[meteorite-list] Mars Opportunity Rover Finds a Meteorite

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed Jan 19 13:21:24 2005
Message-ID: <200501191821.KAA05788_at_zagami.jpl.nasa.gov>

http://space.com/missionlaunches/mars_meteor_050119.html

Mars Opportunity Rover Finds a Meteorite
By Leonard David
space.com
19 January 2005

Scientists have confirmed that the Opportunity Mars rover has run across
a meteorite, sitting within the robot's exploration zone at Meridiani
Planum.

"We have definitive word now... it's a meteorite," Steve Squyres,
principal science investigator for the Mars Exploration Rover program
told SPACE.com. Squyres is based at Cornell University in Ithaca, New York.

Opportunity has been using both cameras and science gear to study the
intriguing pitted rock on Mars, now dubbed "Heat Shield Rock".

Wheeling about the open landscape of Meridiani Planum, Opportunity had
been busily inspecting heat-shield wreckage -- hardware leftovers from
the spacecraft's plummet to Mars in January of last year.

Completing one of several debris surveys, the robot then turned and
drove north toward Heat Shield Rock. The rover traversed about 33 feet
(10 meters), parking itself at the desired standoff distance of about
3.3 feet (one meter) to acquire remote sensing of the rock.

Opportunity then acquired additional remote sensing, bumped forward
closer to the rock, putting the odd object within the work volume of the
tools mounted at the tip of the robot's mechanical arm.

Tempting target

Initial looks at the rock stirred considerable speculation that the
object could be a meteorite - speculation now confirmed. Opportunity's
Mini-Thermal Emission Spectrometer (Mini-TES) was suggestive that the
find was metal in nature.

Last week, Squyres took a wait-and-see mode, eagerly awaiting tell-tale
data recorded by Opportunity to be transmitted to Earth last weekend.
The rover's Mossbauer Spectrometer was moved into position over the
suspect meteorite, to determine the composition and abundance of
iron-bearing minerals.

Earlier last week, Laurie Leshin, Director of the Center for Meteorite
Studies at Arizona State University in Tempe, Arizona was tempted by the
images to conclude that the object was, indeed, a meteorite.

"Not sure if it is or not, but it does sorta look like one," Leshin told
SPACE.com. "Looks a lot like an iron [meteorite] to me."

Given the robot's suite of science instruments, Leshin said the rover
should be able to identify whether or not the rock was a meteorite.

Questions to ponder

The fact that Opportunity might have come across a meteorite raises a
number of issues, Leshin hypothesized before the confirmation by Squyres
and his science team.

"To me it is interesting for several speculative reasons," Leshin said.
First of all, depending on the size, it may indicate that it fell during
the time of a thicker atmosphere, she said.

"But we haven't done the calculation yet. Things much bigger than it
appears to be wouldn't be slowed down by today's thin atmosphere [on
Mars], and thus they would make a crater rather than a 'soft landing'",
Leshin explained.

Leshin also conjectured about the shiny nature of the object. "Is it
because - meteorites don't react with the atmosphere as on Earth or has it
been sandblasted?" Lastly, iron metal is one of the most susceptible
things to weathering/rust in the presence of water.

"Thus, a nicely preserved meteorite -- unless we're unlucky and it fell
yesterday, which we would never know -- strongly supports the idea that
current weathering rates [on Mars] are incredibly low," she said.
Received on Wed 19 Jan 2005 01:21:14 PM PST