Mars is an active place (we have the HiRISE images and scientific evidence to support this exciting contemporary view of the planet) and late Sunday night it will become even more active: after several months in transit followed by seven minutes of terror, Curiosity – the Mars Science Laboratory (MSL) rover – should find itself on the surface of the Red Planet and ready to explore Gale Crater for the next Martian year.

To support the MSL mission and add an extra dash of drama, the HiRISE camera onboard the Mars Reconnaissance Orbiter (MRO) will attempt to capture Curiosity descending through the Martian atmosphere by parachute. This attempt is similar to our successful image of the Phoenix lander descending by parachute back on May 25, 2008. Success depends on (1) the MSL mission’s own success and (2) our camera being at the right location in orbit and looking at the right spot at the right moment. The engineers and scientists have checked and rechecked their calculations, the commands have been successfully sent up to MRO, and now we hold our breath until Sunday night hoping that all of the logistics come together for a successful image.

Many of us HiRISE team members will be here at the HiRISE Operations Center beginning Sunday night to wait for this image to hit our servers for processing early in the morning on Monday. We plan to eat pizza and Cheetos, watch NASA TV’s coverage of the landing, and monitor telemetry and data processing. If all goes well, if MSL lands safely and if the HiRISE camera actually captures the descent, then you will likely hear (and see) more Monday morning. In the following days, weeks, and months we also plan to take additional images from orbit of Curiosity hard at work on the Martian surface.

If you are in Tucson, Arizona, other locations with NASA centers, or would like to follow along with the landing online, there are a variety of events scheduled this weekend that you might enjoy:

• Science Downtown (Tucson) presents “Tucson Lands on Mars” on Saturday, August 4 from 10 a.m. to 5 p.m.
• NASA’s Multi-Center Social Media Event for Mars Landing
• NASA TV coverage begins Sunday, August 5 at 8:30 p.m. PDT
• Universe Today’s Live Webcast of the Curiosity Rover Landing begins Sunday, August 5 at 8:00 p.m. PDT

Follow along! We’re in the midst of twittering an entire planning cycle, start to finish. Right now we’re in what’s called “IO week 1″, the second week of a 5-week planning process. You can follow the hashtag #hitwycle to see all the updates in real time.

This blog entry describes it in much more detail, from when we tried to do this last fall. Unfortunately, that time the spacecraft went into safe mode, and we had to stop the experiment. Here’s hoping for better luck this time! :\

Cast of characters:

CIPP (Co-I of the Pay Period, science team member who prioritizes and helps plan the images from a scientific point of view): @nick_space

HiTS (HiRISE Targeting Specialist, operations team member who plans the images from a technical point of view): @laughingrid

Cycle Coordinator (person at JPL who combines and deconflicts all the targets from the different MRO instruments): @milkysa

One difference is that this time the CIPP (@nick_space) is here in Tucson. So it’s pretty easy to walk over to his office and ask him a question. Despite that, we’ve actually had a few discussions over twitter instead. Talk about lazy!! The good side of that is that you get to follow the day-to-day planning and see what it’s really like to plan two weeks of HiRISE images!

Links:

HiTwycle – HiRISE Twitters a Planning Cycle

HiTwycle on twitter

A DTM (or synonymously DEM for Digital Elevation Model) is a grid, or raster, file describing elevation values at regularly spaced points, or posts.

HiRISE DTMs are made from two images of the same area on the ground, taken from different look angles. All the stereo pairs acquired so far are available here. Not all of these have been made into DTMs due to the time-intensive process. Creating a DTM is complicated and involves sophisticated software and a lot of time, both computing time and man-hours.

As mentioned in a previous post, the great advantage of a HiRISE DTM is the high resolution of the source imagery. As a general guide, terrain can be derived at a post spacing about 4X the pixel scale of the input imagery. HiRISE images are usually 0.25 – 0.5 m/pixel, so the post spacing is 1-2 m with vertical precision in the tens of centimeters.

The three basic stages of creating a DTM are:

1. Prepare the images for ingestion into the stereo software
2. Triangulate the images
3. Extract terrain

In order to prepare the images, we must first correct the geometry by removing any optical distortions inherent to HiRISE. Then the spacecraft pointing information at the time of each observation is gathered.

Triangulation is also called bundle adjustment. This step requires the most operator skill and time. The result is a transformation of the original images to epipolar space. What this means is that all the stereo information is now captured in the horizontal direction, or x-parallax. During triangulation, we also align the stereo model to MOLA elevations, so the end result is tied to the global elevation map produced by the MOLA instrument team. This is the same map that you see in the context map pane of every HiRISE observation page.

Once the images are triangulated, then terrain can be extracted. This step is computationally intensive, but automated, so it just takes a lot of computer time. The output of terrain extraction is reviewed for any artifacts or errors. These are edited out if possible. Since editing is extremely time-consuming, it is only done on easily corrected errors and in the areas of most interest to the researcher. The less editing we have to do, the better, so a lot of effort goes into preparing the images so that the input is as high quality as possible. The excellent contrast and value range of HiRISE imagery usually result in high quality terrain extraction that requires minimal editing.

After we have terrain, we can make other products, such as orthoimages. An orthoimage is a picture that has been orthorectified. This means that the pixels have been projected so that at each pixel it is as if you are looking directly down at the terrain. In the original stereo images, we rely on the fact that there are topographical distortions (parallax) to derive the elevations in the terrain model. In the orthoimages, all topographic distortions have been removed.

The final products are map projected using the same mapping definitions as the regular HiRISE RDR products.

A really useful (and cool) thing to do with the orthoimages is to drape them over the terrain for 3D viewing. Below is a subimage from the Newton Gullies DTM showing the imagery draped over the terrain.

You can see animated fly-throughs made with HiRISE DTMs by going to the HiClips page and clicking on the JPL Flythrough Clips. This is a great way to see and understand the geological relationships from a ground perspective.

Researchers use DTMs to take measurements and model geological processes. DTMs are very powerful research tools. In fact, almost every HiRISE DTM produced results in publication. There is a long waiting list for these products because they are so valuable and so difficult to produce. Several institutions involved with HiRISE contribute to DTM production to maximize the number of projects produced and to avoid duplication of effort.

Standard PDS products linked to the DTM project page are usually quite large files. The links provided will download the files to your system. To get a quick view of what the project looks like, click on the Extras links to see a reduced version of the products, displayed as images, grayscale, shaded relief and colorized altimetry.

Standard PDS products:

• The DTM in standard PDS image object (.IMG) format with an embedded label
• The left orthoimage at the same resolution as the DTM, in JPEG2000 format with detached label
• The left orthoimage at the resolution of the original image, in JPEG2000 format with detached label
• The right orthoimage at the same resolution as the DTM, in JPEG2000 format with detached label
• The right orthoimage at the resolution of the original image, in JPEG2000 format with detached label

Extras available in the PDS Extras directory (letters in parentheses correspond to PDS file names such as <Product_ID>.br.jpg):

• Browse (br), annotated browse (ab), and thumbnail (th) jpegs of the DTM as a grayscale image
• Browse (sb), annotated browse (sa), and thumbnail (st) jpegs of the DTM as a shaded relief image
• Browse (cb), annotated browse (ca), and thumbnail (ct) jpegs of the DTM as colorized altimetry
• Browse (br), annotated browse (ab), and thumbnail (th) jpegs of the lower resolution orthoimages

PDS product naming convention for HiRISE DTMs:

PRODUCT_ID = aabcd_xxxxxx_xxxx_yyyyyy_yyyy_Vnn
where
aa = DT, indicating it’s a DTM product
b = type of data

• E = areoid elevations
• 1 = orthoimage pixels from first image
• 2 = orthoimage pixels from second image

c = projection (others are possible but these are the important ones)

• E = Equirectangular
• P = Polar Stereographic

d = grid spacing (think of this as pixel scale in meters)

• A = 0.25 m
• B = 0.5 m
• C = 1.0 m
• D=2.0 m

xxxxxx_xxxx = orbit number and latitude bin from SOURCE_PRODUCT_ID[1]
yyyyyy_yyyy = orbit number and latitude bin from SOURCE_PRODUCT_ID[2]
V = letter indicating producing institution

• U = USGS
• A = University of Arizona
• C = CalTech
• N = NASA Ames
• J = JPL
• O = Ohio State
• Z = other

nn= 2 digit version number

Below is an example of the set of annotated browse images for the Russell Crater Dunes DTM.

The grayscale image of the DTM looks weird, if you have not looked at lots of these before, but keep in mind that the color of the pixels represents elevation. The higher the elevation, the brighter the pixel. Lower elevations are darker. The shaded relief is another way of visualizing the topography. The pixels are illuminated from a certain direction, to show the relief of the topography, rather than the elevation. It is also emphasizes any artifacts in the DTM. In the example here, many artifacts (errors) can be seen such as the faceted areas and boxes in the lower left and top of the image. These artifacts are usually caused by areas of low contrast (such as in this project) or sharply differing shadows. Most HiRISE DTMs will not have a lot of these artifacts, fortunately! The area of most interest to the researcher who requested this DTM was the long slope with the gullies, which was well-illuminated and had good contrast. So in that area, there were few, if any, artifacts. Adding color-coded elevation to the shaded relief creates the colorized altimetry map, where the lowest elevations are purple, green is the median elevation value, and white is the highest elevation. In the Russell Crater Dunes project shown here, the difference in elevation from the highest to the lowest point is almost 590 meters (~1935 ft.). That is a tall dune!!

We are happy to be able to share HiRISE DTMs with the scientific community and with the public. We will continue to release more DTMs as they become available, so stay posted!

We are now returning to our normal mode of operations after several long months of being in safe mode. The anomaly on August 26th was the last in a series of computer glitches on board the MRO spacecraft that caused a reboot. The engineering teams have been working incredibly hard to get the anomaly figured out and prevent a possible side-effect from causing really serious problems. While they may not understand the original problem, and there is a chance it may happen again, they’re confident that at least it will not threaten the mission, so they’ve given us the go-ahead to resume normal operations.

Safe mode is a way of running the spacecraft where all of the science instruments are turned off and quiet. We still receive engineering telemetry so we can monitor temperatures and voltages. There are also “survival” heaters that prevent HiRISE from getting too cold in this mode.

During this time, the uplink operations staff has gotten a little restless. (more…)

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! ☺

You might remember that we were planning on releasing HiRISE images to the public on a monthly basis. That plan was delayed by issues with our processing software, hardware and other events. A productive summer working on these issues culminated last week with one of our larger releases of Mars images!  Here are some statistics about our September 2009 release, which includes the images the HiRISE camera took of the Martian surface between Mars Reconnaissance Orbiter (MRO) orbits 12,600 to 14,199, or roughly April 4 through August 6, 2009:

• 2,996 RDRs, 1 TB
• 42,370 EDRs, 1 TB
• 34,481 RDR Extras, 1.6 TB
• 83,784 EDR Extras, 0.02 TB
• 636 Anaglyphs, 0.01 TB

Totals for this release: 163,631 image products, 3.6 TB

This brings our total released product numbers and data volume to:

• 22,676 RDRs, 12 TB
• 317,120 EDRs, 10.4 TB
• 192,270 RDR Extras, 15.3 TB
• 612,769 EDR Extras, 0.1 TB
• 2,892 Anaglyphs, 0.5 TB

Total: 1,148,363 images, 37.5 TB

In summary, we released nearly 1500 observations, most of those with both black & white and color RDR products. Several newer observations matched up with older observations from a slightly different angle of the same location on the surface, resulting in 636 awesome new anaglyphs. The RDRs are the fully processed, geometrically projected products best for scientific inquiry. If you really want to, though, anyone can download and process HiRISE data from scratch. You can do this using ISIS software, which is publicly available for free download. See the ISIS Web site for download information, processing instructions, and tutorials.

Starting this week, I will be looking over the observations taken August 6 through August 26 before MRO went into safe mode and make sure they are ready for release. We plan to release these images in early October. We are also in the process of reprocessing those Extended Science Phase mission images prior to all the latest processing pipeline fixes and updates.  Once we are satisfied with that data set, we will release them to the public and then start reprocessing the images from the Primary Science Phase…a major project that should keep me and the rest of Downlink busy for several months!

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:

“Martians invade Glacier – Mars scientists visit park to study, compare rocks.”

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.

We were pleased to welcome Linda Ronstadt (!!!) to the HiRISE Operations Center last week. We gave her and a few of her friends & family a presentation about the HiRISE mission, and we showed them some of our images in false color, 3-D and on the HiWall. Linda was incredibly nice and enthusiastic, and she had lots of great questions for us. Turns out rock stars love HiRISE! At least, we hope she enjoyed it as much as we did!

It’s summer again in the southern hemisphere of Mars, so we’re continuing our mosaic of the landing ellipse for the lost Mars Polar Lander. ESP_013368_1035 was the first of the new images to be released, and we’ve gotten a lot of people asking where to send their candidates. You can either contact us directly, or add to the comments in our previous blog post about the search.

The Unmanned Spaceflight forums have a long discussion on the previous search efforts. Many candidates were proposed, and the community’s discussion about them is quite enlightening.

Emily Lakdawalla at the Planetary Society also started a coordinated search effort last year. I don’t know if that effort is still ongoing, but her page on how to use HiRISE images in the search is still a great resource. It includes examples of known hardware, cosmic ray hits and other artifacts, and more tips on searching.

In addition to the list of images on the previous blog entry, these new images have been released: (we’ll try to keep this list up to date as more are released)

• ESP_013368_1035
• ESP_013078_1030
• ESP_013223_1025
• ESP_013289_1035
• ESP_013566_1025
• ESP_013500_1035
• ESP_013711_1030
• ESP_013724_1030
• ESP_013935_1030
• ESP_013790_1035
• ESP_014001_1040
• ESP_014080_1040

Thanks for all your interest, and good luck searching!

9/2/09: ETA new images released in September PDS release.