Andrew Feustel was chosen as a NASA Mission Specialist in 2000. He was on the final space-shuttle mission to the Hubble Telescope in 2009. In 2011, he went on the penultimate shuttle mission to the International Space Station, clocking up four spacewalks. He has a Ph.D. in geology from Queens University in Ontario, Canada, and restores cars in his spare time.
Lisa Grossman: You just emerged from six days in a cave in Sardinia, Italy. Why were you down there?
Andrew Feustel: I was training with an international team of astronauts. The idea was for them to become better at what they need to do best: to work together as international teams in stressful environments, but making critical decisions to get the job done.
LG: Why a cave?
AF: It allows us to operate in a high-stress environment, where the decisions you make and everything you do—even walking—is difficult, and the consequences of those decisions are real and significant. It's dark in there. You can get injured if you don't follow proper safety protocols.
LG: What was it like?
AF: It's like mountain climbing in the dark. We traveled almost a kilometer underground throughout the six nights we spent in this cave. We had to use rappelling ropes and harnesses to move up and down the cave walls.
And it was dark. There was total blackness when the lights went out, and those lights are your means of survival. Without lights you're lost. One of the jokes each day was, "Let's wait until tomorrow to do that, when the sun comes out so we can see." But of course the sun never came out. It was a fantastic experience.
LG: Was it like space at all?
AF: You can't say a cave is like space. But there are parts of living in a cave for six nights that are analogous to being on a space mission.
Some of the techniques we use, like tethering—where we have short ropes or hooks that keep us attached to the climbing apparatus—are similar to a spacewalk. You have to be sure that every move you make is very calculated. Things don't come naturally. You have to be precise. In that sense it was very much like space. And working with an international crew—that was similar.
LG: Do you think you might get to use these skills in lava tubes on Mars, for example?
AF: Not directly. We weren't there to learn how to be cavers. We were learning to work on an international team to accomplish common goals and objectives.
LG: How did it feel when you came out?
AF: It felt a little bit like when I came home from space. Coming out of the cave, the first thing that strikes you is the smell of earth. My experience of spaceflight was the same. When the hatch of the space shuttle was opened, it wasn't the visuals that struck me, it was the fact that I could smell Earth. I could smell the grass, I could smell mold. It lit up my imagination and reminded me I was coming home. I didn't expect coming out of the cave to bring back those same memories. That was a little bit surprising.
This article originally appeared in New Scientist.