Science: Space Watch's First Catch

Three weeks ago, headlines announced that the U.S. had detected a mysterious "dark" satellite wheeling overhead on a regular orbit. There was nervous speculation that it might be a surveillance satellite launched by the Russians, and it brought the uneasy sensation that the U.S. did not know what was going on over its own head. But last week the Department of Defense proudly announced that the satellite had been identified. It was a space derelict, the remains of an Air Force Discoverer satellite that had gone astray. The dark satellite was the first...