The Calm After the Cometary Storm

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

DC Agle (818) 393-9011
Jet Propulsion Laboratory, Pasadena, Calif.

NEWS RELEASE: 2003-007 January 6, 2004

The Calm After the Cometary Storm

Having weathered its out-of-this-world sandblasting by cometary
particles hurtling toward it at about six times the speed of a rifle
bullet, NASA's Stardust spacecraft begins its two-year, 1.14 billion
kilometer (708 million mile) trek back to its planet of origin.

"On January 2, comet Wild 2 gave up its particles but it did not do so
without a fight," said Stardust Project Manager Tom Duxbury of NASA's
Jet Propulsion Laboratory, Pasadena, Calif. "Our data indicates we
flew through sheets of cometary particles that jostled the spacecraft
and that on at least 10 occasions the first layer of our shielding was
breeched. Glad we had a couple more layers of the stuff."

Stardust entered the comet's coma - the vast cloud of dust and gas
that surrounds a comet's nucleus - on December 31, 2003. From that
point on it kept its defensive shielding between it and what
scientists hoped would be the caustic stream of particles it would fly
through. And fly through cometary particles Stardust did, but not in
the fashion the team envisioned while designing the mission.

"We thought we would see a uniform increase in the number of particles
the closer we came to the comet's nucleus and then a reduction," said
University of Washington scientist Dr. Don Brownlee, Stardust's
Principal Investigator. "Instead, our data indicate we flew through a
veritable swarm of particles and then there would be almost nothing
and then we would fly through another swarm."

Stardust scooped up these cometary particles, impacting at 6.1
kilometers per second (3.8 miles per second), for almost instantaneous
analysis from onboard instruments and stored other particles for
later, in-depth analysis, here on Earth. Along with this cosmic taste
testing, the spacecraft also took some remarkable images of comet Wild
2's five-kilometer wide (3.1-mile wide) nucleus.

"Our navigation camera was designed to assist in navigation, not
science," said Stardust's imaging team lead Ray Newburn. "But these
are the best images ever taken of a comet and there is a remarkable
amount of information in those 72 pictures. Not only did we image the
jets of material spewing out from the comet, but for the first time in
history we can actually see the location of their origin on the
surface of the comet."

At about 11:25 am Pacific Standard Time (2:25pm EST) on Jan. 2, only
minutes after its closest approach with the comet, Stardust pointed
its high gain antenna at Earth and began transmitting a data stream
that took over 30 hours to send but will keep cometary scientists busy
for years to come. About six hours later another event took place that
goes a long way to literally increasing the scientists task load
exponentially.

"Six hours after encounter we retracted the collector grid, with what
we are all confident is an abundance of cometary particles, into the
spacecraft's sample return capsule," added Duxbury. "The next time the
sample return capsule is going to be opened is in a clean room at the
Johnson Space Center in the days following Earth return in January
2006."

Scientists expect in-depth terrestrial analysis of the samples will
reveal much about comets and the earliest history of the solar system.
Chemical and physical information locked within the particles could be
the record of the formation of the planets and the materials from
which they were made. More information on the Stardust mission is
available at

http://stardust.jpl.nasa.gov/ .

Stardust, a part of NASA's Discovery Program of low-cost, highly
focused science missions, was built by Lockheed Martin Space Systems,
Denver, Colo., and is managed by JPL for NASA's Office of Space
Science, Washington, D.C. JPL is a division of the California
Institute of Technology in Pasadena.

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