[meteorite-list] Deep Impact Successfully Releases Impactor

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sun Jul 3 11:59:57 2005
Message-ID: <200507031559.j63Fx6521606_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2005-108

DC Agle (818) 393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
 
Dolores Beasley (202) 358-1753
NASA Headquarters, Washington
 
Lee Tune (301) 405-4679
University of Maryland, College Park
 
2005-108

Deep Impact Status Report
July 03, 2005

One hundred and seventy-one days into its 172-day journey to comet
Tempel 1, NASA's Deep Impact spacecraft successfully released its
impactor at 11:07 p.m. Saturday, Pacific Daylight Time (2:07 a.m.
Sunday, Eastern Daylight Time).

At release, the impactor was about 880,000 kilometers (547,000 miles)
away from its quarry. The separation of flyby spacecraft and the
washing-machine-sized, copper-fortified impactor is one in a series
of important mission milestones that will cap off with a planned
encounter with the comet at 10:52 p.m. Sunday, PDT (1:52 a.m. on
July 4, EDT).

Six hours prior to impactor release, the Deep Impact spacecraft
successfully performed its fourth trajectory correction maneuver. The
30-second burn changed the spacecraft's velocity by about one kilometer
per hour (less than one mile per hour). The goal of the burn is to
place the impactor as close as possible to the direct path of
onrushing comet Tempel 1.

Soon after the trajectory maneuver was completed, the impactor
engineers began the final steps that would lead to it being ready for
free flight. The plan culminated with activation of the impactor's
batteries at 10:12 p.m., PDT (1:12 a.m. Sunday, EDT). Deep Impact's
impactor has no solar cells; the vehicle's batteries are expected to
provide all the power required for its short day-long life.

In order to release the impactor, separation pyros fired allowing a
spring to uncoil and separate the two spacecraft at a speed of about
35 centimeters per second (0.78 mile per hour).

With Tempel 1 closing the distance between it and impactor at about
10 kilometers (6 miles) per second, there is little time for mission
controllers to admire their work. Twelve minutes after impactor release
the flyby began a 14-minute long divert burn that slowed its velocity
relative to the impactor by 102 meters per second (227 miles per hour),
moving it out of the path of the onrushing comet nucleus and setting the
stage for a ringside seat of celestial fireworks to come less than 24
hours later.

Deep Impact mission controllers have confirmed the impactor's S-band
antenna is talking to the flyby spacecraft. All impactor data including
the expected remarkable images of its final dive into the comet's nucleus
will be transmitted to the flyby craft -- which will then downlink them
to Deep Space Network antennas that are listening 134 million kilometers
(83 million miles) away.

While all is going as expected on the Deep Impact spacecraft the comet
itself is putting on something of a show. The 14-kilometer-long
(8.7-mile-long) comet Tempel 1 displayed another cometary outburst on
July 2 at 1:34 a.m. PDT (4:34 a.m.EDT) when a massive, short-lived blast
of ice or other particles escaped from inside the comet's nucleus and
temporarily expanded the size and reflectivity of the cloud of dust and
gas (coma) that surrounds it. The July 2 outburst is the fourth observed
in the past three weeks.

Three of the outbursts appear to have originated from the same area on the
surface of the nucleus but they do not occur every time that that area
faces the Sun.

"The comet is definitely full of surprises so far and probably has a few
more in store for us," said Deep Impact Project Manager Rick Grammier of
NASA's Jet Propulsion Laboratory, Pasadena, Calif. "None of this overly
concerns us nor has it forced us to modify our nominal mission plan."

Information and images from a camera aboard Deep Impact's impactor and
flyby spacecraft can be watched in near-real time at www.nasa.gov/deepimpact .

For additional information about Deep Impact on the Internet, visit
http://deepimpact.jpl.nasa.gov .

-----------------------------------------------------------------------

http://www.nasa.gov/mission_pages/deepimpact/multimedia/imp-mri-070305.html

Separation Anxiety Over for Deep Impact
07.03.05

[Image of the impactor taken after separation]

This image of Deep Impact's impactor probe was taken by the mission's
mother ship, or flyby spacecraft, after the two separated at 11:07 p.m.
Pacific time, July 2 (2:07 a.m. Eastern time, July 3). The impactor is
scheduled to collide with comet Tempel 1 at 10:52 p.m. Pacific time,
July 3 (1:52 a.m. Eastern time, July 4). The impactor can be seen at
the center of the image.

Image credit: NASA/JPL-Caltech
Received on Sun 03 Jul 2005 11:59:06 AM PDT