Here's a report on a new hazard: high-velocity trash in space. "". . .on the very first trip human beings tooks to a strange new world [the moon], we planted a flag--and left a pile of garbage."" That garbage, at least, is immobile; but the most useful Earth orbits now carry millions of pieces of speeding, man-made debris, some of which has already cracked a space shuttle window and shattered a Soviet satellite. After a much-simplified look at the histories of the universe, astronomy, and rocket science, the authors describe orbital clutter--from paint flakes and food waste to empty booster stages--left by the 5000 satellites that have been launched; then explore ways of tracking and controlling it. Their style is lively (Explorer I weighed ""only ten pounds, about as much as your leg""); numbers and statistics are backed by a large, current bibliography. The b&w photos are frequent, but clark and unremarkable. Index.