NASA's
aging Mars rover Spirit has a bit more power under its hood thanks to some Martian
winds that cleaned dust from its vital solar panels.
The handy cleaning
occurred earlier this month and was discovered by engineers scanning data from
Spirit's power subsystem.
"We
will be able to use this energy to do significantly
more driving," said Colette Lohr, a rover mission manager at NASA's
Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Our drives have been
averaging about 50 minutes, and energy has usually been the limiting factor. We
may be able to increase that to drives of an hour and a half."
The last
time winds scoured Spirit's solar array clean was in June 2007, but a massive
dust storm on Mars later that year piled new grit atop the rover, mission
managers said.
Thanks to
the recent Martian winds, Spirit's daily power levels rose to 240 watt-hours,
an increase of about 30 watt-hours, mission managers said. For comparison, 30
watt-hours is the same amount of energy used by a 30-watt light bulb during one
hour.
"It
may not sound like a lot, but it is an important increase," said rover
team engineer Jennifer Herman, who first discovered the power boost while
studying data beamed home by Spirit on Feb. 6 - the rover's 1,812 Martian day
exploring the red planet.
Before the
cleaning event, Spirit was generating about 210 watt-hours of power, with only
25 percent of the available sunlight penetrating the dust layer coating its
top-mounted solar array. After the cleaning, the amount of sunlight getting
through jumped to about 28 percent.
Spirit
needs about 180 watt-hours just to survive on the Martian surface and maintain
contact with its human handlers on Earth. The extra 30 watt-hours nearly
doubles the amount of power the rover now has for driving across Mars or using
its science instruments and robotic arm, mission managers said.
Spirit is
currently rolling across a low, rocky plateau dubbed "Home Plate," which sits
within the rover's Gusev Crater landing site on Mars. Originally built for a
planned 90-day mission, Spirit and its robotic
twin Opportunity have now spent more
than five years exploring their respective Martian landing sites on
opposite sides of the planet.
Both Spirit
and Opportunity have suffered some aches and pains associated with their
unexpected longevity on the surface of Mars. Most recently, Spirit experienced
an odd bout of amnesia when it failed to record and report a day of activities
to flight controllers on Earth last month.
Spirit has
since recovered from the glitch and driven about 30 feet (9 meters) after
overcoming a stubborn rock that blocked its path in late January. Rover
scientists hope to guide Spirit to the other side of its "Home Plate" territory
in the weeks to come.
On the
other side of Mars, Spirit's twin Opportunity is doggedly driving across the
plains of its Meridiani Planum landing site as it heads towards a monster
crater called Endeavour. Last week, Opportunity drove about 446 feet (nearly
136 meters) in one of a series of long hauls en route to the crater. The rover
has visited a several craters, each larger than the last, in its more than five
years of Mars exploration.
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