Spirit Rover is Switched Off to Save NASA Money (Update)

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To save the Mars Expedition Rover (MER) program some cash, controllers will be forced to switch one of the four-year old rovers into “hibernation mode”. NASA wants to cut $4 million from the MER budget, so extreme measures are needed. Sadly, operations will need to be limited and it has been announced today that activities will be stopped on Spirit for the coming weeks. Mission scientists are obviously demoralized.

[UPDATE (03/25/08): NASA has now announced that it has “absolutely no plans” to turn off the Mars rovers, only hours after mission scientists announced they had new directives from the organization to cut $4 million from budget cuts. When more news is forthcoming I will post an article as to what is going on… ]

This appears to be the case of a mission being too successful for its own good.

The MER project was only intended to last for a few months, but the two rovers, Spirit and Opportunity, have surpassed all expectations and continued to explore the planet for four whole years. They are so efficient, that they have braved the worst dust storms, battled through technical issues and even freed themselves from quicksand, there seems to be nothing standing in their way of these super robotic troopers…

Except NASA budget cuts.

When the money runs out, the rovers have to be shut down and this is exactly what is going to happen to Spirit, currently located on a sunny slope at Gusev Crater. Even though the rovers are in the middle of an extensive exploratory phase of the Martian landscape, a NASA directive must be enforced to save $4 million from the project’s $20 million annual budget.

Shutting down Spirit isn’t the only budget-saving measure to be taken. Opportunity’s tasks will now be severely cut; limiting commands to be sent from controllers to every other day, rather than daily.

MER controllers are said to be very demoralized by these measures. Although budget cuts can never come at a “good time”, the timing of this announcement is terrible as both rovers are operating at full strength and still have vast amounts of potential.

The problem is that NASA is currently being stretched to accommodate other Mars missions currently in operation. But when should a highly successful mission like the MER project end? Up till now, most Mars surface missions are good until they break down. In the case of Spirit and Opportunity, neither is showing many signs of breaking. So for now, controllers will have to hover by the “off” switch while budget requirements are met.

Source: PhysOrg.com

The Mars Curse

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Admittedly, Mars has drawn more space missions than the rest of the Solar System’s planets, but why have nearly two thirds of all Mars missions failed in some way? Is the “Galactic Ghoul” or the “Mars Triangle” real? Or is it a case of technological trial-and-error? In any case, the Mars Curse has been a matter of debate for many years, but recent missions to the Red Planet haven’t only reached their destination, they are surpassing our wildest expectations. Perhaps our luck is changing…

In 1964, NASA’s Mariner 3 was launched from Cape Canaveral Air Force Station. In space, its solar panels failed to open and the batteries went flat. Now it’s orbiting the Sun, dead. In 1965, Russian controllers lost contact with Zond 2 after it lost one of its solar panels. It lifelessly floated past Mars in the August of that year, only 1,500 km away from the planet. In March and April, 1969, the twin probes in the Soviet Mars 1969 program both suffered launch failure, 1969A exploded minutes after launch and 1969B took a U-turn and crashed to earth. More recently, NASA’s Mars Climate Orbiter crashed into the Red Planet in 1999 after an embarrassing measurement unit mix-up caused the satellite to enter the atmosphere too low. On Christmas 2003, the world waited for a signal from the UK Mars lander, Beagle 2, after it separated from ESA’s Mars Express. To this day, there’s been no word.

Looking over the past 48 years of Mars exploration, it makes for sad reading. A failed mission here, a “lost” mission there, with some unknowns thrown in for good measure. It would seem that mankind’s efforts to send robots to Mars have been thwarted by bad luck and strange mysteries. Is there some kind of Red Planet Triangle (much like the Bermuda Triangle), perhaps with its corners pointing to Mars, Phobos and Deimos? Is the Galactic Ghoul really out there devouring billions of dollars-worth of hardware?

The strange-looking DR 6 nebula as observed by the Spitzer telescope - well, it could be the face of the Galactic Ghoul… (credit: NASA)

The “Galactic Ghoul” has been mentioned jokingly by NASA scientists to describe the misfortune of space missions, particularly Mars missions. Looking at the statistics of failed missions, you can’t help but think that there are some strange forces at play. During NASA’s Mars Pathfinder mission, there was a technical hitch as the airbags were deflated after the rover mission landed in 1998, prompting one of the rover scientists to mention that perhaps the Galactic Ghoul was beginning to rear its ugly head:

The great galactic ghoul had to get us somewhere, and apparently the ghoul has decided to pick on the rover.” – Donna Shirley, JPL’s Mars program manager and Sojourner’s designer, in an interview in 1997

Well, there are plenty of answers that explain the losses of these early forays to Mars, putting the Galactic Ghoul to one side for now.

Beginning with the very first manmade objects to land on the Martian surface, Mars 2 and Mars 3, Soviet Union-built Mars lander/orbiter missions in 1971. The lander from Mars 2 is famous for being the first ever robotic explorer on the surface of Mars, but it is also infamous for making the first manmade crater on the surface of Mars. The Mars 3 lander had more luck, it was able to make a soft landing and transmit a signal back to Earth… for 20 seconds. After that, the robot was silenced.

The first rover to land on Mars - Made in Russia (credit: Planetary Society)

Both landers had the first generation of Mars rovers on board; tethered to the landing craft, they would have had a range of 15 meters from the landing site. Alas, neither was used. It is thought that the Mars 3 lander was blown over by one of the worst dust storms observed on Mars.

To travel from Earth to Mars over a long seven months, separate from its orbiter, re-enter the Martian atmosphere and make a soft landing was a huge technological success in itself – only to get blown over by a dust storm is the ultimate example of “bad luck” in my books! Fortunately, both the Mars 2 and 3 orbiters completed their missions, relaying huge amounts of data back to Earth.

The ill-fated NASA Mars Observer before launch (credit: NASA)

This isn’t the only example where “bad luck” and “Mars mission” could fall into the same sentence. In 1993, NASA’s Mars Observer was only three days away from orbital insertion around Mars when it stopped transmitting. After a very long 337 day trip from Earth it is thought that on pressurizing the fuel tanks in preparation for its approach, the orbiters propulsion system started to leak monomethyl hydrazine and helium gas. The leakage caused the craft to spin out of control, switching its electronics into “safe” mode. There was to be no further communication from Mars Observer.

Human error also has a part to play in many of the problems with getting robots to the Red Planet. Probably the most glaring, and much hyped error was made during the development of NASA’s Mars Climate Orbiter. In 1999, just before orbital insertion, a navigation error sent the satellite into an orbit 100 km lower than its intended 150 km altitude above the planet. This error was caused by one of the most expensive measurement incompatibilities in space exploration history. One of NASA’s subcontractors, Lockheed Martin, used Imperial units instead of NASA-specified metric units. This incompatibility in the design units culminated in a huge miscalculation in orbital altitude. The poor orbiter plummeted through the Martian atmosphere and burned up.

An artists impression of the Mars Climate Orbiter (credit: NASA)

Human error is not only restricted to NASA missions. The earlier Russian Phobos 1 mission in 1988 was lost through a software error. Neglecting a programming subroutine that should never have been used during space flight was accidentally activated. The subroutine was known about before the launch of Phobos 1, but engineers decided to leave it, repairing it would require the whole computer to be upgraded. Due to the tight schedule, the spaceship was launched. Although deemed “safe”, the software was activated and the probe was sent into a spin. With no lock on the Sun to fuel its solar panels, the satellite was lost.

The Russian Phobos 1 mission to probe Mars and moon Phobos (credit: NASA)

To date, 26 of the 43 missions to Mars (that’s a whopping 60%) have either failed or only been partially successful in the years since the first Marsnik 1 attempt by the Soviet Union in 1960. In total the USA/NASA has flown 20 missions, six were lost (70% success rate); the Soviet Union/Russian Federation flew 18, only two orbiters (Mars 2 and 3) were a success (11% success rate); the two ESA missions, Mars Express, and Rosetta (fly-by) were both a complete success; the single Japanese mission, Nozomi, in 1998 suffered complications en-route and never reached Mars; and the British lander, Beagle 2, famously went AWOL in 2003.

Despite the long list of failed missions, the vast majority of lost missions to Mars occurred during the early “pioneering” years of space exploration. Each mission failure was taken on board and used to improve the next and now we are entering an era where mission success is becoming the “norm”. NASA currently has two operational satellites around Mars, Mars Odyssey and the Mars Reconnaissance Orbiter. The European Mars Express is also in orbit.

The Mars Exploration Rovers Spirit and Opportunity continue to explore the Martian landscape as their mission keeps on getting extended.

Recent mission losses, such as the British Beagle 2, are inevitable when we look at how complex and challenging sending robotic explorers into the unknown. There will always be a degree of human error, technology failure and a decent helping of bad fortune, but we seem to be learning from our mistakes and moving forward. There definitely seems to be an improving trend toward mission success over mission failure.

Perhaps, with technological advancement and a little bit of luck, we are overcoming the Mars Curse and keeping the Galactic Ghoul at bay as we gradually gain a strong foothold on a planet we hope to colonize in the not-so-distant future

Salt Deposits on Mars Might Be the Right Place to Search for Life

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Researchers announced today that they have discovered large salt deposits on the surface of Mars. These deposits point to places where large quantities of water existed on the surface of the Red Planet, perhaps for millions of years. And this might be some of the best places to go looking for evidence of life, past and present.

A team led by Mikki Osterloo at the University of Hawaii, Honolulu have turned up approximately 200 separate spots on southern Mars that seem to have ancient deposits of sodium chloride. In other words, they’ve found table salt sitting on the surface of Mars.

The sites, discovered by NASA’s Mars Odyssey spacecraft, range in size from 1 square km (.6 square miles) to 25 square kms.

So how did this salt get there? One possibility is that it came from groundwater, reaching the surface in low spots. The water would evaporate and leave the mineral deposits over the course of millions of years. Since the sites are largely disconnected from one another, it rules out the possibility the salt was left by an ocean that evaporated billions of years ago.

“Many of the deposits lie in basins with channels leading into them,” said Philip Christensen, co-author and principal investigator for the camera at Arizona State University. “This is the kind of feature, like salt-pan deposits on Earth, that’s consistent with water flowing in over a long time.”

Don’t go looking for life today, though. The scientists think the salt deposits were formed approximately 3.5 to 3.9 billion years ago. This was a time when Mars had much warmer and wetter conditions than the frigid, dry climate on the planet today.

Until now, researchers have been looking for other evidence of past water on the surface of Mars, like clay or sulfate minerals. Clay is evidence that a region was weathered by water, and sulfates are caused by water evaporation. These salts offer an alternative place to look for evidence of past life.

To get salt deposits of this size, you would need to have large quantities of water sitting on the surface of Mars for a long time. And this is crucial in the search for life. You want a habitat that endures for a long time.

Original Source: NASA/JPL News Release

Mars’ Violent, Volcanic Past … and Possible Future?

Planetary geologists have a relatively simple method for calculating the age of a planet’s surface: count the number of impact craters in a region. The older the surface, the more craters there will be from meteorites that have struck the planet over the ages. Areas with fewer craters are generally interpreted as younger surfaces where other geological processes such as volcanic activity or plate tectonics, have erased the impact scars. A new analysis of impact cratering using images from the Mars Express has revealed that Mars has undergone at least five violent, global volcanic upheavals, shaping the surface of Mars we see today.

Using the High Resolution Stereo Camera (HRSC) on Mars Express, planetary scientists are learning more about Mars’ past. “We can now determine the ages of large regions and resurfacing events on the planet,” says Gerhard Neukum. Resurfacing occurs when volcanic eruptions spread lava across the planet’s surface. But unlike Earth, where resurfacing happens gradually and slowly, Mars has had a series of violent volcanic periods. This occurred more than 3.8 thousand million years ago. In between these episodes, the planet has been relatively calm.

Mars Chronology Model.  Credits: Neukum and HRSC Team, 2008, chronology: Neukum & Hartmann, 2001
During these volcanic episodes, eruptions of lava flowed across Mars. The internal heat generated by the volcanic activity also caused water to erupt from the interior, causing wide-scale flash flooding.

Why did Mars behave like this? Geophysical computer-based models suggest that the planet has been trying to establish a system of plate tectonics, as there is on Earth where the crust is broken into slowly moving plates. On Mars, the volcanic episodes represent the planet almost, but not quite, developing plate tectonics.

We recently saw a landslide on Mars. Could we possibly see a volcanic eruption? “The interior of the planet is not cold yet, so this could happen again,” says Neukum.

Original News Source: ESA Press Release

Ancient Lake on Mars Found by HiRISE a Good Place to Look for Life

Despite what it might look like, this is not the beach of a lakeside resort here on Earth. It’s what remains of a dried up lake on the surface of Mars, yet another fantastic image brought to us by the cameras on the High Resolution Imaging Science Experiment (HiRISE.) This is a closeup of the largest of the “fans” leftover from the lake in the bottom of Holden Crater, an 87-mile (140-kilometer) wide crater in the bottom of the larger Holden Basin on Mars.

What’s interesting about a dried up lake bed, besides the spectacular image? Well, it’s the perfect place to start a search for life on Mars. A nice, calm lake would be a likely place for life to form. This site is one of the six possible landing sites for the NASA’s Mars Science Laboratory, which launches next year and will try to answer the question of whether life on Mars existed at one time, or continues to thrive there.

In addition to the possiblity that the lake was at one time inhabited by Martian life, the crater is full of rocks and sediment that are of interest to geologists studying the history of Mars. Called “megabreccia”, the floor of the crater contains a mixture of boulders, sediment and clay. Before the impact that formed the crater, sediments were deposited in the bottom of Holden Basin by channels of water running across the basin. Blocks of the surface as large as 50 meters (164 feet) across were thrown up when the crater was made.

“When large craters form, they produce very large blocks of material. We see them on Earth. Popigai Crater in Russia is one example. But we’d never seen them on Mars, and we knew they ought to be there. Now we’ve seen them with HiRISE,” said John Grant of the Smithsonian National Air and Space Museum, who is the first author on a paper about Holden Crater recently published in the journal Geology.

The crater’s history is even more complicated: the rim of the crater was breached by surrounding water, creating a massive flood that stirred up the sediments on the bottom and re-filled the crater. Boulders and debris from the event are strewn over the top of the megabreccia, and are also covered in fine sediment and clay that settled on them from the lake before it dried up. The volume of water in this catastrophic flood would have been larger than that contained within Lake Huron.

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Both images used here are in false color to help reveal details. This second image shows the layers produced by the impact and subsequent flooding, most noticeable on the walls in the upper left-hand corner. Mars was likely wetter during its early history, and the flow of water later in its life was probably reserved to catastrophic events such as the breach of Holden crater.

Images like this and more have been really pouring in from HiRISE. To see more, check out their site and our coverage here at UT on this fantastic image of an avalanche in progress on Mars, and this picture of the Earth and Moon together in one beautiful shot.

Source: University of Arizona Press Release

Observing the Atmospheres of Venus and Mars Leak into Space (Video)

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It turns out that Venus and Mars aren’t actually that different after all. Although Mars has very little atmosphere to speak of and Venus has a stifling, thick, poisonous one, they have one thing in common: the Sun. The solar wind constantly batters the Solar System’s planets, stripping their atmospheres into space. Is it possible that Mars may once have had a thick atmosphere like Venus’, but has long since leaked away?

The twin ESA spacecraft, Venus Express and Mars Express, have very similar instruments on board and are currently orbiting the two planets. Mars Express arrived on December 25th 2003 and Venus Express arrived on April 11th 2006. Venus Express was intended as a “copy” of the older Mars Express design, but some upgrades were required. Primarily, as Venus is two times closer to the Sun, Venus Express needed better protection from solar radiation. There will also be an increase in ionizing high-energy particles hitting the orbiter, so this had to be taken into account.

Apart from a few minor upgrades, the twin Express missions are able to carry out the same observations on both planets, providing ESA scientists with a unique opportunity to compare results of both spacecraft. In fact, for the first time ever, researchers are able to carry out comparative planetology of two planets with two orbiting spacecraft as they are carrying similar instrumentation.

One such instrument is the Analyser of Space Plasmas and Energetic Atoms (ASPERA) that can be found on both spacecraft. ASPERA has detected atmospheric particles leaking into space as the solar wind hits the planetary atmospheres. Both Mars and Venus, despite their difference in orbits and size, exhibit similar patterns of particle loss. As the planets have no uniform magnetic field surrounding the atmosphere, atmospheric particles are easily swept away. In the case of the Earth, our atmosphere is protected by a strong magnetosphere blanketing us from the ferocious solar wind.

Ultimately ESA scientists hope to analyse the rate of particle loss from Mars and Venus so a better picture of planetary evolution can be arrived at. It is possible that the solar wind may be responsible for the very thin Martian atmosphere. Mars is a tiny planet (only half the size of Earth); whereas Venus is often considered to be Earth’s “sister” as it is approximately the same size. Perhaps the low Mars gravity allowed a higher rate of atmospheric loss than Venus.

What ever the conclusion, mission scientists have a lot of work to do. The results will not only help us understand the development of Mars and Venus, it will also aid our understanding about how the Earth is evolving and may give us some clues to the future.

Video: The strong interaction of the solar wind with the atmosphere of Venus (ESA)

Source: ESA

A One-Way, One-Person Mission to Mars

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Will humans ever really go to Mars? Let’s face it, the obstacles are quite daunting. Not only are there numerous, difficult, technical issues to overcome, but the political will and perseverance of any one nation to undertake such an arduous task just can’t be counted on. However, one former NASA engineer believes a human mission to Mars is quite doable, and such an event would unify the world as never before. But Jim McLane’s proposal includes a couple of major caveats: the trip to Mars should be one-way, and have a crew of only one person.

McLane worked at NASA for 21 years before leaving in 2007 to work for a private engineering firm. Being able to look from afar at NASA’s activities has given him a new perspective, he says.

But McLane was still at NASA when he originally had an idea for a one-way, one-person mission to Mars. He calls his proposal the “Spirit of the Lone Eagle,” in deference to Charles Lindbergh’s solo flight from New York to Paris in 1927.

McLane’s idea came from his acquaintance with a Russian cosmonaut. “I noticed the cosmonaut seemed to be a slightly different type of person than the American astronaut,” McLane said. “Cosmonauts are primarily pilots, and like test pilots, they are very focused on getting the job done. The current American astronauts are picked for things such as their speaking ability and social skills, and most of them have advanced degrees. But the cosmonaut struck me as an adventurous, get-things-done-type person, like our original astronauts back in the 1960’s.”

A return to the “get it done” attitude of the 1960’s and a goal of a manned landing within a short time frame, like Apollo, is the only way we’ll get to Mars, McLane believes. Additionally, a no-return, solo mission solves many of the problems currently facing a round-trip, multiple person crew.

“When we eliminate the need to launch off Mars, we remove the mission’s most daunting obstacle,” said McLane. And because of a small crew size, the spacecraft could be smaller and the need for consumables and supplies would be decreased, making the mission cheaper and less complicated.

While some might classify this as a suicide mission, McLane feels the concept is completely logical.

“There would be tremendous risk, yes,” said McLane, “but I don’t think that’s guaranteed any more than you would say climbing a mountain alone is a suicide mission. People do dangerous things all the time, and this would be something really unique, to go to Mars. I don’t think there would be any shortage of people willing to volunteer for the mission. Lindbergh was someone who was willing to risk everything because it was worth it. I don’t think it will be hard to find another Lindbergh to go to Mars. That will be the easiest part of this whole program.”

And like Apollo, such a mission would stimulate new technology and reinvigorate science. McLane feels a mission to Mars should be international in scope, encompassing contributions from multiple nations to represent a milestone for the whole human race.

Mars mission.  Image Credit:  NASA

“I think people have forgotten how exciting the Apollo program was, and this would bring that excitement back,” he said. “And it wasn’t just here in the US; the whole world was excited. This enthusiasm would be the greatest effect of a program that places a man on Mars, over and above anything else, whether it makes jobs, or stimulates the economy, or creates technology spinoffs. We’re all humans and the idea of sending one of our kind on a trip like that would be a wonderful adventure for the entire world. The whole world would get behind it.”

And the whole world would be watching, said McLane, so it wouldn’t be as if the lone astronaut would be completely by himself. “You would have constant communication,” he said. “The astronauts on the International Space Station have an army of people on earth keeping track of what they are doing. They really have no peace. Somebody is constantly planning and monitoring their activities. I don’t think being lonely will be much of a problem on a mission to Mars.”

Of course McLane’s hope is the solo astronaut would be joined by others shortly in the future. Orbital mechanics provides a desirable launch window from Earth to Mars every 26 months. “This person wouldn’t be there by himself for very long. It’s just returning home that would be impossible,” he said. Another option McLane has offered is a one-man and one-woman crew, possibly creating an Adam and Eve-type situation.

Unmanned landers would carry living accommodations, supplies and communication equipment to Mars’ surface before the human mission would even launch. The best location on Mars would be a low, sheltered area, perhaps at the bottom of a canyon, which would provide protection from radiation and weather, as well as the highest possible atmospheric pressure.

While technical issues abound for even the simplest human mission to Mars, McLane says technical issues didn’t deter the Apollo program, and they shouldn’t deter a mission to another planet.

“I can remember during the early days of the Apollo program, there were even many more technical issues than we face today in going to Mars,” said McLane. “People don’t realize that, or have forgotten that fact. Several things were tremendous unknowns back then, any one of which could have been a showstopper for a human moon landing.”

McLane said the early designers of the Apollo spacecraft gambled that in 3 or 4 years, high powered transistors and small guidance computers would be developed. That was the only way the spacecraft would be lightweight enough to land on the moon. “It was almost science fiction, but someone thought it could be done in just a few years, and sure enough the technology was perfected in time to make the mission possible,” he said.

James C. McLane.  Image Credit:  courtesy James McLane
Image: Jim McLane during his career at NASA.

While Apollo 11 astronaut Buzz Aldrin and noted author and physicist Paul Davies have also advocated a one-way trip to Mars, in our risk-averse society most people look askance at such an idea.

Even though explorers in the past traveled, for example, to the south or north pole, knowing they might never return, and thousands of immigrants moved to the US in the 18- and 1900’s, knowing they would never see their homeland again, the human psyche has seemingly changed enough that a one-way ticket off the planet is not acceptable. According to psychologist Molly Dooley from Springfield, IL, it might take a major crisis on Earth for humans to seriously consider such a mission. “Usually it’s the disenfranchised that are willing to take those kinds of risks,” she said. “When our present situation no longer works for us, we become more willing to take risks. The difference between the folks who are interested and those who aren’t is their attachment to their current situation.”

McLane says the main reason NASA hasn’t been able to focus on a human mission to Mars is simple: NASA doesn’t get nearly enough money. “This has been the case for many years,” he said. “They didn’t get enough money to fix problems with the shuttle, and they’ve always been chronically short of money. How we fund NASA is a big handicap, since every year, NASA has to go begging to Congress for funds and justify their budget. The Chinese space program, on the other hand, has an advantage in that they budget their projects in five-year increments. If we really want to go somewhere, we’ll have to change how NASA gets its money.”

But McLane thinks NASA is at fault for not even considering a one-way mission to Mars. “For over forty years they’ve studied all sorts of options, but haven’t admitted to ever looking at a one-way mission to Mars,” he said. “We shouldn’t be stuck on this rock forever. I believe it’s in our human nature to try to go somewhere else, and we’ve almost worn this world out. I think now is the time to reach out and go somewhere else to start with a clean slate. There is no reason not to try.”

HiRISE Captures Stunning Images of Mars Avalanches in Action

A Mars Avalanche, taken by NASAs HiRISE instrument on the Mars Reconnaisance Orbiter (Credit: NASA/HiRISE)

Magnificent images of avalanches of ice and rock in the northern polar regions of Mars have been captured by NASA Mars Reconnaissance Orbiter’s (MRO) High Resolution Imaging Science Experiment (HiRISE). These images are not of landslides that have happened in the past, they are actual Mars avalanches happening at the moment of observation. This rare event will be of tremendous value to Mars scientists currently analysing the effects of seasons on the landscape and will provide information on the geological activity of the planet…

This event occurred along a scarp (a distinct cliff, with a steep runoff) around the North Polar Region where surface ice can be found in large quantities. The HiRISE instrument was being used to assess seasonal changes around the North Pole when four areas of activity were seen along the scarp. HiRISE was witness to something more familiar on Earth than on Mars: avalanches.

This particular scarp is a high cliff over 700 m (2300 ft) tall and slopes at over 60 degrees. A mixture of ice, rock and dust can be seen, frozen in time, as it is plummeting down the slope, ejecting a plume of dust as the debris begins to settle on the gentle slope at the bottom of the cliff. The ejected cloud is approximately 180 meters across and extends about 190 meters beyond the base of the cliff. It is worth noting that the clouds are large 3D structures reaching into the Martian atmosphere and not 2D patterns on the surface (shadows from the plume can be seen to the lower left of the clouds of dust).

Mars polar region including scarp where avalanches were discovered - approximate locations of avalanches ringed (credit: NASA/JPL/UA)

The Martian landscape does not change very much over millions of years. Unlike the Earth, Mars does not have a thick, eroding atmosphere blasting away at the surface features. The lack of water also reduces these erosion effects. Mars also has very little geological activity as core reactions are thought to have slowed or even stopped – there is therefore very little tectonic movement, no major earthquakes and no evidence for present volcanic activity.

So what caused these avalanches? HiRISE scientists have some ideas:

  • Disappearance of carbon dioxide frost, dislodging rocks.
  • Expansion and contraction of ice due to seasonal temperature differences.
  • Small Mars-quakes.
  • A nearby meteorite impact.
  • Vibrations from other avalanches causing other avalanches along the scarp

Detail of the avalanches occurring along the scarp (credit: NASA/JPL/UA)

It seems most likely that the trigger may be down to seasonal changes. As the North Polar Region heats up (progressing toward summer), solid carbon dioxide (“dry ice”) may be subliming, weakening rocks around the edge of the cliff. The same could be said for the thermal expansion and contraction of water ice as the seasonal air temperature becomes warmer or cooler.

Whatever the cause, we are very lucky to have captured this event, the science collected from these observations will be critical to understanding how the Martian landscape can change very rapidly. The HiRISE instrument continues to return the most magnificently detailed images of the Red Planets surface, these observations of Mars avalanches will certainly go into the Mars Reconnaissance Orbiter’s Hall of Fame…

Source: HiRISE Project Site

Latest Mars Images Round-up

With three orbiters and two rovers currently at Mars, there are always interesting images coming back from the Red Planet. Here’s a round-up of the latest images from the five different spacecraft. First up is a fascinating image from the Mars Odyssey spacecraft of dust devil tracks. It’s amazing just how many tracks there are in just this one image. Martian dust devils can be up to fifty times as wide and ten times as high as dust devils seen on Earth. This image was taken by Odyssey’s Thermal Emission Imaging System (THEMIS), and shows an area in the south polar region, just east of Daly Crater. Resolution is about 17 meters per pixel. Original Image link.


NASA’s Mars Exploration Rover Spirit has this view northward from the position at the north edge of the “Home Plate” plateau where the rover will spend its third Martian winter. And no, that’s not a pool of water in the image. It’s just rippled sand in the “El Dorado” sand dune field, and the image is shown in false color.

Husband Hill is on the horizon. Spirit used its panoramic camera (Pancam) to capture this image during the rover’s 1,448th Martian day, on January 29, 2008.
Original image link.

This view from the Opportunity rover shows a close-up of bedrock from the inside of Victoria Crater, where the rover is currently studying a stratigraphic layer of rocks. This area is informally named “Lyell,” which is the lowermost of three layers the rover has examined at a bright band around the inside of the Crater.

Opportunity used its panoramic camera (Pancam) to capture this image with low-sun angle at a local solar time of 3:21 p.m. during the rover’s 1,433rd Martian day, on February 4, 2008. This image, too, is in false color to highlight the ripples and bands in the bedrock.
Original Image link.

Mars Express Candor Chasma.  Image Credits: ESA/ DLR/ FU Berlin (G. Neukum)
ESA’s Mars Express took snapshots of Candor Chasma, a valley in the northern part of Mar’s huge canyon, Valles Marineris, as it was in orbit above the region on 6 July 2006.

The High Resolution Stereo Camera on the orbiter obtained the data,with a ground resolution of approximately 20 m/pixel. Candor Chasma lies at approximately 6° south and 290° east.
Original Image link.

HiRISE Volcanic Vent.  Credit: NASA/JPL/University of Arizona

This image taken by the Mars Reconnaissance Orbiter (MRO) shows a volcanic vent. A volcanic vent is an opening in the crust of a planet that emits lava (molten rock) and volcanic gases. The rough texture of the plains surrounding the vent iindicates that it is lava.

There is a large number of snake-like features emanating from the vent. The parallel lines that outline the features are levees, which mark the edges of channels that carried molten lava. As lava flows, it moves slowest at its edges and bottom because the lava sticks to the non-flowing rocks, and as the lava slows, it cools off and hardens.

Levees form when the sides harden but the center of the flow keeps moving. As the eruption episode ends, and the lava drains, the center is left lower than the sides producing these high-standing structures. Of course, these lava flows are very, very old.
Original Image page.

Mars Gullies Produced by Dry Granular Debris and Not by Recent Water Flow

The High Resolution Imaging Science Experiment (HiRISE) on board NASA’s Mars Reconnaissance Orbiter (MRO) observed what appeared to be fresh gullies formed by a rapid release of water on the Martian surface in 2006. However, new computer models simulating the creation of gullies on the surface of Mars suggest that they are in fact created by the flow of dry debris (i.e. landslides) and not by the flow of water. A blow for the microbial life hunters and a huge blow for mission planners looking for easy sources of water for manned missions…

The MRO isn’t the only orbiter to view apparent gullies forged by spurts of water. The Mars Orbiter Camera (MOC) onboard NASA’s Mars Global Surveyor (MGS) also made news in 2006 when scanning the cratered regions of Terra Sirenum and Centauri Montes. Images taken several years apart revealed some changes in the most recent pictures, highlighting what looked like outflow channels from surges of liquid water (pictured below). What made this especially exciting was that this was possible evidence for the existence of liquid water flowing on Mars within the past few years (albeit very quickly).
Before and after pictures by MOC of a gully inside a crater (credit: NASA/JPL)
New work by scientists at the University of Arizona appears to conflict with these observations. In an attempt to demonstrate the characteristics of water flowing in Martian conditions, Associate Professor Jon D. Pelletier (Geophysics) and colleagues used topological data from the HiRISE instrument (the most advanced imaging system currently orbiting Mars) and modelled the flow of water down a slope. What the simulation showed was a surprise; the researchers went into the project thinking they were going to prove that the gullies were formed by water. Instead, they had shown that the shapes and characteristics of the observed gullies most resembled that of the modelled gullies shaped by dry debris tumbling down a slope.

The dry granular case was the winner. I was surprised. I started off thinking we were going to prove it’s liquid water.” – Jon D. Pelletier

Looking at the comparison between the two cases (water and dry debris flow) and the HiRISE observations, it is very easy to see the striking resemblance between dry debris flow and what is actually observed. The water simulation appears to be more diffuse, lacking the characteristic “fingers” reaching down the slope.

On hearing the news in 2006 that there was a possibility of liquid water flowing on the Martian surface, biologists hoped that a new tool had been found to pinpoint where sub-surface deposits of liquid water may be stored. This will have provided future missions with a location to hunt for life in the most likely place, near fresh gullies, near a source of water. Unfortunately it seems that these gullies are in fact shaped by small landslides, not by surges of water from a sub-surface reservoir.

Research to be published in the March issue of Geology, entitled: “Recent bright gully deposits on Mars: wet or dry flow?“.

Source: University of Arizona News