NASA astronaut Scott Kelly is returning to Earth today, after spending nearly a year
aboard the International Space Station.
Kelly’s extended stay on the orbital lab was for NASA’s year-long mission.
It’s an experiment to see how long-term spaceflight affects the human body.
The idea behind the mission is to help NASA better prepare for trips into deep space.
A crewed mission to Mars, for instance, is going to take upwards of several months.
NASA wants to know how astronauts will fare during these missions.
They also want to figure out how to mitigate any negative health effects along the way
and when the astronauts get there.
Kelly collected several body samples prior to and during his flight to document how his
body has been changing.
NASA also had a unique opportunity with Kelly, since he has an identical twin, Mark Kelly,
who is a former astronaut himself.
Mark is serving as a “control” subject in this experiment by remaining on Earth.
Since the twins are genetically identical, samples from the brothers can be compared
to show just how much Scott’s body has adapted to living in microgravity for so long.
Researchers can then try to tease out if there is a genetic basis for some of the health
changes people experience in space.
As for what those body changes will be, NASA will find out once Kelly gets back to Earth.
But the agency has a pretty good idea of what they’ll see, based on the experiences of
other astronauts.
Many people who live in space experience problems with their cardiovascular system; microgravity
causes bodily fluids like blood to float up into the torso region, so veins in the legs
weaken and can’t contract blood as easily.
Astronauts also have a hard time with their spatial orientation and balance, since they
don’t have the same cues in space to tell them which way is up.
And people also report vision changes, potentially due to fluid building up in the brain behind
the eyes.
It’s something that’s affected Kelly during his time in space.
[KELLY] You know, I have a little bit of, i think, effect on my vision that is very
consistent with what I experienced last time.
There are a whole host of other physical changes that Scott may experience too — including
changes in his gut microbiome and how his RNA is expressed.
His muscles and bones are likely a lot weaker too; on Earth, we “work out” these systems
just by standing and walking as gravity pulls us down.
Without gravity, astronauts have to compensate as much as possible by doing specific exercises.
Once Kelly is back on solid ground, NASA will try to figure out how space has really affected
him.
First Kelly will do a field test as soon as he gets back to Earth to see how well he adjusts
to a gravity environment again.
He’ll then undergo months of sampling and medical tests, the results of which won’t
be released until at least 2017.
But Kelly will still get to enjoy the comforts of Earth as the experiment continues.
[KELLY] When I get back to Houston, I’ll go to the astronaut crew quarters at the Johnson
Space Center for several hours of medical tests that end at about 3 in the morning,
then i’m going to go home and jump in my pool.