PHOTOS: Best of Scott Kelly's #YearInSpace pics

- Space superman Scott Kelly's yearlong mission is one for the NASA history books.

The NASA astronaut has been living at the International Space Station since last March. By the time he lands in Kazakhstan on Tuesday, he will have spent 340 consecutive days in space, a U.S. record.

Kelly will have completed 5,440 laps around the planet. Logged 143.8 million miles. Welcomed nine visiting spacecraft. Shared the place with 14 other humans, including his roommate for the long haul, Russian cosmonaut Mikhail Kornienko, also returning to Earth.

He drank nearly 200 gallons of recycled urine and sweat, collected from himself and everyone else on board.

He snapped hundreds of breathtaking pictures of the home planet and posted them on Instagram and Twitter as @StationCDRKelly, not to be confused with ShuttleCDRKelly, retired astronaut Mark Kelly, his identical twin. The brothers have taken part in an unprecedented twins study over the past year.

The 52-year-olds say they're proud to have served as guinea pigs for future Mars expeditions. For NASA, getting astronauts to Mars in 20 years is what this yearlong mission is all about.'

PHOTOS: Click through the gallery above. You can slide the thumbnails over for more photos.

Up Next:

Up Next

  • PHOTOS: Best of Scott Kelly's #YearInSpace pics
  • SpaceX 1st: Recycled rocket soars with recycled capsule
  • 'Mannequin Skywalker' rides Blue Origin's new crew capsule
  • Annual Geminid meteor shower to appear in a sky near you
  • NASA's most requested photo, the ‘Blue Marble', turns 45
  • Blowing in the wind: NASA video shows global view of atmosphere's swirls
  • Mini-shuttle glides to safe landing in desert test flight
  • In Tampa stop, year-in-space astronaut shares his ups and downs
  • Puerto Rican astronaut gets double dose of hurricanes
  • NOAA video shows 2017 solar eclipse shadow over the United States