mars reconnaissance orbiter Archives

October 20, 2014December 23, 2015 by Bob King

MRO Spies Tiny, Bright Nucleus During Comet Flyby of Mars

High resolution image pairs made with HiRISE camera on MRO during Comet Siding Spring's closest approach to Mars on October 19. Shown at top are images of the nucleus region and inner coma. Those at bottom were exposed to show the bigger coma beginning of a tail. Credit: NASA/JPL/Univ. of Arizona

Not to be outdone by the feisty Opportunity Rover, the HiRISE camera on NASA’s Mars Reconnaissance Orbiter (MRO) turned in its homework this evening with a fine image of comet C/2013 Siding Spring taken during closest approach on October 19.

The highest-resolution images were acquired by HiRISE at the minimum distance of 85,750 miles (138,000 km). The image has a scale of 453 feet (138-m) per pixel.

The top set of photos uses the full dynamic range of the camera to accurately depict brightness and detail in the nuclear region and inner coma. Prior to its arrival near Mars astronomers estimated the nucleus or comet’s core diameter at around 0.6 mile (1 km). Based on these images, where the brightest feature is only 2-3 pixels across, its true size is shy of 1/3 mile or 0.5 km. The bottom photos overexpose the comet’s innards but reveal an extended coma and the beginning of a tail extending to the right.

Annotated photo of Comet Siding Spring taken by the Opportunity Rover on October 19 when near closest approach. Credit: NASA/JPL-Caltech/Cornell Univ./ASU/TAMU

To photograph a fast-moving target from orbit, engineers at Lockheed-Martin in Denver precisely pointed and slewed the spacecraft based on comet position calculations by engineers at JPL. To make sure they knew exactly where the comet was, the team photographed the comet 12 days in advance when it was barely bright enough to register above the detector’s noise level. To their surprise, it was not exactly where orbital calculations had predicted it to be. Using the new positions, MRO succeeded in locking onto the comet during the flyby. Without this “double check” its cameras may have missed seeing Siding Spring altogether!

Meanwhile, the Jet Propulsion Lab has released an annotated image showing the stars around the comet in the photo taken by NASA’s Opportunity Rover during closest approach. From Mars’ perspective the comet passed near Alpha Ceti in the constellation Cetus, but here on Earth we see it in southern Ophiuchus not far from Sagittarius.

Comet Siding Spring continues on its way today past the planet Mars in this photo taken on October 20. Copyright: Rolando Ligustri

“It’s excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the instruments we’re using to study Mars,” said Opportunity science team member Mark Lemmon of Texas A&M University, who coordinated the camera pointing. “The views from Mars rovers, in particular, give us a human perspective, because they are about as sensitive to light as our eyes would be.”

After seeing photos from both Earth and Mars I swear I’m that close to picturing this comet in 3D in my mind’s eye. NASA engineers and scientists deserve a huge thanks for their amazing and successful effort to turn rovers and spacecraft, intended for other purposes, into comet observatories in a pinch and then deliver results within 24 hours. Nice work!

September 18, 2014December 23, 2015 by Elizabeth Howell

Sandy Ridges Pose A Mystery For Future Martian Beach Vacations

A September 2014 image from the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter showing transverse aeolian ridges. Credit: NASA/JPL/University of Arizona

What are these thick dune-like features on Mars, and how were they formed? Scientists are still trying to puzzle out these ridges, which you can see above in a more tropical region of the Red Planet called Iapygia, which is south of Syrtis Major. The thick ridges were captured from orbit by the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE), and we’ve included some more intriguing pictures below the jump.

“Called transverse aeolian ridges, or TARs, the features stand up to 6 meters tall and are spaced a few tens of meters apart. They are typically oriented transverse to modern day wind directions, and often found in channels and crater interiors,” read an update on the University of Arizona’s HiRISE blog.

“The physical process that produces these features is still mysterious. Most TARs display no evidence of internal structure, so it is difficult to discern exactly how they were formed.”

A wider view of the Iapygia region on Mars, where transverse aeolian ridges (TARs) -- dune-like features -- were spotted in 2014. PIcture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona — A wider view of the Iapygia region on Mars, where transverse aeolian ridges (TARs) — dune-like features — were spotted in 2014. PIcture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

This picture from the NASA spacecraft was taken in Iapygia, which is south of Syrtis Major. While scientists say these look similar to TARs in other parts of the Red Planet, the features have layers on the northwest faces and a paucity on the southern side.

Scientists suggest it’s because these TARs may have had wedge-shaped layers, which hints that they would have gotten taller as material was added to the ridges. They hope to do further studies to learn more about how TARs formed in other regions on Mars.

We’ve included other recent releases from the HiRISE catalog below, so enjoy the Martian vistas!

An image of Eridania Basin, a southern region of Mars that once could been a lake or inland sea. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

Scientists are still puzzling out the nature and formation of these light-toned deposits in the old Vinogradov Crater on Mars. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

Older lava flows in Daedalia Planum on Mars. Picture taken by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona

August 6, 2014December 23, 2015 by Elizabeth Howell

The Latest Pictures From Mars Make Us Feel Spoiled

A HiRISE image called "steep north polar peripheral scarp." Credit: NASA/JPL/University of Arizona

Don’t you love it when close-up pictures come beaming to your computer from another planet? Below are some of the latest images from Mars taken by the High Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter.

And by the way, there’s a way for you to request where HiRISE will be pointing next.

All you need to go to this page (called HiWish) and leave a suggestion for where you’d like the spacecraft to look. For some tips on what to do:

Here’s a post from the Planetary Society talking about when a HiWish was granted to Emily Lakdawalla, its senior editor.
Here is a (somewhat dated) post walking you through the process of a HiWish.

The general consensus seems to be picking a spot that is not over-popular, and trying to find a spot that HiRISE has not looked at before or very frequently. Best of luck!

To see more HiRISE images from the latest release, check out this webpage.

A HiRISE image called "Nili Patera." Credit: NASA/JPL/University of Arizona — A HiRISE image called “Nili Patera.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "scalloped surface in Utopia region." Credit: NASA/JPL/University of Arizona — A HiRISE image called “scalloped surface in Utopia region.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "gullied crater wall." Credit: NASA/JPL/University of Arizona — A HiRISE image called “gullied crater wall.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "active dune gullies in Kaiser crater." Credit: NASA/JPL/University of Arizona — A HiRISE image called “active dune gullies in Kaiser crater.” Credit: NASA/JPL/University of Arizona

A HiRISE image called "dark-capped plain and hills in western Arabia region intercrater terrain." Credit: NASA/JPL/University of Arizona — A HiRISE image called “dark-capped plain and hills in western Arabia region intercrater terrain.” Credit: NASA/JPL/University of Arizona

July 11, 2014December 23, 2015 by Elizabeth Howell

Water Or Not? Fresh Martian Trenches Primarily Due To Carbon Dioxide Freezes, Study Says

Artist Illustration of the Mars Reconnaissance Orbiter

Does liquid water currently flow on the surface of Mars? Fresh-looking trenches on the Red Planet have come under a lot of scrutiny, including a 2010 study concluding that 18 dune gullies were primarily formed by carbon dioxide freezing.

A new study looking at several more gullies comes to about the same conclusion. Researchers examined images of 356 sites, with each of these sites captured multiple times on camera. Of the 38 of these sites that showed changes since 2006, the researchers concluded site changes happened in the winter — when it’s too cold for any liquid water to flow.

This image covers a location that has been imaged several times to look for changes in gullies. This is in the Terra Sirenum region, part of the southern highlands in the mid-latitudes. Credit: NASA/JPL/University of Arizona.

“As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water,” stated lead author Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona.

“We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity occurs in winter.”

Observations were made using NASA’s long-running Mars Reconnaissance Orbiter mission, which has been in orbit there since 2006. The researchers said that these lengthy missions are important for examining and confirming findings, because they can revisit data over time and change their conclusions, as needed, as more evidence comes in. Pictures were taken by the High Resolution Imaging Science Experiment (HiRISE) camera.

A 164-yard (150-meter) wide swath of Martian surface at 37.7 degrees south latitude, 192.9 degrees east longitude shows gullies changing between passes of the Mars Reconnaissance Orbiter. The earlier image, at left, was taken May 30, 2007. Near the arrows on the image on right, which was taken May 31, 2013, is a "rubbly flow" near the channel's mouth. Credit: NASA/JPL-Caltech/Univ. of Arizona — A 164-yard (150-meter) wide swath of Martian surface. It shows gullies changing between passes of the Mars Reconnaissance Orbiter. The earlier image, at left, was taken May 30, 2007. Near the arrows on the image on right, which was taken May 31, 2013, is a “rubbly flow” near the channel’s mouth. Credit: NASA/JPL-Caltech/Univ. of Arizona

The first images of gullies in 2000 sparked speculation that liquid water could be responsible for changing the surface today. It’s true that Mars has water frozen in its poles, and observations with several NASA rovers show strong evidence that water once flowed on the surface. But, these trenches are unlikely to show evidence that liquid water is flowing right now.

“Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but is plentiful on Mars. It has been linked to active processes on Mars such as carbon dioxide gas geysers and lines on sand dunes plowed by blocks of dry ice,” NASA stated.

“One mechanism by which carbon-dioxide frost might drive gully flows is by gas that is sublimating from the frost providing lubrication for dry material to flow. Another may be slides due to the accumulating weight of seasonal frost buildup on steep slopes.”

The team added that smaller features could be the result of liquid water, such as this recent study using MRO. It’ll be interesting to see what other data is churned up as the fleet of orbiters continues making observations, and other scientists weigh in on the results.

The work will be published in the journal Icarus.

Source: Jet Propulsion Laboratory

May 28, 2014December 23, 2015 by Elizabeth Howell

Did This Martian Volcano Once Host Life?

A false-color view of Arsia Mons on Mars, including braided fluvial channels (seen in inset) from glacial deposits made 210 million years ago. Credit: NASA/Goddard Space Flight Center/Arizona State University/Brown University

Extremophiles teach us that life is found in unlikely places, which is why after looking at microbes happily living in hot springs or surviving after 18 months in space, scientists are trying to expand our definition of what a habitable environment is. So perhaps this ancient Martian volcano would be an example.

Meet Arsia Mons. It’s the third-tallest volcano on the Red Planet and one of the largest volcanoes we know of in the solar system.

New research shows that a combination of eruptions and a glacier on its northwest side could have formed something called “englacial lakes”, which is water that is created inside glaciers. (The researchers compare this to “liquid bubbles in a half-frozen ice cube.”) These in sum would have been massive, on the order of hundreds of cubic miles.

“This is interesting because it’s a way to get a lot of liquid water very recently on Mars,” stated Kat Scanlon, a graduate student at Brown who led the research, adding that she is also interested to see if signs of a habitable environment turn up in even older regions, of 2.5 billion years old or more.

“There’s been a lot of work on Earth — though not as much as we would like — on the types of microbes that live in these englacial lakes,” Scanlon added. “They’ve been studied mainly as an analog to [Saturn’s moon] Europa, where you’ve got an entire planet that’s an ice covered lake.”

While the glacial ice idea is not new — it’s been talked about since the 1970s — Scanlon’s team pushed the research forward by bringing in new information from NASA’s Mars Reconnaissance Orbiter.

“Scanlon found pillow lava formations, similar to those that form on Earth when lava erupts at the bottom of an ocean,” Brown University stated.

“She also found the kinds of ridges and mounds that form on Earth when a lava flow is constrained by glacial ice. The pressure of the ice sheet constrains the lava flow, and glacial meltwater chills the erupting lava into fragments of volcanic glass, forming mounds and ridges with steep sides and flat tops. The analysis also turned up evidence of a river formed in a jökulhlaup, a massive flood that occurs when water trapped in a glacier breaks free.”

Scanlon estimated that two of the “deposits” would have had lakes of 9.6 cubic miles (40 cubic kilometers) each, while a third would have had 4.8 cubic miles (20 cubic kilometers). They could have stayed liquid for hundreds or perhaps thousands of years.

That’s a short period in the history of life, but Scanlon’s team says it could have been enough for microbes to colonize the locations, if microbes were on Mars in the first place.

You can read more about the research in the journal Icarus.

Source: Brown University

May 22, 2014December 23, 2015 by Shannon Hall

Largest Crater Spotted on Mars Using Before-and-After Pictures

When it comes to the Universe, things often go bump in the night. But whether two galaxies collide, a star explodes in a brilliant supernova, or a meteor hits a massive planet, we tend to catch the aftermath tens to hundreds of thousands of years later.

Of course, there’s always an exception to the rule. In today’s news, astronomers using NASA’s Mars Reconnaissance Orbiter have found a fresh meteor-impact crater. And it’s the biggest seen using before-and-after pictures.

When it comes to the red planet, we’ve seen evidence of fresh craters before, but usually the impact can’t be nailed down to better than a few years’ time. The constant sweep of the obiter’s weather-monitoring camera, the Mars Color Imager (MARCI), however, allowed us to pinpoint the impact to within a day.

The orbiter began its systematic observation of Mars in 2006. Ever since, Bruce Cantor, MARCI’s principle investigator, has examined the camera’s daily images, searching for evidence of dust storms and other observable weather events. Cantor’s findings help NASA operators plan for weather events that may be harmful to the solar-powered rover, Opportunity.

Nearly two months ago, Cantor noticed a black smudge — a telltale sign of an impact — on the red planet. “It wasn’t what I was looking for,” Cantor said in a NASA press release. “I was doing my usual weather monitoring and something caught my eye. It looked usual, with rays emanating from a central spot.”

So Cantor dug through earlier images, discovering that the dark spot wasn’t visible on March 27, 2012, but appeared on March 28, 2012.

MARCI is a low resolution camera, which is what allows it to see a large area of Mars constantly. But without a high resolution image, we can’t pick out the details of the impact-like black smudge. So Cantor performed follow-up observations with the orbiter’s telescope Context Camera (CTX) and the High Resolution Imaging Science Experiment (HiRISE).

CTX has imaged nearly the entire surface of Mars at least once during the orbiter’s seven-plus years of observations. It photographed the site of the newly-discovered crater in January 2012, revealing nothing prior to the impact. But two new craters appear in the recent image.

The largest crater is slightly elongated and spans 48.5 by 43.5 meters, roughly half the length of a football field. “The biggest crater is unusual, quite shallow compared to other fresh craters we have observed,” said HiRISE Principal Investigator Alfred McEwen of the University of Arizona, Tucson.

The impacting object is likely a few meters across. Something that small would burn up in the Earth’s atmosphere, but with a much thinner atmosphere (about 1% as thick as Earth’s), Mars lets most debris right on through.

To add to the details, images from HiRISE revealed more than a dozen smaller craters near the two larger ones seen by CTX. It’s likely that Mars’ atmosphere, as thin as it is, supplied enough pressure to break the incoming meteoroid into smaller pieces, leaving multiple impacts behind.

Image Credit: NASA/JPL-Caltech/Univ. of Arizona — This image from the HiRISE camera, on board NASA’s Mars Reconnaissance Orbiter reveals the two impact craters and many smaller craters around them. Image Credit: NASA / JPL-Caltech / University of Arizona

“Studies of fresh impact craters on Mars yield valuable information about impact rates and about subsurface material exposed by the excavations,” said Leslie Tamppari, deputy project scientist for the Mars Reconnaissance Orbiter mission at NASA’s Jet Propulsion Laboratory. “The combination of HiRISE and CTX has found and examined many of them, and now MARCI’s daily coverage has given great precision about when a significant impact occurred.”

The initial NASA press release can be viewed here.

March 19, 2014December 23, 2015 by Elizabeth Howell

New Gully Appears On Mars, But It’s Likely Not Due To Water

At right, a new gully appears in pictures of the same region of Terra Sirenum on Mars. The picture at left was taken in November 2010, and the right in May 2013. Credit: NASA/JPL-Caltech/Univ. of Arizona

Check out the groove! In the blink of a geological lifetime, a new gully has appeared on the planet Mars. These images from NASA’s Mars Reconnaissance Orbiter show a new channel in the southern hemisphere region of Terra Siernum that appeared between November 2010 and May 2013.

While there’s a lot of chatter about water on Mars, this particular feature is likely not due to that liquid, the agency added.

“Gully or ravine landforms are common on Mars, particularly in the southern highlands. This pair of images shows that material flowing down from an alcove at the head of a gully broke out of an older route and eroded a new channel,” NASA stated.

It’s unclear in what season the activity occurred because the observations took place more than a Martian year apart, NASA added. These ravines tend to happen in the southern highlands and other mid-latitude regions on Mars.

“Before-and-after HiRISE pairs of similar activity at other sites demonstrate that this type of activity generally occurs in winter, at temperatures so cold that carbon dioxide, rather than water, is likely to play the key role,” the agency said.

Last week, the agency also announced that MRO recovered from an unplanned computer swap that put the spacecraft into safe mode. Incidents of this nature have happened four times before, the agency noted.

Source: NASA

February 14, 2014December 23, 2015 by Elizabeth Howell

For Valentine’s Day, Enjoy These Hearts On Earth, Mars And Other Places

A heart-shaped feature in the Arabia Terra region of Mars taken by NASA's Mars Reconnaissance Orbiter. Image Credit: NASA/JPL-Caltech/MSSS.

A Valentine from Earth. pic.twitter.com/7FEIIddAJB

— Karen L. Nyberg (@AstroKarenN) February 14, 2014

While we’re unsure about the status of chocolates and flowers in locations far beyond Earth, there certainly is no lack of hearts for us to look at to enjoy Valentine’s Day. If you look at enough geologic features or gas clouds, statistically some of them will take on shapes that we recognize (such as faces).

Below, we’ve collected some hearts on Mars and other places in the universe. Have we missed any? Share other astronomy hearts in the comments!

This heart-shaped feature on Mars "is actually a pit formed by collapse within a straight-walled trough known in geological terms as a graben," wrote Malin Space Systems in 1999. Picture taken by Mars Global Surveyor. Credit: Malin Space Science Systems, MGS, JPL, NASA — This heart-shaped feature on Mars “is actually a pit formed by collapse within a straight-walled trough known in geological terms as a graben,” wrote Malin Space Systems in 1999. Picture taken by Mars Global Surveyor. Credit: Malin Space Science Systems, MGS, JPL, NASA

A heart-shaped mesa captured by Mars Global Surveyor in 1999, in the Promethei Rupes region. Credit: Malin Space Science Systems, MGS, JPL, NASA

The Heart and Soul nebulae in an infrared mosaic from NASA's Wide-field Infrared Survey Explorer (WISE). It is located about about 6,000 light-years from Earth. Credit: NASA/JPL-Caltech/UCLA — The Heart and Soul nebulae in an infrared mosaic from NASA’s Wide-field Infrared Survey Explorer (WISE). It is located about about 6,000 light-years from Earth. Credit: NASA/JPL-Caltech/UCLA

I heart you @AuroraMAX #aurora heart pic.twitter.com/DJugaWnaCW

— Angel Brise’ (@AngelBrise67) February 12, 2014

Happy Valentine’s Day, everyone! Here’s a heart @NASA_Dawn saw on Vesta. 🙂 pic.twitter.com/y7ABgrX5to

— Keri Bean (@PlanetaryKeri) February 14, 2014

Mars sends love to us all on Valentine’s Day – hearts abounding from the romantics at @NASAJPL pic.twitter.com/mD39hi7lKT

— Chris Hadfield (@Cmdr_Hadfield) February 14, 2014

Know I’ve used this before- but it seems like a good one. Happy Valentine’s Day #EarthHearts #ISSExp20 http://t.co/fc9X9zuCIr

— Nicole Stott (@Astro_Nicole) February 14, 2014

February 13, 2014December 23, 2015 by Elizabeth Howell

Martian Spacecraft Busts A Move To Glimpse Possible Water Flows

Artist's conception of the Mars Odyssey spacecraft. Credit: NASA/JPL

Just a few days ago, we posted about possibly salty water flows on Mars. Of note, the NASA press release noted, moisture is likely more prevalent in the morning and the Mars Reconnaissance Orbiter does most observations in the afternoon, local time. That’s too bad, we thought. But wait! It turns out that NASA Mars Odyssey spacecraft is going to change its orbit to get a better look.

It’s going to take nearly two years for NASA to maneuver the long-running Odyssey to the right spot, but at that point mission managers expect the spacecraft still has another decade of observations ahead of it based on current fuel consumption. That’s great considering that the spacecraft has been beaming back images since 2001!

Odyssey will be the first spacecraft to do dedicated morning observations of the planet since any NASA orbiter of the 1970s, which dates observations back to the Viking era (except for a few glimpses by European Space Agency spacecraft and previous NASA orbiters). Advances in imaging mean we will get a far clearer view of the ground than ever before.

“The change will enable observation of changing ground temperatures after sunrise and after sunset in thousands of places on Mars,” NASA stated. “Those observations could yield insight about the composition of the ground and about temperature-driven processes, such as warm-season flows observed on some slopes, and geysers fed by spring thawing of carbon-dioxide ice near Mars’ poles.”

Morning water-ice clouds on Mars spotted by Viking 1 in 1976. Mars Odyssey's new orbit will reveal more of these types of morning observations. Credit: NASA/JPL — Morning water-ice clouds on Mars spotted by Viking 1 in 1976. Mars Odyssey’s new orbit will reveal more of these types of morning observations. Credit: NASA/JPL

The first maneuver took place Tuesday (Feb. 11) when a brief firing of Odyssey’s engines got the spacecraft pushing faster for an orbital shift. It will drift in that direction until November 2015, when controllers will do another maneuver to keep it in a stable location.

Right now, Odyssey is in a near-polar orbit that keeps local daylight at the same time below it. There have been a few changes to the timing over its dozen years of operation:

First six years (approx. 2001-2007): The orbit was mostly at 5 p.m. local solar time (as it flew north to south) and 5 a.m. local solar time on the south-to-north orbit. “That orbit provided an advantage for the orbiter’s Gamma Ray Spectrometer to have its cooling equipment pointed away from the sun,” NASA stated. At that time, the spectrometer found evidence of water ice, through the spectrum of hydrogen.
Next five years (approx. 2007-2012): The orbit shifted to 4 p.m. local solar time on north-to-south, and 4 a.m. south to north. While this allowed the Thermal Emission Imaging System to examine warm ground that made the mineral signatures in infrared pop out more easily, on the flip side of the planet Odyssey’s power system was under more strain because the solar panels couldn’t work as well in predawn light. Odyssey remained in that orbit until about the 2012 landing of the Curiosity rover, then was sent on a maneuver to move its orbit to later in the day to keep the battery functioning.
What’s next: Once Odyssey is in the right spot, the spacecraft will flip its daylight observations to scan the ground at 6:45 a.m. on the south-to-north part of the orbit. The spacecraft was in fact going in that direction already, but the new maneuver gets it there a bit sooner.

“We don’t know exactly what we’re going to find when we get to an orbit where we see the morning just after sunrise,” stated Philip Christensen of Arizona State University, who is THEMIS principal investigator and the person who suggested the move. “We can look for seasonal differences. Are fogs more common in winter or spring? We will look systematically. We will observe clouds in visible light and check the temperature of the ground in infrared.”

“We know that in places, carbon dioxide frost forms overnight,” he added. “And then it sublimates immediately after sunrise. What would this process look like in action? How would it behave? We’ve never observed this kind of phenomenon directly.”

Sources: NASA Jet Propulsion Laboratory and Arizona State University

February 10, 2014December 23, 2015 by Elizabeth Howell

Are These Water Flows On Mars? Quite Possibly, New Observations Reveal

Palikir Crater as seen by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. Visible are warm-season flows called "recurring slope linea" that could have been created by salty liquid water. Credit: NASA/JPL-Caltech/UA/JHU-APL

What a tangled web of water and water ice stories on Mars. There’s likely some underground. There’s definitely some at the north pole. And we are pretty certain water flowed there in the ancient past. But what about surface water today, right now, in the view of our many orbiting cameras at the Red Planet?

One hotspot of debate are flows called “recurring slope lineae”, which are features that appear in warmer temperatures. These would seem to imply some kind of briny water flowing. A team recently checked out 13 of these sites. While they didn’t find any water or salt evidence in the spectra, they did find more iron-bearing minerals on “RSL slopes” compared to those that aren’t. So what’s going on?

“We still don’t have a smoking gun for existence of water in RSL, although we’re not sure how this process would take place without water,” stated Lujendra Ojha, a graduate student at the Georgia Institute of Technology in Atlanta who led two reports on these features. Pictures were taken using NASA’s Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE), which is led by the University of Arizona.

It’s possible that the grains are being sorted by size (more plainly speaking, taking the fine dust away and leaving the larger grains behind), which could happen either with water or without it. Or, water might be present but not in a way that is obvious immediately if the area got darker because of moisture, or the minerals became oxidized. Water could be “missing” from these observations because they took place in the afternoon (meaning they could miss morning dew), or because the dark flows are smaller than the sample size in the picture.

While researchers still aren’t sure, the team says they still believe it’s salty water of some sort that is flowing despite very cold temperatures on Mars.

“The flow of water, even briny water, anywhere on Mars today would be a major discovery, impacting our understanding of present climate change on Mars and possibly indicating potential habitats for life near the surface on modern Mars,” said Richard Zurek, MRO project scientist who is at NASA’s Jet Propulsion Laboratory in California.

A related paper also found that RSL sites are rare on Mars, appearing in only 13 of 200 sites surveyed with similar slopes, latitudes and other features. You can read the accepted versions of the reports as they appear in Geophysical Research Letters and Icarus.