(AP) - NASA and Russia's Roscosmos have named the two men who will spend a year aboard the International Space Station to gather more data about the effects of weightlessness on humans. NASA's Scott Kelly and Roscosmos' Mikhail Kornienko will take part in the mission set to start in spring 2015.

The space agencies said in a statement Monday that the flight would help reduce health risks for planned NASA missions around the moon, an asteroid and ultimately Mars. Crews so far have done only six-month stints on the station. Scott Kelly is the twin brother of fellow astronaut Mark Kelly, the husband of former Arizona congresswoman Gabrielle Giffords. Kelly and Kornienko will start training for the mission next year.