After 340 consecutive days in space, Commander Scott Kelly's return to normal activity on Earth will be gradual. Life in space takes a toll on the human body, changing a person's eyesight, affecting memory and motor control.
A major part of Kelly's mission is to help NASA get a better understanding of those changes so that it may find out what future astronauts might experience on the long journey to Mars. Scientists will also look for genetic changes; an experiment made possible by Kelly's twin brother Mark, who may be used as a control subject.
Sharon Begley of STAT speaks with Here & Now's Jeremy Hobson about what NASA hopes to learn.
This segment aired on March 2, 2016.