The Expedition 39 crew returned to Earth Tuesday after 188 days in space, completing a journey of over 79 million miles and more than 3,000 orbits of the Earth since launching to the International Space Station back in November.
The Soyuz TMA-11M spacecraft carrying Expedition 39 Commander Koichi Wakata of the Japan Aerospace Exploration Agency, Soyuz Commander Mikhail Tyurin of Roscosmos, the Russian Federal Space Agency and Flight Engineer Rick Mastracchio of NASA landed in the steppe of Kazakhstan southeast of Dzhezkazgan at 9:58 p.m. (7:58 a.m. Wednesday, Kazakh time). Helicopters carrying the Russian recovery teams and NASA personnel reached the landing site shortly afterward to assist the crew and conduct medical examinations.
The Soyuz undocked from the Rassvet module on the Earth-facing side of the station at 6:36 p.m. as the station soared 261 statute miles over Mongolia. The 4-minute, 41-second deorbit burn beginning at 9:04 p.m. slowed the Soyuz for its decent into the Earth’s atmosphere and its parachute-assisted landing.
The undocking marked the end of Expedition 39 and the start of Expedition 40 under the command of NASA astronaut Steve Swanson. Wakata, the first Japanese commander of the station, passed the helm of the orbiting complex over to Swanson during a change of command ceremony Monday afternoon. After making their final farewells, Wakata, Mastracchio and Tyurin boarded their Soyuz, and the crews closed the hatches between the vehicles at 3:26 p.m. Tuesday.
Samples from the ongoing microbiome investigation also returned to Earth on the Soyuz TMA-11M. The microbiome study looks at the impact of space travel on the immune system and on human microbiomes – microbes living in and on the human body at any given time. Samples from crew members’ bodies and the space station environment are taken periodically to monitor changes in the immune system and microbiomes. The results of this study may add to research on health impacts to people who live and work in extreme environments on Earth, and help with research on early disease detection, metabolic function and immune system deficiency.
Mastracchio now has logged 228 days in space during four missions. Wakata also now has four missions and has accumulated 348 days in space. Tyurin now has logged 532 days in space during three missions and is 13th on the all-time endurance list.
During Expedition 39, the crew participated in a variety of research, including a human immune system activation and suppression study and a protein crystal growth research study looking for proteins responsible for Huntington's disease and other neurodegenerative conditions. The crew also installed a new plant growth chamber designed to expand in-orbit food production capabilities.
Expedition 39 also saw the arrival of three cargo spacecraft to the orbiting complex -- a Russian Progress resupply vehicle, Orbital Sciences' Cygnus cargo ship and SpaceX Dragon.
Mastracchio performed three contingency spacewalks during his stay aboard the station. The first two were to remove and replace a faulty cooling pump, and the third to remove and replace a failed backup computer relay box.
The space station is more than a scientific research platform. It also serves as a test bed to demonstrate new technology. With the arrival of SpaceX-3, the Expedition 39 crew unloaded new climbing legs for NASA's Robonaut 2 humanoid robot. Designed to take over routine and potentially dangerous tasks from astronauts, Robonaut will take its first steps toward mobility after the legs are attached and tested in the coming months. Ground controllers using the station's robotic arm also installed a new high-definition Earth-viewing camera system, referred to as HDEV, on the outside of the Columbus lab. HDEV is comprised of four commercially available HD cameras and streams online live video of Earth to online viewers around the world.
Swanson and his crewmates, Alexander Skvortsov and Oleg Artemyev of Roscosmos, will operate the station as a three-person crew for two weeks until the arrival of three new crew members -- Reid Wiseman of NASA, Max Suraev of Roscosmos and Alexander Gerst of the European Space Agency. The trio of new flight engineers, who are wrapping up pre-flight activities in Star City, Russia, will fly to the Baikonur Cosmodrome in Kazakhstan on Thursday to begin the homestretch of preparations for their May 28 launch to the station.