Archive for the ‘HiRISE’ category

Microsoft goes to Mars

July 12, 2010

Today, NASA and Microsoft announced a very cool new addition to Microsoft’s Worldwide Telescope (WWT) program: Mars images! Yep, now you can use WWT to cruise around Mars and to view the planet with a handful of datasets, including 13,000 mind-blowingly high-resolution HiRISE images, and even more almost-as-high-resolution MOC images. There is also the standard MOLA colorized topography and a low-resolution approximately true color map.

It’s great to see all of this data being made available to the public! Of course, HiRISE images have been available though the HiRISE website all along, but they are so much more useful when they are map-projected and shown with all the other datasets. I do wish there was an option to show both MOC and HiRISE images on the same map. And hey, while I’m wishing, it would be nice if there were CTX images too, but the camera team for CTX is more stingy with their data than the HiRISE team.

The Mars viewer comes with some nifty pre-loaded tours of Mars, but at least on my computer, the images loaded almost too slowly to match up with the words and there were some buggy moments when multiple image layers interfered to form moire patterns.

In general, I find the interface for the program isn’t as intuitive as it could be. Maybe I’m just too used to using Google Earth’s Mars viewer, but I found the thumbnails along the top and the bottom to be much less user-friendly than the wireframe image outlines that you get in Google Earth. The menus that pop up when selecting guided tours were very flickery and difficult to read on my computer also.

Still, maybe the interface works well for others, and I’m certainly happy to see another easy-to-use way to view all of this data being made public. Just the fact that WWT has so many map-projected HiRISE and MOC images mosaicked together makes it a powerful tool, both for interested amateurs and actual Mars researchers.

You can download the program at this link. Check it out!

Awesome new Mars flyovers

January 27, 2010

Check out these awesome flyovers of Mars, generated by Doug Ellison of UnmannedSpaceflight! These are based on digital elevation models from HiRISE, draped with the HiRISE images, so it’s about as close as we can get to actually flying above the surface of Mars. I particularly like the Gale crater one, but I may be slightly biased, having stared at Gale for the past year or so…

AGU 2009 – Day 2

December 17, 2009

I started off day 2 of AGU at a couple of lunar talks showing off data from the Lunar Reconnaissance Orbiter. Unfortunately, I missed the early sessions about the high-res cameras, but the bright side was that I learned abount some instruments I was less familiar with. First was the Lunar Orbital Laser Altimeter – LOLA. A similar instrument on Mars Global Surveyor, MOLA, revolutionized our view of Mars. The MOLA map has become the standard to which all other mars maps are registered, and LOLA is going to do even better for the moon. LOLA works by sending five laser pulses in a pattern similar to the spots on the “five” side of a die. The spacecraft then recieves the reflected laser light and determines the distance to the surface, and therefore the topography. The advantage of having five spots is that it also gives astoundingly good measurements of the slopes.

Credit: NASA/LOLA team

After the LOLA talks, I heard about the results from the cosmic ray detector, CRaTER, on LRO. Apparently right now is a good time to observe cosmic rays because the sun is not very active. The current weak solar wind pressure allows more cosmic rays into the inner solar system! Understanding the radiation environment is important for sending hardware and people to the moon. One significant result that the CRaTER team reported was that even though the moon blocks cosmic rays as you get close to it, the total radiation increases because rays that hit the surface send up showers of secondary radiation. There is also no evidence that the amount of radiation on the moon decreases when Earth’s magnetosphere tail points toward the moon, as some people had suggested.

An animation of a cosmic ray hitting Earth's upper atmosphere. A similar shower of secondary particles is produced when cosmic rays hit the moon. Image creadit: U. Chicago

After that, I headed over to listen to Mars talks. Serina Diniega gave a nice presentation about her discovery of active gullies forming on dunes in the southern hemisphere. She showed evidence of several dune gullies for which there are “before and after” images showing noticeable changes. Serina suggested that frost accumulating in the upper alcoves of the gullies could trigger the changes, which would be consistent with the observation that most changes happened in southern winter. A related talk by Colin Dundas showed similar results, with HiRISE observations revealing fresh gullies on pole-facing slopes in the southern hemisphere.

An example of a fresh gully deposit in HiRISE image PSP_002200_1380.

After a few more Mars talks, I headed back to the moon to hear about LCROSS. I caught the tail end of a talk about the Lyman-alpha Mapping Project (LAMP) on LRO. This instrument uses the light emitted by hydrogen in stars to illuminate the dark craters on the moon, which is a really cool idea. Interestingly, the permanently shadowed craters look “dark”, implying that they contain something (ice) that absorbs UV light. LAMP also saw the plume kicked up by the LCROSS impact, and detected hydrogen emission, as well as, oddly enough, mercury (Hg) emission. Apparently, Mercury is volatile enough that over geologic time it also gets concentrated in shadowed craters. Future astronauts drinking the moon’s water will have to watch out for mercury poisoning!

Tony Calprete gave a nice overview of the LCROSS mission. He explained that the reason the plume wasn’t visible from earth was because they ended up selecting a crater that was known to have hydrogen, since LRO was going to be positioned to get good observations from orbit. He showed some of the spectra recorded by various instruments, which had evidence for all sorts of good stuff, including H2O, CO2, methane (CH4), SO2, ammonia (NH3), H2S, and even a couple of mystery lines that some people on the team think might be gold! (There’s gold in them thar hills?)

A second LCROSS talk by Peter Schulz focused on the cratering process. The most interesting aspect was the effect of a hollow projectile (such as the big empty centaur rocket used as the LCROSS impactor) on the plume behavior. It turns out a hollow projectile causes the crater ejecta to form a higher plume that spreads out less. He also pointed out that the reason the LCROSS impact did not look like the Deep Impact plume was because deep impact was a very high speed impact into a low-gravity object with a solid projectile, while LCROSS was a slow hollow impactor hitting a body with significant gravity.

Stay tuned for the Day 3 post, which will include some particularly interesting sessions about Venus and astrobiology and society!

Big Picture HiRISE Gallery!

November 6, 2009

Speaking of Mars art, the Big Picture blog (which all of you should be following by now) has a feature on images of Mars taken by HiRISE. Head on over and take a look. Mars is a really pretty and often bizarre-looking place.

[PS – Have you voted today?]


Mars Art: Mind-blowing Swiss Cheese

November 6, 2009

First of all, a reminder to go vote on my article about MSL, which is a finalist in the science writing competition.

Ok, done? Good. I wanted you to do that before I showed you this image because it may very well break your brain. This is a HiRISE image of the so-called “swiss cheese” terrain at the south pole of mars. The terrain is formed by the sublimation of CO2 ice, which forms weird rounded pits. Yes, the round things in this picture are pits.The smooth parts are mesas and the illumination is from the lower right. Pictures like this always make my brain hurt because for some reason I want to see the round depressions as bulges! And if you think this is bad, try watching a scientific presentation with dozens of pictures like this, with varying orientations and illumination angles. I rarely get anything out of Mars south pole talks because my brain is so busy struggling to see the images properly.


Believe it or not, illumination is from the lower right in this image. Click the image to go to the HiRISE page and check out the full sized versions.

New Photos of Stuff on Other Worlds

October 29, 2009

I always make the mistake when on vacation of taking too many pictures of scenery and not enough pictures of people. Years down the road, the most interesting photos are not landscapes, but the ones that we can look at and say “I remember when we did that!”. And that’s why I think it’s great that we now have cameras around the Moon and Mars that can do the same. LROC at the moon has been able to take some spectacular photos of the Apollo landing sites, including a new one shown below. HiRISE at Mars has been able to take photos of the Mars rovers, Viking landers, and more recently the Phoenix lander.

Phoenix went silent as northern Martian winter crept in, covering it with CO2 frost, but the latest HiRISE image, taken in the spring, shows an ice-free Phoenix! It probably won’t wake up again, but it’s good to see our lander again. The spring images are somewhat grainy because the sun had just peeked above the horizon and light levels were very low. Emily Lakdawalla has a post with more information about this and other HiRISE images of Phoenix.


Credit: NASA / JPL / UA / animation by Emily Lakdawalla

If it’s fun to see our robots again, it’s even cooler to see evidence of humans landing on the moon. Now that LRO is in its final orbit around the moon, it is returning some really excellent photos of the Apollo landing sites, including this new one of the Apollo 17 site. You can even see the flag! For more information and closer views, check out the LROC site.


This high-resolution view of the Apollo 17 landing site shows details as small as the flag! Click to go to the LROC site for higher-resolution versions.

Mars Art: HiRISE Dust Devils and Dusty Dunes

October 15, 2009

It’s been a while since I posted any “Mars art” but I just came across this Bad Astronomy post and had to share. The short explanation of the photo is that dust devils spiraling across these sand dunes have removed the red dust but left behind dark sand in artistic swirls. For a more detailed description, check out Bad Astronomy, and to take a closer look at the image itself, head on over to the HiRISE site.


Surreal-looking HiRISE Picture of the Day

June 25, 2009


I don’t have time to write a full post since I am busy trying to get a presentable outline of my PhD thesis prepared to show to my committee next week. So in the mean time, enjoy this beautiful and bizarre HiRISE image of defrosting terrain on Mars. Click the image or this link to go to the HiRISE page and see the full version.

Pretty Dunes in Gale Crater

April 27, 2009

These dunes and ripples share a valley with an anceint, infilled channel on the mound of sediment in Gale Crater, near the end of the proposed MSL traverse. They are especially striking because they are made of dark volcanic sand, mixed with light-toned sand from the sediments filling the channel.

These dunes and ripples share a valley with an ancient, infilled channel on the mound of sediment in Gale Crater, near the end of the proposed MSL traverse. They are especially striking because they are made of dark volcanic sand, mixed with light-toned sand from the sediments filling the channel.

This is a tiny subframe from the HiRISE image PSP_009294_1750.

LPSC 2009: Day 2

March 28, 2009

Day 2 was all about ice in the mars sessions: the morning focused onĀ  the polar caps and the afternoon focused on the subsurface. I also managed to catch a few non-mars talks.

One of the first talks I saw was by Ken Tanaka, famed for his geologic maps of Mars. He showed the results of his studies of the north polar cap, and identified at least two major hiatuses. The official geologic definition of hiatus is: “A cessation in deposition of sediments during which no strata form or an erosional surface forms on the underlying strata; a gap in the rock record.” Tanaka showed examples of locations that demonstrate the different ages of layers, but the main take-home message of his talk was that most of the time, things are not being deposited on the polar cap.

HiRISE color view of defrosting sand dunes. The dark streaks are locations where the ice is gone and the dark sand grains are able to blow across the icy dune surface.

HiRISE color view of defrosting sand dunes. The dark streaks are locations where the ice is gone and the dark sand grains are able to blow across the icy dune surface.

Ken Herkenhoff gave an interesting presentation about HiRISE observations of active processes at the poles. He emphasized that there are many processes that they will understand better after another year of repeated observations, but still had some interesting results. He talked about active streaks in gullies and the strange fans and spots that form on defrosting dunes. Interestingly, these spots tend not to form on the base suface beneath the dines, implying that the material underneath the ice has to be mobile enough to blow around once the ice is partially removed.

HiRISE also observed avalanches in action on the north polar cap! As ice begins to thaw in the spring, debris from the ice cap can come loose and cause an avalanche. These are apparently pretty common, because multiple avalanches were actually caught in action in the same image!

An avalanche in the Martian arctic caught in action.

An avalanche in the Martian arctic caught in action.

Finally, Herkenhoff showed a picture that apparently has everyone baffled. There are lots of streaks seen on the polar cap, but some like the ones in the following image don’t make much sense. It looks like most of the streaks in the image are going down-slope, so you might think they were formed by small avalanches of dust or something. But why do they have such sharp edges? And, more importantly, why are some of them diagonal compared to the rest?!

Strange streaks on the north polar cap. Nobody knowsh why these have such sharp edges, or why one of them is diagonal.

Strange streaks on the north polar cap. Nobody knows why these have such sharp edges, or why some of them are diagonal.

I darted out of the Mars talks just in time to catch an interesting Enceladus presentation by Sue Kieffer. She took a look at the thermodynamics of warm ice in a vaccum and believes that the ratio of ice to water vapor in Enceladus’ famous plumes is half of what was originally reported. Kieffer claimed that the original calculation made a faulty asumption about the range of particle sizes in the plume, which led to a very different estimate. Why is this a big deal? Because it turns out that Kieffer’s calculations fit much better to sublimation than boiling liquid water! Enceladus might not have liquid water at its pole, it might just have warm ice! I’m sure the icy moons community will be looking into this some more and trying to figure out which calculation is correct as soon as possible. It would be really cool if we could prove that there’s liquid water on Enceladus, but the universe doesn’t care what we think is cool, so maybe the little moon is just a warm ice-ball.

The plume of ice and vapor coming from Enceladus' south pole has caused quite a stir, but one talk this year suggested that it could be formed without any liquid water.

The plume of ice and vapor coming from Enceladus' south pole has caused quite a stir, but one talk this year suggested that it could be formed without any liquid water.

Finally, I saw Steve Wood give a really interesting talk in the afternoon about atmospheric collapse on Mars and its effects. Mars’ tilt changes over millions of years, and occasionally it decreases to the point that the global temperatures drop, and CO2 from the atmosphere is dumped on the surface in a thick layer. This talk considered what that blanket of CO2 would do the the martian subsurface and concluded that it would indeed act as a blanket. CO2 ice has a lower thermal conductivity than rock, so the ice and icy soil would act to trap the geothermal heat of the planet, and might cause a subsurface warming of 20 degrees: enough to melt ground ice and drive off the water from some hydrated minerals. This is a really interesting effect and I had never heard of it before!