Scott J. Kelly

2017_summer_tca_-_pbs_-_day_2_46395.jpg

Beth Hoppe, chief programming executive, PBS, from left, and astronauts Scott Kelly and Jessica Meir participate in the "Beyond a Year in Space" panel during the PBS Television Critics Association Summer Press Tour at the Beverly Hilton on Monday, July 31, 2017, in Beverly Hills, Calif. (Photo by Richard Shotwell/Invision/AP)

2017_summer_tca_-_pbs_-_day_2_29656.jpg

Astronaut Scott Kelly participates in the "Beyond a Year in Space" panel during the PBS Television Critics Association Summer Press Tour at the Beverly Hilton on Monday, July 31, 2017, in Beverly Hills, Calif. (Photo by Richard Shotwell/Invision/AP)

SpaceStation.jpg

Expedition 46 Commander Scott Kelly of NASA, Flight Engineer Tim Kopra of NASA and Flight Engineer Tim Peake of the European Space Agency wished the people of Earth a Happy New Year. Kelly is 9 months into a year-long mission, Kopra and Peake arrived Dec. 15 to begin a six-month mission.

7429e830b7885f1f7c0f6a70670039a3.jpg

FILE - In this Wednesday, March 4, 2015 photo provided by NASA, astronaut Scott Kelly sits inside a Soyuz simulator at the Gagarin Cosmonaut Training Center (GCTC) in Star City, Russia. On Thursday, July 16, 2015, a piece of space junk forced the three International Space Station astronauts, including Kelly, to seek emergency shelter in their Soyuz spacecraft docked to the station, in case they had to make a quick getaway. (Bill Ingalls/NASA via AP)

79e86f5a35ed980d710f6a7067000dc2.jpg

In this photo provided by NASA, astronaut Scott Kelly sits inside a Soyuz simulator at the Gagarin Cosmonaut Training Center (GCTC), Wednesday, March 4, 2015 in Star City, Russia. On Saturday, March 28, 2015, Kelly and cosmonaut Mikhail Kornienko will travel to the International Space Station to begin a year-long mission living in orbit. (AP Photo/NASA, Bill Ingalls)

553f221cda797714550f6a706700af2b.jpg

FILE - In this July 25, 2012 file photo, Mark Kelly, retired NASA astronaut and commander of mission STS-134, briefs the media at the European Organization for Nuclear Research in Meyrin near Geneva, Switzerland. Mark and his twin Scott Kelly are taking part in an unprecedented study of identical twins looking into the effects of prolonged weightlessness. Mark will undergo tests on Earth while his brother Scott will embark on a one-year space station stint. (AP Photo/Keystone/Martial Trezzini, File)

461540d1da787714550f6a70670015ab.jpg

FILE - In this Oct. 3, 2010 file photo, astronaut Scott Kelly crew member of the mission to the International Space Station, ISS, looks on in a museum at the Russian leased Baikonur cosmodrome, Kazakhstan. Scott and his twin Mark Kelly are taking part in an unprecedented study of identical twins looking into the effects of prolonged weightlessness. Mark will undergo tests on Earth while his brother Scott will embark on a one-year space station stint. (AP Photo/Dmitry Lovetsky, File)

eb7f2fc4da777714550f6a706700ec81.jpg

FILE - In this May 28, 2008 file photo, space shuttle Discovery commander Mark Kelly, right, gestures as he walks with his twin brother, astronaut Scott Kelly, left, and mission specialist Ron Garan, after arrival at Kennedy Space Center in Cape Canaveral, Fla. Scott and his twin Mark are taking part in an unprecedented study of identical twins looking into the effects of prolonged weightlessness. Mark will undergo tests on Earth while Scott will embark on a one-year space station stint. (AP Photo/Terry Renna, File)

9601ce6eda767714550f6a70670032ac.jpg

FILE - In this Oct. 8, 2010 file photo, U.S. astronaut Scott Kelly, a crew member of the mission to the International Space Station, accompanied by his brother Mark Kelly, right, walks before the launch of the Soyuz-FG rocket at the Russian-leased cosmodrome in Baikonur, Kazakhstan. Scott and his twin Mark are taking part in an unprecedented study of identical twins looking into the effects of prolonged weightlessness. Mark will undergo tests on Earth while Scott will embark on a one-year space station stint. (AP Photo/Dmitry Lovetsky, File)

48f03e48da757714550f6a7067001ea5.jpg

FILE - This undated file photo provided by NASA shows astronauts Mark Kelly, right, and Scott Kelly in the check-out facility at Ellington Field near NASA's Johnson Space Center in Houston. Scott and his twin Mark are taking part in an unprecedented study of identical twins looking into the effects of prolonged weightlessness. Mark will undergo tests on Earth while his brother Scott will embark on a one-year space station stint. (AP Photo/NASA, File)

1c9f9dea734fe2094d0f6a7067009fdd.jpg

This undated photo provided by NASA, astronauts Mark Kelly, right, STS-124 commander, and Scott Kelly are pictured in the check-out facility at Ellington Field near NASA's Johnson Space Center in Houston. NASA announced Friday, March 7, 2014, that Mark Kelly and astronaut Scott Kelly will participate in 10 different investigations. Craig Kundrot, deputy chief scientist of NASA's Human Research Program, says in a news release that the brothers provide a unique opportunity to study two people with the same genetics who were in different environments. Officials say Scott Kelly spent a year in space while Mark Kelly was on Earth. NASA says it is hoping the studies can be the basis for future research initiatives. (AP Photo/NASA)

20121126-191227-pic-89506781.jpg

U.S. astronaut Scott Kelly (left) and Russian cosmonaut Mikhail Kornienko will spend a year on the International Space Station beginning in 2015 to provide a medical foundation for future missions beyond low-Earth orbit. Mr. Kelly’s twin, Mark, is a retired astronaut married to former Rep. Gabrielle Giffords. (Gagarin Cosmonaut Training Center via NASA, Associated Press)

Space_Twins.sff.jpg

In this Thursday, March 17, 2010 picture, Expedition 26 Commander Scott Kelly, left, is reunited with his twin brother, Mark Kelly following a flight back to Ellington Field in Houston from Kustanai, Kazakhstan. Scott Kelly landed in Kazakhstan on March 16 with his Russian crewmates in the Soyuz TMA-01M spacecraft after 159 days in space, 157 days on the International Space Station. Mark Kelly is in the final weeks of training as Commander of the final flight of Endeavour, STS-134, that will spend more than a week docked to the ISS. Endeavour is targeted for launch on April 19, 2011. (AP Photo/NASA, Rob Navias)