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Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Gretchen Cook-Anderson
(202) 358-0836
NASA Headquarters,
Washington, D.C.
News Release: 2005-018
January 19, 2005
Opportunity Rover Finds an
Iron Meteorite on Mars
NASA's Mars Exploration
Rover Opportunity has found an iron meteorite, the first meteorite of any
type ever identified on another planet.
The pitted, basketball-size
object is mostly made of iron and nickel according to readings from
spectrometers on the rover.
Only a small fraction of the meteorites fallen on Earth are similarly
metal-rich. Others are rockier. As an example, the meteorite that blasted
the famous Meteor Crater in Arizona is similar in composition.
"This is a huge surprise,
though maybe it shouldn't have been," said Dr. Steve Squyres of Cornell
University, Ithaca, N.Y., principal investigator for the science
instruments on Opportunity and its twin, Spirit.
The meteorite, dubbed "Heat
Shield Rock," sits near debris of Opportunity's heat shield on the surface
of Meridiani Planum, a cratered flatland that has been Opportunity's home
since the robot landed on Mars nearly one year ago.
"I never thought we would
get to use our instruments on a rock from someplace other than Mars,"
Squyres said. "Think about
where an iron meteorite comes from: a destroyed planet or planetesimal
that was big enough to differentiate into a metallic core and a rocky
mantle."
Rover-team scientists are
wondering whether some rocks that Opportunity has seen atop the ground
surface are rocky meteorites. "Mars should be hit by a lot more rocky
meteorites than iron meteorites," Squyres said. "We've been seeing lots of cobbles
out on the plains, and this raises the possibility that some of them may
in fact be meteorites. We may
be investigating some of those in coming weeks. The key is not what we'll
learn about meteorites -- we have lots of meteorites on Earth -- but what
the meteorites can tell us about Meridiani Planum."
The numbers of exposed
meteorites could be an indication of whether the plain is gradually
eroding away or being built up.
NASA Chief Scientist Dr.
Jim Garvin said, "Exploring meteorites is a vital part of NASA's
scientific agenda, and discovering whether there are storehouses of them
on Mars opens new research possibilities, including further incentives for
robotic and then human-based sample-return missions. Mars continues to
provide unexpected science 'gold,' and our rovers have proven the value of
mobile exploration with this latest finding."
Initial observation of Heat
Shield Rock from a distance with Opportunity's miniature thermal emission
spectrometer suggested a metallic composition and raised speculation last
week that it was a meteorite.
The rover drove close enough to use its Moessbauer and alpha particle
X-ray spectrometers, confirming the meteorite identification over the
weekend.
Opportunity and Spirit
successfully completed their primary three-month missions on Mars in April
2004. NASA has extended their missions twice because the rovers have
remained in good condition to continue exploring Mars longer than
anticipated. They have found
geological evidence of past wet environmental conditions that might have
been hospitable to life.
Opportunity has driven a
total of 2.10 kilometers (1.30 miles). Minor mottling from dust has
appeared in images from the rover's rear hazard-identification camera
since Opportunity entered the area of its heat-shield debris, said Jim
Erickson of NASA's Jet Propulsion Laboratory, Pasadena, Calif., rover
project manager. The rover
team plans to begin driving Opportunity south toward a circular feature
called "Vostok" within about a week.
Spirit has driven a total
of 4.05 kilometers (2.52 miles). It has been making slow progress
uphill toward a ridge on "Husband Hill" inside Gusev Crater.
JPL, a division of the
California Institute of Technology in Pasadena, has managed NASA's Mars
Exploration Rover project since it began in 2000. Images and additional
information about the rovers and their discoveries are available on the
Internet at http://www.nasa.gov/vision/universe/solarsystem/mer_main.html and at http://marsrovers.jpl.nasa.gov.
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