Category: Mars

In December of 2004, the mission scientists for the Mars Exploration Rover Spirit spied a ridge near the top of Husband Hill, one of the seven Columbia Hills located near the middle of Mars? Gusev Crater. Steve Squyres, Principal Scientific Investigator for the MER Mission, started calling the ridge ?Larry?s Lookout? and the mission team decided to send Spirit to that ridge to determine what it was and use it as a ?perch? to take a panorama of the valley that it overlooked. They knew it would be a challenge given the sand, steep slope, and rocks in the area, but the scientists are now discovering that the arduous climb was well worth it. According to one geologist, what Spirit is finding at Larry?s Lookout could turn out to be one of the highlights of the MER mission.

The ?Larry? of Larry?s Lookout is Dr. Larry Crumpler; field geologist, volcanologist, and Research Curator at the New Mexico Museum of Natural History and Science in Albuquerque, New Mexico. He is also a mission scientist for MER.

Spirit had originally approached and climbed Larry?s Lookout from the rear, and from that perspective the Lookout appeared to be just a knob on the hill.

But then the rover moved around to the side of Larry?s Lookout, and took a picture that caught the immediate attention of Squyres and other mission scientists. The image looks north along the ridge of the Columbia Hills with Spirit sitting on Husband Hill, and the camera pointed at Clark Hill. The hills are strewn with rocks, and in the foreground are two tilting rocks. The big outcrop just behind the rocks is Larry?s Lookout.

Dr. Crumpler explained the image and the questions it provoked: ?From this perspective, we can see that the outcrop has a tilted look. The two boulders in front of the outcrop appear to be orientated in the same direction. And in the hill in the distance to the right you can see layers that appear to be oriented at the same angles. And to the left, there are outcrops that are oriented at exactly the same angle. The overall impression is that there is some sort of organized layering or structure to the hills. Our big question is, is it just something draped over top of the hills, like ash fall draped over it like snow, or is it an indication of the internal arrangement of the bedding planes in the hills? Did the hills originally form by bulging up, and were the beds originally horizontal? Or did some sort of weathering occur? Any of those interpretations are interesting because it says something has happened subsequent to the original formation of the rocks and hills themselves.?

Crumpler said that this is one of the most interesting areas that Spirit has yet encountered, and the first indication of extensive bedrock. ?For the first time we have started to feel hopeful that we can make sense of the Columbia Hills,? he said. ?I think it is going to be a highlight of the mission.?

Crumpler says they are seeing evidence of finely bedded materials in the rocks, with very fine laminations that signify bedded, sediment-like materials. ?This all indicates that we?re not just looking at volcanic rocks or old broken up rocks, but there is some sort of organized layering,? he said. ?We?re going to do a full scale campaign to try to understand all of these things.? Although the MER science team still has a plethora of unanswered questions about this area of the Columbia Hills, from the evidence so far, water is likely to be at least part of the final equation.

Spirit is just about to begin studying the rock outcrop informally dubbed ?Methuselah,? just to the left of the rover tracks in the image. ?Spirit is looking at this outcrop that is dipping to the northwest and looks like it is laminated with bedding planes,? said Crumpler. ?It is a foot-high outcrop with an odd angle that indicates structure or a deposition that took place on a slope.?

Over the weekend of April 23-24, Spirit was ordered to take a panoramic image of the outcrop in order to give the scientists an overview of the overall pattern and layout of the area.

Crumpler noted that there is a considerable age difference between the Columbia Hills and the lava plain that Spirit crossed to reach the Hills. He likened the Hills to a sandstone butte surrounded by fresh, young lava flows, similar to the landscape that is found in the United States? Southwest. ?The Hills are much, much older,? Crumpler said. ?You can actually see the contact between the two where the lava flows sort of lapped up on the edges of the Hills. When you cross that boundary you go from the basalts which show only small amounts of weathering and alteration to the rocks on the Columbia Hills that are totally ?grunged-up? and altered, and basically water-soaked at some time in their history.?

?We?re still trying to figure out what?s going on here,? Crumpler added, ?but the outcrop we are looking at is giving us some good clues.?

Crumpler has had extensive experience in field geology, and said he has spent a lot of his time walking across New Mexico?s lava flows, just as Spirit trekked across the lava flow in Gusev Crater. He?s always had an intense interest in the geologic exploration of other planets and has been involved in some of the mapping programs of Mars, Venus and Io. But he says the MER program is the most exciting mission of which he?s been a part.

?Everyday there has been something different that we hadn?t seen the day before, or some new perspective of the terrain, so I always say that ?today? is the most exciting part of the mission.?

?When you?re in the field,? he continued, ?you keep moving because you?re always curious about what you?re going to find at the next outcrop that will tell you more about what you are trying to figure out. But we are very likely to be here (at Larry?s Lookout) for a long time giving this outcrop our full attention.?

So, it appears Larry?s Lookout will be keeping Spirit and the MER scientists busy for awhile, as they try to unravel the mysteries of the Columbia Hills.

Written by Nancy Atkinson

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows the ‘chaotic’ terrain of the Aureum Chaos region on Mars.

The HRSC obtained this image during orbit 456 with a resolution of approximately 25 metres per pixel. The scene shows an area located at about 3? South and 335? East.

Aureum Chaos is located in the eastern part of Valles Marineris, south-west of the 280 kilometre-wide impact crater Aram Chaos. Like this impact basin, both regions are two examples of the chaotic terrain contained in this part of the Valles Marineris.

As the name ?chaos? suggests, this terrain is characterised by randomly oriented, large-scale mesas and knobs that are heavily eroded and dominate the area. As seen in the main colour image, these mesas range from a few kilometres to tens of kilometres wide.

In the north (right-hand side) of this image, a well-defined scarp extends in an east-west direction.

?Slump and collapse? blocks can be distinguished at the base of this scarp, as highlighted in this close-up perspective view.

Near the southern border (middle left-hand side) of the colour image, a roughly five kilometre-wide region of bright material is observed. This material appears to form distinct layers that may have been created by the evaporation of fluids or by hydrothermal activity (see lower right-hand corner of the perspective view below).

Another interesting region of bright material also extends north to south in the centre of the colour image and is also visible along the left side of this perspective view.

The history of Aureum Chaos is complex. It appears that this basin was filled with sediment and then experienced the formation of chaotic terrain. It is thought that this extremely rough terrain is caused by collapse of the surface due to the removal of subsurface ice, magma or water.

By supplying new image data for Aureum Chaos, the HRSC allows scientists to improve their understanding of Mars. In particular, the colour and stereo capability of the HRSC allows improved studies of the planet?s morphology (the evolution of rocks and landforms). By analysing reflected light at different wavelengths, we can determine minerals that make up the various geological features within the scene.

Data from the HRSC, coupled with information from the other instruments on ESA?s Mars Express and other missions, will provide new insights into the geological evolution of the Red Planet and also pave the way for future missions.

Original Source: ESA News Release

University of Colorado at Boulder researchers say a bizarre group of microbes found living inside rocks in an inhospitable geothermal environment at Wyoming’s Yellowstone National Park could provide tantalizing clues about ancient life on Earth and help steer the hunt for evidence of life on Mars.

The CU-Boulder research team reported the microbes were discovered in the pores of rocks in a highly acidic environment with high concentrations of metals and silicates at roughly 95 degrees F in Yellowstone’s Norris Geyser Basin. The new study shows the microbe communities are subject to fossilization and have the potential to become preserved in the geologic record.

Scientists believe similar kinds of geothermal environments may once have existed on Mars, where astrobiologists have intensified the search for past and present life forms in recent years.

A paper by CU-Boulder doctoral student Jeffrey Walker, postdoctoral fellow John Spear and Professor Norman Pace of CU-Boulder’s molecular, cellular and developmental biology department and the Center for Astrobiology appears in the April 21 issue of Nature.

The research was funded by the National Science Foundation and NASA.

“This is the first description of these microbial communities, which may be a good diagnostic indicator of past life on Mars because of their potential for fossil preservation,” said Walker. “The prevalence of this type of microbial life in Yellowstone means that Martian rocks associated with former hydrothermal systems may be the best hope for finding evidence of past life there.”

Located about 20 miles northwest of Yellowstone Lake, Norris Geyser Basin is considered to be the hottest and most active geyser basin in Yellowstone and perhaps the world. It also is extremely acidic, according to the researchers.

“The pores in the rocks where these creatures live has a pH value of one, which dissolves nails,” said Pace. “This is another example that life can be robust in an environment most humans view as inhospitable.”

The process used to identify the organisms developed by Pace is much more sensitive than standard lab-culturing techniques that typically yield a small, biased fraction of organisms from any environment, said Walker. In this method, the researchers detected and identified organisms by reading gene sequences.

“Each kind of organism has a unique sequence, which is used to map its position in the tree of life,” said Walker. “It’s a family tree of sorts that describes the genetic relationship between all known organisms.”

Walker discovered the new microbe community in 2003 after breaking apart a chunk of sandstone-like rock in the Norris Geyser Basin. “I immediately noticed a distinctive green band just beneath the surface,” he said. “It was one of those ‘eureka’ moments.”

An analysis determined the green band was caused by a new species of photosynthetic microbes in the Cyanidium group, a kind of alga that is among the most acid-tolerant photosynthetic organisms known, said Walker. Cyanidium organisms made up about 26 percent of the microbes identified in the Norris Geyser Basin study by the CU-Boulder team, Walker said.

Surprisingly, the most abundant microbes identified by the team were a new species of Mycobacterium, a group of microbes best known for causing human illnesses like tuberculosis and leprosy, Walker said. Extremely rare and never before identified in such extreme hydrothermal environments, Mycobacterium made up 37 percent of the total number of microbes identified by the CU-Boulder team.

Pace described the new life form in the Norris Geyser Basin as “pretty weird.” “It may well be a new type of lichen-like symbiosis,” said Pace, who won a MacArthur Fellowship, or “genius grant,” in 2001. “It resembles a lichen, but instead of being comprised of a symbiosis between a fungus and an alga, it seems to be an association of the Mycobacterium with an alga.”

While photosynthesis appears to be a key energy source for most of the creatures, at least some Yellowstone microbes are believed to get energy from the dissolved metals and hydrogen found in the pore water of the rock, Walker said. A study by the CU-Boulder team published by the National Academy of Sciences in January 2005 indicated Yellowstone microbe populations living in hot springs at temperatures more than 158 degrees F use hydrogen as their primary fuel source.

The research effort in the Norris Geyser Basin shows that rock formation processes occurring in the hydrothermal environment under study make very real fossil imprints of the organisms embedded in the rock at various stages, showing how the distinctive fossils develop over time, according to the research team.

“Remnants of these communities could serve as ‘biosignatures’ and provide important clues about ancient life associated with geothermal environments on Earth or elsewhere in the Solar System,” the authors wrote in Nature.

Original Source: University of Colorado News Release

The terrain that Opportunity is crossing has been steadily getting more wavy. After a long drive southward from “Voyager” crater, Opportunity’s right-front steering motor stalled out on sol 433 during an end-of-drive turn. While performing tests to help the team diagnose the condition of that motor, the rover also continued to make remote-sensing observations. Testing in sol 435 did show motion in the steering motor, but analysis is still underway. The rover resumed normal science and driving operations on sol 436, but with restrictions on use of the right-front steering motor. It drove 30 meters on sol 437. Opportunity and Spirit are capable of driving with one or more steering motors disabled, though turns would be less precise. The latest revision in flight software on both rovers, uploaded in February, gives them improved capabilities for dealing with exactly this type of condition. It gives them upgraded ability to repeatedly evaluate how well they are following the intended course during a drive, and to adjust the steering autonomously if appropriate.

Original Source: NASA/JPL News Release

Since the time billions of years ago when Mars was formed, it has never been a spherically symmetric planet, nor is it composed of similar materials throughout, say scientists who have studied the planet. Since its formation, it has changed its shape, for example, through the development of the Tharsis bulge, an eight kilometer [five mile] high feature that covers one-sixth of the Martian surface, and through volcanic activity. As a result of these and other factors, its polar axis has not been stable relative to surface features and is known to have wandered through the eons as Mars rotated around it and revolved around the Sun.

Now, a Canadian researcher has calculated the location of Mars’ ancient poles, based upon the location of five giant impact basins on the planet’s surface. Jafar Arkani-Hamed of McGill University in Montreal, Quebec, has determined that these five basins, named Argyre, Hellas, Isidis, Thaumasia, and Utopia, all lie along the arc of a great circle. This suggests that the projectiles that caused the basins originated with a single source and that the impacts trace the Martian equator at the time of impact, which was prior to the development of the Tharsis bulge, he says.

Writing in the Journal of Geophysical Research (Planets), Arkani-Hamed calculates that the source of the five projectiles was an asteroid that had been circling the Sun in the same plane as Mars and most of the other planets. At one point, it passed close to the planet, until the force of Martian gravity surpassed the tensile strength of the asteroid, at which point it fragmented. The five large fragments would have remained in the same plane, that of Mars’ then-equator. They hit in different spots around the Martian globe, due to Mars’ rotation on its then-axis and the differing lengths of time the fragments took before impacting on Mars.

Arkani-Hamed describes the locations of the resulting basins, only three of which are well preserved. The two others have been detected by analysis of Martian gravitational anomalies. The great circle they describe on the Martian surface has its center at latitude -30 and longitude 175. By realigning the map of Mars with that spot as the south pole, the great circle marks the ancient equator.

Arkani-Hamed estimates that the mass of the asteroid captured by Mars was about one percent of that of Earth’s Moon. Its diameter was in the range of 800 to 1,000 kilometers [500 to 600 miles], depending upon its density, which cannot be determined.

The significance of Arkani-Hamed’s findings, if borne out by further research, is that the extent of presumed underground water on Mars would have to be reassessed. “The region near the present equator was at the pole when running water most likely existed,” he said in a statement. “As surface water diminished, the polar caps remained the main source of water that most likely penetrated to deeper strata and has remained as permafrost, underlain by a thick groundwater reservoir. This is important for future manned missions to Mars.”

Original Source: AGU News Release

Even before the Mars Science Lander (MSL) touches down descending from its hovering mother ship like a baby spider from an egg case the first of a slew of cameras will have started recording, capturing and storing high-resolution video of the landing area.

The MSL landing will represent a first, says Frank Palluconi, MSL project scientist. After entering the Mars atmosphere like Viking and MER but with a potential landing zone about one fourth the size he says, MSL will show its stuff. “It completes the descent down to the ten-meter [33-foot] level, or so, where the descent vehicle hovers, and it lowers the rover on a tether down to the surface. By that time, the rover has erected its wheels, so it lands on its mobility system. And then the tether is cut and the descent stage flies away and is no longer used. It crashes.”

In addition to the obvious advantages of such a soft landing, hovering and the tether drop are possible to model mathematically, unlike the airbag landing the MER vehicles used. Tethered descent is also scalable, Palluconi says, whereas the much smaller MERs were pushing the envelope of the airbag system’s capability.

Eyes on Mars
Shooting will begin as soon as the heat shield drops from the MSL descent stage. The Mars Descent Imager will take video in megapixel resolution, comparable to modern consumer digital video cameras. Aimed straight down, this camera will provide a spider’s eye view of the landing area a very wide angle at first and continue shooting until the rover touches down on Mars.

Landing videos will be transmitted to Earth by the rover when it becomes fully functional. This visual information, showing the landing area and its surroundings in fine detail, along with the fact that the rover will land on its wheels no tricky navigation off of a landing vehicle needed will allow project scientists to begin working the rover much sooner.

Once the rover’s mast rises and all systems are go, the real work will begin. As with MER, a mast-mounted, two-eyed camera system will feature prominently. The MastCam, like the descent imager and an arm-mounted close-up camera, is being designed and built by Malin Space Science Systems in San Diego, CA. All three rely on similar full-color, high-resolution subsystems. MastCam takes the basic setup found on the MERs twin cameras that will allow scientists to assemble 3D images and refines it considerably. MastCam has twin 10x optical zoom lenses, the same power as found in high-end consumer digital cameras on Earth. This will allow the camera to take not only wide-angle panoramas but also zoom in and focus on fist-sized rocks a kilometer (0.6 miles) away.

MastCam also shoots high definition video, a first for Mars. Both stills and video will be captured in full color, just like with earthbound digital cameras. In addition, MastCam will use a variety of specialized filters. Several members of the Malin Space Science Systems scientific team contributed to the various camera designs, including director James Cameron (Titanic, The Abyss, Aliens), a coinvestigator on the MastCam science team.

Photograph, Vaporize, Analyze
The MSL mast will also hold a unique hybrid optical instrument, never before flown to Mars. Called the ChemCam, this telescopic tool takes close-ups at a distance with a field of view of about 30 cm (1 foot) at ten meters (33 feet) distance. But that’s just the first step for ChemCam. In step two eerily reminiscent of the heat rays described in War of the Worlds a powerful laser will focus through the same telescope at the target. The laser can heat a spot about a millimeter (0.04 inches) in diameter to nearly ten thousand degrees Celsius (18 thousand degrees Fahrenheit). The heat blows away dust, breaks off molecules, breaks up the molecules and even breaks apart atoms in the rocky target.

As a result, the target emits a spark of light. ChemCam can analyze the spark’s spectrum, identifying what elements carbon or silicon, for example the target contained. Called Laser-Induced Breakdown Spectroscopy, or LIBS, this technique is widely used on Earth but will be a first for Mars, says Roger C. Wiens, a planetary scientist at Los Alamos National Laboratory and the principal investigator on the ChemCam project. “LIBS is being used in a number of facets on earth. For example, a company that makes aluminum uses it to check the composition of their aluminum alloy in the molten state.”

Going into space is a different story. Seven years in the making, ChemCam will make MSL much faster than MER at choosing targets, Wiens says. “The Opportunity rover landed in a small crater and here in front of us sat a rock outcrop, which is the first one we had seen on Mars up close and personal. And it was less than ten meters away. [With the ChemCam] we could have immediately analyzed that rock before actually even driving the rover off the pad, and told them that here sits a sedimentary rock outcrop right in front of you. Instead, it took a number of days, and they drove up to the rock and actually sampled it with the contact instruments before they really determined that it was a sedimentary rock outcrop.” With its long optical reach, ChemCam can analyze objects out of reach of the rover’s mechanical arm, even overhead.

In addition, ChemCam will be able to do some chemical analysis of small parts of rock samples, before they are crushed and transported to MSL’s internal analytical instruments

“I think this instrument is going to see a lot of use,” Wiens says, “because we can take a lot of data rapidly. So one of the great things is that we can get a much larger database of rock samples than some of the in-situ techniques. I think it’s going to be an exciting instrument to build and fly.”

Palluconi sees MSL as an intermediary step between MER and the direct search for life on Mars. “I would regard MSL as being kind of a transition mission between the more conventional aspects of planetary exploration, which involve geology and geophysics and, in the case of Mars because of its atmosphere, the climate and weather to ones in the future which will make direct searches for life. So the overall objective of MSL is to make a habitability assessment of the area that the vehicle lands in on Mars.”

The Near Future
Because NASA decided only in December 2004, which of many scientific instruments proposed for MSL will actually fly, all of the scientists whose projects were chosen are scrambling to put the finishing touches on their instruments. “The mission is in phase A, which is a definition phase, so it’s really the earliest formal phase of the mission,” Palluconi says. “Right now the principle work on the science side is figuring out where to place the instruments on the rover, how to meet their thermal needs, how to ensure that they have the fields of view they need and that their other requirements are met. Of course, the vehicle itself is being designed at the same time and the design is being refined. So there’s quite a bit of work to do and we’re probably just about a year away from the preliminary design review, which on the 2009 launch schedule would occur next February.”

Some aspects of the Mars Science Laboratory remain up in the air. Many of the MSL scientific instruments require plenty of power. The proposed source of that power, a radioisotope power supply, requires presidential approval, which lies in the future. And in March 2005, NASA began considering the possibility of flying two MSL rovers in 2011 instead of one in 2009.

Original Source: NASA Astrobiology Magazine

European space scientists have strongly recommended a mission equipped with a Rover as the next scientific mission to Mars as part of the European Space Agency?s [ESA] Aurora programme of planetary exploration.

The mission would conduct a detailed analysis of the Martian environment and search for traces of past or present life. A launch in June 2011, followed by a two year journey, would arrive on the Red Planet in June 2013. A detailed proposal will be prepared for consideration by ESA member states at the agency?s Council Meeting at Ministerial Level in December 2005.

The recommendation was made by European scientists at an international space workshop held at Aston University, Birmingham, England on the 6th and 7th April 2005. The ESA workshop, hosted by the UK?s Particle Physics and Astronomy Research Council [PPARC], brought together space scientists and agency officials from Europe, Canada, North America and the international space community in order to debate robotic mission options up to 2013 in the first phase of the Aurora programme.

Three candidate missions were considered: BeagleNet, ExoMars and its variant ExoMars-Lite. Consideration was also given to the preparatory activities needed to develop a sustainable, long-term Mars Exploration programme and how efforts to 2011 address the requirements of a Mars Sample Return [MSR] mission within an overall Aurora roadmap.

Following scientific and technology presentations of each candidate mission an evaluation process was undertaken by the scientists measured against key criteria. The outcome and consensus of the workshop recommended a mission which blended key technologies and objectives from each of the candidate missions as the first robotic mission in the Aurora programme. This recommendation will form the basis of a detailed proposal by the scientific community to be considered at the ESA?s Council Meeting at Ministerial Level in December 2005.

The recommended mission will consist of a Soyuz launcher to deliver a probe which includes at least one Rover for scientific exploration of the Martian environment. Telecommunications [data relay] between the probe and Earth will be achieved via NASA orbiting spacecraft. The Rover would be equipped with a suite of scientific instruments designed to search for traces of past or present life on Mars; to characterise the shallow subsurface water/geochemical composition and its vertical distribution profile; and to identify surface and environmental hazards to future human missions. Taking into account the exciting and scientifically intriguing results from ESA?s Mars Express orbiter the recommended mission will also incorporate instruments to specifically measure seismic phenomena which could be caused by volcanoes, hydrothermal activity or Marsquakes. The Rover will also contain a drill capable of penetrating the surface to a depth of 2m and a Beagle 2 type life marker experiment such as a Gas Analysis Package [GAP] capable of studying stable isotopes in the atmosphere, rocks, and soil. The entry, descent and landing system [EDLS] will utilise key technologies involving airbags and possibly retrorockets. To be launched by a Soyuz Fregat 2b vehicle in June 2011 from ESA?s spaceport at Kourou in French Guiana the probe and Rover would arrive on the surface of Mars in June 2013 after a two year voyage.

Looking beyond 2011 the scientists confirmed their commitment to collaborating in an international Sample Return Mission in 2016 [which would include sample acquisition and handling, mobility and planetary protection], as a logical sequence to the recommended mission in the future roll out of ESA?s Aurora programme.

Commenting on the workshop Prof. Jean Pierre Swings, Chair of ESA?s Exploration Programme Advisory Committee, said,? This workshop has brought an extremely wide range of scientists together from a diverse range of disciplines to recommend what will be a tremendously exciting mission for European space. It builds upon the success of ESA?s Mars Express whilst driving new technologies that will form the foundation for the future development of the Aurora programme?.

In terms of UK involvement Dr. Mark Sims, University of Leicester and Chair of PPARC?s Aurora Advisory Committee was buoyant,? This is a great result for European planetary exploration with significant involvement for the UK. The UK community has worked hard to ensure that the Aurora programme reflects the scientific and industrial expertise we have in the UK and the recommended mission builds upon the heritage of Beagle 2 and Huygens. We look forward to making major contributions to this scientific mission of discovery to the Red Planet?.

Original Source: ESA News Release

NASA has approved up to 18 more months of operations for Spirit and Opportunity, the twin Mars rovers that have already surprised engineers and scientists by continuing active exploration for more than 14 months.

“The rovers have proven their value with major discoveries about ancient watery environments on Mars that might have harbored life,” said Dr. Ghassem Asrar, deputy associate administrator for NASA’s Science Mission Directorate. “We are extending their mission through September 2006 to take advantage of having such capable resources still healthy and in excellent position to continue their adventures.”

The rovers have already completed 11 months of extensions on top of their successful three-month prime missions. “We now have to make long-term plans for the vehicles because they may be around for quite a while,” said Jim Erickson, rover project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Erickson cautioned though, “Either mission could end tomorrow with a random part failure. With the rovers already performing well beyond their original design lifetimes, having a part wear out and disable a rover is a distinct possibility at any time. But right now, both rovers are in amazingly good shape. We’re going to work them hard to get as much benefit from them as we can, for as long as they are capable of producing worthwhile science results.”

“Spirit and Opportunity are approaching targets that a year ago seemed well out of reach,? said Doug McCuistion, director of NASA’s Mars Exploration Program. ?Their successes strengthen NASA’s commitment to a vision with the ambitious targets of returning samples from Mars and sending human explorers to Mars.”

Opportunity is within a few football fields’ length of a region called “Etched Terrain,” where scientists hope to find rocks exposed by gentle wind erosion rather than by disruptive cratering impacts, and rocks from a different time in Mars’ history than any examined so far. “This is a journey into the unknown, to something completely new,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rover’s science instruments.

To reach the Etched Terrain, rover planners have been pushing the rover fast. Opportunity has overtaken Spirit in total distance driven. It has rolled more than three miles — eight times the original goal. On March 20, Opportunity also set a new martian record of 722 feet in a single day’s drive. Drive-distance estimates can vary by a few percent. The long drives take advantage of crossing a plain so smooth it’s “like an East Coast beach,” said JPL’s Jeff Favretto, mission manager on the Opportunity shift in recent weeks. Also, Opportunity’s solar panels, though now dustier than Spirit’s, still generate enough power to allow driving for more than three hours on some days.

Spirit is in much rougher terrain than Opportunity, climbing a rocky slope toward the top of “Husband Hill.” However, with a boost in power from wind cleaning its solar panels on March 9 and with its formerly balky right-front wheel now working normally, Spirit made some longer one-day drives last week than it had for months. “We’ve doubled our power,” said JPL’s Emily Eelkema, mission manager. “It has given us extra hours of operations every day, so we can drive longer and we’ve used more time for observations.”

The jump in power output has taken some urgency out of Spirit’s southward climb. With Mars now beginning southern-hemisphere spring, the sun is farther south in the sky each day. If not for panel-cleaning, Spirit might be facing the prospect of becoming critically short of power if still on the north-facing slope by early June.

“We still want to get to the summit of Husband Hill and then head down into the ‘Inner Basin’ on the other side,” Squyres said. “But now we have more flexibility in how we carry out the plan. Before, it was climb or die.” Cresting the hill is now not as crucial for solar energy, but it still offers allures of potential exposures of rock layers not yet examined, plus a vista of surrounding terrain. In orbital images, the Inner Basin farther south appears to have terracing that hints of layered rock.

Both rovers do have some signs of wear and exposure. Spirit’s rock abrasion tool shows indications that its grinding teeth might be worn away after exposing the interiors of five times more rock targets than its design goal of three rocks. Researchers probably won’t know the extent of wear until Spirit’s next rock-grinding attempt, which may be weeks away. Also, troubleshooting continues for determining whether Opportunity’s miniature thermal emission spectrometer is still usable despite tests indicating a problem last month. All other instruments on both rovers are still working normally.

Original Source: NASA/JPL News Release

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows part of the Medusa Fossae formation and adjacent areas at the highland-lowland boundary on Mars.

The HRSC obtained this image during orbit 917 with a resolution of approximately 13 metres per pixel. The scene shows an area located at about 5? South and 213? East.

The Medusa Fossae formation is an extensive unit of enigmatic origin found near the Martian ?highland-lowland dichotomy boundary? between the Tharsis and Elysium centres of volcanic activity. This dichotomy boundary is a narrow region separating the cratered highlands, located mostly in the southern hemisphere of Mars, from the northern hemisphere’s lowland plains.

The cratered highlands stand two to five kilometres higher than the lowland plains, so the boundary is a relatively steep slope. The processes that created and modified the dichotomy boundary remain among the major unanswered issues in Mars science.

The boundary between the old volcanic plateau region and part of the widespread deposits of the Medusa Fossae formation, called Amazonis Sulci, is shown in this image. In general, the formation appears as a smooth and gently undulating surface, but is partially wind-sculpted into ridges and grooves, as shown in the mosaic of nadir images.

It is commonly agreed that the materials forming Medusa Fossae were deposited by pyroclastic flows or similar volcanic ash falls. The plateau walls of the volcanic massif are partly covered by lava flows and crossed in places by valleys which were most likely carved by fluvial activity.

The remains of water-bearing inner channels are visible in the centre of the valleys and at the bottom of the massif. Superposition of the lobe-fronted pyroclastic flows indicates that the water erosion ended before their deposition. Later, a ?bolide? impacted near the massif and the ejecta blanket was spread as a flow over parts of the plateau, implying water or ice was present in the subsurface at the time of impact.

A bolide is any extraterrestrial body in the 1-10 kilometre size range, which impacts on a planetary surface, explodes on impact and creates a large crater. This is a generic term, used when we do not know the precise nature of the impacting body, whether it is a rocky or metallic asteroid, or an icy comet, for example.

Original Source: ESA News Release

Shifting glaciers and exploding volcanoes aren?t confined to Mars? distant past, according two new reports in the journal Nature.

Glaciers moved from the poles to the tropics 350,000 to 4 million years ago, depositing massive amounts of ice at the base of mountains and volcanoes in the eastern Hellas region near the planet?s equator, based on a report by a team of scientists analyzing images from the Mars Express mission. Scientists also studied images of glacial remnants on the western side of Olympus Mons, the largest of the volcano calderas in the solar system. They found additional evidence of recent ice formation and movement on these tropical mountain glaciers, similar to ones on Mount Kilimanjaro in Africa.

In a second report, the international team reveals previously unknown traces of a major eruption of Hecates Tholus less than 350,000 million years ago. In a depression on the volcano, researchers found glacial deposits estimated to be 5 to 24 million years old.

James Head, professor of geological sciences at Brown University and an author on the Nature papers, said the glacial data suggests recent climate change in Mars? 4.6-billion-year history. The team also concludes that Mars is in an ?interglacial? period. As the planet tilts closer to the sun, ice deposited in lower latitudes will vaporize, changing the face of the Red Planet yet again.

Discovery of the explosive eruption of Hecates Tholus provides more evidence of recent Mars rumblings. In December, members of the same research team revealed that calderas on five major Mars volcanoes were repeatedly active as little as 2 million years ago. The volcanoes, scientists speculated, may even be active today.

?Mars is very dynamic,? said Head, lead author of one of the Nature reports. ?We see that the climate change and geological forces that drive evolution on Earth are happening there.?

Head is part of a 33-institution team analyzing images from Mars Express, launched in June 2003 by the European Space Agency. The High Resolution Stereo Camera, or HRSC, on board the orbiter is producing 3-D images of the planet?s surface.

These sharp, panoramic, full-color pictures provided fodder for a third Nature report. In it, the team offers evidence of a frozen body of water, about the size and depth of the North Sea, in southern Elysium.

A plethora of ice and active volcanoes could provide the water and heat needed to sustain basic life forms on Mars. Fresh data from Mars Express ? and the announcement that live bacteria were found in a 30,000-year-old chunk of Alaskan ice ? is fueling discussion about the possibility of past, even present, life on Mars. In a poll taken at a European Space Agency conference last month, 75 percent of scientists believe bacteria once existed on Mars and 25 percent believe it might still survive there.

Head recently traveled to Antarctica to study glaciers, including bacteria that can withstand the continent?s dry, cold conditions. The average temperature on Mars is estimated to be 67 degrees below freezing. Similar temperatures are clocked in Antarctica?s frigid interior.

?We?re now seeing geological characteristics on Mars that could be related to life,? Head said. ?But we?re a long way from knowing that life does indeed exist. The glacial deposits we studied would be accessible for sampling in future space missions. If we had ice to study, we would know a lot more about climate change on Mars and whether life is a possibility there.?

The European Space Agency, the German Aerospace Center and the Freie Universitaet in Berlin built and flew the HRSC and processed data from the camera. The National Aeronautics and Space Administration (NASA) supported Head?s work.

Original Source: Brown University