NASA Spacecraft Hours From Comet Encounter

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
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http://www.jpl.nasa.gov

Stardust-Next Mission Status
NASA Spacecraft Hours From Comet Encounter Feb. 14, 2011

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-050&cid=release_2011-050

PASADENA, Calif. -- As of today, Feb. 14, at 9:21 a.m. PST (12:21 p.m. EST), NASA's Stardust-
NExT mission spacecraft is within a quarter-million miles (402,336 kilometers) of its quarry, comet
Tempel 1, which it will fly by tonight. The spacecraft is cutting the distance with the comet at a rate
of about 10.9 kilometers per second (6.77 miles per second or 24,000 mph).

The flyby of Tempel 1 will give scientists an opportunity to look for changes on the comet's surface
since it was visited by NASA's Deep Impact spacecraft in July 2005. Since then, Tempel 1 has
completed one orbit of the sun, and scientists are looking forward to discovering any differences in
the comet.

The closest approach is expected tonight at approximately 8:40 p.m. PST (11:40 p.m. EST).

During the encounter phase, the spacecraft will carry out many important milestones in short order
and automatically, as the spacecraft is too far away to receive timely updates from Earth. These
milestones include turning the spacecraft to point its protective shields between it and the anticipated
direction from which cometary particles would approach. Another milestone will occur at about four
minutes to closest approach, when the spacecraft will begin science imaging of the comet's nucleus.

The nominal imaging sequence will run for about eight minutes. The spacecraft's onboard memory is
limited to 72 high-resolution images, so the imaging will be most closely spaced around the time of
closest approach for best-resolution coverage of Tempel 1's nucleus. At the time of closest encounter,
the spacecraft is expected to be approximately 200 kilometers (124 miles) from the comet's nucleus.

The mission team expects to begin receiving images on the ground starting at around midnight PST (3
a.m. on Feb. 15 EST). Transmission of each image will take about 15 minutes. It will take about 10
hours to complete the transmission of all images and science data aboard the spacecraft.

Live coverage on NASA TV and via the Internet begins at 8:30 p.m. PST (11:30 p.m. EST) from
mission control at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Coverage also will include
segments from the Lockheed Martin Space System's mission support area in Denver. A post-flyby
news conference is planned on Feb. 15 at 10 a.m. PST (1 p.m. EST).

For NASA TV streaming video, scheduling and downlink information, visit:
http://www.nasa.gov/ntv .

The live coverage and news conference will also be carried on one of JPL's Ustream channels. During
events, viewers can take part in a real-time chat and submit questions to the Stardust-NExT team at:
http://www.ustream.tv/user/NASAJPL2 .

During its 12 years in space, Stardust became the first spacecraft to collect samples of a comet (Wild
2 in 2004), which were delivered to Earth in 2006 for study. The Stardust-NExT mission is managed
by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in
Denver built the spacecraft and manages day-to-day mission operations.

A press kit and other detailed information about Stardust-NExT is online at:
http://stardustnext.jpl.nasa.gov .

Media contacts:

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

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

Blaine Friedlander 607-254-6235
Cornell University, Ithaca, N.Y.
bpf2@cornell.edu
-end-

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