NASA Extends Mars Rovers’ Mission

NASA has approved an extended mission for the Mars Exploration Rovers,
handing them up to five months of overtime assignments as they finish
their three-month prime mission.

The first of the two rovers, Spirit, met the success criteria set for
its prime mission. Spirit gained check marks in the final two boxes on
April 3 and 5, when it exceeded 600 meters (1,969 feet) of total drive
distance and completed 90 martian operational days after landing.

Opportunity landed three weeks after Spirit. It will complete the
two-rover checklist of required feats when it finishes a 90th martian
day of operations April 26. Each martian day, or “sol,” lasts about 40
minutes longer than an Earth day.

“Given the rovers’ tremendous success, the project submitted a
proposal for extending the mission, and we have approved it,” said
Orlando Figueroa, Mars Exploration Program director at NASA
Headquarters, Washington, D.C.

The mission extension provides $15 million for operating the rovers
through September. The extension more than doubles exploration for
less than a two percent additional investment, if the rovers remain in
working condition. The extended mission has seven new goals for
extending the science and engineering accomplishments of the prime
mission.

“Once Opportunity finishes its 91st sol, everything we get from the
rovers after that is a bonus,” said Dr. Firouz Naderi, manager of Mars
exploration at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.,
where the rovers were built and are controlled. “Even though the
extended mission is approved to September, and the rovers could last
even longer, they also might stop in their tracks next week or next
month. They are operating under extremely harsh conditions. However,
while Spirit is past its ‘warranty,’ we look forward to continued
discoveries by both rovers in the months ahead.”
JPL’s Jennifer Trosper, Spirit mission manager, said even when a
memory-management problem on the rover caused trouble for two weeks,
she had confidence the rover and the operations team could get through
the crisis and reach the 90-sol benchmark. “We never felt it was over,
but certainly when we were getting absolutely no data from the
spacecraft and were trying to figure out what happened, we were
worried,” she said.

Trosper was less confident about Spirit’s prospects for reaching the
criterion of 600 meters by sol 91, given the challenging terrain of
the landing area within Gusev Crater. On sol 89 Spirit accomplished
that goal and set a short-lived record for martian driving, with a
single-sol distance of 50.2 meters (165 feet) that pushed the odometer
total to 617 meters (2,024 feet). Two days later, Opportunity
shattered that mark with a 100-meter (328-foot) drive.

Beyond the quantifiable criteria, such as using all research tools at
both landing sites and investigating at least eight locations, the
rovers have returned remarkable science results. The most dramatic
have been Opportunity’s findings of evidence of a shallow body of
salty water in the past in the Mars Meridiani Planum region.

“We’re going to continue exploring and try to understand the water
story at Gusev,” said JPL’s Dr. Mark Adler, deputy mission manager for
Spirit. Spirit is in pursuit of geological evidence for an ancient
lake thought to have once filled Gusev Crater.

Reaching “Columbia Hills,” which could hold geological clues to that
water story, is one of seven objectives for Spirit’s extended mission.
Opportunity has a parallel one, to seek geologic context for the
outcrop in the “Eagle” crater by reaching other outcrops in the
“Endurance” crater and perhaps elsewhere. Other science objectives are
to continue atmospheric studies at both sites to encompass more of
Mars’ seasonal cycle, and to calibrate and validate data from Mars
orbiters for additional types of rocks and soils examined on the
ground.

Three new engineering objectives are to traverse more than a kilometer
(0.62 mile) to demonstrate mobility technologies; to characterize
solar-array performance over long durations of dust deposition at both
landing sites; and to demonstrate long-term operation of two mobile
science robots on a distant planet. During the past two weeks, rover
teams at JPL have switched from Mars-clock schedules to Earth-clock
schedules designed to be less stressful and more sustainable over a
longer period.