NASA welcomed Scott Kelly and Mikhail Kornienko home to Earth on March 1 after their "One-Year Mission" in space.
But they weren't up there a full year. They were on the International Space Station (ISS) for 340 days.
The question many of us are probably thinking is: Can't NASA count? Why not make it a full 365 days?
Well, it turns out that it has more to do with rockets than calendars.
In a Reddit AMA question-and-answer session about the "one-year mission" with NASA scientists, RKO36 asked: "I can't [get] past the fact the year in space was only 0.93 years and not 1 year. Why?"
The scientists responded:
It is determined by Soyuz launch schedules. 11 months in space is close to 12 months and much longer than the usual 6 month rotations on ISS. So calling it the one-year mission (abbreviated 1YM) is just a convenience. (Close enough, right?)
The Russian space agency Roscosmos sets the Soyuz space capsule launch schedules, so they're the ones who decide when astronauts get to go to and leave the ISS.
But the Russians had cosmonaut Kornienko up there for a year, too, so I don't understand why Roscosmos didn't just decide to set the Soyuz landing for March 16 to make it the full 365 days.
As the NASA scientists said, perhaps 340 days is "close enough."
