A astronaut is heading home soon after nearly a year away.

FOX's Chris Foster reports:

Scott Kelly leaves the International Space Station Tuesday.

He'll have spent 340 consecutive days in space, the most for an American astronaut:

(Kelly) "Yeah I could go another 100 days, I could go another year if I had to. It would just depend on what I was doing and if it made sense, although I do look forward to getting home here next week."

Kelly, speaking to reporters from the International Space Station, one last time.

NASA scientists want to know how so much time in space might affect astronauts going to Mars:

(Kelly) "A loss of connection with folks on the ground that you care for and love and you want to spend time with that I think is a challenge. Obviously, going to Mars there are a lot of other challenges, but none of these that we can't overcome."

Chris Foster, FOX News.

Follow Scott Kelly's journey from space on Twitter: @StationCDRKelly