Ice excavated from the subsurface, by a crater 6m (20 feet) in diameter, sublimates away over the course of the martian summer. Each of these HiRISE images are 35m (115 feet) across and were taken in October 2008 and January 2009.
Image credit: NASA/JPL-Caltech/University of Arizona

An exciting new paper came out in yesterday’s issue of Science magazine, with HiRISE team member Shane Byrne as the lead author. Water ice has been discovered being exposed by fresh Martian craters!

This is exciting for several reasons: first, these are very tiny craters – only a few meters (yards) across. This means they’re not excavating very deep into the crust of Mars. So the ice has to be really shallow – less than a few feet below the surface! Secondly, the location of these craters is surprising – they’re between 40-55 degrees north latitude. This is far from the polar regions, where we’d expect to find ice (for example, where the Phoenix mission landed at 68 degrees north, ice was found by digging down into the dirt).

The third exciting aspect of this ice is its purity. We’d expect this ice to be mixed in with dirt and dust and rock. Instead, we found that it’s 99% pure ice! (Only 1% is dirt mixed in.) This can be measured because we watched the ice disappear over time. By taking repeated images of the same spot, HiRISE got a time sequence as the ice slowly faded. It faded so slowly that it has to be almost all ice – a dirtier mixture would have faded much faster as it sublimated (went directly from a solid to a gas) in Mars’s extremely dry atmosphere.

Speaking of dry atmospheres, this also has interesting implications about the history of the Martian climate – there had to have been more water vapor in the atmosphere in the recent past than we previously thought. We still have lots of questions about how this ice formed, how much of it there is, and how many more of these craters we’ll find. Luckily, we’ve got a long mission ahead of us to explore these issues!

This discovery is also a great example of how the instruments on MRO work together. CTX initially detected these new craters as “dark spots,” and HiRISE followed up to confirm that they’re really impact craters. Some of those HiRISE images revealed some very bright white material, and then CRISM confirmed that material really is water ice. The instruments worked together to accomplish the best combined science. Go team! ☺

Here are some more detailed stories, images, and multi-media:

• Really nice movie with Shane Byrne talking about the discovery and excellent animations showing the locations of the craters and the time-evolution of the ice disappearing: NASA multimedia – then go to “Video Gallery” on the right, and click on “Mars – Exposed”.

• NASA press release, and all of the images and materials from the press conference

• UA news story

We’ve seen many more news stories & blogs – thanks for the interest, everyone! It’s great that everyone thinks this is as exciting as we do! ☺

Originally posted at Spaced Out (Again):

We are going to try to Twitter a planning cycle for the HiRISE (http://hirise.lpl.arizona.edu) experiment. The idea is to give people a feeling of all the work we have to do to get images from Mars out of a very special piece of equipment. Here are a couple of things you need to know to follow what is going on.

The scientist in charge of the scientific support for the cycle is called the CIPP. For cycle 75, that is @nick_space. Nick will be assisted by his Post-Doc., Anya, who is @mozhetbyt

The targeting specialist ensures that the plan produced can be implemented and keeps the CIPP from doing anything stupid. The targeting specialist is called the HiTS and for cycle 75 that is @laughingrid.

The HiRISE project has its own Twitter account (@HiRISE) which can also be followed.
We will try to use #hitwycle as a search hashtag for tweets.

(more…)

The HiRISE team met up this summer in Whitefish, Montana. In between meetings, we were also able to take several geologic field trips and hikes. Glacier National Park has many cool (haha) glacial features, of course, and we also learned about some interesting sedimentology that occurred in the ancient geologic past. The patterns we saw in the sedimentary rocks are similar to those discovered by the Mars Opportunity Rover – cross-bedding and festooned ripples that form when sand is laid down under a body of water. The shape and direction of the ripples can tell you how much water was present, how fast it was flowing, and whether it was a river, a lake, or an ocean. These are important questions we’d like to answer about the history of water on Mars.

The park also has wonderful examples of glacial geology. HiRISE has taken images of many features thought to be related to glaciers, so it’s important to understand the terrestrial analogs that lead scientists to think these are evidence of flowing ice on Mars. For example, we hiked along a moraine composed of jumbled rocks the Grinnell Glacier left behind as it flowed downhill. In addition to the remains of the (rapidly disappearing) glacier itself, we also saw typical glacial erosional structures such as U-shaped valleys, hanging valleys, and cirques. For a HiRISE image of cirque-like features, see PSP_005730_1405.

On one of our field trips, we were accompanied by reporter Michael Jamison of The Missoulian. This story was on the front page of the paper the following day:

I thought the story was really good – a quirky (but so are we!) description of why we would want to stare at the rocks in such a magnificent setting, and their relevance to our mission to Mars. We all thought it was funny when he called Alfred McEwen, our Principle Investigator, a “Marsman”!

HiRISE Team in Glacier National Park, in front of a classic U-shaped valley carved by glacial erosion.

Here are a few excerpts from yesterday’s University of Arizona story about our PDS release:

The HiRISE team has so far released a total 26.9 terabytes of data…. That amounts to more data than has been released by all previous deep space missions combined.

“If I showed each HiRISE image for 10 seconds, it would take me about 4 years to show them all,” said UA’s Alfred McEwen, HiRISE principal investigator.

…

Spacecraft motion pushes this electronic array so that it records the view down to Mars’ surface at a ground speed of about 3.2 kilometers per second, or about 7,000 miles per hour.

Skeptics doubted that a technique called “time integration delay,” needed to compensate for extremely short exposure times – about one ten-thousandth of a second per pixel – could produce sharp, unsmeared images.

But the technique has worked “wonderfully well,” thanks to accurate spacecraft pointing and stability and precise exposure time calculations, McEwen said.

Click here for full story.

It seems the landslides in PSP_007338_2640 have caught a lot of attention!

There has been a lot of online and print news coverage: CNN, Time, Fox News, Astronomy, Space.com, New Scientist, National Geographic, and our local Arizona Daily Star, among many others. The New York Times made a really nice slide show that includes the avalanche, the Earth-Moon image, as well as other great images from our big PDS release. Blogs are talking about it (Cumbrian Sky and the Bad Astronomy Blog, to name just two). People over at unmannedspaceflight.com are discussing the avalanches a lot, too. (I’m sure there are tons I’ve missed – apologies – if you feel left out, post it in a comment below!)

A co-worker heard NPR’s Wait, Wait, Don’t Tell Me featured a question about the avalanches on Saturday. It was even the Astronomy Picture of the Day yesterday!

I’ve talked personally to a lot of people about it, too. It’s amazing how it’s caught everyone’s interest. I think most people who see it for the first time have the same “Holy crap!” reaction that we all had when we first saw it here at HiROC. Then they start trying to figure out what’s going on, what caused it, what it means, how we can take more data and look at past images to narrow down different hypotheses… which is exactly the process that scientists go through!

The best part of the story, I think, is how the landslide was serendipitously captured in an image, and then accidentally noticed! HiRISE has sent back such an incredible volume of highly detailed data, no one person has time to study it all in full resolution. We’ve released 17 Terabytes, thousands of images, and it’s very likely that more surprises like this are waiting to be discovered in them. So go look at more HiRISE images; let us know what you find! We can’t wait to see how Mars can surprise us further.

Thanks for being as excited about HiRISE and Mars as we are!

Today a press release went out about a forthcoming paper in the journal Geology (click here for full text online or here to download a PDF). John Grant, a Co-Investigator on the HiRISE science team, is the lead author, and most of the co-authors are also on our science team.

What is a megabreccia? A breccia is a jumbled-up mixture of broken rocks, cemented together by a finer-grained material. We see them in impact craters and volcanoes on the Earth, places where there was a lot of violent energy to break up rocks. A megabreccia is just a larger version of that – something we can see with HiRISE resolution, as opposed to something you’d have to pick up in your hand to identify. The megabreccia in Holden formed when the explosion that opened the crater shattered rocks, mixed them up, and then the fragmented ejecta collapsed back down into the crater. Before HiRISE, we didn’t have the resolution to detect these textures.

This is a cutout of an image taken in Holden Crater, showing the megabreccia texture, in false color as usual. A context map is shown to the right, showing where in the crater rim this image is located (click these images to enlarge). The blocks here are mostly darker, and they’re embedded in a lighter-toned material. The dark chunks are kind of “scooped out,” which means they’re more easily eroded than the surrounding light-colored rock. Scientists think this may be because they’re sedimentary rocks, formed at the bottom of a lake or river. The stripey dark blobs on top are sand dunes that are slowly covering up the area again.

This megabreccia is located in an area scientists find fascinating for other reasons, too: there are clays that were laid down over a long period of time when it had to be wet. This implies there was once a lake in this crater – perhaps more than once over its history. At one point, the lake broke through the rim of the crater, releasing a huge flood of liquid water. You can see the channel this formed in the context map above. This flood eroded away material that was covering the megabreccia, exposing it for HiRISE to see.

The HiRISE image PSP_003077_1530 shows another part of Holden Crater, and the caption includes more information about the geologic history of the area.

HiRISE caught an avalanche in action! http://hirise.lpl.arizona.edu/PSP_007338_2640

It was so exciting to find this image! The image was intended to be part of a series of seasonal monitoring observations of a dune field. We’re watching to see how the winter carbon dioxide frost disappears as spring comes to the northern polar areas (which is pretty cool in itself! See PSP_007043_2650, for example.) PSP_007338_2640 happened to be the first image we took after powering back on after a safing event. So we were examining the image to make sure the camera was still working OK (it is – as you can see from this beautiful image & the many others we’ve taken since!). If it hadn’t been for that, we might not have noticed this for weeks! (In case you haven’t noticed, we have a LOT of images to look at! )

My first reaction was just, “What is that?” So I asked some of the scientists around HiROC, and they got excited, too. Everyone was talking about it all day, putting together ad-hoc color products (the full color processing takes a while to get through our processing pipelines) and looking at other images nearby for similar events. Because this was part of a series of images in the same spot, we had a “before” image as well (PSP_007140_2640). It’s a little hard to compare the two images because the bright carbon dioxide frost is changing as well, and we took the two images from different angles. But you can see in the second image that there are some spots up above on the cliff that are missing their bright frost covering. Perhaps that’s where the rock (or ice) fall started? The springtime sun is warming these icy layers, which could cause sublimation (solid ice changing to gas). Certainly there is a lot of dust being raised to form this big cloud, too, whether the dust was mixed in with the ice blocks, or just kicked up off the lower, dustier layers. As we continue monitoring this site and other polar areas, we’re sure to learn a lot more about the processes captured in this image.

ETA: Emily Lakdawalla made a great animation of the before/after shots, posted on the Planetary Society blog. So cool!

On this NPR Science Friday episode, HiRISE Principal Investigator Alfred McEwen and M.I.T. planetary geophysicist Maria Zuber discuss new results that illuminate the story of water on Mars with host Ira Flatow.

Also, available free on iTunes, are a collection of videos from the Phoenix Mission’s Open House, highlighting the University of Arizona’s Mars-related projects including UofA speakers McEwen, Phoenix P.I. Peter Smith, GRS and TEGA P.I. William Boynton, and planetary geologist Vic Baker.

Finally, during last week’s UofA football game, our marching band played a tribute to Mars and in particular Phoenix with a little ditty written by band director Jay Rees. I don’t know if a recording of the performance is available online, but here’s a snippet of the song:

“Follow the water” is NASA’s song,
UA’s happy to sing along.
We shall see what we shall see.
We might find biology!

Three HiRISE papers are coming out in a special issue of the journal Science today. Our science team has been working hard on analyzing the images we take, and they’ve discovered some interesting things.

One paper talks about a few aspects of the history of water on Mars: HiRISE images of “rock glaciers” and bright deposits in gullies that might be extremely recent. HiRISE observations of an area called Athabasca Valles were used to show that it is actually covered with a thin veneer of lava. A third paper discusses thin layers in the North Polar cap. HiRISE is able to discern very fine layering (seen in an excerpt of image PSP_001636_2760 at left), as well as the color and thickness of each layer. Since these layers were laid down over hundreds of thousands of years of Martian history, they provide a record of climate change on the planet.

You can find a lot of things on the HiRISE website that are impossible to include in a print journal – like full-resolution color versions of the images from the papers, and (my favorite) cool 3-D flyover movies of the stereo observations. Our webmaster designed this lovely page for accessing these special products. Have fun flying over Mars!

Saturday’s front-page of the Arizona Daily Star featured a good article about HiRISE with a humorous photo of Chris S. shoulder surfing as Anjani P. worked.

This is of course a typical scene as these images are coming down. Someone will be “driving”, so to speak: browsing, “surfing”, zooming, panning, contrast stretching and more, using the amazing image processing tools that our partners at the USGS in Flagstaff have developed. And someone else (or two, or three, or a dozen) will be standing over their shoulders, watching and collaborating. Or in Chris’s case, probably making jokingly snide comments.

But it makes for a world of difference between what you, out there, the public, experience and what we experience. Bridging that gap is a challenge for our public outreach team as the mission continues. We’ve got the benefit of having the brightest minds in planetary geology offering live commentary and analysis using the finest tools and top-of-the-line workstations. The experience of seeing the image is very dynamic; jumping between resolutions, zooming in to dunes and boulders and rocky outcrops, “stretching” the image to pull out detail hidden in dark shadow or blended in on bright surfaces.

I guess what I’m trying to say is that while our excitement is evident from the posts here, communicating exactly why we’re excited is much more difficult. Unless you could be here shoulder surfing….