NASA's Deep Space Comet Hunter Mission Comes to an End

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

D.C. Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

Lee Tune 301-405-4679
University of Maryland, College Park, Md.
ltune@umd.edu

News release: 2013-287 Sept. 20, 2013

NASA's Deep Space Comet Hunter Mission Comes to an End

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-287&cid=release_2013-287

PASADENA, Calif. - After almost 9 years in space that included an unprecedented July 4th impact
and subsequent flyby of a comet, an additional comet flyby, and the return of approximately 500,000
images of celestial objects, NASA's Deep Impact mission has ended.

The project team at NASA's Jet Propulsion Laboratory in Pasadena, Calif., has reluctantly
pronounced the mission at an end after being unable to communicate with the spacecraft for over a
month. The last communication with the probe was Aug. 8. Deep Impact was history's most traveled
comet research mission, going about 4.7 billion miles (7.58 billion kilometers).

"Deep Impact has been a fantastic, long-lasting spacecraft that has produced far more data than we
had planned," said Mike A'Hearn, the Deep Impact principal investigator at the University of
Maryland in College Park. "It has revolutionized our understanding of comets and their activity."

Deep Impact successfully completed its original bold mission of six months in 2005 to investigate
both the surface and interior composition of a comet, and a subsequent extended mission of another
comet flyby and observations of planets around other stars that lasted from July 2007 to December
2010. Since then, the spacecraft has been continually used as a space-borne planetary observatory to
capture images and other scientific data on several targets of opportunity with its telescopes and
instrumentation.

Launched in January 2005, the spacecraft first traveled about 268 million miles (431 million
kilometers) to the vicinity of comet Tempel 1. On July 3, 2005, the spacecraft deployed an impactor
into the path of comet to essentially be run over by its nucleus on July 4. This caused material from
below the comet's surface to be blasted out into space where it could be examined by the telescopes
and instrumentation of the flyby spacecraft. Sixteen days after that comet encounter, the Deep Impact
team placed the spacecraft on a trajectory to fly back past Earth in late December 2007 to put it on
course to encounter another comet, Hartley 2 in November 2010.

"Six months after launch, this spacecraft had already completed its planned mission to study comet
Tempel 1," said Tim Larson, project manager of Deep Impact at JPL. "But the science team kept
finding interesting things to do, and through the ingenuity of our mission team and navigators and
support of NASA's Discovery Program, this spacecraft kept it up for more than eight years, producing
amazing results all along the way."

The spacecraft's extended mission culminated in the successful flyby of comet Hartley 2 on Nov. 4,
2010. Along the way, it also observed six different stars to confirm the motion of planets orbiting
them, and took images and data of Earth, the moon and Mars. These data helped to confirm the
existence of water on the moon, and attempted to confirm the methane signature in the atmosphere of
Mars. One sequence of images is a breathtaking view of the moon transiting across the face of Earth.

In January 2012, Deep Impact performed imaging and accessed the composition of distant comet
C/2009 P1 (Garradd). It took images of comet ISON this year and collected early images of ISON in
June.

After losing contact with the spacecraft last month, mission controllers spent several weeks trying to
uplink commands to reactivate its onboard systems. Although the exact cause of the loss is not
known, analysis has uncovered a potential problem with computer time tagging that could have led to
loss of control for Deep Impact's orientation. That would then affect the positioning of its radio
antennas, making communication difficult, as well as its solar arrays, which would in turn prevent the
spacecraft from getting power and allow cold temperatures to ruin onboard equipment, essentially
freezing its battery and propulsion systems.

"Despite this unexpected final curtain call, Deep Impact already achieved much more than ever was
envisioned," said Lindley Johnson, the Discovery Program Executive at NASA Headquarters, and the
Program Executive for the mission since a year before it launched. "Deep Impact has completely
overturned what we thought we knew about comets and also provided a treasure trove of additional
planetary science that will be the source data of research for years to come."

The mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in
Huntsville, Ala. JPL manages the Deep Impact mission for NASA's Science Mission Directorate in
Washington. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. The
California Institute of Technology in Pasadena manages JPL for NASA.

To find out more about Deep Impact's scientific results, visit: http://go.nasa.gov/19ki9LG .
For more information about Deep Impact, visit: http://www.nasa.gov/deepimpact .

-end-

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