Sep 26 2001
From The Space Library
At a news conference, NASA scientists announced the preliminary findings of Deep Space 1’s 22 September flyby of Comet Borrelly, a type of comet that originates in a region near Pluto. NASA’s Deep Space 1 spacecraft, operating two years past its planned mission duration, had passed within 1,400 miles (2,250 kilometers) of Borrelly, returning the best images and data of a comet ever captured. The encounter was only the second time that a spacecraft had come within such a distance of a comet’s nucleus, as well as the first close flyby of a comet of Borrelly’s type. In 1986 ESA’s Giotto spacecraft had flown within 373 miles (600 kilometers) of Halley’s comet, which belongs to a category of comets that originate from outside Earth’s solar system. In addition, NASA scientists reported that the data captured by Deep Space 1 had substantially enhanced existing scientific knowledge of comets. Scientists found a number of Deep Space 1’s observations surprising, including the discoveries that the comet’s icy jets discharge in tall columns rather than in a diffuse spray, that a cloud of charged particles emanates from off the comet’s center, and that solar wind flows asymmetrically around the particle cloud. (Warren E. Leary, “Probe Sends Postcards from Comet’s Core,” New York Times, 26 September 2001; NASA, “Deep Space 1,” http://nmp.nasa.gov/ds1/ (accessed 17 November 2008).
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