The Year-Long Space Mission: This Time It’s Not About the Money
In late March, two regularly-rotated crewmen—one American and one Russian—will be launched with a special flight plan. They will not be replaced at the end of their standard six-month tour, but will remain in orbit for a back-to-back second six months. The relief mission that would have carried their replacements will instead carry two short-term fliers who will then almost immediately return to Earth aboard the craft that would normally have carried the relieved six-monthers.
People have flown for a full year in space before, on the Russian Mir space station. Two of them flew 365 days exactly in 1987-1988, a quarter century ago. The 3rd and 4th landed in 1995 and 1999. But the four cosmonauts who made such flights demonstrated little more than sheer physical and mental fortitude by surviving, because little useful medical data was gathered.
This time, the longterm crew will have a sophisticated battery of medical sensors as well as well-tested health maintenance equipment, such as exercise devices. More importantly, they will have a well-defined list of subtle physiological trends to be meticulously monitored, a list resulting from studies of several dozen six-month expeditions by earlier ISS crewmembers. Some of the effects, such as significant eyeball deterioration, were not even known during the previous long missions.