Archive for the ‘MRO’ category

AGU Day 3: MRO

December 18, 2008

A long walk to Circuit City and a few dollars later, I am now the proud owner of a new AC adaptor! Luckily today is all posters so I have some time to post a summary of yesterday’s events.

Yesterday was a day chock full of Martian goodness, and it started off bright and early with a summary of the results from the Mars Reconaissance Orbiter’s primary mission. MRO has returned about 74 terabytes of science data to earth, which is more data than all the other Mars missions EVER combined.

The Context Camera (CTX) has mapped 40% of the surface of Mars at a resolution of 6 meters per pixel, which just boggles my mind. That used to be “high resolution” data, but now it’s just context for HiRISE and CRISM. Some of the highlights from CTX include the discovery of dozens of fresh craters from impacts that occured during the mission, and CTX images show that much of the Martian surface is cris-crossed with “inverted” channels. These form because at the bottom of a river, larger rocks tend to collect. Then when the river dries up and the terrain erodes, the river-bottom is “armored” by those rocks, so it resists erosion and becomes a ridge instead of a trough. CTX can also be used to make 3D anaglyphs, like this (scaled-down) one of the Gale crater landings site and traverse, which I have been studying. The full mosaic that I’m using is made up of a dozen or so CTX images and is about 40,000×40,000 pixels!

p18_008147_1749_xn_05s222w_080422__p16_007356_1749_xi_05s222w_080220_anaglyph3

CRISM has mapped 63% of the surface at low (200 m per pixel) resolution, plus thousands of high-res observations. They have found evidence for hydrated minerals all over the place (though often in very small outcrops). These include the famous phyllosilicates (clays), sulfates, hydrated silica, and even some of the elusive carbonates (though not enough carbonate to explain where the thick CO2 atmosphere went).

HiRISE reported that they have taken 9549 images, and a grand total of 8,212 gigapixels of data. I was especially interested by their report that some fresh craters at mid-latitudes seem to have punched through the rocky, dusty surface and uncovered ice!  They are pretty sure it is ice because in the biggest craters it shows up in CRISM, and it fades over time as you would expect for sublimating ice.

SHARAD, the radar sounder reported their mapping of the ice caps, including the puzzling fact that despite the huge amount of ice, the crust doesn’t seem to be bowed down, indicating that Mars has a colder and thicker crust than expected. SHARAD also was recently in the news for proving that there are icy glaciers on Mars. They also showed that some things that people thought were ice are actually not, such as this image from Cerberus Palus:

Radar sounding shows that this is not ice

Radar sounding shows that this is not ice

MARCI, the fisheye lens that maps the entire Martian surface every day and acts as a weather satellite on Mars has been used to warn the rover team of approaching dust storms and has been very valuable for studying the repeated weather patterns on Mars. Also, Jim Bell presented some of the stuff that I have been helping him with, making maps of the surface with MARCI images, and videos of changes such as the dust streaks in Gusev crater.

A MARCI mosaic of Valles Marineris that I made.

A MARCI mosaic of Valles Marineris that I made.

A movie of the changing dust streaks at Gusev crater. The numbers are Ls, which indicates season (0 is northern spring, 180 is northern fall)

A movie of the changing dust streaks at Gusev crater. The numbers are Ls, which indicates season (0 is northern spring, 180 is northern fall)

I think I will stop there for now, and go actually attend the conference some more. I have more to report from yesterday’s afternoon session though, so I’ll post that later.

Mars Art: Dunes in Abalos Undae

November 24, 2008

This week’s Mars Art is a HiRISE view of Dunes in Abalos Undae. Pictures of sand dunes taken by HiRISE never get old for me. There is something about the undulating, regular shapes of dunes that is fascinating and beautiful and peaceful. There is a great quote about dunes in the book “Physics of Blown Sand and Desert Dunes” by R.A. Bagnold that goes on quite poetically about them, but unfortunately I don’t have it close at hand. Consider this an IOU. which Briony has posted below! Meanwhile, enjoy the picture, and read more about it here.

psp_010219_2785_irbnomapbrowsecrop

Update from Briony: Here’s an awesome Bagnold quote, hopefully the one that Ryan was referring to:

In places vast accumulations of sand weighing millions of tons move inexorably, in regular formation, over the surface of the country, growing, retaining their shape, even breeding, in a manner which, by its grotesque imitation of life, is vaguely disturbing to an imaginative mind.
~ Bagnold (1941)

More About Mars Glaciers

November 23, 2008

I posted previously about the announcement that buried glaciers had been discovered on Mars, but now I’ve had time to actually take a look at the article in Science. The important point of the article is not that these formations were discovered (we’ve actually known about them for some time) but that, using radar on the Mars Reconaissance Orbiter, scientists were able to penetrate the surface of these mysterious glacier-looking things and prove that they are mostly ice!

You may be wondering how you could have a big, lobate, flowing tongue of stuff that isn’t mostly ice. Well, all you need is something viscous to flow. A pile of rocks, with just a tiny bit of ice holding them together and lubricating the flow can mimic the shape of a glacier of pure ice. Conveniently enough, I got interested in these last year when I was taking a geomorphology class, and found some pictures of terrestrial examples in the Andes with Google Earth:
cerro-catedral-rock-glacier

You can see the lobate flows oozing their way down from the peaks, but in this case, you’re looking at something that is almost entirely rock. Many people thought that the glaciers that people were seeing on Mars were similar, but there was no way to test this until MRO got there with its radar sounder, SHARAD. Radar waves bounce off of rock, but are quite good at penetrating ice. So, when MRO flew over the glaciers, the scientists bounced radar off the glaciers and saw this:

sharad_glaciers

This shows along the top what the surface would look like if it was just made of rock, and then it shows the actual data below. You can see that the lobes of “stuff” have a radar reflection at their surface, but some of the radar penetrates and bounces off of another boundary beneath the surface. This is showing that some of the radar reflects off of the surface but some travels down through the ice until it hits solid ground underneath. Rock glaciers wouldn’t do this, but glaciers of almost pure ice would!

The paper has a very nicely written concluding paragraph that I will post here, with slight annotations. It explains why the glaciers are there and why they are significant:

Why would such large quantities of snow and
ice accumulate in the eastern Hellas region in
particular? Over time scales of millions of years,
Mars undergoes large changes in spin-axis obliquity (tilt), forcing changes in insolation (sunlight energy that reaches the surface), and hence
in climate and the subsequent distribution of
ice. Climate simulations performed with
a model that includes the current water cycle but
assumes an obliquity of 45° predict snow accumulation
in the eastern Hellas region from a
south polar water source that operates efficiently
at the southern summer solstice, when the southern
polar cap releases large amounts of water
vapor. This vapor moves northward and is deflected
by cold air moving southward from the
Hellas basin; the subsequent cooling causes strong
condensation and precipitation in the area of the
LDAs (Lobate Debris Aprons), which we have shown to contain
primarily water ice. We therefore conclude that
these deposits harbor large quantities of water ice
derived from high-obliquity epochs, now concealed
beneath a thin protective layer. This ice
survives from climatic conditions markedly different
from today’s and is potentially accessible
to future landed missions, not only for scientific
study but as a resource to support exploration.

Buried Glaciers on Mars!

November 21, 2008

Gosh, why are there so many news articles about Mars when I’m busy? Here’s the press release, and Bad Astronomy and Universe Today have both weighed in, so I’ll let you read them. Here’s a picture of a Martian glacier:
glacier

Plumbing on Mars: HiRISE Reveals Groundwater Cracks

September 26, 2008

This image from the HiRISE camera on the Mars Reconaissance Orbiter, shows cracks in the rocks on Mars that once formed the underground plumbing through which groundwater traveled.

Groundwater flow on Mars has been speculated for a long time, but it takes powerful cameras like HiRISE to actually find the evidence. These cracks resisted erosion because they were filled with minerals deposited by groundwater, so now we can see them as positive relief.

From the press release:

“This study provides a picture of not just surface water erosion, but true groundwater effects widely distributed over the planet,” said Suzanne Smrekar, deputy project scientist for the Mars Reconnaissance Orbiter at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Groundwater movement has important implications for how the temperature and chemistry of the crust have changed over time, which in turn affects the potential for habitats for past life.”

Too bad we didn’t find these a year ago so they could be considered as an MSL landing site…

How to Look at Mars

August 20, 2008

There is so much Mars data out there that it hard to keep track of all of it! Thankfully there are some useful tools that let anyone look easily look at orbital data of anywhere on the planet.

The first is a program called “jmars“. This java-based program distributed by Arizona State University lets you overlay all sorts of global datasets, from MOLA topography to THEMIS nighttime infrared maps to H2O abundance from the Odyssey gamma ray spectrometer. It also shows the location of high-resolution images from MOC, HiRISE and CTX, and lets you either load a low-resolution version of the images right in jmars, or click a link and web-browse to a higher-resolution version. I use this program all the time. Here’s a screenshot of what I’m (supposed to be) working on right now. It shows a THEMIS day-IR map of the Meridiani region of Mars with CTX images overlaid on top and outlines of the locations of all the HiRISE (red) and MOC (pink) images of the area. (click for a bigger version)

I also discovered yesterday that you can generate a 3D view of Mars with jmars also! Check out this view of Valles Marineris (no vertical exaggeration).

The second tool that I often use is Google Earth. “But wait!” you say, “I thought we were talking about Mars!” Oh, we are. The trick is, you just drape earth in Mars data and everything works great! Here’s a link to a website describing how to set up Google earth to display all sorts of Mars data. Follow the directions and soon you too can click and zoom on a globe that looks like this:

Have fun!

New insights into ancient water on Mars

July 17, 2008

The evidence for a warmer, wetter ancient Mars just keeps piling up! In 2 new papers, the team for the CRISM spectrometer onboard NASA’s Mars Reconnaissance Orbiter has reported new evidence for water on the surface of ancient Mars, based on the ubiquitous presence of water-bearing minerals.

Universe Today has a great post up on the findings, so I won’t repeat too much of Nancy’s explanation.

In brief, the CRISM team has identified a whole new suite of minerals on Mars, in addition to a few already observed, that only form with copious amounts of water. While some of these minerals are associated with local deposits that look like sedimentary layers set down by surface water, others seem to be present across vast regions of the ancient southern highlands. In particular, the minerals tend to be associated with the ejecta, floors, and central peaks of craters in the ancient terrains. Because the impacts probably dug up the minerals from several kilometers down in the crust, the crust must have been altered by water to at least that depth. For example, the image below shows where CRISM has detected phyllosilicates (a hydrated clay mineral) in one region of the highlands. Because almost every crater has a phyllosilicate detection, the basement material has probably interacted with water throughout this region.


Mustard et al. (2008), Figure 4a

We tend to think of “Mars” as one place with a history that can be described by one storyline, even though Mars is a whole planet with as much surface area as dry land on Earth. What’s really great about these findings is that they really bring home that the surface of Mars probably had just as many different environments as Earth does now. Mars scientists have used the composition of minerals and their geologic context to identify ancient hydrothermal springs, shallow seas, lakes, and floods on Mars. With all of these different environments, life very well may have been able to eke out an existence in one of them…

Dust Devils at the Phoenix Landing Site

May 7, 2008

It’s finals week in Cornell-land, so I apologize for the lack of posting. As always, I will sate your appetites with a picture. This time, it is an image from the context camera (CTX) on the Mars Reconnaissance Orbiter, showing giant dust devils near the landing site for Phoenix. Coolness! Phoenix is landing on May 25 (only 18 days left!), and will probably be able to catch a glimpse of dust devils like these from the ground. Emily has more thoughts on this over at the Planetary Society blog.

It’s a good camera…

March 4, 2008

It’s a busy week. All three of us are preparing to go to the Lunar and Planetary Science Conference next week and show off our research, which means that we have to make our research look good enough to show off. It’s a good thing the HiRISE team keeps releasing fantastic images so that I have something to post until we get to the conference. (we will be blogging about the conference as much as possible… stay tuned!)

Check out this picture. That’s the Earth and the Moon, as seen from Mars by the HiRISE camera. As you can see, that is a mighty fine telescope. Click the picture to learn more…

psp_005558_9040.jpg

Avalanches on Mars!

March 3, 2008

Check. This. Out. The HiRISE camera caught avalanches in action near the north pole of Mars. It’s spring right now, and the ice is thawing. That means that the polar layers are becoming unstable as the ice sublimates away, which leads to avalanches. What is awesome is that in this image, they caught more than one avalanche happening at the same time, implying that these things are super-common!

psp_007338_2640.jpg