The Gagarin Cosmonaut Training Center (GCTC) aircraft is seen parked at the Kraini Airport after flying Expedition 43 NASA Astronaut Scott Kelly, Russian Cosmonauts Mikhail Kornienko, center, and Gennady Padalka of the Russian Federal Space Agency (Roscosmos) from Star City, Russia, Saturday, March 14, 2015, Baikonur, Kazakhstan. The trio are preparing for launch to the International Space Station in their Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time. As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit: (NASA/Victor Zelentsov)

Well wishers welcome Expedition 43 NASA Astronaut Scott Kelly, Russian Cosmonauts Gennady Padalka and Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos) after as they arrive in Baikonur, Kazakhstan, Saturday, March 14, 2015. The trio are preparing for launch to the International Space Station in their Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time. As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit: (NASA/Victor Zelentsov)

Expedition 49 backup crew members Mark Vande Hei of NASA, left, Alexander Misurkin, center, and Nikolai Tikhonov of Roscomos, left, report to Russian space officials after arriving in Baikonur, Kazakhstan on Friday, Oct. 7, 2016. The trio are preparing for launch to the International Spacestation in their Soyuz MS-02 spacecraft from the Baikonur Cosmodrome in Kazakhstan on October 19, 2016. Photo Credit: (NASA/Victor Zelentsov)

Expedition 49 crew members Shane Kimbrough of NASA, left, Sergey Ryzhikov, center, and Andrey Borisenko of Roscosmos, left, exit the Gagarin Cosmonaut Training Center (GCTC) aircraft after arriving in Baikonur, Kazakhstan on Friday, Oct. 7, 2016. The trio are preparing for launch to the International Space Station in their Soyuz MS-02 spacecraft from the Baikonur Cosmodrome in Kazakhstan on October 19, 2016. Photo Credit: (NASA/Victor Zelentsov)

Expedition 49 crew members Shane Kimbrough of NASA, left, Sergey Ryzhikov, center, and Andrey Borisenko of Roscosmos, left, pose for a picture after arriving in Baikonur, Kazakhstan on Friday, Oct. 7, 2016. The trio are preparing for launch to the International Spacestation in their Soyuz MS-02 spacecraft from the Baikonur Cosmodrome in Kazakhstan on October 19, 2016. Photo Credit: (NASA/Victor Zelentsov)

Expedition 49 backup crew members Mark Vande Hei of NASA, left, Alexander Misurkin, center, and Nikolai Tikhonov of Roscomos, left, exit the Gagarin Cosmonaut Training Center (GCTC) aircraft after arriving in Baikonur, Kazakhstan on Friday, Oct. 7, 2016. The trio are preparing for launch to the International Spacestation in their Soyuz MS-02 spacecraft from the Baikonur Cosmodrome in Kazakhstan on October 19, 2016. Photo Credit: (NASA/Victor Zelentsov)

Expedition 43 NASA Astronaut Scott Kelly, left, Russian Cosmonauts Gennady Padalka, center, and Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos) are welcomed by officials after arriving in Baikonur, Kazakhstan, Saturday, March 14, 2015. The trio are preparing for launch to the International Space Station in their Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time. As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit: (NASA/Victor Zelentsov)

Expedition 43 NASA Astronaut Scott Kelly, left, Russian Cosmonauts Gennady Padalka, center, and Mikhail Kornienko of the Russian Federal Space Agency (Roscosmos) exit the Gagarin Cosmonaut Training Center (GCTC) aircraft after arriving in Baikonur, Kazakhstan, Saturday, March 14, 2015. The trio are preparing for launch to the International Space Station in their Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan March 28, Kazakh time. As the one-year crew, Kelly and Kornienko will return to Earth on Soyuz TMA-18M in March 2016. Photo Credit: (NASA/Victor Zelentsov)