[meteorite-list] Mars Odyssey Begins Overtime After Successful Mission

[Ron Baalke]

Gretchen Cook-Anderson
Headquarters, Washington                    August 25, 2004
(Phone: 202/358-0836)

Guy Webster 
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-6278)

RELEASE: 04-277

MARS ODYSSEY BEGINS OVERTIME AFTER SUCCESSFUL MISSION

     NASA's Mars Odyssey orbiter begins working overtime 
today after completing a prime mission that discovered vast 
supplies of frozen water, ran a safety check for future 
astronauts, and mapped surface textures and minerals all over 
Mars, among other feats.

"Odyssey has accomplished all of its mission-success 
criteria," said Dr. Philip Varghese, project manager for 
Odyssey at NASA's Jet Propulsion Laboratory, Pasadena, Calif. 
The spacecraft has been examining Mars in detail since 
February 2002, more than a full Mars year of about 23 Earth 
months. NASA has approved an extended mission through 
September 2006.

"This extension gives us another martian year to build on 
what we have already learned," said JPL's Dr. Jeff Plaut, 
project scientist for Odyssey. "One goal is to look for 
climate change. During the prime mission we tracked dramatic 
seasonal changes, such as the comings and goings of polar 
ice, clouds and dust storms. Now, we have begun watching for 
year-to-year differences at the same time of year."

The extension will also continue Odyssey's support for other 
Mars missions. About 85 percent of images and other data from 
NASA's twin Mars rovers, Spirit and Opportunity, have reached 
Earth via communications relay by Odyssey, which receives 
transmissions from both rovers every day.

The orbiter helped analyze potential landing sites for the 
rovers and is doing the same for NASA's Phoenix mission, 
scheduled to land on Mars in 2008. Plans call for Odyssey to 
aid NASA's Mars Reconnaissance Orbiter, due to reach Mars in 
March 2006, by monitoring atmospheric conditions during 
months when the newly arrived orbiter uses calculated dips 
into the atmosphere to alter its orbit into the desired 
shape.

Odyssey was launched April 7, 2001, and used the same 
"aerobraking" technique to shape its orbit during the initial 
months after it reached Mars on October 23, 2001. The 
spacecraft carries three research systems: a camera system 
made up of infrared and visible-light sensors; a spectrometer 
suite with a gamma ray spectrometer, a neutron spectrometer 
and a high-energy neutron detector; and a radiation 
environment detector.

Less than a month after the science mapping campaign began, 
the team announced a major discovery. The gamma ray and 
neutron instruments detected copious hydrogen just under 
Mars' surface in the planet's south polar region. Researchers 
interpret the hydrogen as frozen water -- enough within about 
a meter (3 feet) of the surface, if the ice were melted, to 
fill Lake Michigan a couple times.

Here are a few of Odyssey's other important accomplishments 
so far:

-- As summer came to northern Mars and the north polar 
covering of frozen carbon dioxide shrank, Odyssey found 
abundant frozen water in the north, too.

-- Infrared mapping shows that a mineral called olivine is 
widespread. This indicates the environment has been quite 
dry, because water exposure alters olivine into other 
minerals.

-- Findings indicate the amount of frozen water in some 
relatively warm regions on Mars is too great to be in 
equilibrium with the atmosphere, suggesting that Mars may be 
going through a period of climate change.  Features visible 
near small, young gullies in some Odyssey images may be 
slowly melting snowpacks left over from a martian ice age.

-- The first experiment sent to Mars specifically in 
preparation for human missions found that radiation levels 
around Mars, from solar flares and cosmic rays, are two to 
three times higher than around Earth.

-- Odyssey's camera system has obtained the most detailed 
complete global maps of Mars ever, with daytime and nighttime 
infrared images at a resolution of 100 meters (328 feet).

"We've accomplished everything we set out to do, and more," 
said JPL's Robert Mase, Odyssey mission manager. Although an 
unusually powerful solar flare in October 2003 knocked out 
the radiation environment instrument, Odyssey is otherwise in 
excellent health. The spacecraft has enough fuel onboard to 
keep operating through this decade and the next at current 
consumption rates. The mission extension, with a budget of 
$35 million, essentially doubles the science payoff from 
Odyssey for less than one-eighth of the mission's original 
$297 million cost.

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

-end-