When erstwhile Nazi Wernher von Braun wasn’t busy planning on blasting gas chambers into space, the NASA kingpin concerned himself with the psychological effects of epic flights on astronauts. In a 1954 Collier’s article he co-wrote with A Bridge Too Far author, Cornelius Ryan, the following passage appeared:

I am convinced that we have, or will acquire, the basic knowledge to solve all the physical problems of a flight to Mars. But how about the psychological problem? Can a man retain his sanity while cooped up with many other men in a crowded area, perhaps twice the length of your living room, for more than thirty months?•

A decade later, the French speleologist Michel Siffre began embedding himself in caves and underground glaciers to collect reconnaissance about the deep recesses of the mind when subjected to isolation. Sans takeoff, this sort-of astronaut studied time, developing the field of human chronobiology.

Today, with astronaut Scott Kelley having spent close to a year in space, we have a clearer, if still imperfect, understanding of what it might take for humans to reach Mars with intact minds. From Alessandra Potenza at the Verge:

What will be the psychological challenges that astronauts face on their way to the Red Planet, the furthest away any human being has ever been from home?

The Verge asked Scott Kelly, the former NASA astronaut who spent 340 days on the ISS — the longest any American has lived in space. His one-year mission is a stepping stone to future missions to Mars. Kelly told us how his year in space changed him and how he’s gotten a better appreciation for the environment.

Despite the physical and psychological challenges, Kelly said he’d volunteer for a mission to the Red Planet — with one caveat: he has to have a return ticket to Earth. “Having spent a year on the space station,” he says, “I can’t imagine spending the rest of my life in an environment like that, where you can’t go out and get fresh air.”•