Astronaut Scott Kelly, the American who, at 520 days, holds the record for the most time spent in space, announced Friday that he is retiring, ending a storied career for a NASA veteran.

Kelly just returned from an almost year-long journey to the International Space Station, which was the

American astronaut Scott Kelly who just returned home from the longest mission by an American to the International Space State on record announced his retirement. PHOTO VIA WIKIMEDIA COMMONS.

American astronaut Scott Kelly who just returned home from the longest mission by an American to the International Space State on record announced his retirement. PHOTO VIA WIKIMEDIA COMMONS.

longest single mission to the ISS. The goal of this expedition was to test the effects of prolonged space travel in anticipation of a trip to Mars. While traditional missions to the ISS can last up to six months, this period has not been enough to sufficiently understand the effects of space on astronauts, according to The Boston Globe.

According to USA TODAY, while Kelly was in space, his twin brother served as the control for NASA’s scientific study. Researchers will study the effects that space had on Kelly’s body for the next year. So far, the immediate effects of space include coming back two inches taller than he was when he left, which happens because the spine is able to expand slightly when gravity is not a factor, USA TODAY reported.

In the long term, researchers will study the reaction of the human body to space radiation. They believe that space causes a mild loss of vision, but they are not sure of when this phenomenon occurs and if it progresses with time.

The possible consequences of exposure to space’s extra radiation, it seems, will be a tougher question to crack. Doctors worry that the radiation, which can be more than 300 times the radiation experienced on Earth, according to USA TODAY, can be detrimental to the heart, blood vessels, brain and central nervous system. Of course, the other risks include cancer, which is more likely to form due to the extra DNA mutations caused by radiation.

Outside of the medical discoveries that Kelly’s trip will provide, he has consistently provided new photos that have reshaped our view of Earth. For instance, his photo of Mount Fuji looks not like a mountain but like a sea “barnacle,” NPR stated. While Kelly said he enjoys the spoils of being back on Earth, like sitting down at a real table for dinner to getting his teeth cleaned at the dentist, us mere earthlings should celebrate Kelly’s accomplishments and look forward to the exciting future of space exploration.

As NASA looks toward Mars as a new planet to explore and private space companies come tantalizingly close to bringing space tourism to the masses, it is important for the public to maintain its interest in space and for the government to continue to fund space research. Though there will be challenges ahead, especially as private companies begin to take over some of the responsibilities of NASA, we are truly on the cusp of an exciting period of exploration that will allow our generation and the generations that come after us to understand more about the universe and enjoy views of our world from places once thought unreachable.