NASA's Mars Odyssey Shifting Orbit for Extended Mission

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

Dwayne Brown 202-358-1726
Headquarters, Washington
dwayne.c.brown@nasa.gov

NEWS RELEASE: 2008-191 October 9, 2008

NASA's Mars Odyssey Shifting Orbit for Extended Mission

PASADENA, Calif. -- The longest-serving of six spacecraft now studying Mars is up to new tricks
for a third two-year extension of its mission to examine the most Earthlike of known foreign planets.

NASA's Mars Odyssey is altering its orbit to gain even better sensitivity for its infrared mapping of
Martian minerals. During the mission extension through September 2010, it will also point its camera
with more flexibility than it has ever used before. Odyssey reached Mars in 2001.

The orbit adjustment will allow Odyssey's Thermal Emission Imaging System to look down at sites
when it's mid-afternoon, rather than late afternoon. The multipurpose camera will take advantage of
the infrared radiation emitted by the warmer rocks to provide clues to the rocks' identities.

"This will allow us to do much more sensitive detection and mapping of minerals," said Odyssey
Project Scientist Jeffrey Plaut of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The mission's orbit design before now used a compromise between what works best for the Thermal
Emission Imaging System and what works best for another instrument, the Gamma Ray
Spectrometer.

On commands from its operations team at JPL and at Denver-based Lockheed Martin Space Systems,
Odyssey fired thrusters for nearly 6 minutes on Sept. 30, the final day of the mission's second two-
year extension.

"This was our biggest maneuver since 2002, and it went well," said JPL's Gaylon McSmith, Odyssey
mission manager. "The spacecraft is in good health. The propellant supply is adequate for operating
through at least 2015."

Odyssey's orbit is synchronized with the sun. The local solar time has been about 5 p.m. at whatever
spot on Mars Odyssey flew over as it made its dozen daily passes from between the north pole region
to the south pole region for the past five years. (Likewise, the local time has been about 5 a.m. under
the track of the spacecraft during the south-to-north leg of each orbit.)

The push imparted by the Sept. 30 maneuver will gradually change that synchronization over the next
year or so. Its effect is that the time of day on the ground when Odyssey is overhead is now getting
earlier by about 20 seconds per day. A follow-up maneuver, probably in late 2009 when the overpass
time is between 2:30 and 3:00 p.m., will end the progression toward earlier times.

While aiding performance of the Thermal Emission Imaging System, the shift to mid-afternoon is
expected to stop the use of one of three instruments in Odyssey's Gamma Ray Spectrometer suite.
The suite's gamma ray detector needs a later-hour orbit to avoid overheating of a critical component.
The suite's neutron spectrometer and high-energy neutron detector are expected to keep operating.

The Gamma Ray Spectrometer provided dramatic discoveries of water-ice near the surface
throughout much of high-latitude Mars, the impetus for NASA's Phoenix Mars Lander mission. The
gamma ray detector has also mapped global distribution of many elements, such as iron, silicon and
potassium, a high science priority for the first and second extensions of the Odyssey mission. A panel
of planetary scientists assembled by NASA recommended this year that Odyssey make the orbit
adjustment to get the best science return from the mission in coming years.

Increased sensitivity for identifying surface minerals is a key science goal for the mission extension
beginning this month. Also, the Odyssey team plans to begin occasionally aiming the camera away
from the straight-down pointing that has been used throughout the mission. This will allow the team
to fill in some gaps in earlier mapping and also create some stereo, three-dimensional imaging.

Odyssey will continue providing crucial support for Mars surface missions as well as conducting its
own investigations. It has relayed to Earth nearly all data returned from NASA rovers Spirit and
Opportunity. It shares with NASA's Mars Reconnaissance Orbiter the relay role for Phoenix. It has
made targeted observations for evaluating candidate landing sites.

Mars Odyssey, launched in 2001, is managed by JPL, a division of the California Institute of
Technology, Pasadena, for NASA's Science Mission Directorate, Washington. Lockheed Martin
Space Systems, Denver, is the prime contractor for the project and built the spacecraft. Investigators
at Arizona State University, Tempe, operate the Thermal Emission Imaging System. Investigators at
the University of Arizona, Tucson, head operation of the Gamma Ray Spectrometer. Additional
science partners are located at the Russian Aviation and Space Agency, which provided the high-
energy neutron detector, and at Los Alamos National Laboratories, New Mexico, which provided the
neutron spectrometer.

For more about the Mars Odyssey mission, visit: http://mars.jpl.nasa.gov/odyssey .

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