A Soyuz capsule carrying International Space Station (ISS) crew members U.S. astronaut Scott Kelly, Russian cosmonauts Sergei Volkov and Mikhail Korniyenko descends beneath a parachute near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Ground personnel carry Russian cosmonaut Mikhail Korniyenko shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Ground personnel help International Space Station (ISS) crew member Scott Kelly of the U.S. to get off the Soyuz TMA-18M space capsule after landing near the town of Dzhezkazgan, Kazakhstan, Wednesday, March 2, 2016. (Photo by Krill Kudryavtsev/Pool Photo via AP Photo)





U.S. astronaut Scott Kelly (R) and Russian cosmonauts Sergei Volkov (C) and Mikhail Korniyenko, surrounded by ground personnel, rest shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Russian cosmonaut Mikhail Korniyenko speaks shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Ground personnel help Russian cosmonaut Sergei Volkov to get out of a Soyuz capsule shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





In this handout provided by NASA, The Soyuz TMA-18M spacecraft landing site is seen through the window of an arriving Russian MI-8 helicopter after Expedition 46 Commander Scott Kelly of NASA and Russian cosmonauts Mikhail Kornienko and Sergey Volkov of Roscosmos landed in their capsule on March 2, 2016 near the town of Zhezkazgan, Kazakhstan. Kelly and Kornienko completed an International Space Station record year-long mission to collect valuable data on the effect of long duration weightlessness on the human body that will be used to formulate a human mission to Mars. Volkov returned after spending six months on the station. (Photo by Bill Ingalls/NASA via Getty Images)





International Space Station (ISS) crew member Scott Kelly of the U.S. reacts after landing near the town of Dzhezkazgan, Kazakhstan, on March 2, 2016. US astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko returned to Earth on March 2 after spending almost a year in space in a ground-breaking experiment foreshadowing a potential manned mission to Mars. (Photo by Kirill Kudryavtsev/AFP Photo)





Medics check Russian cosmonaut Mikhail Korniyenko shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Russian cosmonaut Mikhail Korniyenko is seen inside a Soyuz capsule shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Members of a search and rescue team work at the site of landing of a Soyuz capsule carrying International Space Station (ISS) crew members U.S. astronaut Scott Kelly, Russian cosmonauts Sergei Volkov and Mikhail Korniyenko near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





U.S. astronaut Scott Kelly (R) and Russian cosmonauts Sergei Volkov (C) and Mikhail Korniyenko, surrounded by ground personnel, rest shortly after landing near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Bill Ingalls/Reuters/NASA)





A member of a search and rescue team works at the site of landing of the Soyuz TMA-18M spacecraft, which carried International Space Station (ISS) crew members U.S. astronaut Scott Kelly, Russian cosmonauts Sergei Volkov and Mikhail Korniyenko near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Members of a search and rescue team work at the site of landing of the Soyuz TMA-18M spacecraft, which carried International Space Station (ISS) crew members U.S. astronaut Scott Kelly, Russian cosmonauts Sergei Volkov and Mikhail Korniyenko near the town of Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)





Members of NASA support team help International Space Station (ISS) crew member astronaut Scott Kelly of the U.S. to get off a helicopter, who arrived from the landing site to an airport in Dzhezkazgan (Zhezkazgan), Kazakhstan, March 2, 2016. (Photo by Kirill Kudryavtsev/Reuters)