NASA astronaut Scott Kelly and cosmonaut Mikhail Kornienko are expected to spend about 342 days living and working on the International Space Station — marking the orbiting outpost's first yearlong space mission. Cosmonaut Gennady Padalka also joined Kornienko and Kelly on the Russian Soyuz spacecraft that docked with the space station on Friday, March 27, 2015, at 8:33 p.m. EDT. Padalka will stay on the space station for about six months, the usual amount of time people live on the space laboratory.
Kelly's twin brother and former astronaut Mark Kelly will also participate in experiments on Earth to help researchers studying his brother in space. The identical twins will be monitored in a variety of ways throughout the mission and after Scott comes home to help scientists understand how the long-term mission might alter Scott by comparison to his brother.