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A retired NASA astronaut has said the "psychological stress" that results from being in space for a year is as damaging as the radiation he was exposed to each day.
Scott Kelly, who returned from the International Space Station in March, has also commented on the possible health issues he faces in the future as a result of the trip.
He said: “During my time in orbit, I lost bone mass, my muscles atrophied, and my blood redistributed itself in my body, which strained my heart.”
“Every day, I was exposed to 10 times the radiation of a person on Earth, which will increase my risk of a fatal cancer for the rest of my life,” he said, Geek Wire reported .
The 52-year-old added: “Not to mention the psychological stress, which is harder to quantify and perhaps as damaging.”
The comments come as part of an announcement that his memoir, “Endurance: My Year in Space and Our Journey to Mars” will be published in November 2017.
The book is to be co-authored by Margaret Lazarus Dean. The astronaut will also be launching a series of books about his space adventure for young readers.
Scott Kelly on pain of return Part of the motivation for Mr Kelly's year-long stint in space was for NASA to conduct tests to find out how the body responds to pro-longed weightlessness and radiation exposure. The information will be used in the eventual goal of humans reaching Mars.
This is not the first time Mr Kelly has spoken about the downsides of being in space. Before he left the station in March, he said : "Physically I feel pretty good but the hardest part is being isolated in the physical sense from people on the ground who are important to you."
"There's a loss of connection," he said.
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Before he retired from NASA on 1 April , he said: "This year-in-space mission was a profound challenge for all involved, and it gave me a unique perspective and a lot of time to reflect on what my next steps should be on our continued journey to help further our capabilities in space and on Earth."
He holds the record for the most amount of days spent in space by an American.
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