Setting Sail In The Cosmos

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By some measures, this cosmic lob shot is not that impressive, but for solar-sail scientists, the engineering is everything. Few doubt that when sunlight strikes the wings, the spacecraft will accelerate; the key is building wings that can open and pivot, allowing the ship to tack into the solar stream. If this mission works, a more ambitious orbital flight, using the eight-paneled craft, is set for the end of the year. The spacecraft could circle Earth for months, surfing the sun until designers shut it down. "There will be a grandeur to it," says Druyan, "a 70-ft. sail that will be visible to the whole planet."

Grandeur aside, critics wonder if solar sails have a future. The technique is problematic in Earth orbit, since the changing position of the sun relative to the spacecraft makes constant tacking necessary. Sailing is best used for as-the-crow-flies shots to neighboring planets. Even in these cases, progress can be slow, since sunlight exerts, at most, 2 lbs. of pressure per square half-mile, requiring a year or more to rev a spacecraft to interplanetary speeds. Worse, beyond Jupiter, sunlight flickers out almost entirely; to go any farther would require energy beamed from Earth orbit, perhaps by giant laser howitzers. "None of these things has been tested," says Mel Montemerlo, one of NASA's solar-sailing chiefs. "We have a long way to go."

Whether that will continue to seem such a long way may depend on the springtime flight of Cosmos 1. A successful mission has a way of making impossible technologies seem possible--a big burden for a small rocket that will, for one day at least, carry the hopes of the world's space community.

--With reporting by Dan Cray/Pasadena and Dick Thompson/ Washington