Scott Kelly Has Returned To Earth: Now, He’ll Help NASA Prep For A Future Mars Mission

After 340 days on the International Space Station, where he orbited the Earth 5,440 times, watched 11,000 sunrises and sunsets, and floated 144 million miles through space, astronaut Scott Kelly has finally come home.

And now that Scott Kelly is back on Earth — scheduled to arrive in Houston on Wednesday — he and twin brother Mark will become NASA guinea pigs as scientists try to understand the effect of long-term space travel on the mind and body in preparation for a journey to Mars.

Scott Kelly‘s trip back home started Tuesday afternoon, and he landed in Kazakhstan at about 11:30 p.m., NBC News reported. Kelly and his 340-day roommate, cosmonaut Mikhail Kornienko, were met with freezing temperatures when they opened their capsule, Fox News added.

Kelly said the cold air was “amazing,” but the homecoming was a little bittersweet for Scott, even though he was looking forward to it.

“I can’t say that it was a relief. Leaving the space station was bittersweet – I had been there for a long time and looked forward to leaving, but it is a remarkable place. A year is a long time – it felt like I had been up there my whole life my first six months. I am definitely encouraged in our ability to go even longer – if it was for the right reason, I could have stayed however long it took.”

Asked shortly after his arrival if he would consider flying into space again, Kelly said yes, “without a question.” Scott’s time on the ISS was his fourth space mission, and he’s racked up more time in space than any other American — 520 days total.

Scott Kelly’s latest mission will help NASA plan for longer trips. They’ll be studying Kelly and his earth-bound twin, Mark — a retired astronaut — to learn how living in space for long periods of time affects humans on both a physical and emotional level.

While on the ISS, Kelly conducted hundreds of experiments and scientists collected blood, saliva, and urine samples, underwent ultrasounds and bone scans, and more.

“I think that expanding our envelope and our ability to operate is something that will take us further from the planet. Developing technology to do so is very important for our economy and our way of life. By going to Mars one day, we will make things better for us here on Earth.”

NASA wants to send people to Mars by 2035, and the round trip voyage could take two-and-a-half years. Extensive research, therefore, is needed.

Scott Kelly has already suffered some of the effects: brittle bones, vision problems, the uncomfortable shifting of fluid in the body. The biggest concerns for NASA are the effects of living without gravity and with so much dangerous radiation.

Forbes contributor Bruce Lee listed the ill effects of space travel, all of which Scott Kelly is at risk of developing given his lengthy time on ISS and other missions. Doctors will be watching for all of these possible effects and comparing Kelly’s health to his brother’s.

They’ll be looking at the effect of weightlessness on Scott Kelly’s body: the loss of muscle mass from months not working against gravity; bone loss, because bones need gravity for growth; the effect on his height, because the discs of the spine can separate in space; and the movement of fluid to the upper parts of the body, which could affect the senses, and cause changes in the heart and the blood vessels that can lead to dizziness or fainting back on Earth. They’ll also keep an eye on Scott’s ticker, which didn’t work quite so hard while he was on ISS and could’ve weakened as a result.

Radiation exposure may have also messed with Scott Kelly’s immune system, increased his cancer risk, or damaged his brain to the point he could develop Alzheimer’s. The lack of sunlight could’ve also caused Scott to develop anxiety or depression, which would’ve have been helped by the unavoidable separation and isolation. As Lee put it, Scott Kelly will have to be reintroduced into society.

Scott Kelly will be studied for the next few years — he’ll take cognitive and memory tests, his microbiome will be examined, and his physical fitness put through the ringer. In effect, Scott’s journey will help NASA figure out if a journey to Mars is feasible, its dangers, and how to prepare.

[Photo by Bill Ingalls/AP]