The Shooting Gallery

In a warehouse in the New Mexico desert, a chunk of solid aluminum gleams in the flickering fluorescent light. Roughly the size and shape of the New York City telephone book, the aluminum could get shot all day with a high-powered rifle and give the marksman nothing to show for his work but a sore trigger finger. Yet this chunk has been violated. A plastic pellet, smaller than a walnut, has smashed a ragged five-inch hole right through the aluminum's center. It is a sobering sight and an object lesson for NASA's orbital debris program: The pellet, accelerated to 15,000 miles per hour by a powerful gun here at the White Sands Test Facility near Las Cruces, shows the violence a piece of orbiting space junk can wreak on a spacecraft. "In space, you can get relative velocities of more than 30,000 miles per hour," says Don Henderson, project leader ...