[meteorite-list] NASA's Venerable Comet Hunter Wraps Up Mission (Stardust)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 25 Mar 2011 08:49:51 -0700 (PDT)
Message-ID: <201103251549.p2PFnphT026634_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2011-095

NASA's Venerable Comet Hunter Wraps Up Mission
Jet Propulsion Laboratory
March 24, 2011

At 33 minutes after 4 p.m. PDT today, NASA's Stardust spacecraft
finished its last transmission to Earth. The transmission came on the
heels of the venerable spacecraft's final rocket burn, which was
designed to provide insight into how much fuel remained aboard after its
encounter with comet Tempel 1 in February.

"Stardust has been teaching us about our solar system since it was
launched in 1999," said Stardust-NExT project manager Tim Larson from
NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It makes sense
that its very last moments would be providing us with data we can use to
plan deep space mission operations in the future."

The burn to depletion maneuver was designed to fire Stardust's rockets
until insufficient fuel remains to continue, all the while downlinking
data on the burn to Earth some 312 million kilometers (194 million
miles) away. Mission personnel will compare the amount of fuel consumed
in the burn with the amount they anticipated would be burned based on
their fuel consumption models.

Fuel consumption models are necessary because no one has invented a
reliable fuel gauge for spacecraft when in the weightless environment of
space flight. Until that day arrives, mission planners can approximate
fuel usage by looking at the history of the vehicle's flight and how
many times and for how long its rocket motors have fired.

Mission personnel watched the final data from the burn come down at
JPL's Space Flight Operations Facility and at the Stardust-NExT mission
support center at Lockheed Martin Space Systems in Denver.

"Stardust motors burned for 146 seconds," said Allan Cheuvront, Lockheed
Martin Space Systems Company program manager for Stardust-NExT. "We'll
crunch the numbers and see how close the reality matches up with our
projections. That will be a great data set to have in our back pocket
when we plan for future missions."

The Stardust team performed the final burn to depletion because NASA's
most senior comet hunter is a spacecraft literally running on fumes.
Launched on Feb. 7, 1999, Stardust had completed its prime mission back
in January 2006. By that time, Stardust had already flown past an
asteroid (Annefrank), flown halfway out to Jupiter to collect particle
samples from the coma of a comet, Wild 2, and returned to fly by Earth
to drop off a sample return capsule eagerly awaited by comet scientists.
NASA then re-tasked the spacecraft to perform a bonus mission to fly
past comet Tempel 1 to collect images and other scientific data.
Stardust has traveled about 21 million kilometers (13 million miles) in
its journey about the sun in the few weeks since the Valentine's day
comet Tempel 1 flyby, making the grand total from launch to its final
rocket burn about 5.69 billion kilometers (3.54 billion miles).

With all that mileage logged, the Stardust team knew the end was near.
Now, with its fuel tank empty and its final messages transmitted,
history's most traveled comet hunter will move from NASA's active
mission roster to retired.

"This kind of feels like the end of one of those old Western movies
where you watch the hero ride his horse towards the distant setting sun
- and then the credits begin to roll," said Larson. "Only there's no
setting sun in space."

Stardust-NExT was a low-cost mission to expand the investigation of
comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a
division of the California Institute of Technology in Pasadena, managed
the Stardust-NExT project for the NASA Science Mission Directorate,
Washington, D.C., which was part of the Discovery Program managed by
NASA's Marshall Space Flight Center in Huntsville, Ala. Joe Veverka of
Cornell University, Ithaca, N.Y., was the mission's principal
investigator. Lockheed Martin Space Systems, Denver, built the
spacecraft and managed day-to-day mission operations.

For more information about Stardust-NExT, please visit:
http://stardustnext.jpl.nasa.gov.

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

2011-095
Received on Fri 25 Mar 2011 11:49:51 AM PDT