As Earth pulls away from Mars after last month’s close approach, NASA
is developing a spacecraft that will take advantage of the next close
encounter in 2005.That spacecraft, Mars Reconnaissance Orbiter, will
make a more comprehensive inspection of our planetary neighbor than
any previous mission.

For starters, it will examine landscape details as small as a coffee
table with the most powerful telescopic camera ever sent to orbit a
foreign planet. Some of its other tools will scan underground layers
for water and ice, identify small patches of surface minerals to
determine their composition and origins, track changes in atmospheric
water and dust, and check global weather every day.

"We’re reaching an important stage in developing the spacecraft," said
James Graf, project manager for Mars Reconnaissance Orbiter at NASA’s
Jet Propulsion Laboratory, Pasadena, Calif. "The primary structure
will be completed next month." The structure weighs 220 kilograms (484
pounds) and stands 3 meters (10 feet) tall. At launch, after gear and
fuel are added, it will support over 2 tons.

Also next month, the mission’s avionics test bed will be assembled for
the first time and put to use for testing of flight software.

Workers at Lockheed Martin Space Systems, Denver, have already
assembled the spacecraft structure and will later add instruments
being built for it at the University of Arizona, Tucson; at Johns
Hopkins University Applied Physics Laboratory, Laurel, Md.; at the
Italian Space Agency, Rome; at Malin Space Science Systems, San Diego,
Calif.; and at JPL.

"In several ways, Mars Reconnaissance Orbiter will advance NASA’s
follow-the-water strategy for Mars exploration," said Dr. Richard
Zurek, project scientist for the mission.

Current surveys of Mars’ surface composition have found less evidence
of water-related minerals than many scientists anticipated after
earlier discoveries of plentiful channels that were apparently carved
by water flows in the planet’s past. A spectrometer on the
Reconnaissance Orbiter is designed to identify some different types of
water-related minerals and to see smaller-scale deposits. "Instead of
looking for something as big as the Bonneville Salt Flats, we can look
for something on the scale of a Yellowstone hot spring," Zurek said.

Probing below Mars’ surface with penetrating radar, Reconnaissance
Orbiter will check whether the frozen water that NASA’s Mars Odyssey
spacecraft detected in the top meter or two (yard or two) of soil
extends deeper, perhaps as accessible reservoirs of melted water.

Above the surface, an atmosphere-scanning instrument will monitor
changes in water vapor at different altitudes and might even locate
plumes where water vapor is entering the atmosphere from underground
vents, if that’s happening on Mars.

Mars Reconnaissance Orbiter will stream home its pictures and other
information using the widest dish antenna and highest power level ever
operated at Mars. "The amount of data flowing back to Earth from Mars
will be a giant leap over previous missions. It’s like upgrading from
a dial-up modem for your computer to a high-speed DSL connection,"
Graf said.

The Mars Reconnaissance Orbiter will lay the groundwork for later Mars
surface missions in NASA’s plans: a lander called Phoenix selected
last month in a competition for a 2007 launch opportunity, and a
highly capable rover called Mars Science Laboratory being developed
for a 2009 launch opportunity. The orbiter’s high-resolution
instruments will help planners evaluate possible landing sites for
these missions both in terms of science potential for further
discoveries and in terms of landing risks. The orbiter’s
communications capabilities will provide a critical transmission relay
for the surface missions.

Advantageous opportunities to launch Mars missions come in a rhythm of
about every 26 months, shortly before each time Earth overtakes Mars
in the two planets’ concentric tracks around the Sun. NASA’s two Mars
Exploration Rovers and the European Space Agency’s Mars Express
mission were launched during the three months preceding Earth’s most
recent passing of Mars on Aug. 27. The Mars Reconnaissance Orbiter
team has its work cut out for it to have the spacecraft ready for
launch on Aug. 10, 2005, which is about 10 weeks before the next close

JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Reconnaissance Orbiter project for NASA’s Office of
Space Science, Washington, D.C.