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Deep
Impact - Bulls Eye
Eighty-three million miles away, fireworks lit up the cold, dark space as a probe released by an American spacecraft slammed into Comet Tempel 1...
Deep Impact with Comet Tempel 1 draws closer!
BY OUR TECHNOLOGY CORRESPONDENT
26 June, 2005: Deep Impact is almost here! No, we aren't talking about the movie. After a journey of 173 days and 431 million kilometers in space, NASA's Deep Impact spacecraft readies for its rendezvous with Comet Temple on July 4, 2005.
The pioneering, hyper-speed impact between space-borne iceberg and copper-fortified probe is expected at approximately 1:52 a.m. EDT on American Independence Day (10:52 p.m. PDT on July 3). The spectacular collision will be watched and recorded by the Deep Impact spacecraft, and observatories from ground and space.
On July 3, as it approaches Comet Tempel 1 for its cosmic explosion, the Deep Impact spacecraft will put out the 1-meter-wide impactor into the comet's path, which measures about half as big as Manhattan Island. In the next 22 hours, Deep Impact navigators and mission members sitting 133 million kilometers away at JPL, will direct both spacecraft and impactor toward the Comet Tempel 1. The impactor will head into the comet and the flyby craft will pass approximately 500 kilometers (310 miles) below it.
Tempel 1 is hurtling through space at approximately 37,100 kilometers per hour (23,000 miles per hour or 6.3 miles per second). That speed wiill take you from New York to Los Angeles in under 6.5 minutes. Two hours before impact, the Deep Impact's impactor will kick into auto-navigation. From there, it makes its own navigational solutions and thruster firings to make contact with the comet.
"The autonav is like having a little astronaut on board," Grammier said. "It has to navigate and fire thrusters three times to steer the wine cask-sized impactor into the mountain-sized comet nucleus closing at 23,000 miles per hour."
Deep impact is expected to create a crater on Comet Tempel 1 ranged in size from a large house up to a football stadium, and from two to 14 stories deep. Ice and dust debris will be ejected from the crater, revealing the material beneath. The flyby spacecraft has about 13 minutes to take images and spectra of the collision and its result before it is hit by a potential blizzard of particles from the nucleus of Comet Tempel 1.
Deep Impact will provide a glimpse beneath the surface of a comet, where material from the solar system's formation remains relatively unchanged. Mission scientists expect the project will answer basic questions about the birth of the solar system, by offering a better look at the nature and composition of comets.
The Deep Impact spacecraft has four data collectors to watch the effects of the collision with Comet Tempel 1. A camera and infrared spectrometer, which comprise the High Resolution Instrument, are carried on the flyby spacecraft, along with a Medium Resolution Instrument. A duplicate of the Medium Resolution Instrument on the impactor will record the vehicle's final moments before it is run over by Tempel 1.
Said Rick Grammier, Deep Impact project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif: "We are really threading the needle with this one. In our quest of a great scientific payoff, we are attempting something never done before at speeds and distances that are truly out of this world."
Said Deep Impact Principal Investigator Dr. Michael A'Hearn of the University of Maryland, College Park: "The last 24 hours of the impactor's life should provide the most spectacular data in the history of cometary science. With the information we receive after the impact, it will be a whole new ballgame. We know so little about the structure of cometary nuclei that almost every moment we expect to learn something new."
"In the world of science, this is the astronomical equivalent of a 767 airliner running into a mosquito," said Dr. Don Yeomans, a Deep Impact mission scientist at JPL. "The impact simply will not appreciably modify the comet's orbital path. Comet Tempel 1 poses no threat to the Earth now or in the foreseeable future."
The University of Maryland is responsible for overall Deep Impact mission management, and project management is handled by JPL. The spacecraft was built for NASA by Ball Aerospace & Technologies Corporation, Boulder, Colo.
BY OUR TECHNOLOGY CORRESPONDENT |
