Space is not nearly as empty as you might think. In fact, besides its long-term residents, such as communications satellites, space is filled with trash. Flying trash. Earth is surrounded by a layer of camera lens caps, spent rocket boosters, bolts, nuts, buckets of garbage, and countless flecks of dislodged paint and particles of solid fuel from rocket boosters. A fleck of paint may not sound dangerous, but as author James Chiles finds out, when it's moving at 17,000 miles per hour, you had better get out of the way.
This is where the space surveillance network comes in. Chiles takes us on a cross-country tour of the network a collaboration between NASA and the Department of Defense that keeps a constant watch on everything from Mir to objects a few inches across, ensuring the safety of our shuttles and everyone's satellites.
The shuttle spacecraft themselves provide valuable information to NASA's orbital debris program. On a mission in 1995, the shuttle orbiter Columbia took a hit while circling the earth that could have ended the mission had the NASA debris squad not predicted the danger beforehand, based on an earlier shuttle flight. They suggested rotating the orbiter to protect the payload bay, which houses the spacecraft's crucial cooling system.
But there are some pieces that even the combined efforts of the military and NASA can't keep track of. A "silver bullet," as some call it, is small enough to escape radar surveillance, but big enough to destroy.
"There is the possibility that you could be hit by one of those silver bullets on a bad day," says Justin Kerr of NASA. "On that day you want to do the best you can to shield the vehicle."