Category: Mars

Image credit: ESA
Considered suggestive of life, an atmosphere of methane on another planet is considered one of the four best candidates for detecting habitable conditions using remote sensing and telescope spectrographs. While methane can be made both by biological and non-biological processes, it is also degraded by non-biological means, so a high concentration often is interpreted as requiring a source to replenish it. If metabolism is that source, then some of the prerequisites for a steady-state ecosystem may be in play.

On Earth there are four gases linked to the presence of life and habitable conditions: water vapor, carbon dioxide, methane and molecular oxygen (O2, or its proxy, ozone O3). Water is essential to all biology we understand today, while the exchange of carbon dioxide and oxygen constitute the collective respirator for photosynthesis and breathable worlds. The dominant gas on Mars today is by far carbon dioxide.

With methane, there are some methanogenic organisms that require consumption of this gas for their subsistence. Methanogenesis converts carbon dioxide to methane. Since strong chemical reactions quickly destroy (oxidize) methane at the Martian surface, if methane is found today, there must be some replenishment that gives a clue to active biology. Such biosynthesis leaves a ubiquitous signature of life even in specimens where there are no fossils visible.

Michael J. Mumma of Goddard Space Flight Center first reported in a poster at a recent planetary conference [DPS] that his preliminary search for methane with both of two ground-based infrared telescopes had found something interesting. His survey turned up intriguing signs of what may be methane’s spectral line in the Martian atmosphere.

These hints have now been confirmed by the European orbiter, Mars Express. Using an instrument called the Planetary Fourier Spectrometer (PFS), the work reported in Nature magazine identified the characteristic spectral fingerprint of methane. “We have detected methane at concentrations of ten parts per billion,” said Vittorio Formisano of the Institute of Physics of Interplanetary Space in Rome and the principal investigator in the PFS team.

The current martian atmosphere is 99% thinner than the Earth’s. The surface temperature averages -64 F (-53 C), but varies between 200 below zero during polar nights to 80 F (27 C) at midday peaks near the equator. The global picture of Mars is sometimes compared terrestrially to Antarctic dry regions, only colder.

Carbon, nitrogen and methane would be the gaseous precursors to what would be required to sustain or transform Mars from its current inhospitable state to a warmer, microbe-friendly planet. Because researchers believe that methane can persist in the Martian atmosphere for less than 300 years, any methane they find can be assumed to arise from recent biological processes, produced, for example, by methane-producing bacteria. This close link gives methne its less scientific name of swamp gas.

The European Mars Express mission is capable of detecting methane in the martian atmosphere. As Agustin Chicarro, Mars Express Project Scientist said, these “investigations will provide clues as to why the north of the planet is so smooth and the south so rugged, how the Tharsis and Elysium mounds were lifted up and whether active volcanoes exist on Mars today.”

There are some problems with trying to understand the history of methane and other greenhouse gases on Mars. There is no evidence on Mars of large limestone deposits from the first billion years, which would be directly linked to large amounts of C02, a greenhouse gas.

Methane — which can be created naturally by volcanic eruptions or produced by primitive life — thus may be a missing piece of the puzzle to finding out if organic remnants might once have sustained a primordial Mars. The last period of active volcanism on Mars is well before the last 300 years that methane can survive in the martian atmosphere of today. University of Buffalo volcanologist, Tracy Gregg, told Astrobiology Magazine, “the youngest surficial activity discovered to date (and it’s probably 1 million years old, which would be considered quite young, and possibly “active” on Mars) is in a region that contains no large volcanic structures of any kind.” Mars’ gigantic volcano Mons Olympus was active until 100 million years ago.

Earlier observations had speculated on methane concentrations as high as 50-70 parts per million, not what Mars Express detected as ten parts per billion. This low level could not likely sustain a global pattern suggestive of a biosphere, but might support local ecologies if methane has some underground source. Whatever the final concentration might be, its appearance in such an unstable atmosphere has taken on importance to unravel the mysteries of a martian biosphere. The most frequently mentioned example of a martian methane economy centers on a deep biosphere of methane rich biochemistry, or anerobic methanogens.

Original Source: Astrobiology Magazine

Image credit: ESA
During recent observations from the ESA Mars Express spacecraft in orbit around Mars, methane was detected in its atmosphere.

Whilst it is too early to draw any conclusions on its origin, exciting as they may be, scientists are thinking about the next steps to take in order to understand more.

From the time of its arrival at Mars, the Mars Express spacecraft started producing stunning results. One of the aims of the mission is analysing in detail the chemical composition of the Martian atmosphere, known to consist of 95% percent carbon dioxide plus 5% of minor constituents. It is also from these minor constituents, which scientists expect to be oxygen, water, carbon monoxide, formaldehyde and methane, that we may get important information on the evolution of the planet and possible implications for the presence of past or present life.

The presence of methane has been confirmed thanks to the observations of the Planetary Fourier Spectrometer (PFS) on board Mars Express during the past few weeks. This instrument is able to detect the presence of particular molecules by analysing their ?spectral fingerprints? – the specific way each molecule absorbs the sunlight it receives.

The measurements confirm so far that the amount of methane is very small ? about 10 parts in a thousand million, so its production process is probably small. However, the exciting question ?where does this methane come from?? remains.

Methane, unless it is continuously produced by a source, only survives in the Martian atmosphere for a few hundreds of years because it quickly oxidises to form water and carbon dioxide, both present in the Martian atmosphere. So, there must be a mechanism that refills the atmosphere with methane.

?The first thing to understand is how exactly the methane is distributed in the Martian atmosphere,? says Vittorio Formisano, Principal Investigator for the PFS instrument. ?Since the methane presence is so small, we need to take more measurements. Only then we will have enough data to make a statistical analysis and understand whether there are regions of the atmosphere where methane is more concentrated?.

Once this is done, scientists will try to establish a link between the planet-wide distribution of methane and possible atmospheric or surface processes that may produce it. ?Based on our experience on Earth, the methane production could be linked to volcanic or hydro-thermal activity on Mars. The High Resolution Stereo camera (HRSC) on Mars Express could help us identify visible activity, if it exists, on the surface of the planet?, continues Formisano. Clearly, if it was the case, this would imply a very important consequence, as present volcanic activity had never been detected so far on Mars.

Other hypotheses could also be considered. On Earth, methane is a by-product of biological activity, such as fermentation. ?If we have to exclude the volcanic hypothesis, we could still consider the possibility of life,? concludes Formisano.

?In the next few weeks, the PFS and other instruments on-board Mars Express will continue gathering data on the Martian atmosphere, and by then we will be able to draw a more precise picture,? says Agustin Chicarro, ESA Mars Express Project Scientist.

Thanks to the PFS instrument, scientists are also gathering precious data about isotopes in atmospheric molecules such as water and carbon dioxide – very important to understand how the planet was formed and to add clues on the atmospheric escape. The PFS also gives important hints about water-cloud formation on the top of volcanoes, and shows the presence of active photochemical processes in the atmosphere.

Original Source: ESA News Release

Researchers from both NASA and the European Space Agency are reported to have independently found evidence of methane in the Martian atmosphere – on Earth, methane is a by-product of life. Methane gas would be destroyed by the Sun’s radiation, so something would need to be replenishing it in the atmosphere. Neither agency has gone public with their findings yet; however, as they’re working to confirm their results with other instruments.

Image credit: NASA/JPL
NASA’s Spirit will begin trekking toward hills on its eastern horizon in the next few days, entering a new phase of the rover’s exploration of Mars just before its prime three-month mission ends and its extended mission begins, rover team members said today.

The range of peaks named “Columbia Hills” is an island of older rock surrounded by a younger volcanic layer which surfaces the plain that Spirit has been crossing, said Dr. Ray Arvidson of Washington University, St. Louis. He is deputy principal investigator for the science payload on both Spirit and its twin rover, Opportunity.

Older rocks may hold evidence of an ancient body of water thought to have once filled Gusev Crater. Spirit landed inside that 150-kilometer-wide (95-mile-wide) crater 12 weeks ago, and the rover’s main task is to find geological clues about whether the region ever had a wet environment. Spirit has spent much of its time since landing driving toward a 200-meter-wide (660-foot-wide) crater nicknamed “Bonneville.” Rover scientists had anticipated that the impact that excavated Bonneville might have ejected rocks old enough to hold clues about whether Gusev held water.

“The ejecta from Bonneville didn’t get excavated from deep enough to get below the volcanic layer,” Arvidson said. So, after finishing an examination of a light-colored rock on the crater’s rim, Spirit will head for the hills.

NASA’s Jet Propulsion Laboratory, Pasadena, Calif., built each of the two Mars Exploration Rovers for a prime mission of 90 martian days of operation. Both rovers are healthy and could operate for several additional months, said JPL’s Matt Wallace, mission manager. A martian day, or sol, lasts about 40 minutes longer than an Earth day, and Spirit’s 82nd sol began on Friday. “Spirit will start driving toward the hills on sol 84 or a little after that,” Wallace said.

Scientists have examined the terrain between Bonneville Crater and Columbia Hills in photographs taken from orbit by NASA’s Mars Global Surveyor and found several features to inspect along the route. These include some small craters and a dark streak apparently left by a whirlwind that removed dust.

Science team member Dr. Larry Crumpler of New Mexico Museum of Natural History, Albuquerque, said, “It won’t be a continuous drive, like a bad road trip. We’ll actually get out and do some touristy things along the way.”

With stops for “traverse science” along the way, the trip of about 2.3 kilometers (1.3 miles) to the near edge of Columbia Hills will probably take 60 to 90 sols, Arvidson said.

Beginning next week and continuing into the extended mission, Spirit’s controllers will switch from working on Mars time – with schedules set to coincide with day or night at Gusev crater – to an Earth time schedule easier to maintain for the long haul. The Opportunity team will shift the following week, Wallace said.

Opportunity is also at the start of a trek. This week, it climbed out of the small impact crater informally named “Eagle Crater” that it had been examining since it landed nine weeks ago. Rocks in an outcrop within the crater have provided evidence that the site was once under flowing water. In coming weeks, Opportunity will drive about 750 meters (nearly half a mile) to a crater nicknamed “Endurance,” where scientists hope to find and examine a thicker set of bedrock layers to learn more about the duration of the region’s wet history.

Before leaving Eagle Crater, Opportunity inspected the soil at five sites in the opposite half of the crater from the outcrop. The target patches show a diversity of particle sizes and shapes on the surface. “We’re seeing the effects of differences in wind speed,” said Bethany Ehlmann, a science team collaborator from the University of Washington, St. Louis. In some patches more than others, winds have removed small particles and left large particles behind, she said.

Spherical gray particles that have been fancifully called blueberries are plentiful in some soil patches higher on the inner slope of the crater than near the center of the crater. A reading by Opportunity’s Moessbauer spectrometer on one of the higher patches found the highest concentration of hematite seen so far in the mission, reported Dr. Goestar Klingelhoefer of the University of Mainz, Germany. He is the lead scientist for that instrument, which is used for identifying iron-containing minerals. The type of hematite Opportunity has been finding usually forms on Earth under wet environmental conditions. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu .

Original Source: NASA/JPL News Release

Image credit: UA
The spiral troughs of Mars’ polar ice caps have been called the most enigmatic landforms in the solar system. The deep canyons spiraling out from Red Planet?s North and South poles cover hundreds of miles. No other planet has such structures.

A new model of trough formation suggests that heating and cooling alone are sufficient to form the unusual patterns. Previous explanations had focused on alternate melting and refreezing cycles but also required wind or shifting ice caps.

“I applied specific parameters that were appropriate to Mars and out of that came spirals that were not just spirals, but spirals that had exactly the shape we see on Mars.” said Jon Pelletier, an assistant professor of geosciences at the University of Arizona in Tucson. “They had the right spacing, they had the right curvature, they had the right relationship to one another.”

His report, “How do spiral troughs form on Mars?,” is published in the April issue of the journal Geology. One of his computer simulations of the troughs graces the cover.

How the icy canyons formed in a spiral has puzzled scientists since the pattern was first spotted by the Viking spacecraft in 1976.

Pelletier, a geomorphologist who studies landforms on Earth such as sand dunes and river channels, has a fondness for natural patterns that are regularly spaced.

Spirals fit the bill, and while perusing a book on mathematical patterns in biology, he was struck by the spiral shape formed by slime molds. He wondered whether the mathematical equation that described how the slime mold grew could also be applied to geological processes.

“There’s a recipe for getting spirals to form,” he said. So he tried it out, using information that described the situation on Mars.

Temperatures on Mars are below freezing most of the year. During very brief periods during the summer, temperatures on the polar ice caps get just high enough to let the ice melt a bit, Pelletier said.

He proposes that during that time, cracks or nicks in the ice’s surface that present a steep side toward the sun might melt a bit, deepening and widening the crack. Heat from the sun also diffuses through the ice.

Much as ice cubes evaporate inside a freezer, on Mars, the melting ice vaporizes rather than becoming liquid water.

The water vapor, when it hits the cold, shady side of the little canyon, condenses and refreezes. So the canyon expands and deepens because one side is heated occasionally while the other side always remains cold.

“The ambient temperatures on Mars are just right to create this form. And that’s not true anywhere else in the solar system,” he said. “The spirals are created because melting is focused in a particular place.”

Pelletier said the differential melting and refreezing is the key to the formation of Mars’ spiral troughs.

So he put mathematical descriptions of the heating and cooling cycles into the spiral-generating equation and ran computer simulations to predict what would occur over thousands of such cycles. He did not include wind or movement of polar ice caps in his model.

The computer made patterns that match what’s seen on Mars, even down to the imperfections in the spirals.

“The model I have predicts the spacing between these things, how they’re curved, and how they evolve over time to create spiral feature,” he said.

“A lot of planetary sciences is about making educated guesses about the imagery that we see. We can’t go there, we can’t do do field experiments,” he said. “The development of numerical models provides strong suggestions as to what’s essential to create the form that we see,” and allows scientists to test their assumptions, he said.

Original Source: UA News Release

Image credit: NASA/JPL
This image is the first 360 degree view from the Mars Exploration Rover Opportunity’s new position outside “Eagle Crater,” the small crater where the rover landed about two months ago. Scientists are busy analyzing Opportunity’s new view of the plains of Meridiani Planum. The plentiful ripples are a clear indication that wind is the primary geologic process currently in effect on the plains. The rover’s tracks can be seen leading away from Eagle Crater.

At the far left are two depressions – each about a meter (about 3.3 feet) across – that feature bright spots in their centers. One possibility is that the bright material is similar in composition to the rocks in Eagle Crater’s outcrop and the surrounding darker material is what’s referred to as “lag deposit,” or erosional remnants, which are much harder and more difficult to wear away. These twin dimples might be revealing pieces of a larger outcrop that lies beneath. The depression closest to Opportunity is whimsically referred to as “Homeplate” and the one behind it as “First Base.” The rover’s panoramic camera is set to take detailed images of the depressions today, on Opportunity’s 58th sol. The backshell and parachute that helped protect the rover and deliver it safely to the surface of Mars are also visible near the horizon, at the left of the image.

Original Source: NASA/JPL News Release

Image credit: NASA/JPL
NASA’s Opportunity rover has demonstrated some rocks on Mars probably formed as deposits at the bottom of a body of gently flowing saltwater.

“We think Opportunity is parked on what was once the shoreline of a salty sea on Mars,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science payload on Opportunity and its twin Mars Exploration Rover, Spirit.

Clues gathered so far do not tell how long or how long ago liquid water covered the area. To gather more evidence, the rover’s controllers plan to send Opportunity out across a plain toward a thicker exposure of rocks in the wall of a crater.

NASA’s Associate Administrator for Space Science Dr. Ed Weiler said, “This dramatic confirmation of standing water in Mars’ history builds on a progression of discoveries about that most Earthlike of alien planets. This result gives us impetus to expand our ambitious program of exploring Mars to learn whether microbes have ever lived there and, ultimately, whether we can.”

“Bedding patterns in some finely layered rocks indicate the sand-sized grains of sediment that eventually bonded together were shaped into ripples by water at least five centimeters (two inches) deep, possibly much deeper, and flowing at a speed of 10 to 50 centimeters (four to 20 inches) per second,” said Dr. John Grotzinger, rover science-team member from the Massachusetts Institute of Technology, Cambridge, Mass.

In telltale patterns, called crossbedding and festooning, some layers within a rock lie at angles to the main layers. Festooned layers have smile-shaped curves produced by shifting of the loose sediments’ rippled shapes under a current of water.

“Ripples that formed in wind look different than ripples formed in water,” Grotzinger said. “Some patterns seen in the outcrop that Opportunity has been examining might have resulted from wind, but others are reliable evidence of water flow,” he said.

According to Grotzinger, the environment at the time the rocks were forming could have been a salt flat, or playa, sometimes covered by shallow water and sometimes dry. Such environments on Earth, either at the edge of oceans or in desert basins, can have currents of water that produce the type of ripples seen in the Mars rocks.

A second line of evidence, findings of chlorine and bromine in the rocks, also suggests this type of environment. Rover scientists presented some of that news three weeks ago as evidence the rocks had at least soaked in mineral-rich water, possibly underground water, after they formed. Increased assurance of the bromine findings strengthens the case rock-
forming particles precipitated from surface water as salt concentrations climbed past saturation while water was evaporating.

Dr. James Garvin, lead scientist for Mars and lunar exploration at NASA Headquarters, Washington, said, “Many features on the surface of Mars that orbiting spacecraft have revealed to us in the past three decades look like signs of liquid water, but we have never before had this definitive class of evidence from the martian rocks themselves. We planned the Mars Exploration Rover Project to look for evidence like this, and it is succeeding better than we had any right to hope. Someday we must collect these rocks and bring them back to terrestrial laboratories to read their records for clues to the biological potential of Mars.”

Squyres said, “The particular type of rock Opportunity is finding, with evaporite sediments from standing water, offers excellent capability for preserving evidence of any biochemical or biological material that may have been in the water.”

Engineers at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif., expect Opportunity and Spirit to operate several months longer than the initial rover’s three-month prime missions on Mars. To analyze hints of crossbedding, mission controllers programmed Opportunity to move its robotic arm more than 200 times in one day, taking 152 microscope pictures of layering in a rock called “Last Chance.”

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for NASA’s Office of Space Science, Washington. For images and information about the project on the Internet, visit:

http://www.nasa.gov

http://marsrovers.jpl.nasa.gov

http://athena.cornell.edu

Original Source: NASA News Release

Image credit: NASA/JPL
The Mars Exploration Rover Opportunity’s landing site is now viewable in panorama as the rover exited the crater which scientists consider one of the investigative landmarks on the red planet.

This image mosaic, compiled from navigation and panoramic camera images during the 33rd, 35th, and 36th sols on Mars, shows a panoramic view of the crater where the rover had been exploring since its dramatic arrival in late January 2004.

The crater, now informally referred to as “Eagle Crater,” is approximately 22 meters (72 feet) in diameter. Opportunity’s lander is visible in the center of the image. Track marks reveal the rover’s progress. The rover cameras recorded this view as Opportunity climbed close to the crater rim as part of a soil survey campaign.

After a slightly slippery start yestersol, Opportunity made it out of “Eagle Crater”on sol 57, which ends at 8:45 p.m. PST on March 22. The drive along the crater’s inner slope that was initiated on the last sol continued this sol until Opportunity exited its landing-site crater.

The rover tried driving uphill out of its landing-site crater during its 56th sol, ending at 10:05 p.m. March 21, PST, but slippage prevented success.

The rover remained healthy, and it later completed a turn to the right and a short drive along the crater’s inner slope.

Controllers sent it on a different route for exiting the crater and images from the navigation camera confirmed that the rover is now about 9 meters (about 29.5 feet) outside of the crater.

The rover also conducted remote sensing observations between naps this sol. After completing the drive out of the crater, the navigation camera imaged Opportunity’s brand new view of the plains of Meridiani Planum.

Opportunity flipped more meters on its odometer during the latest drives along the current soil survey campaign, surpassing the total drive distance of 1997’s Sojourner rover.

During the martian night, rover planners will awaken Opportunity to take miniature thermal emission spectrometer observations of the ground and the atmosphere.

Original Source: Astrobiology Magazine

Image credit: NASA/JPL
Observing the sky with the green filter of it panoramic camera, the Mars Exploration Rover Spirit came across a surprise: a streak across the sky. The streak, seen in the middle of this mosaic of images taken by the navigation and panoramic cameras, was probably the brightest object in the sky at the time. Scientists theorize that the mystery line could be either a meteorite or one of seven out-of-commission spacecraft still orbiting Mars. Because the object appeared to move 4 degrees of an arc in 15 seconds it is probably not the Russian probes Mars 2, Mars 3, Mars 5, or Phobos 2; or the American probes Mariner 9 or Viking 1. That leaves Viking 2, which has a polar orbit that would fit with the north-south orientation of the streak. In addition, only Viking 1 and 2 were left in orbits that could produce motion as fast as that seen by Spirit. Said Mark Lemmon, a rover team member from Texas A&M University, Texas, “Is this the first image of a meteor on Mars, or an image of a spacecraft sent from another world during the dawn of our robotic space exploration program? We may never know, but we are still looking for clues.”

Original Source: NASA/JPL

Image credit: NASA/JPL
A major ingredient in small mineral spheres analyzed by NASA’s Mars Exploration Rover Opportunity furthers understanding of past water at Opportunity’s landing site and points to a way of determining whether the vast plains surrounding the site also have a wet history.

The spherules, fancifully called blueberries although they are only the size of BBs and more gray than blue, lie embedded in outcrop rocks and scattered over some areas of soil inside the small crater where Opportunity has been working since it landed nearly two months ago.

Individual spherules are too small to analyze with the composition-reading tools on the rover. In the past week, those tools were used to examine a group of berries that had accumulated close together in a slight depression atop a rock called “Berry Bowl.” The rover’s Moessbauer spectrometer, which identifies iron-bearing minerals, found a big difference between the batch of spherules and a “berry-free” area of the underlying rock.

“This is the fingerprint of hematite, so we conclude that the major iron-bearing mineral in the berries is hematite,” said Daniel Rodionov, a rover science team collaborator from the University of Mainz, Germany. On Earth, hematite with the crystalline grain size indicated in the spherules usually forms in a wet environment.

Scientists had previously deduced that the martian spherules are concretions that grew inside water-soaked deposits. Evidence such as interlocking spherules and random distribution within rocks weighs against alternate possibilities for their origin. Discovering hematite in the rocks strengthens this conclusion. It also adds information that the water in the rocks when the spherules were forming carried iron, said Dr. Andrew Knoll, a science team member from Harvard University, Cambridge, Mass.

“The question is whether this will be part of a still larger story,” Knoll said at a press briefing today at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Spherules below the outcrop in the crater apparently weathered out of the outcrop, but Opportunity has also observed plentiful spherules and concentrations of hematite above the outcrop, perhaps weathered out of a higher layer of once-wet deposits. The surrounding plains bear exposed hematite identified from orbit in an area the size of Oklahoma — the main reason this Meridiani Planum region of Mars was selected as Opportunity’s landing site.

“Perhaps the whole floor of Meridiani Planum has a residual layer of blueberries,” Knoll suggested. “If that’s true, one might guess that a much larger volume of outcrop once existed and was stripped away by erosion through time.”

Opportunity will spend a few more days in its small crater completing a survey of soil sites there, said Bethany Ehlmann, a science team collaborator from Washington University, St. Louis. One goal of the survey is to assess distribution of the spherules farther from the outcrop. After that, Opportunity will drive out of its crater and head for a much larger crater with a thicker outcrop about 750 meters (half a mile) away.

Halfway around Mars, NASA’s other Mars Exploration Rover, Spirit, has been exploring the rim of the crater nicknamed “Bonneville,” which it reached last week. A new color panorama shows “a spectacular view of drift materials on the floor” and other features, said Dr. John Grant, science team member from the National Air and Space Museum in Washington. Controllers used Spirit’s wheels to scuff away the crusted surface of a wind drift on the rim for comparison with drift material inside the crater.

A faint feature at the horizon of the new panorama is the wall of Gusev Crater, about 80 kilometers (50 miles) away, said JPL’s Dr. Albert Haldemann, deputy project scientist. The wall rises about 2.5 kilometers (1.6 miles) above Spirit’s current location roughly in the middle of Gusev Crater. It had not been seen in earlier Spirit images because of dust, but the air has been clearing and visibility improving, Haldemann said.

Controllers have decided not to send Spirit into Bonneville crater. “We didn’t see anything compelling enough to take the risk to go down in there,” said JPL’s Dr. Mark Adler, mission manager. Instead, after a few more days exploring the rim, Spirit will head toward hills to the east informally named “Columbia Hills,” which might have exposures of layers from below or above the region’s current surface.

The main task for both rovers is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University, Ithaca, N.Y., at http://athena.cornell.edu.

Original Source: NASA/JPL News Release