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.
Image right: NASA's Mars Exploration Rover Opportunity has found an iron meteorite on Mars, the first meteorite of any type ever identified on another planet. Image credit: NASA/JPL/Cornell. + High resolution/full caption.
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
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
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
and at http://marsrovers.jpl.nasa.gov/home/index.html
Guy Webster (818) 354-6278
NASA's Jet Propulsion Laboratory
Gretchen Cook-Anderson (202) 358-0836 NASA Headquarters, Washington, D.C.