By the Numbers: Astronaut Scott Kelly's Year in Space

PHOTO: US astronaut Scott Kelly gestures as his space suit is tested at the Russian-leased Baikonur cosmodrome, prior to blasting off to the International Space Station (ISS) on March 27, 2015. PlayKirill Kudryavtsev/Getty Images
WATCH Scott Kelly's Mission: 340 Days in Space

U.S. astronaut Scott Kelly will return to Earth this week after spending a year on the International Space Station.

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For most of us earthlings, 340 days in space is pretty hard to imagine. It entails:

  • 143,846,525 miles of space travel
  • 5,440 orbits
  • 10,260 sunrises and sunsets
  • 640 hours on a treadmill to stay in shape
  • 20 medical tests
  • The sunsets seem to be a favorite for Kelly, 52, who has become known for posting beautiful photos of them from orbit.

    This is Kelly's fourth mission, bringing his lifetime total to 520 days in space. NASA hopes the medical tests conducted on Scott Kelly and his twin brother, retired astronaut Mark Kelly, over the course of the mission will help them understand the effect of space travel on the body.

    Scott Kelly's journey home started Monday when he handed over command to fellow astronaut Tim Kopra.

    Kelly is expected to land in Kazakhstan tonight and return to Houston Wednesday.