Europa's Hidden Ice Chemistry

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Jia-Rui Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook@jpl.nasa.gov

Elizabeth Zubritsky 301-614-3458
Goddard Space Flight Center, Greenbelt, Md.
elizabeth.a.zubritsky@nasa.gov
anita.heward@europlanet-eu.org

Feature: Oct. 4, 2010

Europa's Hidden Ice Chemistry

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-319&cid=release_2010-319

The frigid ice of Jupiter's moon Europa may be hiding more than a presumed ocean: it is likely
the scene of some unexpectedly fast chemistry between water and sulfur dioxide at extremely
cold temperatures. Although these molecules react easily as liquids—they are well-known
ingredients of acid rain—Mark Loeffler and Reggie Hudson at NASA's Goddard Space Flight
Center in Greenbelt, Md., now report that they react as ices with surprising speed and high yield
at temperatures hundreds of degrees below freezing. Because the reaction occurs without the aid
of radiation, it could take place throughout Europa's thick coating of ice—an outcome that
would revamp current thinking about the chemistry and geology of this moon and perhaps others.

"When people talk about chemistry on Europa, they typically talk about reactions that are driven
by radiation," says Goddard scientist Mark Loeffler, who is first author on the paper being
published in Geophysical Research Letters. That's because the moon's temperature hovers around
86 to 130 Kelvin (minus 300 to minus 225 degrees Fahrenheit). In this extreme cold, most
chemical reactions require an infusion of energy from radiation or light. On Europa, the energy
comes from particles from Jupiter's radiation belts. Because most of those particles penetrate just
fractions of an inch into the surface, models of Europa's chemistry typically stop there.

"Once you get below Europa's surface, it's cold and solid, and you normally don't expect things
to happen very fast under those conditions," explains co-author Reggie Hudson, the associate lab
chief of Goddard's Astrochemistry Laboratory.

"But with the chemistry we describe," adds Loeffler, "you could have ice 10 or 100 meters
[roughly 33 or 330 feet] thick, and if it has sulfur dioxide mixed in, you're going to have a
reaction."

"This is an extremely important result for understanding the chemistry and geology of Europa's
icy crust," says Robert E. Johnson, an expert on radiation-induced chemistry on planets and a
professor of engineering physics at the University of Virginia in Charlottesville.

From remote observations, astronomers know that sulfur is present in Europa's ice. Sulfur
originates in the volcanoes of Jupiter's moon Io, then becomes ionized and is transported to
Europa, where it gets embedded in the ice. Additional sulfur might come from the ocean that's
thought to lie beneath Europa's surface. "However," says Johnson, "the fate of the implanted or
any subsurface sulfur is not understood and depends on the geology and chemistry in the ice
crusts."

In experiments that simulated the conditions on Europa, Loeffler and Hudson sprayed water
vapor and sulfur dioxide gas onto quarter-sized mirrors in a high-vacuum chamber. Because the
mirrors were kept at about 50 to 100 Kelvin (about minus 370 to minus 280 degrees Fahrenheit),
the gases immediately condensed as ice. As the reaction proceeded, the researchers used infrared
spectroscopy to watch the decrease in concentrations of water and sulfur dioxide and the
increase in concentrations of positive and negative ions generated.

Despite the extreme cold, the molecules reacted quickly in their icy forms. "At 130 Kelvin [about
minus 225 degrees Fahrenheit], which represents the warm end of the expected temperatures on
Europa, this reaction is essentially instantaneous," says Loeffler. "At 100 Kelvin, you can saturate
the reaction after half a day to a day. If that doesn't sound fast, remember that on geologic
timescales—billions of years—a day is faster than the blink of an eye."

To test the reaction, the researchers added frozen carbon dioxide, also known as dry ice, which is
commonly found on icy bodies, including Europa. "If frozen carbon dioxide had blocked the
reaction, we wouldn't be nearly as interested," explains Hudson, "because then the reaction
probably wouldn't be relevant to Europa's chemistry. It would be a laboratory curiosity." But the
reaction continued, which means it could be significant on Europa as well as Ganymede and
Callisto, two more of Jupiter's moons, and other places where both water and sulfur dioxide are
present.

The reaction converted one-quarter to nearly one-third of the sulfur dioxide into product. "This is
an unexpectedly high yield for this chemical reaction," says Loeffler. "We would have been
happy with five percent." What's more, the positive and negative ions produced will react with
other molecules. This could lead to some intriguing chemistry, especially because bisulfite, a type
of sulfur ion, and some other products of this reaction are refractory—stable enough to stick
around for a while.

Robert Carlson, a senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena,
Calif., who collaborates with the two researchers, notes that earlier hints of water and sulfur
dioxide reacting as solids were found but not explained. "The Loeffler and Hudson results show
that really interesting acid–base reactions are going on," he says. "I am anxious to see what might
happen when other species are added and how the minor concentrations of sulfur dioxide on the
satellite surfaces affect the overall chemistry."

The ultimate test of the laboratory experiments will be whether evidence of any reaction products
can be found in data collected during remote observations or future visits to Europa. Johnson
agrees that if subsurface sulfur dioxide on Europa "reacts to form refractory species, as [the
researchers] indicate, then the picture changes completely. " These results not only will affect our
understanding of Europa, but can also be further refined and tested with the proposed Europa
Jupiter System mission.

NASA's Jet Propulsion Laboratory in Pasadena, California, will manage NASA's contributions to
the Europa Jupiter System mission for NASA's Science Mission Directorate in Washington.
ESA's Directorate of Science and Robotic Exploration will manage the European contribution to
the Jupiter mission. JPL is a division of the California Institute of Technology in Pasadena.

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Classrooms Invited to Virtually Join 'Saturn Smackdown' on Mon., Oct. 4

Classrooms Invited to Virtually Join 'Saturn Smackdown' on Mon., Oct. 4
This is a feature from the NASA/JPL Education Office.

09.30.10 -- How do scientists and engineers plan a NASA mission from conception to launch and successful arrival at a planetary destination? It takes a lot of people working together as a team!

Classrooms can participate in "Saturn Smackdown," a live humorous debate featuring team members from the Cassini Mission at Saturn on Monday, Oct. 4, from 10 a.m. to 11:30 a.m. (Pacific Time). Trina Ray, who works in the Cassini Science Project Office, and Todd Barber, the mission's lead propulsion engineer, will give students a taste of the healthy intellectual debate that occurs while mission teams plan space events. During the program, classrooms can email questions and suggested mission plans for Trina and Todd to perform. Please include your school name and grade level.

The Saturn Smackdown will be performed live at the Division of Planetary Science meeting at the Pasadena Convention Center. A student audience at the meeting will also participate in the program.

Classrooms can watch the Smackdown live at http://www.ustream.tv/nasajpl2.

Teachers can email questions during the program to jplspaceeducation@gmail.com . They can also ask questions using the chat box on the Ustream page.

To learn more about the Cassini mission, go to http://saturn.jpl.nasa.gov/index.cfm

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Atmosphere Checked, One Mars Year Before a Landing

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

News release: 2010-316 Sept. 29, 2010

Atmosphere Checked, One Mars Year Before a Landing

PASADENA, Calif. -- What will the Martian atmosphere be like when the next Mars
rover descends through it for landing in August of 2012?

An instrument studying the Martian atmosphere from orbit has begun a four-week
campaign to characterize daily atmosphere changes, one Mars year before the arrival
of the Mars Science Laboratory rover, Curiosity. A Mars year equals 687 Earth days.

The planet's thin atmosphere of carbon dioxide is highly repeatable from year to year
at the same time of day and seasonal date during northern spring and summer on
Mars.

The Mars Climate Sounder instrument on NASA's Mars Reconnaissance Orbiter maps
the distribution of temperature, dust, and water ice in the atmosphere. Temperature
variations with height indicate how fast air density changes and thus the rates at which
the incoming spacecraft slows down and heats up during its descent.

"It is currently one Mars year before the Mars Science Laboratory arrival season," said
atmospheric scientist David Kass of NASA's Jet Propulsion Laboratory, Pasadena,
Calif. "This campaign will provide a set of observations to support the Mars Science
Laboratory engineering team and Mars atmospheric modelers. The information will
constrain the expected climate at their landing season. It will also help define the
range of possible weather conditions on landing day."

During the four years the Mars Climate Sounder has been studying the Martian
atmosphere, its observations have seen conditions only at about three in the afternoon
and three in the morning. For the new campaign, the instrument team is inaugurating
a new observation mode, looking to both sides as well as forward. This provides views
of the atmosphere earlier and later in the day by more than an hour, covering the
range of possible times of day that the rover will pass through the atmosphere before
landing.

JPL, a division of the California Institute of Technology, provided the Mars Climate
Sounder instrument and manages the Mars Reconnaissance Orbiter and Mars
Science Laboratory projects for NASA's Science Mission Directorate, Washington. For
more about NASA's Mars exploration program, see http://marsprogram.jpl.nasa.gov .

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Public Invited to Free Climate Change Science Symposium at JPL

Public Invited to Free Climate Change Science Symposium at JPL
This is a feature from the NASA/JPL Education Office.

09.29.10 -- JPL's Green Club is sponsoring a free public science symposium about climate change on Saturday, Oct. 16,
from 2 to 4 p.m. at JPL. Climate scientists with expertise in Earth's atmosphere, ocean and ice will present a series of brief
talks on the scientific evidence for global warming. Attendees will learn what they as individuals and as part of society can
do to address global warming.
Brief question-and-answer periods will follow each presentation.

This event is open to the public on a first-come, first-served basis, with a seating capacity of 200. All ages are welcome but
the presentations will be geared to adults. The symposium will be held in JPL's von Karman Auditorium. Directions to the
Lab can be found here: http://www.jpl.nasa.gov/about_JPL/maps.cfm .

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New Views of Saturn's Aurora, Captured by Cassini

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Jia-Rui Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook@jpl.nasa.gov

Anita Heward 011-44-7756-034243
European Planetary Science Congress, Rome, Italy
anita.heward@europlanet-eu.org

Image advisory: 2010-313 Sept. 23, 2010

New Views of Saturn's Aurora, Captured by Cassini

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-313&cid=release_2010-313

PASADENA, Calif. – A new movie and images showing Saturn's shimmering aurora
over a two-day period are helping scientists understand what drives some of the solar
system's most impressive light shows.

The new, false-color images and video are available online at: http://www.nasa.gov/cassini
and http://saturn.jpl.nasa.gov.

The movie and images are part of a new study that, for the first time, extracts auroral
information from the entire catalogue of Saturn images taken by the visual and infrared
mapping spectrometer instrument (VIMS) aboard NASA's Cassini spacecraft. These
images and preliminary results are being presented by Tom Stallard, lead scientist on a
joint VIMS and Cassini magnetometer collaboration, at the European Planetary Science
Congress in Rome on Friday, Sept. 24.

In the movie, the aurora phenomenon clearly varies significantly over the course of a
Saturnian day, which lasts around 10 hours 47 minutes. On the noon and midnight sides
(left and right sides of the images, respectively), the aurora can be seen to brighten
significantly for periods of several hours, suggesting the brightening is connected with the
angle of the sun. Other features can be seen to rotate with the planet, reappearing at the
same time and the same place on the second day, suggesting that these are directly
controlled by the orientation of Saturn's magnetic field.

"Saturn's auroras are very complex and we are only just beginning to understand all the
factors involved," Stallard said. "This study will provide a broader view of the wide
variety of different auroral features that can be seen, and will allow us to better
understand what controls these changes in appearance."

Auroras on Saturn occur in a process similar to Earth's northern and southern lights.
Particles from the solar wind are channeled by Saturn's magnetic field toward the
planet's poles, where they interact with electrically charged gas (plasma) in the upper
atmosphere and emit light. At Saturn, however, auroral features can also be caused by
electromagnetic waves generated when the planet's moons move through the plasma that
fills Saturn's magnetosphere.

Previous data from Cassini have contributed to a number of detailed snapshots of the
aurora. But understanding the overall nature of the auroral region requires a huge number
of observations, which can be difficult because Cassini observation time close to Saturn is
in high demand, Stallard said.

However, VIMS observations of numerous other scientific targets also include auroral
information. Sometimes the aurora can be clearly seen, but sometimes Stallard and
colleagues add multiple images together to produce a signal. This wide set of observations
allows Cassini scientists to understand the aurora in general, rather than the beautiful
specific cases that dedicated auroral observations allow, Stallard said.

Stallard and his colleagues have investigated about 1,000 images from the 7,000 that
VIMS has taken to date of Saturn's auroral region.

The new, false-color images show Saturn's aurora glowing in green around the planet's
south pole. The auroral information in the two images was extracted from VIMS data
taken on May 24, 2007, and Nov. 1, 2008. The video covers about 20 Earth hours of
VIMS observations, from Sept. 22 and 23, 2007.

"Detailed studies like this of Saturn's aurora help us understand how they are generated
on Earth and the nature of the interactions between the magnetosphere and the uppermost
regions of Saturn's atmosphere," said Linda Spilker, Cassini project scientist, based at
NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space
Agency and the Italian Space Agency. JPL manages the mission for NASA's Science
Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and
assembled at JPL. The visual and infrared mapping spectrometer team is based at the
University of Arizona, Tucson. Stallard's work on Saturn's auroras is funded by the
Science and Technologies Facilities Council, Swindon, U.K.

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Shining Starlight on the Dark Cocoons of Star Birth

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Whitney Clavin/Guy Webster 818-354-4673/6278
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.b.clavin@jpl.nasa.gov/guy.webster@jpl.nasa.gov

Feature September 23, 2010

Shining Starlight on the Dark Cocoons of Star Birth

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-311&cid=release_2010-311

Astronomers have discovered a new, cosmic phenomenon, termed "coreshine,"
which is revealing new information about how stars and planets come to be.

The scientists used data from NASA's Spitzer Space Telescope to measure
infrared light deflecting off cores -- cold, dark cocoons where young stars and
planetary systems are blossoming. This coreshine effect, which occurs when
starlight from nearby stars bounces off the cores, reveals information about their
age and consistency. In a new paper, to be published Friday, Sept. 24, in the
journal Science, the team reports finding coreshine across dozens of dark
cores.

"Dark clouds in our Milky Way galaxy, far from Earth, are huge places where
new stars are born. But they are shy and hide themselves in a shroud of dust so
that we cannot see what happens inside," said Laurent Pagani of the
Observatoire de Paris and the Centre National de la Recherche Scientifique,
both in France. "We have found a new way to peer into them. They are like
ghosts because we see them but we also see through them."

Pagani and his team first observed one case of the coreshine phenomenon in
2009. They were surprised to see that starlight was scattering off a dark core in
the form of infrared light that Spitzer could see. They had thought the grains of
dust making up the core were too small to deflect the starlight; instead, they
expected the sunlight would travel straight through. Their finding told them that
the dust grains were bigger than previously thought -- about 1 micron instead of
0.1 micron (a typical human hair is about 100 microns).

That might not sound like a big difference, but it can significantly change
astronomers' models of star and planet formation. For one thing, the larger grain
size means that planets -- which form as dust circling young stars sticks
together -- might take shape more quickly. In other words, the tiny seeds for
planet formation may be forming very early on, when a star is still in its pre-
embryonic phase.

But this particular object observed in 2009 could have been a fluke. The
researchers did not know if what they found was true of other dark clouds -- until
now. In the new study, they examine 110 dark cores, and find that about half of
them exhibit coreshine.

The finding amounts to a new tool for not only studying the dust making up the
dark cores, but also for assessing their age. The more developed star-forming
cores will have larger dust grains, so, using this tool, astronomers can better
map their ages across our Milky Way galaxy. Coreshine can also help in
constructing three-dimensional models of the cores -- the deflected starlight is
scattered in a way that is dependent on the cloud structures.

Said Pagani, "We're opening a new window on the realm of dark, star-forming
cores."

Other authors are Aurore Bacmann of the Astrophysics Laboratory of Grenoble,
France, and Jürgen Steinacker, Amelia Stutz and Thomas Henning of the Max-
Planck Institute for Astronomy, Germany. Steinacker is also with the
Observatoire de Paris, and Stutz is also with the University of Arizona, Tucson.

The Spitzer measurements are based on data from the mission's public archive,
taken before the telescope ran out of its liquid coolant in May 2009 and began
its current warm mission.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer
Space Telescope mission for NASA's Science Mission Directorate, Washington.
Science operations are conducted at the Spitzer Science Center at the
California Institute of Technology, also in Pasadena. Caltech manages JPL for
NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and
http://www.nasa.gov/spitzer .

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Teacher Professional Development in Downey, Calif.

Teacher Professional Development in Downey, Calif.
This is a feature from the NASA/JPL Education Office.

09.23.10 -- Free teacher workshops are being offered this fall at the Columbia Memorial
Space Center in Downey, Calif. The workshops are a collaboration between the Space Center
and the NASA/JPL Educator Resource Center. Interested educators must RSVP to the Columbia
Memorial Space Center in advance at (562) 231-1200.

Lunar and Meteorite Sample Certification
October 16, 2010, 10:00-12:00 p.m.
Recommended for teachers, grades K-12

NASA makes real moon rocks and regolith (moon dirt) available for teachers to borrow.
The samples are from NASA's historic Apollo missions. This certification workshop is required
in order to bring the excitement of real lunar rocks and regolith samples to your students.

Robotics and the Marsbound Challenge
November 6, 2010, 10:00-12:00 p.m.
Recommended for teachers, grades 5-12

Learn how to use the Marsbound Challenge board activity to teach students how to plan a mission
to Mars, practice basic math skills and work in collaborative groups just like real engineers. In this activity,
students begin with a $250,000,000 budget and see what they can achieve! On Blooms Taxonomy, this activity
is at the evaluation level.

For more information and directions to the Columbia Memorial Space Center, go to
www.ColumbiaSpaceScience.org .

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Students Can Be 'Scientists for a Day' With Saturn Mission

Students Can Be 'Scientists for a Day' With Saturn Mission
This is a feature from the NASA/JPL Education Office.

09.21.10 -- How do scientists decide what images the Cassini spacecraft should take of Saturn and its
moons? Students have the opportunity to learn the scientific process when they enter Cassini's Scientist
for a Day Essay Contest. The contest is for students in grades 5 through 12. The deadline for entries is
Wed., Oct. 27, 2010, at noon Pacific Time.

Students will be presented with three scientifically interesting locations around Saturn or its moons for the
Cassini spacecraft to capture. They will have to research each location and choose which image they think
would yield the best scientific results. Each student must explain his or her choice in a 500-word essay.
Winners participate in a teleconference with Cassini scientists from NASA's Jet Propulsion Laboratory.

For more info, including videos about Saturn and its moons, visit: http://saturn.jpl.nasa.gov/education/scientistforaday9thedition/ .

Questions can be sent to: scientistforaday@jpl.nasa.gov

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Spring on Titan Brings Sunshine and Patchy Clouds

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook@jpl.nasa.gov

Anita Heward 011-44-7756-034243
European Planetary Science Congress, Rome, Italy
anita.heward@europlanet-eu.org

Spring on Titan Brings Sunshine and Patchy Clouds

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-308&cid=release_2010-308

The northern hemisphere of Saturn's moon Titan is set for mainly fine spring weather, with
polar skies clearing since the equinox in August last year. The visual and infrared mapping
spectrometer (VIMS) aboard NASA's Cassini spacecraft has been monitoring clouds on Titan
regularly since the spacecraft entered orbit around Saturn in 2004. Now, a group led by
Sébastien Rodriguez, a Cassini VIMS team collaborator based at Université Paris Diderot,
France, has analyzed more than 2,000 VIMS images to create the first long-term study of
Titan's weather using observational data that also includes the equinox. Equinox, when the
sun shone directly over the equator, occurred in August 2009.

Rodriguez is presenting the results and new images at the European Planetary Science
Congress in Rome on Sept. 22.

Though Titan's surface is far colder and lacks liquid water, this moon is a kind of "sister
world" to Earth because it has a surface covered with organic material and an atmosphere
whose chemical composition harkens back to an early Earth. Titan has a hydrological cycle
similar to Earth's, though Titan's cycle depends on methane and ethane rather than water.

A season on Titan lasts about seven Earth years. Rodriguez and colleagues observed
significant atmospheric changes between July 2004 (early summer in Titan's southern
hemisphere) and April 2010 (the very start of northern spring). The images showed that cloud
activity has recently decreased near both of Titan's poles. These regions had been heavily
overcast during the late southern summer until 2008, a few months before the equinox.

Over the past six years, the scientists found that clouds clustered in three distinct latitude
regions of Titan: large clouds at the north pole, patchy clouds at the south pole and a narrow
belt around 40 degrees south. "However, we are now seeing evidence of a seasonal
circulation turnover on Titan -- the clouds at the south pole completely disappeared just before
the equinox and the clouds in the north are thinning out," Rodriguez said. "This agrees with
predictions from models and we are expecting to see cloud activity reverse from one
hemisphere to another in the coming decade as southern winter approaches."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency
and the Italian Space Agency. JPL manages the mission for NASA's Science Mission
Directorate, Washington, D.C. The visual and infrared mapping spectrometer team is based at
the University of Arizona, Tucson.

For a full version of this release, go to: http://www.europlanet-
eu.org/outreach/index.php?option=com_content&task=view&id=288&Itemid=41

For more information about Cassini, go to: http://www.nasa.gov/cassini and
http://saturn.jpl.nasa.gov .

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Mars Rover Opportunity Approaching Possible Meteorite

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Guy Webster 818-354-6278
Jet Propulsion Laboratory
Pasadena, California

Mars Rover Opportunity Approaching Possible Meteorite

PASADENA, Calif. -- Images that NASA's Mars Exploration Rover Opportunity took at the end
of an 81-meter (266-foot) drive on Sept. 16 reveal a dark rock about 31 meters (102 feet) away.
The rover's science team has decided to go get a closer look at the toaster-sized rock and
determine whether it is an iron meteorite.

"The dark color, rounded texture and the way it is perched on the surface all make it look like an
iron meteorite," said science-team member Matt Golombek of NASA's Jet Propulsion
Laboratory, Pasadena, Calif. Opportunity has found four iron meteorites during the rover's
exploration of the Meridiani Planum region of Mars since early 2004. Examination of these rocks
has provided information about the Martian atmosphere, as well as the meteorites themselves.

The newfound rock has been given the informal name "Oileán Ruaidh" (pronounced ay-lan
ruah), which is the Gaelic name for an island off the coast of northwestern Ireland. The rock is
about 45 centimeters (18 inches) wide from the angle at which it was first seen.

Opportunity has driven 23.3 kilometers (14.5 miles) on Mars. The drive to this rock will take the
total combined distance driven by Opportunity and its twin, Spirit, to more than 31 kilometers
(19.26 miles).

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars
Exploration Rover mission for the NASA Science Mission Directorate, Washington. Opportunity
landed on Mars in January 2004 for what was planned as a three-month mission. For more
information about the mission, see http://marsrovers.jpl.nasa.gov .

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