Early last summer, during the second half of the space shuttle Discovery 's most recent mission—a rendezvous with the international space station—there were plenty of things to worry about: the state of the ceramic pieces protruding from the shuttle's underside, for instance, and the damaged thermal blanket below the cockpit. Then, of course, hanging over the mission itself was the specter of the Columbia tragedy in 2003. But when Eileen Collins, Discovery 's commander, looked down at her planet more than 200 miles below, she had another concern. Something in Central Africa didn't look right. “I was just taking a glance out the window,” Collins says, “and I saw dozens of fires. And the way they were burning, it looked like it wasn't a natural event. It was widespread.”

Since the late 1990s NASA has been working with scientists to help monitor large-scale environmental degradation. Biologists are using the space images to map endangered species, track whale populations, and monitor coral reefs and wetlands.“There are still a few places in the world where the only image out there is an astronaut photograph,” says Julie Robinson, an earth scientist at the Johnson Space Center in Houston. A number of biologists are also using NASA images to predict future deforestation.

“From an astronaut's perspective, you see the earth has limited resources,” Collins adds. “During sunrise and sunset, when you look off at the earth's horizon, you can see how thin the atmosphere is. You can see how people share the air. You also see just how beautiful the earth is from space. It makes me want to protect what we have more so.”

—Frank Bures