Archive for the ‘MRO’ category

Mars Polar Cap Mystery Solved

May 26, 2010

If you’ve ever seen a picture of the north polar cap of Mars, you’ve probably wondered why it has those spiral troughs in it. Until recently, you would be in good company: it’s a question that has been plaguing scientists for 40 years. But it has finally been solved! Go check out my new article at Universe Today to find out more!

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…

Putative “recent” lakes on Mars

January 5, 2010

I have a new article up at Universe Today about the discovery of possible lakes on Mars as recently as 3 billion years ago. I’m skeptical of the conclusion because there are a lot of uncertainties in crater age-dating on Mars, and the whole argument hangs on the discovery of small channels between pits that are supposedly due to flowing water, but it’s interesting nonetheless.

Stay tuned, I have more Universe Today articles on the way this week!

AGU 2009 – Day 1

December 16, 2009

For those not familiar with the conference, the fall meeting of the American Geophysical Union is a terrifyingly, overwhelmingly large conference. Each year, something like 16,000 geoscientists descend on San Francisco to share their work. It is also one of the major planetary science conferences, so a lot of new results are first presented here.

Moscone Center in San Francisco. This building is filled with science at every fall AGU meeting.

This year, the first talks that I checked out on Monday were about radar observations of Mars. By sending radar waves from spacecraft to the surface and then recieving the reflected waves, we can learn a lot about Mars. In particular, since radar penetrates tens to hundreds of meters below the visible surface, it can reveal otherwise hidden structures. This has been especially successful at mapping the structure of the polar caps, because radar penetrates through ice quite well.

Roger Phillips gave a talk summarizing some of the results from the SHARAD radar instrument on MRO. Among other thers, SHARAD has found evidence that the spiral troughs in the north polar ice cap have migrated over time, as predicted many years ago by theoretical models. SHARAD has also found ancient buried canyons in the polar ice, which menas the ice caps have been around for quite a while. There are also some exiting new results implying that the material filling valleys in the Deuteronilus Mensae area is quite transparent to radar waves, and might in fact be something like glacier ice.

Image credits: NASA/ESA/JPL-Caltech/ASI/University of Rome/University of Washington St. Louis

After the radar talks, there were a whole bunch of presentations about aqueous alteration on Mars. One of the main lessons that I took away from those talks was that Mars is still a very confusing place. For example, Hap McSween used data from the Mars rovers and characterized typical soils at both landing sites. He found that the compositions of soils are roughly 70% unaltered material and 30% alteration products. He also showed that the soil compositions are quite similar between the two landing sites, which are on opposite sides of the planet, and that the unaltered portion of the soil is similar to the rocks at both sites.

However, the next talk by Josh Bandfield used orbital data and found that in general rocks on Mars have more of the mineral olivine than the soils. This is a somewhat different result than the rover data, and it might imply that rocks on Mars actually have more magnesium and iron than previously thought.

Other talks related to Mars alteration focused on “clay” and sulfate minerals detected on Mars. One that I found particularly interesting was by Paul Niles, who pointed out that Mars is an “obliquity-driven” planet. In other words, its tilt varies widely, and the Mars we see now is not typical. Niles suggested that during more typical periods, ice might have formed large layers at Mawrth Vallis, a location known for its strong hydrated mineral features. Melting at the base of that ice could have leached the rocks, explaining the presence of specific Al-bearing clay minerals.

Map of water-bearing minerals at Mawrth Vallis. Image credit: ESA/OMEGA team

Another interesting talk was by Itav Halevy, who took a look at how the presence of SO2 gas influences the formation of carbonate minerals. It turns out, even a tiny amount of SO2 gas (which is often released by volcanoes) can prefent the formation of CaCO3. If there is iron around, FeCO3 (the mineral siderite) forms instead. The implication is that sulfur minerals should form in different locations than clay minerals and siderite.

Continuing with the sulfur theme, Albert Yen talked about some results from the Spirit rover. He said that basically, if the rover had to get stuck, it picked a really fascinating place to do it! Based on the compositions measured, it turns out that there is too much sulfur in the soil to balance it out by assuming it is combined with other elements like Fe and Mg. That means there might be pure elemental sulfur mixed in with the soil, which would be consistent with hydrothermal activity!

My officemate and occasional contributor here at the Martian Chronicles, Briony Horgan, also gave a nice talk summarizing some of her recent work. For a long time there has been a question about the so-called “surface type 2” on mars. This surface type has higher than usual Si, but that could be due to a different type of lava, or alteration of the more common basalt seen elsewhere on Mars. Briony presented new evidence, based on the overall shape of the spectra of surface type 2 regions, that these areas might be due to a silica glass coating! This sort of coating could form when thin films of water from thawing ground ice altered the surface of sand grains, and would imply relatively recent alteration processes on mars.

Finally, the day ended with the Whipple prize lecture, which was unfortunately full of some misleading information about the history and status of Mars science. But that’s the topic for a future post.

Be a Martian!

November 17, 2009

Fact #1: As a Mars scientist, I am incredibly spoiled. There are so many missions to Mars right now sending back so much data, that even if they all went silent tomorrow, it would be decades before we managed to look at all the data and figure out what it’s telling us.

Fact #2: There are lots of people out there (I’m looking at you, loyal readers!) who would love to be able to actively participate in exploring Mars. I mean, have you seen the stuff that the folks at UnmannedSpaceflight have managed to put together? They do more with the data from Mars than a lot of scientists!

So, given those two facts, you can see why I think the new “Be a Martian” collaboration between NASA and Microsoft is a great idea. Check out this excerpt from the press release:

Drawing on observations from NASA’s Mars missions, the “Be a Martian” Web site will enable the public to participate as citizen scientists to improve Martian maps, take part in research tasks, and assist Mars science teams studying data about the Red Planet.

“We’re at a point in history where everyone can be an explorer,” said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. “With so much data coming back from Mars missions that are accessible by all, exploring Mars has become a shared human endeavor. People worldwide can expand the specialized efforts of a few hundred Mars mission team members and make authentic contributions of their own.”

How cool is that? It’s a really brilliant idea, and I hope it goes well. A similar project was pioneered by galactic astronomers who had way too many pictures of galaxies to deal with, so they opened up the database to the public in the form of GalaxyZoo. It was a tremendous success, with thousands of people helping to classify millions of galaxies.

I just created my account and played around a bit, and it looks like a very user-friendly introduction to Mars science. You can contribute in two main ways: aligning images to contribute to a global map, and also counting craters. Both of these tasks can sort of be done by computers, but humans will always be better.

There’s more to the Be a Martian site than just work though, there are also lots of goodies like videos and Mars wallpapers, and great information about Mars. There is even a “movie theater” where you can watch the first few episodes of a series of videos called “The Martians”, that focus on people from all over the country who are involved with Mars, ranging from members of the rover teams to enthusiastic amateurs to actors putting on a play about Mars! There are more episodes on the way, and I encourage you to keep watching… you might see someone you recognize. ;)

Bottom line, it looks like a great site, and a great way to get involved in Mars exploration and learn about everyone’s favorite Red Planet and the people who are fascinated by it. What are you waiting for? Head on over and sign up! I’ll see you on Mars!

 

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 scientificblogging.com 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.

ESP_014379_0925

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.

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.

Watching out for Dust Storms

April 15, 2009

NASA just sent out this press release discussing the various ways that we watch out for dust storms that might be dangerous to the rovers. I have actually used data from the Mars Color Imager (MARCI) that they mention in the release, but I used it for the exact opposite task! I wrote programs that search through the images taken by that camera (there are a lot of them, it gets global coverage every day!) over a certain timeframe and choose the least dusty ones. This is useful for removing the effect of the atmosphere and tracking changes on the surface: for example, if I run my program before and after the huge dust storm in 2007, you can see the wind streaks in Gusev crater changing.

Anyway, here’s the NASA press release. You may also be interested in Emily’s post about recent dust activity on Mars.

PASADENA, Calif. — Heading into a period of the Martian year prone to major dust storms, the
team operating NASA’s twin Mars rovers is taking advantage of eye-in-the-sky weather reports.

On April 21, Mars will be at the closest point to the sun in the planet’s 23-month, elliptical orbit.
One month later, the planet’s equinox will mark the start of summer in Mars’ southern
hemisphere. This atmospheric-warming combination makes the coming weeks the most likely
time of the Martian year for dust storms severe enough to minimize activities of the rovers.

“Since the rovers are solar powered, the dust in the atmosphere is extremely important to us,” said
Bill Nelson of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., chief of the engineering team
for Spirit and Opportunity.

Unexplained computer reboots by Spirit in the past week are not related to dust’s effects on the
rover’s power supply, but the dust-storm season remains a concern. Spirit received commands
Tuesday to transmit more engineering data in coming days to aid in diagnosis of the reboots.

After months of relatively clear air, increased haze in March reduced Spirit’s daily energy supply
by about 20 percent and Opportunity’s by about 30 percent. Widespread haze resulted from a
regional storm that made skies far south of the rovers very dusty. Conditions at the rovers’ sites
remained much milder than the worst they have endured. In July 2007, nearly one Martian year
ago, airborne dust blocked more than 99 percent of the direct sunlight at each rover’s site.

The rovers point cameras toward the sun to check the clarity of the atmosphere virtually every
day. These measurements let the planning team estimate how much energy the rovers will have
available on the following day. Observations of changes in the Martian atmosphere by NASA’s
Mars Reconnaissance Orbiter, which reached Mars in 2006, and NASA’s Mars Odyssey, which
reached Mars in 2001, are available to supplement the rover’s own skywatch.

The Mars Color Imager camera on Mars Reconnaissance Orbiter sees the entire planet every day
at resolution comparable to weather satellites around Earth.

“We can identify where dust is rising into the atmosphere and where it is moving from day to
day,” said Michael Malin of Malin Space Science Systems, San Diego, principal investigator for
Mars Color Imager. “Our historical baseline of observing Martian weather, including data from
the Mars Global Surveyor mission from 1998 to 2007, helps us know what to expect. Weather on
Mars is more repetitive from year to year than weather on Earth. Global dust events do not occur
every Mars year, but if they do occur, they are at this time of year.”

Two other instruments — the Thermal Emission Imaging System on Mars Odyssey and the Mars
Climate Sounder on Mars Reconnaissance Orbiter — monitor changes in airborne dust or dust-
related temperatures in Mars’ upper atmosphere. Orbiters also aid surface missions with radio
relays, imaging to aid drive plans, and studies of possible future landing sites.

When orbital observations indicate a dust-raising storm is approaching a rover, the rover team can
take steps to conserve energy. For example, the team can reduce the length of time the rover will
be active or can shorten or delete some communication events.

In recent weeks, frequent weather reports from Bruce Cantor of Malin’s Mars Color Imager team
let the rover team know that the March increase in haziness was not the front edge of a bad
storm. “Bruce’s weather reports have let us be more aggressive about using the rovers,” said Mark
Lemmon, a rover-team atmospheric scientist at Texas A&M University, College Station. “There
have been fewer false alarms. Earlier in the mission, we backed off a lot on operations whenever
we saw a small increase in dust. Now, we have enough information to know whether there’s
really a significant dust storm headed our way.”

At other times, the weather reports prompt quick precautionary actions. On Saturday, Nov. 8,
2008, the rover team received word from Cantor of a dust storm nearing Spirit. The team deleted
a communication session that Sunday and sent a minimal-activity set of commands that Monday.
Without those responses, Spirit would likely have depleted its batteries to a dangerous level.

Winds that can lift dust into the air can also blow dust off the rovers’ solar panels. The five-year-
old rover missions, originally planned to last for three months, would have ended long ago if
beneficial winds didn’t occasionally remove some of the dust that accumulates on the panels. A
cleaning event in early April aided Opportunity’s power output, and Spirit got two minor
cleanings in February, but the last major cleaning for Spirit was nearly a full Martian year ago.

Nelson said, “We’re all hoping we’ll get another good cleaning.”

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars
Exploration Rovers, Mars Odyssey and Mars Reconnaissance Orbiter for NASA’s Science
Mission Directorate, Washington. More information about the rovers is at
http://www.nasa.gov/rovers .  Dust reports from the Thermal Emission Imaging System,
operated by Arizona State University, Tempe, are at http://themis.asu.edu/dustmaps/ . Weather
reports from the Mars Color Imager team are at
http://www.msss.com/msss_images/latest_weather.html .

The MOC Book: Polar Processes

February 28, 2009

I’m falling behind on my blogging of the MOC “book”! We read a lot this week, so I will just stick to the highlights. In other words: mostly pictures, less text. This paper is really all about the pictures anyway! (if you’re just tuning in to the MOC series, check out posts 1,2,3 and 4)

The Martian poles are extremely fascinating but extremely bizarre places. The polar caps are made of water and CO2 ice, and as that ice freezes and thaws, it forms some strange landscapes.

a) South polar "swiss cheese" terrain, formed by sublimating CO2 ice. b) North polar pitted terrain. It is not clear why the north and south pole look so different.

a) South polar "swiss cheese" terrain, formed by sublimating CO2 ice. b) North polar pitted terrain. It is not clear why the north and south pole look so different.

The north and south polar caps are very different-looking, and there is no good explanation for why. This image shows layers from the south and north polar cap. The southern layers are very rough and rugged-looking, while the north polar layers are much smoother.

a) Rough, rugged layers in the south polar cap; b) Very smooth layers in the north polar cap. These layers may reflect changes in the Martian climate driven by changes in the planet's tilt and orbital eccentricity.

a) Rough, rugged layers in the south polar cap; b) Very smooth layers in the north polar cap. These layers may reflect changes in the Martian climate driven by changes in the planet's tilt and orbital eccentricity.

The layers in the north polar cap are amazingly coherent. They can be traced for hundreds of kilometers in some places:

Layers in the north polar cap can be traced for hundreds of kilometers. Prior to MOC, it was thought that the polar cap layers were tens of meters thick, and could be explained solely by changed in the planet's tilt. The fact that these layers are so narrow indicates that there are higher-frequency changes contributing to layer formation.

Layers in the north polar cap can be traced for hundreds of kilometers. Prior to MOC, it was thought that the polar cap layers were tens of meters thick, and could be explained solely by changed in the planet's tilt. The fact that these layers are so narrow indicates that there are higher-frequency changes contributing to layer formation.

Not all of the polar layers are perfectly flat, though. There are some examples of layers that have been deformed, or which intersect with each other, implying that they were subject to tectonics and erosion between periods of deposition.

a) An "angular unconformity", implying that enough time elapsed for some of the layers to become tilted and eroded before the next set were depositied. b) Deformation implies that these layers have a complex history as well.

a) An "angular unconformity", implying that enough time elapsed for some of the layers to become tilted and eroded before the next set were depositied. b) Deformation implies that these layers have a complex history as well.

The paper had a lot of observations, but not many conclusions about the Martian poles. The poles are still not well understood, though missions like Phoenix and MRO are helping to shed some light on the mysterious processes that shape the polar regions.

New Google Mars

February 2, 2009

Google Earth’s latest edition was just released and guess what? It has a Mars setting! There was a way to overlay Mars data on the Earth globe in previous versions, but now that’s no longer necessary: just click a button and you’re on Mars. You can choose from a variety of global maps including topography, Viking images, Day and nighttime infrared, and visible color. It also has footprints for high resolution cameras like HiRISE, CTX, MOC, CRISM, and HRSC, with links to the full-resolution images. And most exciting, it has 3D topography! Now you can fly around in Valles Marineris or check out the view from Olympus mons.

The view from the edge of the Olympus Mons caldera in Google Mars.

The view from the edge of the Olympus Mons caldera in Google Mars.

Olympus Mons dominates the horizon in this Google Mars view.

Olympus Mons dominates the horizon in this Google Mars view.

Another way-cool feature is the ability to zoom into panoramas taken by rovers and landers, as shown here for Opportunity.

The Opportunity rover's traverse. Each camera icon is a panorama that you can zoom into.

The Opportunity rover's traverse. Each camera icon is a panorama that you can zoom into.

Part of the Rub al-Khali panorama taken by the opportunity rover.

Part of the Rub al-Khali panorama taken by the opportunity rover.

And finally, you can load selected Context Camera images right onto the globe, to take a high-res look at areas of interest, such as the Olympia Fossae troughs shown here. I don’t know what’ you’re waiting for: go download the program and try this out for yourself!

CTX image of the Olympia Fossae troughs.

CTX image of the Olympia Fossae troughs.