Robinson, author of the so-so, non-fiction An American in Leningrad (1982), makes his fictional debut: a generally unfortunate, often silly comet-chaser. Young NSA linguist Charles Griffin, analyzing an intercepted Russian phone call, unearths a possible code word, beda, ""disaster."" Then he determines that a Russian transport plane, full of dissident physicists, was shot down by its own people. Also--beda again--the Russians are preparing to deal with a disastrous coastal flood. Meanwhile, a Russian space probe heads around behind the sun in hot pursuit of Halley's comet. Charles, who's beginning to add up the Big Picture, blabs everything to his Russian girlfriend. Surprise! She's a KGB spy. So when Leana duly makes her report, the KGB moves quickly to kill Charles. Leana, annoyed and upset, goes on an anti-KGB rampage, murdering agents, exposing networks, reporting to the NSA. Halley's comet emerges from behind the sun, now noticeably off course: yes, the Russian ""probe"" was a bomb! The comet will hit the Moon, driving it into a lower orbit; this in turn will produce devastating tidal flooding on Earth. So, a heroic US shuttle crew, up in space to test a powerful Star Wars laser, must crash head-on into Halley's comet in order to divert the comet and save the Western world. Flaws: legion. Virtues: none. Result: absurd.