MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 Contact: Martha J. Heil 818/354-0850 IMAGE ADVISORY November 29, 2001 COMET ROCKS AND ROLLS IN SIMPLE MOVIE NASA scientists have strung together images of comet Borrelly to produce short movies of the comet as it travels through space. In one clip, the bare, rocky, icy nucleus wobbles back and forth to reveal its textured surface, with some smooth and some bumpy landscapes. The observations were taken when NASA's Deep Space 1 spacecraft was between 3,700 and 9,500 kilometers (between 2,300 and 5,900 miles) from the comet in September 2001. In the second clip, jets of gas and dust shoot from all sides of the comet's nucleus as it rotates a quarter turn. The biggest jet, shooting from the central sunlit part of the comet, is probably in line with the axis around which the nucleus rotates. This large jet is eroding the central part of the comet, smoothing parts of the terrain into rolling hills. The erosion will eventually break the comet into pieces. Coarsely textured parts of the comet at both ends are geologically inactive areas. These images were taken from between 22,500 and 4,980 kilometers (about 14,000 to 3,000 miles) away. The images are available online from NASA's Jet Propulsion Laboratory, Pasadena, Calif., at . NASA TV will broadcast a video file of the comet movies at 12, 3, 6 and 9 p.m. EST Thursday, Nov. 29. NASA TV is located on satellite GE2, Transponder 9C, audio 3880 MHz; orbital position 85 degrees west longitude, with audio at 6.8 MHz. Scientists are studying these images and other Deep Space 1 data for a better understanding of comets and their role in the solar system. Deep Space 1's pass through comet Borrelly's surrounding cloud of gas and dust yielded the best pictures ever of a comet's rocky, icy nucleus. The images appear to show the comet rotating but it is actually the spacecraft that changed position as it passed close to the comet's nucleus. Deep Space 1 completed its primary mission testing ion propulsion and 11 other advanced, high-risk technologies in September 1999. NASA extended the mission, taking advantage of the ion propulsion and other systems to undertake this chancy but exciting, and ultimately successful encounter. More information is available on the home page at . Deep Space 1 was launched in October 1998 as part of NASA's New Millennium Program, which is managed by JPL for NASA's Office of Space Science, Washington, D.C. The California Institute of Technology manages JPL for NASA. Image credit: NASA/JPL ##### 11/29/01 MJH