Monday is the last full day for Scott Kelly on board the International Space Station.

Kelly hands over command of the ISS on Monday and on Tuesday he returns to Earth.

Both Kelly and Russian Cosmonaut Mikhail Kornienko have spent nearly a year on board the space station.

When they arrive back on Earth Tuesday in a Soyuz capsule, they will have spent 340 days in space.

That’s a record for an American astronaut and a big accomplishment in NASA’s overall goal to send humans to the red planet.

“Our time here has demonstrated not only the capability of us to stay in space for a long time and to do well,” said Kelly, “but also the capability of the ground teams to support us and the systems that keep us alive and the resupply and do this in a way that is forward thinking towards a potential flight to Mars.”

NASA is using this year long mission in space to understand how the mind and body are impacted by long duration missions in microgravity.

Scott’s mission isn’t over when he returns to Earth.

He’ll continue to provide samples to NASA, helping compare his results to his twin brother’s.

But first things first when Scott returns back to land.

“I’m looking forward to fresh food, like a salad believe it or not,” said Scott Kelly.

The astronaut says he’s also looking forward to spending time with family and friends.

He says he also can’t wait for fresh air, a breeze, the sun on his face and running water.

Work will continue on the International Space Station.

NASA Astronaut Jeff Williams is preparing to launch next month from Kazakhstan.

What NASA is looking for from the Kelly twins

Scott’s twin brother and former astronaut Mark Kelly is helping as well back on Earth.

“I provide data, and that data is sometimes somebody comes to my house in Tucson, a phlebotomist from NASA will come and take 30 tubes of blood, saliva samples, urine and other things.”

In this video from NASA's Johnson Space Center, learn more about what scientists are looking for in samples from the Kelly twins.