[meteorite-list] NASA Rover Finds Meteorite on Surface of Mars

From: jbaxter112_at_pol.net <jbaxter112_at_meteoritecentral.com>
Date: Tue Jan 18 20:27:22 2005
Message-ID: <32519.10.250.10.1.1106098035.squirrel_at_sq04.pol.net>

Hi Ron,

When you consider infintesimal the odds of finding a meteorite here on
Earth after traversing as short a distance as the rovers have, you have to
ask whether there are local factors on Mars which dramatically increase
the number of meteorites per square kilometer on the surface there. I
assume the lack of water there would probably significantly decrease
weathering relative to Earth. I wonder also, though, whether the influx
of meteorites to the surface there may be significantly greater than on
Earth leading to a higher surface density. Are you aware of models or data
that would predict a higher influx of meteorites to the Martian surface?

Regards,
Jim Baxter

>
>
> http://www.montereyherald.com/mld/montereyherald/news/politics/10674958.htm
>
>
> NASA rover finds meteorite on surface of Mars
> JOHN ANTCZAK
> Associated Press
> January 18, 2005
>
> LOS ANGELES - In a stroke of luck, the NASA rover Opportunity has
> discovered a basketball-size metal meteorite sitting on the surface of
> Mars, the mission's main scientist said Tuesday.
>
> Opportunity came upon the meteorite last week while it was taking a look
> at a spacecraft shell that was jettisoned before landing after
> protecting the rover during its plunge through the martian atmosphere.
>
> Tests performed during the weekend confirm it is a nickel-iron
> meteorite, said Steve Squyres, a Cornell University scientist who is the
> principal investigator for NASA's Mars Exploration Rovers mission.
>
> "I didn't see this one coming," Squyres said. "I try very hard to
> anticipate the things that we might find and the things we might need to
> know, and be prepared for things, but an iron meteorite was not
> something that I was expecting."
>
> Whether or not other meteorites are found may help scientists determine
> whether the martian surface is being covered by wind-blown materials or
> whether surface material is being stripped away, Squyres said.
>
> Opportunity landed Jan. 24 on the Meridiani plains, halfway around the
> planet from where its twin, Spirit, set down in the Gusev Crater region
> on Jan. 3, 2004.
>
> Opportunity, a six-wheeled robot geologist, quickly discovered rocks
> showing that its area of Meridiani was once soaked in water, the major
> scientific finding of the twin-rover mission. After that it explored
> rocks in a deep crater and then went to conduct an engineering study of
> its jettisoned heat shield. The meteorite was sitting nearby.
>
> "I've actually told the team that we probably shouldn't linger here long
> because this is obviously the place at Meridiani Planum where large
> metal objects fall from the sky," Squyres joked.
>
> The meteorite immediately appeared different from anything scientists
> had seen at either landing site.
>
> "And then we looked at it with our infrared spectrometer and it looked
> like the martian sky, which is really weird," he said. The metal
> surface, he explained, was reflecting sky radiation instead of emitting
> much of its own.
>
> During the weekend, the rover drove to the meteorite and deployed its
> instrument arm to confirm its origin.
>
> The rover used its brush to remove dust but did not try to grind into
> the meteorite with its rock abrasion tool because of the outcome of a
> test conducted by the tool's maker, Honeybee Robotics of Manhattan.
>
> "We contacted the meteorite department at the American Museum of Natural
> History in New York and they were generous enough to give us a piece of
> nickel-iron meteorite to try grinding into, and in like an hour of
> grinding we wore away about 25 percent of the grinding heads," Squyres
> said.
>
> "We designed our rock abrasion tool for rock. We didn't design it for
> nickel-iron alloys."
>
> Scientists are not interested in the meteorite itself. Rather, they want
> to see if other objects spotted out on the Meridiani plains are also
> meteorites and what that might tell them about Mars.
>
> "You've got sort of a steady rain of meteorites on to the martian
> surface. It's at a very slow rate, but they are going to accumulate over
> time." Squyres said.
>
> If sand is continually blowing in and being deposited on the surface,
> burying things and building up terrain over time, meteorites will be
> covered and few will be seen, he said. But if fine surface material is
> being continuously stripped away by the wind, coarse things like
> meteorites will be left behind and their accumulation will show.
>
> "So whether you're seeing a net accumulation or a net burial of the
> meteorites is going to tell you something about what the erosion or
> deposition rates are out on the plains," he said.
>
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Received on Tue 18 Jan 2005 08:27:15 PM PST