Since its launch in 2010, HiWish has been quite successful. We’ve captured images of Mars for well over 500 public suggestions, an average of about one per day. Updates to the HiWish web application were made in the summer of 2011, and they include the following:

• the interactive maps of Mars now expand to fill most of the available page size instead of using a fixed, small size
• there is an additional basemap option: Night-time Infrared. Also, the Day-time Infrared basemap is higher resolution. These maps are made from THEMIS data by NASA’s Ames Research Center and we appreciate the work done by those teams
• markers for CRISM data can now be drawn on the suggestion maps, and they link to the corresponding publicly available download
• you can stretch (or shrink) your suggestion’s rectangle to match the longest (or shortest) observation length that HiRISE typically takes. It still defaults to our average image length. After placing a suggestion, click on the marker and you’ll be able to resize it to match a particular feature’s length.
• there is now a “browse” map where you can just explore, without creating a suggestion
• global maps of HiRISE Digital Terrain Models and of HiWish observations to date

Thanks for using HiWish, and keep the suggestions coming!

Howdy, readers. About every two years, the orbits of Mars and Earth work to put Mars behind the Sun when viewed from Earth. In this arrangement, the Sun makes it pretty tough to communicate with the various spacecraft we’ve got orbiting the Red Planet and creeping around on its surface. This arrangement, called “solar conjunction,” lasts for about five weeks. During this time, we generally reduce operations to the bare minimum required to keep these marvels running. MRO’s HiRISE is no exception, do we haven’t been taking images for the past five weeks.

That ends today, though. Mars recently came out of solar conjunction and operations have been ramping up. We ought to be starting our first post-conjunction image at around 9 PM Tucson time (MST) tonight, February 22.

I mention this fact to draw your attention to a pretty cool feature of the Google Earth desktop application. It’s been around for a while, but you might not have heard about it. It’s called Live from Mars, and it shows you the orbits of MRO and Odyssey as they’re orbiting Mars right now. You can also see the image footprints for upcoming HiRISE (MRO) and THEMIS (Odyssey) observations. Even cooler, you can virtually ride along with MRO or Odyssey, your point of view tracking along those orbits.

To set it up, launch the latest version of the Google Earth desktop application. Find the little menu button that looks like Saturn, and click it to drop down the menu. Select Mars.

Once Mars comes into view, go to the Layers panel and open up the Mars Gallery group. You should see Live from Mars. Open up that group, and you’ll see Live from Odyssey and Live from MRO. Open up the Live from MRO group and you’ll find MRO Orbit, Fly Along, and HiRISE Footprints. Activate those and you’ll see a segment of the MRO orbit; you might see a HiRISE footprint or two, but our images are so small compared to the size of Mars that you might need to zoom in a bit to find them.

If you double-click the Fly Along item, your point of view will switch to that of MRO orbiting Mars. As you travel along, you’ll come across upcoming HiRISE observations, such as the one called out in the above image.

Cool, isn’t it?

Our cycle of twittering (”HiTwycle“) is now over – the last image is on the ground, validated, processed, and will soon be released. (We release data in 100-orbit increments, which don’t necessarily fall along cycle boundaries, so the first half of cycle 89 will be released in May and the second half in June.)

It was fun to share some of the behind-the-scenes details with our followers! I thought it was pretty funny when Nick or I were too lazy to walk over to each others’ offices to ask a question, and asked each other over twitter instead. ha! I guess those questions probably give you a feel for the nitty-gritty of planning a cycle, anyway. I hope it was interesting! If you have any questions, feel free to ask them in the comments.

If you missed it and want to read through the saga, I made an archive of tweets with the #hitwycle hashtag. (I didn’t start this until part-way through, though, so unfortunately the first few days of tweets are missing. Soon you can check the Library of Congress for them! ) You can see the whole archive here:

http://www.twapperkeeper.com/hashtag/hitwycle

Some of my favorites are below.
Read the rest of this entry »

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:

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:

HiRISE has been conducting a survey of polar scarps where several dust avalanches were caught in action in the previous Mars year. The first new avalanche found by this campaign can be seen in the images from HiRISE observation ESP_016228_2650.

Questions remain about how these dust avalanches are triggered, though it is believed to be related to the spring warming of CO₂. You can find out more in Patrick Russell’s caption for HiRISE observation PSP_007338_2640.

January was a particularly eventful month for HiRISE. Let’s hit the HiLights (in no particular order).

#1. A special issue of the journal Icarus was devoted entirely to HiRISE. It contains over twenty scientific papers produced using HiRISE as a primary data source, representing years of research by dozens of scientists. You can find out more by reading our press release.

A plot of HiRISE stereo observations in Tharsis and Valles Marinaris

#2. We observed the Phoenix Lander in springtime, as frost slowly melted around its landing site. There was some small hope that Phoenix would be attempting to awake from ‘Lazarus’ mode but evidently the Mars Odyssey orbiter has not heard its signal.

The Phoenix Mars Lander as of January 2010

#3. Our image that captured a dust avalanche on a dune was very popular around the web. Astronomer Phil Plait called it “another dose of Martian awesome” and provided a great analysis on his blog.

Active dust flow caught by HiRISE

#4. Our image of ancient viscous flows on the floor of Mars’s largest impact basin stood out (to me). “HiRISE images are revealing some very strange landforms on the floor of Hellas,” says HiRISE P.I. Alfred McEwen. You can read more in the caption for ‘Contortions on the Floor of Hellas Basin‘.

An section of a Hellas Basin flow in 3-D

#5. Our first DTM’s were released, the initial results of a very labor-intensive process. These precise 3-D maps provide a wealth of information for scientists. But in addition, they will make for very cool simulated fly-over movies. Doug Ellison of UMSF has published some on his youtube page. In a related effort, UMSF user Bernhard Braun produced 3-D HiRISE data using photoclinometry (”shape from shading”).

Doug Ellison’s fly-thru of Candor Chasma

#6. HiWish, our public suggestion page, was made available to great fanfare (thanks). We’ve received over 700 target suggestions in the ten days since launching it, and some of these are already being planned as upcoming observations.

Adding a new target in HiWish on the slopes of Olympus Mons

#7. Mars and Earth made their closest approach of the year, at a distance of about six light minutes. Thus, MRO is in the middle of a high data rate period. HiRISE has been making the most of this, taking 20-30 images per day lately.

Plot of observations received vs. time (includes calibration images)

The response to HiWish has been incredible! We’ve had well over one hundred target suggestions from the public since launch. Here are some more questions and answers that will go in our FAQ.

What are some strategies to improve my suggestion’s chances?

First, make sure you justify the image in terms of small-scale features that might be seen, things like boulders or thin layers or dunes, not giant volcanoes or channels. We need to know how HiRISE’s meter-scale resolution is necessary, especially if there are existing MOC, CTX, HSRC or other images of the area.

Second, choose an appropriate science theme. There are one-sentence descriptions below the map, and detailed descriptions via clicking on the science theme name.

Third, choose a location on Mars that isn’t very popular—avoid regions with lots of other suggestions. Other suggestions are shown with white markers (when you are zoomed in on the map).

How long might it take for my image to be taken and released?

This is very difficult to predict. First, there’s the caveat that we can’t guarantee that we’ll get to it. It depends on how highly a Science Theme Lead prioritizes it. They look at suggestions on a monthly basis. Uplink, downlink and validation are a matter of weeks. And, our PDS releases occur on a monthly basis. So in the absolute best case, it is a matter of months. Remember that you are competing against other suggestions and for the STL’s prioritization.

No doubt you have been introduced to HiWish. We’ve gotten a lot of questions about it, including the following. We’ll add these answers to our FAQ.

My registration failed? What can I do?

We’ve streamlined the registration process, so please try again (with a new username). We do not know the reason why so many people have had trouble registering, but will continue to work on the problem.

Why can’t I save my suggestion? The button is grayed-out!

Please make sure you have provided four things: a title, a science rationale, a region of interest on the map (thick white rectangle with blue marker), and a science theme.

I filled out the suggestion, but can’t get to the next step. What’s wrong?

There should be an error message next to the field that needs to be changed. Typically, this is an invalid character in the title, or something of that nature.

Where Is the Face On Mars?

We have already looked at this in image PSP_003234_2210.

Cydonia

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!

ESP_013948_1410, the kind of data we can't wait to get more of!

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. Read the rest of this entry »