Word: halley
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Dates: during 1970-1979
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...When Halley's Comet last streaked across the skies in 1910, it was for many an unwelcome visitor. Fearful that the earth would be enveloped by deadly gases in its glowing tail, people bought comet pills to ward off its effects, and held end-of-the-world gatherings. In 1985, when the comet returns-as it does every three-quarters of a century -it should get a friendlier reception. In fact, NASA is planning a scientific welcoming party in space...
Last week the space agency announced the award of $1.15 million contracts to Boeing and Lockheed for preliminary studies of a new rocket. Its purpose: to power an unmanned spacecraft that will intercept Halley's Comet as it sweeps around the sun. Known as the solar electric propulsion system, the engine could become the workhorse of deep space, carrying probes on far-flung missions across the solar system...
...rare (once every 180 years) planetary alignment to survey the entire outer solar system. Those missions that were approved often did not receive funding for complete analysis of the return data. Others--to map the moon and check it for metal deposits, to research solar phenomena, to rendezvous with Halley's Comet--never got past appropriations subcommittees...
Ground controllers will then begin navigating the craft into closer and closer orbits of the sun by properly trimming the sail. Then they can put the ship-moving at a top speed of 198,000 kilometers (124,000 miles) an hour-on a course to intercept Halley's comet in March 1986. Jettisoning the sail, and "flying station" just two kilometers above the comet's head, the ship will take TV pictures and readings to determine the visitor's composition and origin. Says J.P.L.'s Murray: "We don't have a clue about comets...
Should plans for the space sailer hit a snag, earthlings could still get their first closeup view of Halley's comet in 1986. Another group at J.P.L. is working on the design of a spaceship that would be propelled by an ion engine; a small, continuous amount of thrust would be provided by the engine's ejecting ions produced when a beam of electrons (generated by electric current from solar cells) is sent through vaporized mercury. Such a low-thrust ion engine could, like the sunjammer's sail, maneuver a ship to a rendezvous with the comet...