The first 12-month mission to the International Space Station and first space-based study involving twins starts when NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko leave from Baikonur Cosmodrome for a stay that will span Expedition 43 and 44.
Scott and Mark Kelly, the only identical twins who are also astronauts, volunteered themselves for the study. Mark, a retired astronaut, will remain on Earth while Scott spends his year aboard the ISS.
The experimental endurance mission is twice as long as current space station stays. It ends March 2016.
The study creates a unique opportunity to disentangle the health effects of Space on the human body from those of genetics.
NASA explains that the findings are expected to shed light on the impact of spaceflight on the genes in the human body and the effect of stress components like radiation, confinement and microgravity on the subjects' proteins and metabolites. Some projects will examine the common ISS-occupant health problems, such as eye disorders caused by low gravity.
Date written/update: 2015-02-26