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CONTACT: Lee Tune 301/405-4621 or ltune@accmail.umd.edu

News Release: July 7, 1999

'Deep Impact' a University of Maryland-Led Mission to Excavate and Study a Comet's Nucleus Wins NASA Approval

COLLEGE PARK, MD -- A University of Maryland proposed space mission to penetrate deep into the nucleus of a comet and uncover secrets about the origin of the solar system has won approval by NASA. The $240 million mission -- which was conceived by University of Maryland astronomy professor Michael A'Hearn -- will be the first to study the interior of a comet, which astronomers believe contains material unchanged since the formation of the solar system.

"We are excited that NASA selected 'Deep Impact' from among five strong mission proposals," said A'Hearn, principal investigator for the mission and one of the world's leading experts on comets. "And we are even more excited about the scientific potential of this mission. It promises to greatly further our understanding of the composition of comets and of the materials and processes that led to the formation of the planets and other bodies in our solar system. Learning more about the composition of comets also should help us better understand the past history and future risks of comet impacts with the earth."

The launch of the Deep Impact mission is planned for January 2004. The schedule calls for the mission to reach its target, comet Tempel 1, at the beginning of July, 2005 with impact on July 4. The spacecraft will actually consist of two craft that will separate when the comet is reached. The first craft is an instrument platform that will fly slowly by the comet and record data and images of the impact, crater formation, and comet interior. The second craft is the "impactor," which upon reaching Tempel 1 will separate from the flyby craft and be propelled at 10 kilometers per second into a target site on the sunlit side of the comet. The kinetic energy of the 500 kilogram copper impactor is expected to create a large (120 meters diameter), deep (25 meters) crater and vaporize the impactor in the process.

Optical and infrared instruments on the flyby craft will provide visual images and infrared spectral mapping of the impact and crater. In the visual range, a high resolution camera will provide detailed images while a medium resolution one will provide targeting information and views of the complete crater and nucleus. The craft will have redundant storage of data to guard against any data loss.

"Because the impact will be spectacular and observable from Earth, the mission should be of great interest to the public and will provide a tremendous opportunity for students and others to learn more about comets, the formation of the solar system and the role of comets in the history of Earth," said Lucy McFadden, an associate research scientist in the University of Maryland's department of astronomy and director of education and public outreach for the Deep Impact mission.

According to McFadden, the public will have opportunities to be directly engaged in the mission by viewing the July 4th impact both through small telescopes and in nearly real time images from the flyby craft that will be received on earth minutes after the impact occurs.

Amateur and professional astronomers around the world will be enlisted to host viewing parties that will provide the public with a chance to directly participate in the mission and see the impact. Millions of people will likely be able to view the impact at home on their TV sets as well, since images from the flyby craft will be made available via satellite to television stations and other media outlets around the world.

In addition, information and images about the mission and its findings will be made available to students and the public through a mission web site and educational materials that will be provided to schools. It is expected that the web site will become active by the end of this month (http://www.ss.astro.umd.edu/deepimpact/).

In addition to the University of Maryland-led science team, the mission partners are the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. and Ball Aerospace and Technology Corporation of Boulder, Colo. The technical implementation is managed by JPL with Ball responsible for all flight hardware.