In a meteorite crater blasted into arctic Canada 23 million years ago, scientists and engineers are spending the long, light-filled northern summers practicing being on Mars. “While much research has been directed to solving the problem of getting humans to Mars and back,” writes Pascal Lee in the May/June 2002 issue of The Planetary Report, “little attention and almost no dedicated field studies have addressed what humans will do once they reach the Red Planet.

“How will human explorers live and work on Mars?”

An astronaut in low earth orbit 150 miles up—on the space shuttle, say, or in the International Space Station—will intercept the occasional cosmic ray: “You'll see flashes of light, of color, even with your eyes closed,” said James Pawelczyk. An assistant professor of physiology and kinesiology at Penn State, Pawelczyk is a former NASA astronaut who flew as payload specialist aboard the shuttle Columbia in 1998, logging 16 days and 6.4 million miles in space.