[meteorite-list] Mars Rover Inspects Intriguing Rock - A Meteorite?

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Jan 18 12:40:50 2005
Message-ID: <200501181740.JAA10556_at_zagami.jpl.nasa.gov>

http://www.space.com/missionlaunches/mars_rock_050117.html

Mars Rover Inspects Intriguing Rock - A Meteorite?
By Leonard David
space.com
17 January 2005

Scientists controlling the Opportunity Mars rover are taking an up-close
look at an intriguing pitted rock on Mars, now dubbed "Heat Shield Rock".

A speculative view about the object is that the Mars robot has come
across a meteorite. A detailed investigation of the rock is underway,
work that should reveal the true nature of the object.

Wheeling about the open landscape of Meridiani Planum, Opportunity has
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 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.

Meteorite or "meteorwrong"?

Initial looks at the rock have stirred speculation the object could be a
meteorite. Furthermore, Opportunity's Mini-Thermal Emission Spectrometer
(Mini-TES) is suggestive that the find is made of metal.

In wait-and-see mode is Steve Squyres of Cornell University, principal
investigator for the science instruments onboard Opportunity, as well as
the Spirit rover busy at work on the other side of Mars.

Squyres said data taken by Opportunity's Alpha Particle X-Ray
Spectrometer -- a device that accurately determines the elements that
make up rocks and soils - is to arrive over the weekend. So too is
information about the rock from use of the rover's Mossbauer
Spectrometer. This equipment can determine the composition and abundance
of iron-bearing minerals.

Too early to tell if it's a meteorite, said Laurie Leshin, Director of
the Center for Meteorite Studies at Arizona State University in Tempe,
Arizona.

"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."

Leshin said, however, that her Meteorite Center identifies loads of
"meteorwrongs" per year. "Looks can be deceiving."

Given the robot's suite of science instruments, identifying the makeup
and origin of the rock should be forthcoming.

Questions to ponder

If Opportunity has come across a meteorite, a number of issues arise.

"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 rock. "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.

Whether or not Opportunity has come across a meteorite is yet to be
determined. "I will say that we've lent a bunch of iron meteorites to
the Mini-TES team to compare with it!"
Received on Tue 18 Jan 2005 12:40:33 PM PST