Tag Archives: gale crater

Strata at Base of Mount Sharp

Ingenious new technique shows Mars’ Mount Sharp to be very porous

Some outside-the-box thinking allowed NASA to calculate the density of Mount Sharp on Mars — and the results aren’t at all what they expected.

Strata at Base of Mount Sharp

A view from the Kimberly formation on Mars taken by NASA Curiosity rover. The strata in the foreground dip towards the base of Mount Sharp.
Image credits NASA / JPL-Caltech.

Curiosity has been on a lonely trek on the surface of Mars for almost a decade now. It landed there in 2012 and has been exploring the planet ever since. But its journey is teaching us a lot about our galactic neighbor, including the surprising porosity of its rocks.

Mount Sharp, Mount Porous

“What we were able to do is measure the bulk density of the material in Gale Crater,” says Travis Gabriel, a graduate student at the Arizona State University School of Earth and Space Exploration, who computed the densities of the rocks Curiosity has been driving over.

I really like this study. For starters, Curiosity wasn’t ‘meant’ to be able to measure the densities of huge bodies of rock when it was designed — at least, not in the way the team did it.

First off, some context: Curiosity can be used to estimate rock density, but this is based on chemical analysis of rocks it can actually bore through (so it’s limited to making surface measurements). Gale Crater (wherein Mount Sharp, officially “Aeolis Mons”, nestles) definitely qualifies as a ‘huge body of rock’ with its 96-mile (154 km) diameter, and its depths are definitely out of Curiosity’s reach.

To estimate densities, the rover will essentially dig into a rock, take out the residue, and analyze its mineralogical composition. Based on the particular species identified and their ratios, ground control can then estimate how dense said rock is. And NASA was content with this for the longest time. But the present study casts doubt on those previous estimates.

“Working from the rocks’ mineral abundances as determined by the Chemistry and Mineralogy instrument, we estimated a grain density of 2810 kilograms per cubic meter,” Gabriel says. “However the bulk density that came out of our study is a lot less — 1680 kilograms per cubic meter.”

What the team did instead was to use Curiosity’s accelerometers and gyroscopes to read densities. These devices are pretty much exactly like that in any smartphone (only more accurate and expensive), and are used to determine Curiosity’s orientation and its motions. NASA uses readings from these devices to steer Curiosity across the face of Mars, just like you’d use those in your smartphone to steer towards the nearest pub.

These devices work round-the-clock, however — not just when you’re on the move. And those on Curiosity are sensitive enough to pick up on the local gravitational tug at whichever spot it finds itself on.

The team took engineering data beamed back by Curiosity ever since 2012, when it touched down on Mars. These readings were crunched to produce measurements of gravitational forces in more than 700 points across the rover’s track. The readings revealed that as Curiosity began ascending Mount Sharp, it started experiencing higher gravitational pulls. Which was expected.

But the increase was far weaker than what we’d expect to see in such a case, the authors report.

“The lower levels of Mount Sharp are surprisingly porous,” says lead author Kevin Lewis of Johns Hopkins University.

“We know the bottom layers of the mountain were buried over time. That compacts them, making them denser. But this finding suggests they weren’t buried by as much material as we thought.”

The findings help flesh out our understanding of how Mount Sharp came to be. Martian craters the size of Gale have central peaks raised by the very impact that scooped out the crater (Gale’s is Mount Sharp). So we know why Sharp is so tall. Its top layers also seem to be made out of wind-swept sediments, which are more easily eroded than rock. The prevailing theory up to now was that these sediments pressed down on the Mount and crater, compressing them into hardier rock, before eventually being swept away by the wind.

But the new findings suggest Mount Sharp’s lower layers have been compacted by only a half-mile to a mile (1 to 2 kilometers) of material — much less than if the crater had been completely filled.

“There are still many questions about how Mount Sharp developed, but this paper adds an important piece to the puzzle,” said Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, which manages the mission.

“I’m thrilled that creative scientists and engineers are still finding innovative ways to make new scientific discoveries with the rover.”

This is definitely an interesting find — one that points to even more secrets yet to be unlocked on the slopes of Mount Sharp. The study also produced a powerful technique that NASA can use with Curiosity and future rovers to investigate far-off worlds. In essence, it’s pretty much the same principle as that used in gravimetry, but I definitely like seeing how much creativity the team brought to this study.

The paper “A surface gravity traverse on Mars indicates low bedrock density at Gale crater” has been published in the journal Science.

Curiosity rover finds that its landing crater on Mars could have been habitable for 700 million years

The Curiosity Rover is earning its keep, sending back more and more valuable information about the Red Planet.

A rendering of Gale Crater, with Mount Sharp at its center. The Curiosity rover is currently exploring this area, trying to find whether Mars could have supported life. Image credits: NASA.

When researchers and engineers decided to land Curiosity inside Gale Crater, they didn’t choose randomly. The crater, which contained a massive lake, was chosen because due to its structure, there’s a good chance of learning many of Mars’ geological secrets. While it was already established that Mars held water, the conditions of the water and the overall environment is still unclear. Now, this research shows that not only was the planet hosting a lot of water — it had lakes much like those on Earth.

Geochemist Joel Hurowitz from Stony Brook University led a large team that analyzed over 100 meters of rock layers in Gale Crater. To reconstruct the past environment, they measured the aluminum inside each layer, plotting it against minerals like sodium and calcium, which easily leach out of the rock. Basically, warm water is more chemically active than cold water. During warm conditions, water is better at dissolving and absorbing stuff (just like how sugar melts easier in hot water). In this case, if a rock has a lot of aluminum but not so much sodium or calcium, it indicates that it formed in a warmer environment.

Oxygen was another key component they looked at. There are sharp differences between deeper and more shallow water, in terms of oxygen content. By adding the oxygen content into the mix, researchers were able to show that the lake was a diverse feature, much like those on Earth. These conditions also apparently lasted for a very long time: some 700 million years!

“These were very different, co-existing environments in the same lake,” said Joel Hurowitz of Stony Brook University, lead author of the report. “This type of oxidant stratification is a common feature of lakes on Earth, and now we’ve found it on Mars. The diversity of environments in this Martian lake would have provided multiple opportunities for different types of microbes to survive.”

“This is a new level of detail in terms of our understanding of the chemical environment in this lake on Mars,” Hurowitz added. “It gives us a much more complete picture of the habitability of this lake.”

A simulation depicts a lake partially filling Mars Gale Crater. Illustration: NASA / JPL-Caltech.

We still don’t know if Mars did have any life (and if it did, we shouldn’t get our hopes up for anything bigger than microbial), but having a complex lake system, with warm water ranging from shallow to deep is definitely exciting. It means it could have supported several different types of microbes. Some microbes thrive in low-oxygen environments, while other prefer the opposite. Keep in mind that scientists are looking into a time when photosynthesis hadn’t even evolved on Earth, so we’re not sure what kind of microbial life Mars might have hosted.

“We’re learning that in parts of the lake and at certain times, the water carried more oxygen,” said Roger Wiens, a planetary scientist at Los Alamos National Laboratory and co-author of the study, published today in the journal Science. “This matters because it affects what minerals are deposited in the sediments, and also because oxygen is important for life. But we have to remember that at the time of Gale Lake, life on our planet had not yet adapted to using oxygen–photosynthesis had not yet been invented. Instead, the oxidation state of certain elements like manganese or iron may have been more important for life, if it ever existed on Mars. These oxidation states would be controlled by the dissolved oxygen content of the water.”

A drilled hole made by Curiosity. Image credits: NASA / JPL.

Researchers were surprised by the accuracy of the Curiosity analysis, and how much we can deduct from that. But put together, this makes a lot of sense.

“What was causing iron minerals to be one flavor in one part of the lake and another flavor in another part of the lake?” Hurowitz asked. “We had an ‘Aha!’ moment when we realized that the mineral information and the bedding-thickness information mapped perfectly onto each other in a way you would expect from a stratified lake with a chemical boundary between shallow water and deeper water.”

A hypothesized model of a redox-stratified lake in Gale crater — just like a lake on Earth. Source: NASA / JPL.

In total, Curiosity has been on Mars for over 1,700 sols (martian days, which are 24 hours, 39 minutes long), traveling 16 km from the bottom of Gale Crater towards the peak of Mount Sharp. Its main objective is determining whether Mars could have supported life, by analyzing nature and inventory of organic carbon compounds, investigating the chemical components which could serve as the building blocks of life, identifying biosignatures of life, investigating the chemical, isotopic, and mineralogical composition of the Martian surface, interpreting geological processes taking place and assessing the broad spectrum of surface radiation, which is necessary for a future manned mission to Mars.

As for whether Mars does host life now, unfortunately, that’s not an answer Curiosity is equipped to answer. We’ll have to wait a few more years for NASA’s next Mars mission to figure that one out.

Journal Reference: J. A. Hurowitz et al — Redox stratification of an ancient lake in Gale crater, Mars. DOI: 10.1126/science.aah6849

NASA’s Mars Curiosity Rover Arrives at Martian Mountain

Image via NASA.

It’s been a while since we’ve talked about the Curiosity rover, but that doesn’t mean that it stopped studying the Red Planet. Now, NASA’s rover has reached one of its main destinations: Mars’ Mount Sharp, a Mount-Rainier-size mountain at the center of the vast Gale Crater and the rover mission’s long-term prime destination.

“Curiosity now will begin a new chapter from an already outstanding introduction to the world,” said Jim Green, director of NASA’s Planetary Science Division at NASA Headquarters in Washington. “After a historic and innovative landing along with its successful science discoveries, the scientific sequel is upon us.”

The journey to Mount Sharp was long and tenuous, but it was worth the wait. Curiosity will now focus on studying the lower slopes, in an attempt to understand more about the planet’s geology. The study will start on an outcrop called Pahrump Hills and divert from the initially planned route, as depicted above.

“It has been a long but historic journey to this Martian mountain,” said Curiosity Project Scientist John Grotzinger of the California Institute of Technology in Pasadena. “The nature of the terrain at Pahrump Hills and just beyond it is a better place than Murray Buttes to learn about the significance of this contact. The exposures at the contact are better due to greater topographic relief.”

The decision to change the initial route was made on previous results yielded by Curiosity. The rover was walking along the Murray Formation – a relatively soft 130 million year old geological formation; because it is so soft, it doesn’t preserve impact scars, which is one of Curiosity’s main points of focus. Geologists wanted to move it along a different path, which might provide more useful information. Also, one other issue was the wheel wear reported by the rover’s sensors. In late 2013, it was researching an area littered with hard, sharp rocks which were poking small holes in its wheels – since then, scientists have been constantly redirecting Curiosity’s path to help protect the wheels.

The Murray Formation. Image via NASA.

“The wheels issue contributed to taking the rover farther south sooner than planned, but it is not a factor in the science-driven decision to start ascending here rather than continuing to Murray Buttes first,” said Jennifer Trosper, Curiosity Deputy Project Manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “We have been driving hard for many months to reach the entry point to Mount Sharp,” Trosper said. “Now that we’ve made it, we’ll be adjusting the operations style from a priority on driving to a priority on conducting the investigations needed at each layer of the mountain.”

Even with Curiosity’s amazing technology, there is only so much information you can gather with a remote controlled vehicle. NASA is currently starting to prepare a manned mission to the Mars, scheduled some time in the 2030s.

Source: NASA.

Curiosity rover snaps a video of Martian moonrise

The otherwordly new video features one of the two Martian moons – Phobos, as it rises on the sky. Even though the movie only has 32 seconds, the action actually took place over the course of 27 minutes.

Mars has two moons: Phobos (which is just 22 km wide on average), and Deimos, which is even smaller. They are believed to be asteroids trapped a long time ago by the Martian gravitational field.

This video isn’t the first from Curiosity to represent Phobos – just five weeks after it landed on Mars, it sed its workhorse MastCam camera to photograph the moon as it crossed the face of the sun, covering a small fraction of the star.

The Curiosity rover landed inside a geological feature called Gale Crater last August, kicking off a planned two-year surface mission to find out if the Red Planet was ever able to support (microbial) life. So far, the mission was a great success, as the rover already showed that a site called Yellowknife Bay was indeed habitable billions of years ago.

phobos

Via WikiCommons

This set of images shows the results from the rock abrasion tool from NASA's Mars Exploration Rover Opportunity (left) and the drill from NASA's Curiosity rover (right). (c) NASA/JPL-Caltech/Cornell/MSSS

Astonishing news from NASA: evidence of hospitable environment for ancient Martian life found

I just finished watching NASA‘s latest and definitely most important Curiosity briefing to date. There the Curiosity team announced findings nothing short of spectacular: a slew of chemical elements, minerals and other chemicals have been found in the rover’s first drilled rock sample on Mars,  hinting that, at least in the vicinity of the sample site, living microbes might have lived during ancient Mars.

This set of images shows the results from the rock abrasion tool from NASA's Mars Exploration Rover Opportunity (left) and the drill from NASA's Curiosity rover (right). (c) NASA/JPL-Caltech/Cornell/MSSS

This set of images shows the results from the rock abrasion tool from NASA’s Mars Exploration Rover Opportunity (left) and the drill from NASA’s Curiosity rover (right). (c) NASA/JPL-Caltech/Cornell/MSSS

Considering the rover is only in its preliminary phase of its 18 months long mission and the findings come from the first ever drilled sample, the NASA scientists have hit a definite hole in a one.

Sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon – all key ingredients of life have been identified in the drilled sedimentary rock near an ancient stream bed in Gale Crater on the Red Planet. Moreover, the rock consists in a large proportion of  fine-grained mudstone containing clay minerals, sulfate minerals and other chemicals, suggesting that the Yellowknife Bay area the rover is exploring was the end of an ancient river system or an intermittently wet lake bed.

“A fundamental question for this mission is whether Mars could have supported a habitable environment,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at the agency’s headquarters in Washington. “From what we know now, the answer is yes.”

Although the findings are still preliminary, during the briefing the Curiosity mission lead scientists reported that this ancient wet environment  was not harshly oxidizing, acidic or extremely salty – a fundamental statement, since it suggests that a body of freshwater was once present near the Gale crater region, unlike other environments on Mars.

“Clay minerals make up at least 20 percent of the composition of this sample,” said David Blake, principal investigator for the CheMin instrument at NASA’s Ames Research Center in Moffett Field, Calif.

Life on Mars… once upon a time

Again, the clay minerals serve as a positive indicator of the former presence of water, since it’s the reaction product between freshwater and an igneous mineral, like olivine. The presence of calcium sulfate along with the clay suggests the soil is neutral or mildly alkaline. What’s maybe the most groundbreaking find resulting from the drilled rock is the presence of a mixture of oxidized, less-oxidized and even non-oxidized chemicals. Together they act like a sort of battery providing an energy gradient typically required by microbial life on Earth to exploit to live.

“The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,” said Paul Mahaffy, principal investigator of the SAM suite of instruments at NASA’s Goddard Space Flight Center in Greenbelt, Md.

The analysis was performed by Curiosity’s Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments.

“We have characterized a very ancient, but strangely new ‘gray Mars’ where conditions once were favorable for life,” said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology in Pasadena, Calif. “Curiosity is on a mission of discovery and exploration, and as a team we feel there are many more exciting discoveries ahead of us in the months and years to come.”

What’s really interesting, however, aside from the possibility that Mars was indeed once host to life is that the conditions are highly reminiscent of those found on Earth. What this also means is that reversing conditions today through terraforming becomes a more and more viable idea.

For now, however, Curiosity is scheduled to stay around the Yellowknife Bay area for a few more weeks before heading  for the  Gale Crater’s central mound, Mount Sharp.  Here stacks filled with layers of clay, sulfate and other types of minerals have been identified from orbit, and an inspection from up close may serve valuable  information as to the duration and diversity of habitable conditions.

We’ll keep you posted with more findings as they surface.

Curiosity takes a deep breath, analyzes Martian atmosphere

Curiosity took a break from its usual rock sampling activities and instead focused on the air, trying to figure out how Mars lost the biggest part of its atmosphere, leaving it with 100 times less than what Earth has.

 

Researchers believe in the distant past, Mars was a pretty different sight from what we see today, with a thick, rich atmosphere and permanent water. They’re not just throwing away a hunch on this, there’s a big chunk of evidence which points towards a wet past for Mars, but this changed a long time ago: the drought probably started some 600 million years ago.

The rover inhaled the Martian air, analyzing samples taken in the Gale crater, where Curiosity is hanging around these days. Its Sample Analysis at Mars (SAM) instruments suggest that Mars suggests that Mars lost its atmosphere through a process which favored only the retention of the heavier isotopes, with the lighter ones simply drifting off to outer space. The initial results show that the heavier isotopes of carbon in atmospheric carbon dioxide have increased by 5 per cent – a rather subtle, but meaningful change; the same thing happened with heavier argon isotopes. This suggests that the top of the atmosphere, devoid of any heavy elements was lost in outer space.

Another highlight for Curiosity’s research is methane; methane is a simple precursor to life, basically you would expect to find it everywhere you’d find living creatures. But the bad thing is, as far as Curiosity can tell, there’s extremely little methane (if any) in the Martian atmosphere.

“Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we’re just excited to be searching for it,” said SAM Tunable Laser Spectrometer lead Chris Webster. “While we determine upper limits on low values, atmospheric variability in the Martian atmosphere could yet hold surprises for us.”

Still, nothing is clear, and SAM will move on to even more interesting things: it will analyze its first solid samples, searching for organic compounds in the rocks and minerals found in Gale Crater.

Source: NASA