Twins In Space: NASA's Twin Astronauts Mark and Scott Kelly (Photos)

Astronaut Double Take: Identical Twins Headed for Space Station

Twin brothers Scott Kelly and Mark Kelly, both NASA astronauts, were once set to meet in space in 2011. Mark commanded the last mission of the space shuttle Endeavour, STS-134, while Scott led the International Space Station's Expedition 26 mission. The shuttle mission was delayed beyond Scott's time on the station, so they ultimately never met up in space. Now the twin astronauts are volunteering for science experiments as Scott Kelly prepares for a one-year mission. [Read the Full Story]

NASA's Astronaut Twins, Scott and Mark Kelly

Scott Kelly, left, and his identical twin brother Mark pose for a photo at the Cosmonaut Hotel in Baikonur, Kazakhstan on March 26, 2015, one day before Scott was scheduled to launch on a one-year mission to the International Space Station.

NASA's Kelly Brothers: Identical Twin Astronauts

NASA Astronauts Mark Kelly and Scott Kelly, identical twins, are pictured participating in the Joint STS-134, Expedition 25 and Expedition 26 International Space Station Emergency Scenario training. At the time, both Kelly brothers planned to be at the space station at the same time for a joint 2011 shuttle-station mission.

Kelly Twins

Astronauts Mark Kelly (right) and Scott Kelly are pictured in the check-out facility at Ellington Field near NASA's Johnson Space Center.

Mark Kelly and Scott Kelly

Astronauts Mark Kelly, STS-134 Commander, and Scott Kelly, Expedition 26 Commander. [Read the Full Story]

NASA's Kelly Astronaut Twins Reunited

NASA astronaut Scott Kelly (left), Expedition 26 commander, is reunited with his twin brother, Mark Kelly on March 17, 2011, following a flight back to Ellington Field, Houston from Kustanay, Kazakhstan. Scott Kelly landed in Kazakhstan on March 16 with his Russian crewmates in the Soyuz TMA-01M spacecraft after 159 days in space. [Read the Full Story]

NASA Astronaut Scott Kelly

Scott Kelly will spend a year on the International Space Station. Some of his work will involve comparison experiments with his twin brother and former astronaut, Mark Kelly, who will be on Earth. Image uploaded on Aug. 12, 2013. [Read the Full Story]

Back on the Planet

Expedition 26 commander Scott Kelly, wearing a turquoise wristband in honor of sister-in-law Gabrielle Giffords, looks out the window of a Russian Search and Rescue helicopter before the two hour helicopter ride to Kustanay, Kazakhstan shortly after he and fellow crew members Oleg Skripochka and Alexander Kaleri landed in their Soyuz TMA-01M capsule near the town of Arkalyk, Kazakhstan on Wednesday, March 16, 2011. [Read the Full Story]

Astronaut Twins Headed to Space

Twin brothers Scott Kelly and Mark Kelly, both NASA astronauts, were once set to meet in space in 2011. Mark commanded the last mission of the space shuttle Endeavour, STS-134, while Scott led the International Space Station's Expedition 26 mission. The shuttle mission was delayed beyond Scott's time on the station, so they ultimately never met up in space. Now the twin astronauts are volunteering for science experiments as Scott Kelly prepares for a one-year mission. [Read the Full Story]

Astronaut Mark Kelly on the Space Shuttle

Astronaut Mark Kelly takes a moment for a photo near the commander's station on the forward flight deck of Space Shuttle Discovery during the STS-124 mission.

Astronaut Mark Kelly at 2012 State of the Union

Former NASA astronaut Mark Kelly applauds President Barack Obama after the 2012 State of the Union address. Kelly sat with First Lady Michelle Obama in the First Lady's box during the president's speech while his wife, Arizona Congresswoman Gabrielle Giffords, attended on the floor of the House chamber on Jan. 24, 2012.