JPL: Stardust mission

From: Brian D Williams (
Date: Tue Mar 20 2001 - 07:53:13 MST

PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011

Contact: Martha J. Heil (818) 354-0850


Stardust Team Develops Technique to Keep Camera Clear

     In December, Stardust, the mission to Comet Wild 2 to
capture dust particles and return them to Earth, cleared a
coating that was clouding its camera optics by applying heat.
Today, team members are investigating the reappearance of the
coating, which is similar to the frost on a car windshield, and
they plan to use the same heating technique again to clean up the

     The camera is designed to guide Stardust to its encounter
with Comet Wild 2 in 2004 and is still capable of meeting its
objectives. As Stardust passed by Earth last January, it snapped
pictures of the Moon with excellent resolution and similar
pictures will be acquired of the comet during the Wild 2 flyby.
Engineers deduced that the clouding of the lens might be due to a
substance that evaporates and settles, clinging to the coldest
parts of the camera.

     "We believe that the heating option will give us back our
improved sensitivity performance and reduced scattered light,
thereby providing excellent images at Comet Wild 2," said
Stardust project manager Tom Duxbury of NASA's Jet Propulsion
Laboratory, Pasadena, Calif. A longer period of heating may
clean the optics permanently. If not, heat will be applied again
as the spacecraft gets closer to the comet.

     The mission will bring back more than 1,000 dust particles
from the coma, the cloud of dust and gas that surrounds a comet.
Stardust's Cometary and Interstellar Dust Analyzer (CIDA),
provided by the Max-Planck-Institut fur extraterrestrische Physik
of Garching, Germany, will capture comet dust, study its
composition, and transmit the data back as the spacecraft flies
through space. A dust flux monitor, provided by the University of
Chicago, will measure the comet particle count and size during
the encounter.

     During the latest imaging sessions, the filter wheel, which
allows imaging in different colors of light, was found to be
stuck in one position, the optical navigation position, which
uses a clear filter. This could be due to any of several
possible situations, such as a faulty power supply, a shorted
coil or a locked wheel. The imaging at the comet will only be
minimally affected since the camera will continue to take black
and white pictures of an object that probably has very little
color. The primary objectives of the camera, which guide the
spacecraft to the comet and take images of the comet nucleus,
will still be carried out in full.

     Stardust, a part of NASA's Discovery Program of low-cost,
highly focused science missions, was built by Lockheed Martin
Astronautics and Operations, Denver, Colo. is managed by the Jet
Propulsion Laboratory, Pasadena, Calif., for NASA's Office of
Space Science, Washington, D.C. JPL is a division of the
California Institute of Technology, Pasadena, Calif. The
Principal Investigator is astronomy professor Donald E. Brownlee
of the University of Washington in Seattle. More information on
the Stardust mission is available at

03/19/01 MJH

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