PHOENIX (AP) Astronaut Mark Kelly and his twin brother will help NASA study the effects of spaceflight on the human body.
NASA announced Friday that Mark Kelly and astronaut Scott Kelly will participate in 10 different investigations.
Craig Kundrot, deputy chief scientist of NASA's Human Research Program, says in a news release that the brothers provide a unique opportunity to study two people with the same genetics who were in different environments.
Officials say Scott Kelly spent a year in space while Mark Kelly was on Earth.
NASA says it is hoping the studies can be the basis for future research initiatives.
Mark Kelly is the husband of former U.S. Rep Gabrielle Giffords, who has been recovering after being shot in the head in 2011.
He and Giffords are working on a book on gun control.