[meteorite-list] Dawn Mission Status: Spacecraft Tests Ion Engine

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 9 Oct 2007 15:21:24 -0700 (PDT)
Message-ID: <200710092221.PAA18477_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2007-115

Dawn Mission Status: Spacecraft Tests Ion Engine
Jet Propulsion Laboratory
October 09, 2007

NASA's Dawn spacecraft successfully completed the first test of its ion
propulsion system over the weekend. The system is vital to the success
of Dawn's 8-year, 1.6 billion-kilometer (3-billion-mile) journey to
asteroid Vesta and dwarf planet Ceres.

"Dawn is our baby and over the weekend it took some of its first steps,"
said Dawn project manager Keyur Patel of NASA's Jet Propulsion
Laboratory in Pasadena, Calif. "We have two months more checkout and
characterization remaining before Dawn is considered mission
operational, but this is a great start."

Members of the Dawn mission control team have been sending up commands
and checking out spacecraft systems ever since its successful launch on
Sept. 27. The first test firing of one of Dawn's three ion engines was
the culmination of several days of careful preparation.

On Saturday, Oct. 6 at 6:07 p.m. Pacific Daylight Time (9:07 p.m.
Eastern Daylight Time), the ion propulsion system began thrusting. Over
the next 27 hours, spacecraft controllers and navigators at JPL
monitored the engine's performance as it was put through its paces.

"We evaluated the engine's capabilities at five different throttle
levels," said Jon Brophy, the Dawn project's ion propulsion manager at
JPL. "From flight idle through full throttle, the engine performed
flawlessly."

Dawn's ion engines are extremely frugal powerhouses. The 27 hours of
thrusting from the ion engine resulted in the consumption of less than
.28 kilograms (10 ounces) of the spacecraft's xenon fuel supply -- less
than the contents of a can of soda. Dawn's fuel tank carries 425
kilograms (937 pounds) of xenon propellant. 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 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: Los Alamos National
Laboratory, New Mexico; 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://dawn.jpl.nasa.gov .

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

Media contacts: DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.

Dwayne Brown 202-358-1726
NASA Headquarters, Washington

2007-115
Received on Tue 09 Oct 2007 06:21:24 PM PDT