Category: Mars

Scientists have identified a water-signature mineral called goethite in bedrock that the NASA’s Mars rover Spirit examined in the “Columbia Hills,” one of the mission’s surest indicators yet for a wet history on Spirit’s side of Mars.

“Goethite, like the jarosite that Opportunity found on the other side of Mars, is strong evidence for water activity,” said Dr. Goestar Klingelhoefer of the University of Mainz, Germany, lead scientist for the iron-mineral analyzer on each rover, the Moessbauer spectrometer. Goethite forms only in the presence of water, whether in liquid, ice or gaseous form. Hematite, a mineral that had previously been identified in Columbia Hills bedrock, usually, but not always, forms in the presence of water.

The rovers’ main purpose is to look for geological evidence of whether their landing regions were ever wet and possibly hospitable to life. The successful results so far — with extended missions still underway — advance a NASA goal of continuing Mars exploration by robots and, eventually, by humans, said Doug McCuistion, Mars Exploration Program Director at NASA Headquarters.

Klingelhoefer presented the new results from a rock in the “West Spur” of Mars’ “Husband Hill” at a meeting of the American Geophysical Union in San Francisco this week.

Spirit has now driven past the West Spur to ascend Husband Hill itself. One remaining question is whether water was only underground or ever pooled above the surface, as it did at Opportunity’s site. “As we climb Husband Hill and characterize the rock record, we’ll be looking for additional evidence that the materials were modified by ground water and searching for textural, mineralogical and chemical evidence that the rocks were formed in or modified by surface water,” said Dr. Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the rover instruments.

The amount of worrisome friction in Spirit’s right front wheel has been decreasing. Meanwhile, rover wranglers at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., continue to minimize use of that wheel by often letting it drag while the other five wheels drive. “Babying that wheel seems to be helping,” said JPL’s Jim Erickson, rover project manager. Both rovers continue working in good health about eight months after their primary three-month missions. “Looks as though Spirit and Opportunity will still be with us when we celebrate the landing anniversaries in January,” Erickson said.

Opportunity has completed six months of inspecting the inside of “Endurance Crater” and is ready to resume exploration of the broad plains of the Meridiani region. It has recently seen frost and clouds marking the seasonal changes on Mars. At this week’s conference, rover science-team member Dr. Michael Wolff of the Brookfield, Wisconsin branch of the Boulder, Colorado-based Space Science Institute is reporting those and other atmospheric observations. “We’re seeing some spectacular clouds,” Wolff said. “They are a dramatic reminder that you have weather on Mars. Some days are cloudy. Some are clear.”

A portion of Mars’ water vapor is moving from the north pole toward the south pole during the current northern-summer and southern-winter period. The transient increase in atmospheric water at Meridiani, just south of the equator, plus low temperatures near the surface, contribute to appearance of the clouds and frost, Wolff said. Frost shows up some mornings on the rover itself. The possibility that it has a clumping effect on the accumulated dust on solar panels is under consideration as a factor in unexpected boosts of electric output from the panels.

As its last major endeavor inside Endurance Crater, Opportunity made a close inspection of rock layers exposed in a part of the crater wall called “Burns Cliff.” Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rover instruments, said, “In the lower portion of the cliff, the layers show very strong indications that they were last transported by wind, not by water like some layers higher up. The combination suggests that this was not a deep-water environment but more of a salt flat, alternately wet and dry.”

JPL has managed the 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. Information about NASA and agency programs is available on the Web at http://www.nasa.gov.

Original Source: NASA/JPL News Release

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows a region of Reull Vallis in the southern hemisphere of Mars.

The image shows an area located at about latitude 42? South and longitude 102? East. The image was taken with a ground resolution of about 21 metres per pixel during Mars Express orbit 451 in May 2004.

Reull Vallis is an outflow channel that extends 1500 kilometres across Promethei Terra in the direction of Hellas Basin. It is approximately 20 kilometres wide and has cut into the surrounding plain to a depth of 1800 metres. It is the major outflow channel in the region and exhibits a high degree of surface modification, suggesting a complex evolution.

In this image, Reull Vallis extends from the east to the north-west and is connected to a tributary in the south (Teviot Vallis). Distinct parallel structures are visible in the channels, possibly caused by glacial flow of loose debris mixed with ice. Small depressions, located on the flow features, are probably caused by the sublimation of ice.

Numerous impact craters, visible on the flanks of the valley, have been filled with material from these flows. Distinct flow features can be recognised within impact craters, for example, the 15-kilometre wide crater in the west (bottom) of the image.

There is a clear morphological distinction between the heavily eroded south-west and the plains of the north-east, which have experienced much less erosion. While most landforms throughout the image have a rounded, softened appearance, younger structures have a distinctly sharp and raised morphology.

On the southern and western edges of the colour image, large impact craters are visible. Their diameters range from 15 to 35 kilometres. These craters have heavily eroded rims and are partly filled with material. Erosion has left distinct, branched gully systems at the edge of the large crater that is located on the southern edge of the image.

Original Source: ESA News Release

Image credit: Ball Aerospace
The camera that will take thousands of the sharpest, most detailed pictures of Mars ever produced from an orbiting spacecraft was delivered today for installation on NASA’s Mars Reconnaissance Orbiter.

The Mars Reconnaissance Orbiter (MRO) will be launched on Aug. 10, 2005, carrying a payload of six science instruments and a communications relay package to boost the ongoing exploration of the red planet.

The largest science instrument on the spacecraft will be the University of Arizona’s High Resolution Imaging Science Experiment (HiRISE), a 65 kilogram (145 pound) camera with a half-meter (20-inch) diameter primary mirror.

HiRISE has been delivered for installation on the MRO spacecraft at Lockheed Martin Space Systems in Denver, Colo. Ball Aerospace & Technologies Corp. of Boulder, Colo., designed, built and tested the $35 million HiRISE camera. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., manages the MRO mission for NASA’s Science Mission Directorate, Washington, D.C.

HiRISE will produce ultra-sharp photographs over 6 kilometer (3.5 mile) swaths of the martian landscape with a best imaging at 25 centimeters (10 inches) per pixel, said Alfred S. McEwen of the UA’s Lunar and Planetary Laboratory, principal investigator for HiRISE.

“By combining a fine imaging scale (25 centimeters to 32 centimeters a pixel, or 10 inches to 12.5 inches a pixel) and high signal-to-noise ratio, it is possible to resolve features as small as one meter (about 40 inches) wide, a scale currently well-studied only by landers,” McEwen said. “HiRISE will get such views over any selected region of Mars, providing a bridge between orbital remote sensing and landed missions.” Mission scientists will combine stereo image pairs to produce detailed maps of the topography and combine images taken with filters to produce false-color images.

HiRISE will study deposits and landforms created by geologic and climatic processes, and it will help scientists assess future Mars mission landing sites.

(The next Mars lander will be NASA’s first Scout mission, called “Phoenix,” scheduled for launch in 2007. Peter Smith of UA’s Lunar and Planetary Lab heads the Phoenix mission, the first mission to Mars being led by an academic institution.)

“Ball Aerospace has done a fantastic job building an instrument that meets our challenging performance requirements,” McEwen said. “The HiRISE camera can collect the equivalent of about a thousand megapixel images in just three seconds.”

“With the delivery of the HiRISE hardware, team activities now shift to the UA and Lockheed Martin,” McEwen said. “We’ll do a series of flight-like tests before the spacecraft gets shipped to Kennedy Space Center next spring.” In these operational readiness tests, data from the camera on the spacecraft at Lockheed Martin will be sent to NASA’s Jet Propulsion Laboratory in Pasadena, Calif., then to the HiRISE Operations Center (HiROC) on the UA campus in Tucson.

“Rather than data coming down from the Deep Space Network, which will happen once the spacecraft is actually orbiting Mars, we’ll command HiRISE as it sits in a clean room at Lockheed Martin,” Eric Eliason said. Eliason manages activities at HiROC, which is located in the Lunar and Planetary Lab’s Sonett Building.

A dozen people currently staff HiROC. That number will double when the primary mission begins in 2006. Their tasks include writing command software, planning observations, uplinking commands, downlinking data, processing raw data into useful images and monitoring the instrument, Eliason said.

HiRISE co-investigators are:

* Candice Hansen, Jet Propulsion Laboratory, deputy principal investigator
* Alan Delamere, Delamere Support Systems
* Eric Eliason, UA
* Virginia Gulick, NASA Ames/SETI Institute
* Ken Herkenhoff, USGS Flagstaff
* Nathan Bridges, Jet Propulsion Laboratory
* Nick Thomas, University of Bern (Switzerland)
* Randolph Kirk, USGS Flagstaff
* John Grant, Smithsonian Institution
* Laszlo Keszthelyi, USGS Flagstaff
* Mike Mellon, University of Colorado
* Steve Squyres, Cornell University
* Cathy Weitz, Planetary Science Institute (Tucson)

The Mars Reconnaissance Orbiter scheduled for launch in August 2005 will be captured in Mars orbit by a “Mars orbit insertion” maneuver in March 2006.

Initially, the spacecraft will fly around Mars in a highly elliptical orbit. The orbit will become more circular over the next several months by a technique called “aerobraking.” On each of its close swings by Mars in elliptical orbit, the spacecraft is low enough that it skims the surface of Mars’ atmosphere, creating drag on the spacecraft. The orbiter’s path around the planet becomes more circular on each successive planet flyby.

HiRISE will begin taking photographs when the spacecraft is in a circular orbit, in November 2006. The primary science mission is for two years, or slightly more than a martian year. The orbiter can also serve as a telecommunications relay link for landers launched to Mars in 2007 and 2009. Nominally, the orbiter mission ends Dec. 31, 2010.

Original Source: University of Arizona News Release

Image credit: NASA
Scientists have long been tantalized by the question of whether life once existed on Mars. Although present conditions on the planet would seem to be inhospitable to life, the data sent back over the past 10 months by NASA’s two exploration rovers, Spirit and Opportunity, showed a world that might once have been warmer and wetter — perhaps friendly enough to support microbial organisms.

Now a Cornell University-led Mars rover science team reports on the historic journey by the rover Opportunity, which is exploring a vast plain, Meridiani Planum, and concludes with this observation: “Liquid water was once present intermittently at the martian surface at Meridiani, and at times it saturated the subsurface. Because liquid water is a key prerequisite for life, we infer that conditions at Meridiani may have been habitable for some period of time in martian history.”

The article is one of 11 published this week (Dec. 3, 2004) in a special issue of the journal Science, authored by scientists connected with the Mars rover mission, several from Cornell and from the Jet Propulsion Laboratory in Pasadena, Calif., the mission’s manager. The issue covers Opportunity through its first 90 days of exploring its landing site of Eagle crater in Meridiani Planum. This was before the rover drove to and entered the large crater dubbed Endurance, from which it is now about to emerge.

Steve Squyres, Cornell professor of astronomy and leader of the rovers’ Athena science team, is the lead author of the main paper, “The Opportunity Rover’s Athena Science Investigation at Meridiani Planum, Mars.” In another paper, on which he is also the lead author, Squyres again refers to the geological record at Meridiani Planum as suggesting that conditions were suitable for “biological activity” for a period of time in the history of mars. In the article, “In Situ Evidence for an Ancient Aqueous Environment at Meridiani Planum, Mars,” he writes: “We cannot determine whether life was present or even possible in the waters at Meridiani, but it is clear that by the time the sedimentary rocks in Eagle crater were deposited, Mars and Earth had already gone down different environmental paths. Sample return of Meridiani rocks might well provide more certainty regarding whether life developed on Mars.”

The Mars rover mission is not designed to look for microbial life but to look for evidence of whether conditions were once right for life. As Squyres recently stated, “What we were seeking was rocks that were actually formed in liquid water so that we could read the record in those rocks, not just to say liquid water was on Mars but to learn something about what the environmental conditions were like, would they have been suitable for life and, importantly, do the minerals that were formed have the capability to preserve for long periods of time evidence of former life? That’s probably the single most important thing we have found: evidence for minerals at Meridiani that are the kinds of things that are very good at preserving evidence of ancient life for very long periods of time.”

Opportunity bounced down on Jan. 25, 22 days after its twin, the rover Spirit, landed on the opposite side of Mars in Gusev crater. Last August Science published a special issue on Spirit.

“This is the first peer-reviewed presentation of the data from Opportunity,” notes Jim Bell, Cornell associate professor of astronomy and the lead scientist for the rovers’ Pancam color imaging system.

Bell also is prominent in the special issue of Science , including his lead authorship of a paper, “Pancam Multispectral Imaging Results from the Opportunity Rover at Meridiani Planum.”

When Opportunity landed on the red planet last January, the robot geologist sent back images of its landing site that were unlike any of the other places where earlier lander probes and rovers had gone. Instead of rusty deserts of dusty soil and boulders strewn to the horizon, Opportunity had landed in a relatively small crater in a vast sea of sand nearly devoid of rocks. Fortunately, an intriguing outcrop of bedrock presented itself nearby, which scientists hoped would be a sample of the original crust underneath the layers of dust.

The scientists were not disappointed. Scattered among the outcrop rocks were large numbers of small, round mineral deposits that the Athena science team named “blueberries.” On Earth, such formations appear when large amounts of water course through rock layers, leaching out the iron-bearing minerals into small spherical rocks and granules. The rovers also detected large amounts of sulfate salt deposits. Enough evidence was collected by Opportunity in the two months it spent examining Eagle crater that the science team felt confident enough to announce in early March that liquid water had flowed over the crater’s rocks long ago, possibly for a long time. Following on this, the latest Science articles largely focus on Opportunity’s most important scientific and geological accomplishment: the discovery of evidence that liquid water once flowed through the region.

Like the coverage given to Spirit in the August issue of Science , the latest edition contains several foldouts with big color panoramas and images from Opportunity’s region of exploration.

Original Source: Cornell News Release

Image credit: Pioneer Astro
Part lander, part aircraft, the gashopper (no, not grasshopper) is a unique concept being considered by NASA for future robotic exploration of Mars. Unlike landers, such as the Viking spacecraft, Beagle 2, or the upcoming Phoenix lander which can only examine a few square metres of ground, the gashopper could land, perform scientific analysis and launch itself back into the air to fly hundreds of kilometres to a new location.

The gashopper would get its electricity from a large set of solar panels built on top of its wings. It would use this electricity to retrieve carbon dioxide from the Martian atmosphere, and then store it as a liquid inside the aircraft. When enough gas was stored up to make a flight, it would heat up a hot bed of pellets and then pass the CO2 through it. Now hot, the gas would act as a propellant, and allow the gashopper to lift off vertically from the surface of Mars. Once airborne, it could then fire more gas out a rear thruster and begin flying as an airplane, using its large wings for lift and maneuverability. When it was ready to land, the aircraft could slow its airspeed, and then touch down gently as a vertical lander.

The proposal comes from the mind of Robert Zubrin, author of The Case for Mars, President of the Mars Society, and the President of Pioneer Astronautics. It’s one of 219 research projects selected by NASA for Small Business Research and Development contract awards.

Zubrin sees the gashopper not only as a technology for exploring Mars, but as a proof of concept for many engineering challenges that NASA will have to overcome in future missions, both robotic and human. “If we’re going to do a sample return mission, we’ll want to know how to make propellant for the return journey,” explains Zubrin, “and the gashopper will also let us test many liftoffs and landings with hazard avoidance in all kinds of terrain.

“The gashopper will be using native carbon dioxide for fuel, so it won’t contaminate the soil with hydrocarbons,” continues Zubrin. This is important, because spacecraft from Earth using hydrocarbons for fuel could contaminate the landing site with chemicals that could confuse the search for life. “Once the gashopper gets moving, it’ll find a pristine Martian surface to explore.”

The simplest gashopper could actually be quite light, as little as 50 kg (110 pounds). Compare this to the current Mars Exploration Rovers, which both weigh in at 185 kg (380 pounds). Tack on some more weight, and the gashopper could carry a few mini-rovers, like the tiny Sojourner that visited Mars as part of the Pathfinder mission. These could be targeted at the most interesting features based on the gashopper’s aerial reconnaissance of the area.

Image credit: Pioneer Astro
Another advantage of the gashopper is that is could completely ignore terrain. When NASA selected the landing sites for its Mars landers, it purposefully chose locations that were relatively flat, so the rovers could drive at a useful speed. The gashopper could land at the edge of a deep chasm, examine the area, jump down to the bottom and get back out again. It would give scientists unprecedented range and flexibility when searching for evidence of past water or life on Mars.

Of course, there’s a catch. The limiting feature of the gashopper is the electricity required to pressurize and heat the carbon dioxide propellant. This process consumes a lot of power, and the gashopper would need more than a month using its solar cells to refuel and recharge its batteries before it could take off again.

To generate more electricity, NASA could consider using a Radioisotope Thermal Generator, similar to those carried by Cassini, the Viking landers, or the upcoming Mars Science Laboratory (due for launch in 2009). With a more powerful electrical system, the gashopper could lift off every few days, and essentially be able to roam the entire planet of Mars.

Zubrin’s company, Pioneer Astronautics, has already done a significant amount of testing and research for the concept, and they developed a prototype ballistic gashopper for NASA’s Jet Propulsion Lab in 2000. The engine worked well in the lab, and they were able to get a remote-controlled vehicle with a mass of 50 kg to fly in a simulated Martian gravity (using a helium balloon to provide stability).

Instead of sitting on one spot, or slowly crawling across the surface of Mars, future robotic explorers to visit the Red Planet may take to the skies and soar. Well… hop, anyway.

Written by Fraser Cain

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows Crater Hale in the Argyre basin of the southern hemisphere of Mars.

The image shows an area close to the northern rim of the Argyre basin, located at latitude 36? South and longitude 324? East, and was taken with a ground resolution of about 40 metres per pixel during Mars Express orbit 533 in June 2004.

Slight periodic colour and brightness variations in parts of the image indicate atmospheric waves in clouds.

Crater Hale, with its terraced walls, central peak and a part of the inner ring is visible in the upper (eastern) part of the image. The region has been eroded heavily by deposits caused by this impact, and subsequent processes.

On the southern rim of Hale, parts of the crater wall have moved downslope towards the crater?s centre. At the bottom (western) part of the picture, the surface shows a network of fluvial channels which may have been caused by running water.

The HRSC experiment on ESA?s Mars Express mission is led by the Principal Investigator Prof. Dr Gerhard Neukum, of the Freie Universitaet Berlin, who also designed the camera. The science team for the experiment consists of 45 Co-Investigators from 32 institutions and 10 nations.

The camera was developed at the German Aerospace Center (DLR) and built in co-operation with industrial partners EADS Astrium, Lewicki Microelectronic GmbH and Jena-Optronik GmbH.

The HRSC is operated by the DLR Institute of Planetary Research, through ESA?s European Space Operations Centre in Darmstadt, Germany.

Image resolution has been decreased for use on the internet. The colour image was processed using the HRSC nadir (vertical view) and three colour channels.

Original Source: ESA News Release

Image credit: Beagle 2
Colin Pillinger is married and has two children. He lives on a small farm in Cambridgeshire, where his livestock keep him busy out of working hours. He first became interested in ‘space science’ by reading Dan Dare comics and listening to ‘Journey Into Space’ on the radio.

“The loss of Beagle-2 I would say was very frustrating to everyone who worked on the project including myself, because the craft carried the first instruments down onto the Martian surface that would actually look for Carbon based organisms, as apposed to carrying out a chemical analysis of the Martian soil by adding liquid nutrients, which is what the Label Release Experiment did on the Vikings landers back in 1976,” explained Professor Pillinger.

2004 has truly been ‘The year of Mars’ with the European Space Agency’s Mars Express doing remarkable science in Martian orbit, while sending back highly detailed images of the planet, and with the successful landing of the two NASA/JPL rovers Spirit and Opportunity in January which have done good geological science leading to the discovery that a huge quantity of water once flowed on the red planet.

“Finding out that a large amount of water existed on Mars in the past was good news because it brings the possibility of some form of life on the planet that bit closer,” explained Colin. “Meteorites from Mars that have landed on Earth show clear evidence that conditions appropriate to life did exist on the red planet, including in the recent past.

“However, features in the meteorites which have been described as nanofossils are highly controversial. Unfortunately, we cannot be sure that organic matter found in the meteorites is the remnant of organisms that lived on Mars and not due to contamination on Earth. We need to repeat the experiments on rocks that never left Mars,” he continued.

A short time ago I talked to Sir Patrick Moore about the best chance of finding life in the solar system, and I posed this question to Professor Pillinger as well. In our interview, Sir Patrick had said, “I believe our best chance of finding life is on the planet Mars. We now know that a lot of water once existed on this planet sometime in the past, and the latest surface rovers (Spirit and Opportunity), along side orbiting space probes like Mars Express, have shown that the Martian conditions are more favorable for life to evolve their today than at any time in the past. If the conditions are right, life will always find a way to exist.”

Prof. Pillinger replied “The fact that Mars Express has also confirmed the existence of methane in the thin Martian atmosphere, is interesting too.

“There have been two independent astronomical observations that first detected the presence of methane while Mars Express just confirmed it, and we now know that the amount of this gas is more than can be accounted for by volcanic activity.”

On Earth, there are many creatures, large and small, that produce methane. The simplest biological sources, including peat bogs, rice fields and ruminant animals (cows, sheep, etc.), continuously supply fresh gas to replace that destroyed by oxidation.

Methane also has a very short lifetime on Mars because of the oxidizing nature of the atmosphere, so its presence would indicate a replenishing source, which may be life, even if it is buried beneath the surface. If this methane exists, the Mars Express Orbiter has an instrument which should be able to detect it in the atmosphere.

“The Beagle-2 lander would have looked for signatures of life on Mars, whether long-dead or still-living, by measuring the ratio of two different types of carbon in the rock,” explained Prof. Pillinger. “Biological processes on Earth favor the lighter isotope of carbon, carbon-12, over the heavier carbon-13. Hence, a high carbon-12 to carbon-13 ratio is taken as evidence of life and has been found in rocks up to 4000 million years old, even where geological processing has occurred.”

Dr. Gilbert V. Levin, an experimenter with the original 1976 Viking Mission to Mars has been following this methane discovery with great interest. He has been advocating for years that Viking did find evidence of life on Mars with the Labeled Release life detection experiment, but other scientists are still skeptical.

I asked Colin if the discoveries by Spirit and Opportunity in 2004, or the recent discovery of methane supported Dr. Levin’s findings.

“I have heard of Dr. Levin. I think it is a firm understanding among planetary scientists that the Viking life investigation experiment only detected a chemical reaction rather than finding life on Mars itself. There is no point in harking on about the past, it’s time to move on and look for the real evidence of the carbon-based organisms that may exist on Mars today. That is where the Beagle 2 experiment differed from that of the Viking landers.”

Is there any other evidence that life may exist on the red planet, I asked? “Yes, meteorites from Mars that have landed on Earth show clear evidence that conditions appropriate to life did exist on the planet, including in the recent past, unfortunately, we cannot be sure that organic matter found in the meteorites is the remnant of organisms that lived on Mars and not due to contamination on Earth. We need to repeat the experiments on rocks that never left the Red Planet.

“At the moment there is no new Beagle Mars Lander project; however, I think this is an exciting time to look for life on Mars, and Beagle was well equipped to try and find it, which is why it has been very frustrating for my team and myself. I think that a new British Beagle lander should be built at this time to go to Mars and look for signs of life on the planet’s surface.”

By Science Correspondent Richard Pearson

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows the detailed structure of Coprates Catena, a southern part of the Valles Marineris canyon system on Mars.

The image was taken during orbit 438 with a ground resolution of approximately 43 metres per pixel. The displayed region covers an area centred at about latitude 14? South and longitude 301? East.

Coprates Catena is a chain of collapsed structures, which run parallel to the main valley Coprates Chasma.

These collapsed structures vary between 2500 and 3000 metres deep, which is far less than the depth of the main valley at 8000 metres. A few landslides can be seen on the valley walls.

The valley chains have no connection to the lowland plains as compared to the main valleys. This indicates that their origin is solely due to the expansion of the surface, or collapse, with removal of underlying material (possibly water or ice).

On the valley floor, brighter layers are exposed, which could be material of the same composition as seen in other parts of Valles Marineris, where sulphates have been measured by the OMEGA spectrometer instrument on board Mars Express.

Original Source: ESA News Release

Operators of NASA’s Mars Exploration Rover Opportunity have determined that a proposed route eastward out of “Endurance Crater” is not passable, so the rover will backtrack to leave the crater by a southward route, perhaps by retracing its entry path.

“We’ve done a careful analysis of the ground in front of Opportunity and decided to turn around,” said Jim Erickson, rover project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “To the right, the slope is too steep — more than 30 degrees. To the left, there are sandy areas we can’t be sure we could get across.”

Before turning around, Opportunity will spend a few days examining the rock layers in scarp about 10 meters (33 feet) high, dubbed “Burns Cliff.” From its location at the western foot of the cliff, the rover will use its panoramic camera and miniature thermal emission spectrometer to collect information from which scientists hope to determine whether some of the layers were deposited by wind, rather than by water. The rover will not reach an area about 15 meters (50 feet) farther east where two layers at different angles meet at the base of the cliff.

“We have pushed the vehicle right to the edge of its capabilities, and we’ve finally reached a spot where we may be able to answer questions we’ve been asking about this site for months,” said Dr. Steve Squyres, rover principal investigator at Cornell University, Ithaca, N.Y. “But after we’re done here, it’ll be time to turn around. Going any farther could cut off our line of retreat from the crater, and that’s not something anybody on the team wants to do.”

Opportunity entered the stadium-size crater on June 8 at a site called “Karatepe” along the crater’s southern rim. Inside the crater, it has found and examined multiple layers of rocks that show evidence of a wet environment in the area’s distant past.

Opportunity and its twin, Spirit, successfully completed their primary three-month missions on Mars in April. NASA has extended their missions twice, most recently on Oct. 1, because the rovers have remained in good condition to continue exploring Mars longer than anticipated.

Engineers have finished troubleshooting an indication of a problem with steering brakes on Spirit. The brakes are designed to keep the rover wheels from being bumped off course while driving. Spirit has intermittently sent information in recent weeks that the brakes on two wheels were not releasing properly when the rover received commands to set a new course. Testing and analysis indicate that the mechanism for detecting whether the brakes are released is probably sending a false indication. The rover team will disregard that signal and presume the brakes have actually released properly when commanded to do so. This anomaly has not been observed on the Opportunity rover.

“We’re going back to using the full steering capabilities of Spirit,” Erickson said.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Science Mission Directorate, Washington, D.C. Additional information about the project is 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

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, is Europe?s highest-resolution picture so far of the Martian moon Phobos.

This HRSC image shows new detail that will keep planetary scientists busy for years, working to unravel the mysteries of this moon. The image shows the Mars-facing side of the moon, taken from a distance of less than 200 kilometres with a resolution of about seven metres per pixel during orbit 756.

Images of Phobos as shown here had already been taken at lower resolution in previous orbits (413, 649, 682, 715 and 748). In the coming months, these first pictures will be followed by a series of images taken in subsequent fly-bys.

The Mars Express spacecraft periodically passes near Phobos about one hour before it flies at an altitude of only 270 kilometres above the Martian surface, just above the atmosphere. Within minutes, the orbiting spacecraft turns from its attitude where it points at Mars to train its camera on this little world.

The HRSC provided an unprecedented near-simultaneous group of 10 different images of the surface, enabling the moon’s shape, topography, colour, ?regolith? light-scattering properties, and rotational and orbital states to be determined. The regolith is the small-grained material covering most non-icy planetary bodies, resulting from multiple impacts on the body?s surface.

These images have surpassed all previous images from other missions in continuous coverage of the illuminated surface, not blurred and at the highest resolution. The US Viking Orbiter obtained a few small areas sampled at an even higher resolution of a few metres per pixel, but these were not so sharp due to the close and fast fly-by.

The global ?groove? network is seen in sufficient detail to cover the Mars-facing surface continuously from near the equator up to the north pole with regular spacing between the grooves. It now may be possible to determine whether the grooves existed before the large cratering events, and exist deep within Phobos, or came after the cratering events and were superimposed on them.

Much more detail is seen inside the various-sized craters, showing some with marked albedo variations. Some craters have dark materials near the crater floors, some have regolith that slid down the crater walls, and some have very dark ejecta, possibly some of the darkest material in our Solar System.

This tiny moon is thought to be in a ?death spiral?, slowly orbiting toward the surface of Mars. Here, Phobos was found to be about five kilometres ahead of its predicted orbital position. This could be an indication of an increased orbital speed associated with its secular acceleration, causing the moon to spiral in toward Mars.

Eventually Phobos could be torn apart by Martian gravity and become a short-lived ring around Mars, or even impact on the surface. This orbit will be studied in more detail over the lifetime of the Mars Express.

Original Source: European Space Agency