craft.
* The Expedition 20 crew lands in Arkalyk, Kazakhstan