<P> The One - Year Mission was a scientific research project aboard the International Space Station , which studied the health effects of long - term spaceflight . Scott Kelly and Mikhail Korniyenko spent 342 days ( 11 months , 3 days ) in space , with scientists performing medical experiments . Kelly and Kornienko launched on 27 March 2015 on Soyuz TMA - 16M along with Gennady Padalka . The mission encompassed Expeditions 43 , 44 , 45 and 46 . The pair safely landed in Kazakhstan on March 2 , 2016 , returning aboard Soyuz TMA - 18M with Sergey Volkov . The mission supported the NASA Twins study , which helps shed light on the health effects of long duration spaceflight , which is of interest for Mars missions especially . </P>
<P> The One - Year Mission was a scientific research project aboard the International Space Station , which studied the health effects of long - term spaceflight . Scott Kelly and Mikhail Korniyenko spent 342 days ( 11 months , 3 days ) in space , with scientists performing medical experiments . Kelly and Kornienko launched on 27 March 2015 on Soyuz TMA - 16M along with Gennady Padalka . The mission encompassed Expeditions 43 , 44 , 45 and 46 . The pair safely landed in Kazakhstan on March 2 , 2016 , returning aboard Soyuz TMA - 18M with Sergey Volkov . The mission supported the NASA Twins study , which helps shed light on the health effects of long duration spaceflight , which is of interest for Mars missions especially . </P>
who were the two astronauts who stayed a year on the iss
who were the two astronauts who stayed a year on the iss
Scott Kelly Mikhail Korniyenko
Scott Kelly Mikhail Korniyenko