Word: nucleus
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Dates: during 1980-1989
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...about 100 foreign scientists who gathered at Moscow's Institute of Space Research to observe the eagerly awaited rendezvous of the Soviet spacecraft Vega 1 with Halley's comet. At 2:30 a.m. (EST) on March 6, as Vega passed within 5,300 miles of Halley's nucleus and as images of the legendary comet flashed on television screens at the institute, Sagan joined the other foreign scientists in applause, while Soviet scientists and technicians hugged and kissed one another...
...increased to 40 tons a second, and has since varied between 30 and 70 tons. Stewart estimates that the loss of surface ice causes Halley's to shrink 20 ft. to 30 ft. in diameter each time it passes the sun. At that rate, he says, the comet's nucleus, now about four miles in diameter, will swing close to the sun hundreds of times before Halley's disappears forever...
...March 6, when the sun will begin blocking the Venusian view of the comet. On that day, however, the first of an international flotilla of spacecraft will take over Halley's vigil. The Soviet probe Vega 1 will fly through the coma, passing within 6,000 miles of the nucleus. It will be followed by another Soviet craft, two Japanese probes, and the European Space Agency's Giotto, which will make the most daring pass of all. On March 13, Giotto will swoop within about 300 miles of Halley's nucleus and--if it survives the encounter --transmit the first...
...probe was launched from Kourou, French Guiana, last July; as of last week it was 21 million miles from earth and nearly three times as far from Halley's. The little ship and everything on it are built for survival, and with good reason. The dust particles around the nucleus are expected to strike Giotto with such great velocity that a speck weighing a tenth of a gram would penetrate an aluminum plate about 3 in. thick. To prevent damage, the side of the craft facing the comet is covered with a double shield, one made of aluminum...
Should the probe weather its many assaults, the rewards will be splendid. During its four-hour encounter, Giotto will explore the material streaming from the nearby nucleus with a total of ten experiments. As the craft revolves on its axis, a solid-state optical camera extending from the bottom rim like a bent stovepipe will snap a photograph once every four seconds. The pictures will be instantly transmitted to earth and shown live on television. Mass spectrometers will analyze the composition of the dust from the nucleus, and other instruments will examine the properties of the ions in detail...