The docking of the Soyuz vehicle to the Zarya module of the space station will be the start of Expedition 20 and also be the inauguration of the long-awaited presence of a six-person crew on the station. These three crewmembers will be joining the Increment 19 crew (Padalka, Barrett and Wakata), who will also change from Expedition 19 to Expedition 20 crewmembers totaling a six person crew for Expedition 20. It also will mark the moment when all five partner agencies (NASA, ESA, CSA, JAXA and RSA) are represented by crewmembers on the orbiting laboratory.
Expedition 20 will be under the command of Padalka (who was also the Increment 19 commander). Romanenko, the Soyuz TMA-15 commander, will serve as a station flight engineer in his first flight into space. Thirsk is making his second flight into space, having flown aboard shuttle Columbia in 1996 on a Spacelab science mission. Thirsk will become the first Canadian to fly on a long-duration space flight. He is scheduled to return to Earth in the fall on shuttle Atlantis at the conclusion of the STS-129 mission. De Winne also is making his second flight into space.
Expedition 20 is comprised of the crew conducting a suite of science investigations as well as managing a multitude of spacecraft docking with the ISS.
Expedition 19 and 20 includes operating nearly 100 different experiments in human research, technology development; observing the Earth; and performing educational activities and biological and physical sciences aboard the ISS. The experiments have been prioritized based on fundamental and applied research needs established by NASA and the international partners – the Canadian Space Agency (CSA), the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA). Russia manages its experiments and requirements separately.
Within days of the arrival of Expedition 20, Padalka and Barratt are scheduled to complete two spacewalks in Russian Orlan spacesuits to add hardware and reposition equipment on the Pirs Docking Compartment in preparation for the Mini Research Module-2, or MRM-2, a new Russian docking and research module, later in the year.
The Orbiter Endeavour is targeted to launch mid Expedition 20, bringing the STS-127 mission to the station. This flight will deliver the Japanese Experiment Module-Exposed Facility and the Japanese Experiment Logistics Module-Exposed Section for the Kibo laboratory. The exposed section is a “front porch” on which experiments will be mounted for long-duration exposure to the environment in low Earth orbit. The shuttle also will deliver some spare parts for the station and install new batteries in the P6 Truss. The mission also will deliver NASA astronaut Tim Kopra, an Army colonel, to the complex to replace Wakata, who will return to Earth aboard Endeavour. Kopra is making his first flight into space and will remain on board the station until his return flight on Discovery’s STS-128 mission that will deliver his replacement, Nicole Stott. She will spend a little more than three months in orbit and is slated to return to Earth with Romanenko and De Winne on the Soyuz TMA-15, at the completion of Expedition 21.
After the STS-127 mission, the shuttle Discovery on its STS-128 mission will dock with the ISS. This flight will carry a Multipurpose Logistics Module, or MPLM, which will contain supplies and equipment necessary to maintain the six-person crew aboard the station. The crew will remove a materials processing experiment and a European science experiment mounted outside the Columbus module and will remove and replace an empty ammonia tank assembly during the mission's three spacewalks.
After Discovery docks, the Japan Aerospace Exploration Agency’s H-II Transfer Vehicle, or HTV, cargo craft will be launched from the Tanegashima Space Center in Japan and will fly just close enough to the ISS for the station’s arm to reach out and capture it. The arm will then be used to dock the HTV with the Earth-facing port of the Harmony node, where it will deliver approximately six tons of supplies for the crew. The HTV joins the Russian Progress and European Automated Transfer Vehicle as cargo vessels designed to keep the station supplied with critical hardware for day-to-day operations. After a month attached to the outpost, the Canadarm2 will unberth the HTV, enabling it to fire its engines to back away from the station and conduct a deorbit maneuver, allowing it to burn up in the Earth’s atmosphere.
NASA astronaut Jeff Williams, a retired Army colonel and station veteran, and cosmonaut Max Suraev, a Russian Air Force colonel, will launch from the Baikonur Cosmodrome on the Soyuz TMA-16, to replace Padalka and Barratt and begin Expedition 21 under De Winne’s command at the point at which Padalka and Barratt will return to Earth on the Soyuz TMA-14 craft.