For nearly a year, American astronaut Scott Kelly has been living and working at the International Space Station (ISS), with no running water.

　　He told reporters Thursday that it is like camping in the woods for a year. He said the fact that everything floats up there, makes daily life "more difficult."

　　It is "somewhat of a harsh environment" he said. "You don't feel perfectly normal." He and his Russian partner, Mikhail Kornienko, are scheduled to return to Earth March 1. They will travel in a Russian spacecraft and land in Kazakhstan.

　　Kelly said that he feels "pretty good" physically, and that he could go another 100 days, or longer, "if I had to."

　　But the first thing he said he will do after NASA tests him, is jump in his pool in Houston, Texas.

　　He said the hardest part of the journey has been being isolated physically from people on the ground who are important to him.

　　He says it has been a privilege to be on the ISS.

　　"The space station here is a magical place. it's an incredible science facility we have. It's a privilege to fly here. And it's something that I hope more people will have the opportunity to do in the future. You know I think we will just a matter, it's just a matter of time."

　　Kelly and Kornienko's station-record -- 340 days -- is twice as long as a regular mission. The science behind the one-year mission was critical for NASA's Journey to Mars program. The space agency hopes to send humans to Mars by the 2030s. They are hiring people now to be astronauts on a Mars mission.

　　As a veteran of four space flights, Kelly thinks going to Mars is possible.

　　"I think there's nothing that we can't accomplish that we don't, you know, put our minds and resources behind. So, after being here for so long that's one thing I definitely realized you know, If we can dream it we can do it if we really want to."

　　After they touch down on Earth, Kelly said they will be carried in special chairs to a nearby tent. There, they will undergo tests to see what condition their bodies are in after spending that time in space.

　　Biological studies began a year before the two men left Earth. Biological samples were collected and assessments were performed, to be used as a baseline.

　　For comparison, samples were taken during their time at the space station. They will continue for a year or more after their return to Earth.

　　Kelly's identical twin brother, former NASA astronaut Mark Kelly, participated in parallel twin studies on Earth to give scientists more ways to study human space flight.

　　Some questions will be how to deal with bone loss and radiation. Those will be issues for travelers to the planet Mars because the trip will take at least six months.

　　They will need to grow plants for food along the way. While in space, Scott Kelly and his fellow astronauts grew, and then ate, lettuce. They also grew flowers. That is important because some vegetable plants, like tomatoes, begin as flowers.

　　Also important are the psychological and performance challenges. How will people handle living together in a small space? This is critical for crew traveling to Mars.

　　Kelly said it is important to offer private areas to astronauts for a trip to Mars. His space on the ISS was basically a box "the size of a phone booth."

　　The astronaut said he got through the long time by taking it in milestones. For example, he would look to the next crew change, with astronauts leaving and coming. Or the next science experiment.

　　And the last milestone before heading home? It was doing major maintenance on the ISS water system. That happened yesterday.

　　Over the last year, Kelly has taken beautiful pictures of the Earth and sent them out on social media. After looking down on the planet, he said, "The more I look at it... the more I feel like an environmentalist." He said there are "definite areas where the Earth is covered in pollution all the time," and "unexpected storms." He said "this is a human effect... not naturally occurring."

　　"We can fix that if we put our minds to it," Kelly said.

　　Asked for advice for kids who want to be astronauts, Kelly said they need to be experts in a technical field. It is important do what you like, he said. People also need to be well-rounded, because being an astronaut is many jobs in one. Engineer, medical doctor, plumber and pilot are just some of the jobs an astronaut must perform.

　　In the end, 20 years down the road, Scott Kelly said it's not the view or floating in space or "riding the rocket" of which he will be most proud. The thing he likes about the job is doing something he feels "very passionate" about, the extremely hard work.

　　I'm Anne Ball.

　　Anne Ball wrote this story. Kathleen Struck was the editor

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