[meteorite-list] Rovers Still Exploring Mars After 2 Years

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon Jan 2 22:41:12 2006
Message-ID: <200601030339.k033daS10078_at_zagami.jpl.nasa.gov>

http://news.yahoo.com/s/ap/20060102/ap_on_sc/mars_rovers;_ylt=Ah280BfwmFrF.LlFRZJ7snJvieAA;_ylu=X3oDMTBiMW04NW9mBHNlYwMlJVRPUCUl

Rovers Still Exploring Mars After 2 Years
By ALICIA CHANG
Associated Press
January 2, 2006

LOS ANGELES - The warranty expired long ago on

NASA's twin robots motoring around Mars. These two golf cart-sized
vehicles were only expected to last three months.

In two years, they have traveled a total of seven miles. Not impressed?
Try keeping your car running in a climate where the average temperature
is 67 below zero and where dust devils can reach 100 mph.

"These rovers are living on borrowed time. We're so past warranty on
them," says Steven Squyres of Cornell University, the Mars mission's
principal researcher. "You try to push them hard every day because we're
living day-to-day."

The rover Spirit landed on Mars on Jan. 3, 2004, and Opportunity
followed on Jan. 24. Since then, they've set all sorts of records and
succeeded in the mission's main assignment: finding geologic evidence
that water once flowed on Mars.

Part of the reason for their long survival is pure luck. Their lives
were extended several times by dust devils that blew away dust that
covered their solar panels, restoring their ability to generate electricity.

Like most Earth-bound vehicles, these identical robots have their own
personalities.

The overachieving Opportunity dazzled scientists from the start. It
eclipsed its twin by making the mission's first profound discovery ???
evidence of water at or near the surface eons ago that could have
implications for life.

The rock-climbing Spirit went down in the history books by becoming the
first robot to scale an extraterrestrial hill. Last summer, it completed
a daredevil climb to the summit of Husband Hill ??? as tall as the Statue
of Liberty ??? despite fears that it might not survive the weather.

The rovers haven't been all get-up and go ??? technical hiccups have at
times limited their activity, even from the start. At one point, Spirit
had a balky front wheel, but engineers overcame the problem by driving
it in reverse. Last spring, Opportunity got stuck hub-deep in sand while
trying to crest a foot-high dune, and was freed after weeks of effort by
the Earth-bound engineers.

The six-wheeled travelers, managed by NASA's Jet Propulsion Laboratory
in Pasadena, also are showing signs of aging. In November, a motor on
Opportunity's robotic arm stalled and the arm failed to extend while it
was surveying a rock outcrop. The engineers fixed that problem after two
weeks.

This mission is the first time any probe has extensively rolled across
Mars, whose rocky landscape is a dangerous place for man-made objects to
settle and roam.

There have been four previous Mars landings that succeeded. Of those,
NASA's stationary Viking 1 lander operated the longest, from 1976 to
1982. NASA's Sojourner was the first rover, but it stayed close to its
Pathfinder lander.

Spirit and Opportunity parachuted to opposite ends of Mars. Spirit
landed in Gusev Crater, a 90-mile-wide depression south of the Martian
equator. Opportunity followed three weeks later, touching down on
Meridiani Planum on the other side of the planet.

In two years, Spirit has traveled over three miles and beamed back
70,000 images including self-portraits and panoramas of the rust-colored
planet's surface. Opportunity has driven over four miles and transmitted
more than 58,000 images.

Three times NASA has extended the rovers' mission, spending an extra $84
million on top of the $820 million original price tag.

While both rovers have discovered clues of ancient water, they also have
found evidence of a violent past that might have prevented some life
forms from emerging.

Piecing together a definitive history of Mars is far from over,
scientists say, as the rovers head to their next destinations to explore
more rocks and minerals.

Spirit recently descended Husband Hill and is driving toward a basin
that holds geologic promise. Opportunity is rolling to an enormous
depression known as Victoria Crater that is thought to hold more clues
about the planet's past.

"Rock layers are the barcode of Mars history," said John Grotzinger, a
science team member from the Massachusetts Institute of Technology.
"Every time we encounter new layers, it's another piece of the puzzle."
Received on Mon 02 Jan 2006 10:39:36 PM PST