Launch and flight teams are in final preparations for the
planned Jan. 12, 2005, liftoff from Cape Canaveral Air Force
Station, Fla., of NASA’s Deep Impact spacecraft. The mission
is designed for a six-month, one-way, 431 million kilometer
(268 million mile) voyage. Deep Impact will deploy a probe
that essentially will be “run over” by the nucleus of comet
Tempel 1 at approximately 37,000 kph (23,000 mph).

“From central Florida to the surface of a comet in six months
is almost instant gratification from a deep space mission
viewpoint,” said Rick Grammier, Deep Impact project manager
at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif.
“It is going to be an exciting mission, and we can all
witness its culmination together as Deep Impact provides the
planet with its first man-made celestial fireworks on our
nation’s birthday, July 4th,” he said.

The fireworks will be courtesy of a 1-by-1-meter (39-by-39
inches) copper-fortified probe. It is designed to obliterate
itself, as it excavates a crater possibly large enough to
swallow the Roman Coliseum. Before, during and after the
demise of this 372-kilogram (820-pound) impactor, a nearby
spacecraft will be watching the 6-kilometer (3.7-mile) wide
comet nucleus, collecting pictures and data of the event.

“We will be capturing the whole thing on the most powerful
camera to fly in deep space,” said University of Maryland
astronomy professor Dr. Michael A’Hearn, Deep Impact’s
principal investigator. “We know so little about the
structure of cometary nuclei that we need exceptional
equipment to ensure that we capture the event, whatever the
details of the impact turn out to be,” he explained.

Imagery and other data from the Deep Impact cameras will be
sent back to Earth through the antennas of the Deep Space
Network. But they will not be the only eyes on the prize.
NASA’s Chandra, Hubble and Spitzer space telescopes will be
observing from near-Earth space. Hundreds of miles below,
professional and amateur astronomers on Earth will also be
able to observe the material flying from the comet’s newly
formed crater.

Deep Impact will provide a glimpse beneath the surface of a
comet, where material and debris from the solar system’s
formation remain relatively unchanged. Mission scientists are
confident the project will answer basic questions about the
formation of the solar system, by offering a better look at
the nature and composition of the celestial travelers we call

“Understanding conditions that lead to the formation of
planets is a goal of NASA’s mission of exploration,” said
Andy Dantzler, acting director of the Solar System division
at NASA Headquarters, Washington. “Deep Impact is a bold,
innovative and exciting mission which will attempt something
never done before to try to uncover clues about our own

With a closing speed of about 37,000 kph (23,000 mph), what
of the washing machine-sized impactor and its mountain-sized

“In the world of science, this is the astronomical equivalent
of a 767 airliner running into a mosquito,” said Don Yeomans,
a Deep Impact mission scientist at JPL. “It 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,” he added.

Ball Aerospace & Technologies in Boulder, Colo., built NASA’s
Deep Impact spacecraft. It was shipped to Florida Oct. 17 to
begin final preparations for launch. Liftoff is scheduled for
Jan. 8 at 1:39:50 p.m. EST, with another opportunity 40
minutes later.

Principal Investigator A’Hearn leads the mission from the
University of Maryland, College Park. JPL manages the Deep
Impact project for the Science Mission Directorate at NASA
Headquarters. Deep Impact is a mission in NASA’s Discovery
Program of moderately priced solar system exploration

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