Rover Missions Renewed as Mars Emerges from Behind Sun

Donald Savage
Headquarters, Washington
(Phone: 202/358-1547)

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

Sept. 21, 2004
RELEASE : 04-307

Rover Missions Renewed as Mars Emerges from Behind Sun

As NASA's Spirit and Opportunity resumed reliable contact with Earth,
after a period when Mars passed nearly behind the sun, the space agency
extended funding for an additional six months of rover operations, as
long as they keep working.

Both rovers successfully completed their primary three-month missions on
the surface of Mars in April and have already added about five months of
bonus exploration during the first extension of their missions.

"Spirit and Opportunity appear ready to continue their remarkable
adventures," said Andrew Dantzler, solar system division director at
NASA Headquarters, Washington. "We're taking advantage of that good news
by adding more support for the teamwork here on Earth that's necessary
for operating the rovers."

Neither rover drove during a 12-day period this month, while radio
transmissions were unreliable because of the sun's position between the
two planets. Daily planning and commanding of rover activities
recommenced Monday for Opportunity and today for Spirit.

"It is a relief to get past this past couple of weeks," said Jim
Erickson, project manager for both rovers at NASA's Jet Propulsion
Laboratory (JPL), Pasadena, Calif. "Not only were communications
disrupted, but the rovers were also going through the worst part of Mars
southern-hemisphere winter from a solar-energy standpoint."

"Although Spirit and Opportunity are well past warranty, they are
showing few signs of wearing out," Erickson said. "We really don't know
how long they will keep working, whether days or months. We will do our
best to continue getting the maximum possible benefit from these great
national resources."

Rovers' science team members will spend less time at JPL during the
second mission extension. They are able to attend daily planning
meetings by teleconferencing from their home institutions in several
states and in Europe. "All 150 science team members and collaborators
have been provided the tools to be able to participate remotely," said
JPL's Dr. John Callas, science manager for the rover project.
Workstations researchers used at JPL are at their home institutions.
Planning tools include video feeds, workstation display remote viewing,
and audio conferencing.

Besides reducing costs, remote operations allow scientists to spend more
time at home. "We get back to more normal lives, back to our families,
and we still get to explore Mars every day," said Dr. Steve Squyres of
Cornell University, Ithaca, N.Y., principal investigator.

Another change in operations is a shift from seven days per week to five
days per week from October through December. This accommodates a
temporary trim of about 20 percent in the project's engineering team to
about 100 members. The rovers' reduced energy supply, during the rest of
the Martian winter, makes the inactive days valuable for recharging
batteries. By January, the energy situation will have improved for the
solar-powered rovers, provided they are still operating. The team size
will rebound to support daily operations.

As Mars emerges from behind the sun, Spirit is partway up the west spur
of highlands called the "Columbia Hills," a drive of more than 3
kilometers (2 miles) from its landing site. Opportunity is inside
stadium-size "Endurance Crater," headed toward the base of a stack of
exposed rock layers in "Burns Cliff," and a potential exit route on the
crater's south side.

JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Exploration Rover project for NASA's Science Mission
Directorate, Washington. Images and additional information about the
project are available on the Web at:

http://marsrovers.jpl.nasa.gov

http://athena.cornell.edu

For information about NASA programs on the Internet, visit:

http://www.nasa.gov

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