Astronauts chosen for groundbreaking yearlong mission in space NASA and Russia's space agency are pushing ahead with plans for a yearlong stay in space, choosing the two men who will undertake the mission. Scott Kelly, a NASA veteran with more than 180 days in space, and Russia's Mikhail Kornienko are scheduled to launch in spring 2015 to spend a year aboard the International Space Station, according to a NASA news release. A main goal of the expedition is to determine the effects of such a long stay on the human body. "The one-year increment will expand the bounds of how we live and work in space," William Gerstenmaier, associate administrator for human exploration and operations at NASA headquarters in Washington, said in the release. Scientists have been monitoring how shorter stays aboard the ISS -- which has been occupied for 12 years -- have affected physical aspects including muscle mass, strength and bone density. But horizons for manned missions have widened, and researchers are looking to move beyond low-Earth orbit and want to know how microgravity will affect humans in the longer term. Documented effects of spaceflight include a host of sometimes nauseating problems -- among them loss of bone and muscle mass, vision problems and redistribution of fluid in the body. Motion sickness can be severe -- notably Jake Garn, the first member of Congress to fly in space, was retching and wretchedly ill during his April 1985 mission. Astronauts began jokingly to use the "Garn Scale" to rate their own space sickness. A 1999 interview from a Johnson Space Center oral history project reveals this nugget: "Totally sick and totally incompetent" equals one Garn, with most astronauts attaining about one-tenth of a Garn. A NASA source told the Los Angeles Times on Monday morning that the space agency will have details in about a week on the specific tests and experiments that will be performed during the yearlong mission. Kelly, 48, has been with NASA since 1996. He became commander of Expedition 26 on the International Space Station in November 2010 and remained aboard for five months. The plan is for Kelly and Kornienko to launch aboard a Russian Soyuz spacecraft from the Baikonur Cosmodrome in Kazakhstan and to make their return trip to Kazakhstan in spring 2016. Unprecedented views of Mars dust storm Solar prominences erupt and the best is yet to come Military's dogs of war suffer post-traumatic stress disorder too