Before Neil Armstrong took that “giant leap for mankind” on the moon in 1969, he—and every other Apollo astronaut—first had to learn to walk on alien terrain right here on Earth. In addition to training to float in zero gravity and practicing spacewalks in water tanks, NASA needed its astronauts, many of whom came from military aviation backgrounds, to become field scientists. That meant learning to identify rock types, navigate rough terrain in bulky suits and carry out meaningful science in physically punishing environments.
But with no moon or Mars terrain to rehearse on, NASA turned to the next best thing: Earth. The space agency scouted remote locations that felt untouched—vast, rugged and dry enough to mimic the barren landscapes of the moon or Mars.
“There aren't that many places on Earth that scratch all those boxes, and are also easy and safe to get to,” says Teddy Kareta, an astronomer at the Lowell Observatory in Arizona.
From jagged lava fields in Idaho to the bone-dry deserts of Chile, NASA sought out some of our planet’s most extreme environments to simulate surfaces of other worlds.
“There's no perfect analog for the actual moon,” he says. “So, our best guess is to pick a bunch of places that kind of get aspects of the moon right.”
