US astronaut Scott Kelly gestures as his space suit is tested at the Russian-leased Baikonur cosmodrome, prior to blasting off to the International Space Station (ISS), late on March 27, 2015.; Credit: KIRILL KUDRYAVTSEV/AFP/Getty Images

On Tuesday, astronaut Scott Kelly is set to depart from the International Space Station, his home for the past 340 days, and is expected to land in the desert of Kazakhstan early Wednesday.

It’s the longest amount of time an American has ever spent in a single space trip and while he was up there, Kelly conducted a variety of experiments during his almost-year in orbit. But perhaps the most important experiment of all was what happened to his own body while he was up there. They’ll put him through a battery of tests, but they’ll also compare his results to those of his twin brother’s, astronaut Mark Kelly. While Scott has been in space for nearly a year, Mark has been back on earth.  What they find out might help shape missions to other places… like Mars. Jennifer Fogarty is the Deputy Chief Scientist of the Human Research Program at NASA and she joins A Martinez to talk about the sort of impact that space can have on an astronauts body and mind.