The Soyuz TMA-20M spacecraft is seen as it lands with Expedition 48 crew members NASA astronaut Jeff Williams, Russian cosmonauts Alexey Ovchinin, and Oleg Skripochka of Roscosmos near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The Soyuz TMA-20M spacecraft is seen as it lands with Expedition 48 crew members NASA astronaut Jeff Williams, Russian cosmonauts Alexey Ovchinin, and Oleg Skripochka of Roscosmos near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Expedition 48 NASA astronaut Jeff Williams rest in a chairs outside the Soyuz TMA-20M spacecraft a few moments after he and Russian cosmonauts Alexey Ovchinin and Oleg Skripochka of Roscosmos landed in a remote area near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The Soyuz TMA-20M spacecraft is seen as it lands with Expedition 48 crew members NASA astronaut Jeff Williams, Russian cosmonauts Alexey Ovchinin, and Oleg Skripochka of Roscosmos near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The Soyuz TMA-20M spacecraft is seen as it lands with Expedition 48 crew members NASA astronaut Jeff Williams, Russian cosmonauts Alexey Ovchinin, and Oleg Skripochka of Roscosmos near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The Soyuz TMA-20M spacecraft is seen as it lands with Expedition 48 crew members NASA astronaut Jeff Williams, Russian cosmonauts Alexey Ovchinin, and Oleg Skripochka of Roscosmos near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Russian Search and Rescue teams arrive at the Soyuz TMA-20M spacecraft shortly after it landed with Expedition 48 crew members NASA astronaut Jeff Williams, Russian cosmonauts Alexey Ovchinin, and Oleg Skripochka of Roscosmos near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Russian cosmonaut Alexey Ovchinin of Roscosmos rest in a chair outside the Soyuz TMA-20M spacecraft a few moments after he and NASA astronaut Jeff Williams, and Russian cosmonaut Oleg Skripochka of Roscosmos landed in a remote area near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA astronaut Jeff Williams, left, Russian cosmonaut Alexey Ovchinin of Roscosmos, center, and Russian cosmonaut Oleg Skripochka of Roscosmos are seen inside the Soyuz TMA-20M spacecraft a few moments after they landed in a remote area near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA astronaut Jeff Williams, left, Russian cosmonaut Alexey Ovchinin of Roscosmos, center, and Russian cosmonaut Oleg Skripochka of Roscosmos sit in chairs outside the Soyuz TMA-20M spacecraft a few moments after they landed in a remote area near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Russian cosmonaut Oleg Skripochka of Roscosmos rest in a chair outside the Soyuz TMA-20M spacecraft a few moments after he and NASA astronaut Jeff Williams, and Russian cosmonaut Alexey Ovchinin of Roscosmos landed in a remote area near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 7, 2016(Kazakh time). Williams, Ovchinin, and Skripochka are returning after 172 days in space where they served as members of the Expedition 47 and 48 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

The Soyuz TMA-20M rocket launches from the Baikonur Cosmodrome in Kazakhstan on Saturday, March 19, 2016 carrying Expedition 47 Soyuz Commander Alexey Ovchinin of Roscosmos, Flight Engineer Jeff Williams of NASA, and Flight Engineer Oleg Skripochka of Roscosmos into orbit to begin their five and a half month mission on the International Space Station. (Photo Credit: NASA/Aubrey Gemignani)

The Soyuz TMA-20M rocket launches from the Baikonur Cosmodrome in Kazakhstan on Saturday, March 19, 2016 carrying Expedition 47 Soyuz Commander Alexey Ovchinin of Roscosmos, Flight Engineer Jeff Williams of NASA, and Flight Engineer Oleg Skripochka of Roscosmos into orbit to begin their five and a half month mission on the International Space Station. (Photo Credit: NASA/Aubrey Gemignani)

Commander Jeff Williams poses for a photo in the Quest Airlock (A/L) with all of his mission patches. The patches are, from left, STS-101, Soyuz TMA-8, Expedition 13, Soyuz TMA-16, Expedition 21, Expedition 22, Soyuz TMA-20M, Expedition 47, and Expedition 48.

PHOTO DATE: 3-18-16 LOCATION: Bldg 30 - FCR-1 SUBJECT: Expedition 47 flight control team during launch of Expedition 47-48 Crew (Ovchinin, Skripochka, J. Williams) on the Soyuz TMA-20M spacecraft from the Baikonur Cosmodrome in Kazakhstan PHOTOGRAPHER: Lauren Harnett

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmember Jeff Williams of NASA is seen in his seat through a window on the Soyuz TMA-20M spacecraft March 4 as he and his crewmates conducted a “fit check” dress rehearsal during pre-launch training. Williams and Alexey Ovchinin and Oleg Skripochka of Roscosmos will launch March 19, Kazakh time, for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmember Jeff Williams of NASA is seen in his seat through a window on the Soyuz TMA-20M spacecraft March 4 as he and his crewmates conducted a “fit check” dress rehearsal during pre-launch training. Williams and Alexey Ovchinin and Oleg Skripochka of Roscosmos will launch March 19, Kazakh time, for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

Aboard their Gagarin Cosmonaut Training Center aircraft, Expedition 47-48 crewmembers Jeff Williams of NASA (left) and Alexey Ovchinin (center) and Oleg Skripochka (right) of Roscosmos affix a sticker of their crew patch to the wall of the cabin as they flew from their training base to the Baikonur Cosmodrome in Kazakhstan March 3. The trio will launch March 19, Kazakh time, in their Soyuz TMA-20M spacecraft for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmembers Jeff Williams of NASA (left) and Alexey Ovchinin (center) and Oleg Skripochka (right) of Roscosmos pose for pictures March 4 in front of the scaffolding surrounding their Soyuz TMA-20M spacecraft during final pre-launch training. The trio will launch March 19, Kazakh time, for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

ISS047e011906 (03/19/2016) --- NASA and Russian cosmonauts arrive at the international space station Mar 19, 2016. NASA astronaut Jeff Williams and Russian cosmonauts Alexey Ovchinin and Oleg Skripochka docked to the International Space Station in their Soyuz TMA-20M spacecraft. They will spend 6 months onboard the station carrying out scientific experiments, performing maintenance and other duties.

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmembers Jeff Williams of NASA (left) and Alexey Ovchinin (center) and Oleg Skripochka (right) of Roscosmos pose for pictures March 4 in front of their Soyuz TMA-20M spacecraft during final pre-launch training. The trio will launch March 19, Kazakh time, for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmember Jeff Williams of NASA flashes a smile as he suits up in his Russian Sokol launch and entry suit March 4 during final pre-launch training. Williams and Alexey Ovchinin and Oleg Skripochka of Roscosmos will launch March 19, Kazakh time, on the Soyuz TMA-20M spacecraft for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmember Jeff Williams of NASA strikes a thoughtful look in his Russian Sokol launch and entry suit March 4 during leak checks of the suit as part of pre-launch training. Williams and Alexey Ovchinin and Oleg Skripochka of Roscosmos will launch March 19, Kazakh time, on the Soyuz TMA-20M spacecraft for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center

In the Integration Facility at the Baikonur Cosmodrome in Kazakhstan, Expedition 47-48 crewmembers Jeff Williams of NASA (left) and Alexey Ovchinin (center) and Oleg Skripochka (right) of Roscosmos pose for pictures March 4 in front of their Soyuz TMA-20M spacecraft during final pre-launch training. The trio will launch March 19, Kazakh time, for a six-month mission on the International Space Station. Courtesy of Gagarin Cosmonaut Training Center