[meteorite-list] Dawn Glides Into New Year

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 24 Nov 2008 13:49:27 -0800 (PST)
Message-ID: <200811242149.NAA14273_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2008-221

Dawn Glides Into New Year
Jet Propulsion Laboratory
November 20, 2008

NASA's Dawn spacecraft shut down its ion propulsion system today as
scheduled. The spacecraft is now gliding toward a Mars flyby in February
of next year.

"Dawn has completed the thrusting it needs to use Mars for a gravity
assist to help get us to Vesta," said Marc Rayman, Dawn's chief
engineer, of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Dawn
will now coast in its orbit around the sun for the next half a year
before we again fire up the ion propulsion system to continue our
journey to the asteroid belt."

Dawn's ion engines may get a short workout next January to provide any
final orbital adjustments prior to its encounter with the Red Planet.
Ions are also scheduled to fly out of the propulsion system during some
systems testing in spring. But mostly, Dawn's three ion engines will
remain silent until June, when they will again speed Dawn toward its
first appointment, with asteroid Vesta.

Dawn's ion engines are vital to the success of the misson's 8-year,
4.9-billion-kilometer (3-billion-mile) journey to asteroid Vesta and
dwarf planet Ceres. One of these extremely frugal powerhouses can
generate more than 24 hours of thrusting while consuming about .26
kilograms (about 9 ounces) of the spacecraft's xenon fuel supply -- less
than the contents of a can of soda. Over their lifetime, Dawn's three
ion propulsion engines will fire cumulatively for about 50,000 hours
(over five years) -- a record for spacecraft.

Dawn will begin its exploration of asteroid Vesta in 2011 and the dwarf
planet Ceres in 2015. These two icons of the asteroid belt have been
witness to so much of our solar system's history. By utilizing the same
set of instruments at two separate destinations, scientists can more
accurately formulate comparisons and contrasts. Dawn's science
instrument suite will measure shape, surface topography, tectonic
history, elemental and mineral composition, and will seek out
water-bearing minerals. In addition, the Dawn spacecraft itself and how
it orbits both Vesta and Ceres will be used to measure the celestial
bodies' masses and gravity fields.

The Dawn mission to asteroid Vesta and dwarf planet Ceres is managed and
operated by JPL for NASA's Science Mission Directorate, Washington, D.C.
The University of California, Los Angeles, is responsible for overall
Dawn mission science. Other scientific partners include: Max Planck
Institute for Solar System Research, Katlenburg, Germany; DLR Institute
for Planetary Research, Berlin, Germany; Italian National Institute for
Astrophysics, Rome; and the Italian Space Agency. Orbital Sciences
Corporation of Dulles, Virginia, designed and built the Dawn spacecraft.

Additional information about Dawn is online at http://www.nasa.gov/dawn
and http://dawn.jpl.nasa.gov.

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

2008-221
Received on Mon 24 Nov 2008 04:49:27 PM PST