Orbital images from Mars Reconnaissance Orbiter have confirmed that the mysterious rock that appeared near Opportunity was not ejecta from a nearby meteorite impact.

Orbital images from Mars Reconnaissance Orbiter have confirmed that the mysterious rock that appeared near Opportunity was not ejecta from a nearby meteorite impact.

The scientists theorized that there was a very remote chance that a nearby impact has thrown the rock into place, but the images show nothing nearby. Moreover, if there had been an impact we probably would have seen more rocks raining down all around. The images are further confirmation that the rock was kicked up by the rover itself as it rolled along.

Mars Reconnaissance Orbiter spots a new crater on Mars.

Mars Reconnaissance Orbiter spots a new crater on Mars.

The scar appeared at some time between imaging of this location by the orbiter’s Context Camera in July 2010 and again in May 2012. Based on apparent changes between those before-and-after images at lower resolution, researchers used HiRISE to acquire this new image on Nov. 19, 2013. The impact that excavated this crater threw some material as far as 9.3 miles (15 kilometers).

In celebration of the 10th anniversary of the launch of Opportunity, Mars Reconnaissance Orbiter took its photograph.

In celebration of the 10th anniversary of the launch of Opportunity, Mars Reconnaissance Orbiter took its photograph.

The image was not merely for PR. It also provides the scientists operating Opportunity some good information about the region the rover is exploring, thus helping them plan out its further adventures on the surface of Mars.

The Mars Reconnaissance Orbiter team today released a set of images showing Curiosity’s recent travel on Mars, as well as some fascinating closeups of the spacecraft’s heat shield, parachute, and descent stage.

Curiosity's first steps

The Mars Reconnaissance Orbiter team today released a set of images showing Curiosity’s first steps on Mars, as well as some fascinating closeups of the spacecraft’s heat shield, parachute, and descent stage. The image on the left shows the tracks of the rover during its first few days of travel.

Scientists have found more evidence that the streaks on Martian hillsides that darken in warm weather are caused by melting groundwater flowing downhill.

Liquid water on Mars! Scientists have found more evidence that the streaks on Martian hillsides that darken in warm weather are caused by melting groundwater flowing downhill.

Last summer, the team pointing the HiRISE camera on the NASA Mars Reconnaissance Orbiter (MRO) dropped that bombshell: it had identified 7 confirmed and 12 likely sites that contained hundreds of narrow streaks on steep slopes inside crater walls. During warmer seasons, as temperatures rose as high as 27 degrees Celsius, the streaks darkened, and then faded again. Salts could allow brines to be liquid at these temperatures. Today at the Lunar and Planetary Science Conference in The Woodlands, Texas, the HiRISE team announced that it now has doubled it stash of streaks, with the identification of 15 confirmed and 23 likely sites, all in the mid-latitudes of the Southern Hemisphere.

Additional analysis of the spectrographic data also suggests that water could be the cause of the darkening.

What is this stuff?

What is this stuff?

The uncertainty of science: In this week’s release of images from Mars Reconnaissance Orbiter, the science team posted the image on the right and asked, “What is this stuff?”

Here’s a hypothetical geologic history that might explain this scene: layered sediments were deposited by water or airfall (including volcanic pyroclastics). A crudely polygonal patterned ground was created by stresses in the sediments, and groundwater followed the fractures and deposited minerals that cemented the sediments. This was followed by perhaps billions of years of erosion by the wind, leaving the cemented fractures as high-standing ridges.

Of course, this story is almost certainly incomplete if not totally wrong.

Click here to see the close-up subimage from which I cropped the image on the right.

A big sideways slip on Mars

Mars Reconnaissance Orbiter today released an image of a really spectacular transform fault on Mars, a spot where the ground cracked and two sections moved sideways to each other. In this case, the sideways movement was about 300 feet. The image is posted below the fold.

Compare that with the Japanese magnitude 9 earthquake on March 11, which only shifted the seabed sideways 165 feet while raising it 33 feet. The quake that moved these two pieces of Martian bedrock sideways must have been quite a ride.
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The Winds of Mars

changing martian dunes
Images taken 1363 days apart.

In two different papers published in two different journals in the past month, scientists have concluded that — despite the thinness of the planet’s atmosphere — the dunes and sands of Mars are being continually shaped and changed by its winds. In both papers the data from which this conclusion was drawn came from high resolution images taken by the HiRISE camera on Mars Reconnaissance Orbiter.

What is especially interesting about this conclusion is that the climate models that had been developed for the Martian atmosphere, combined with wind measurements gathered by the various Martian landers, had all suggested that the kind of strong winds necessary to move sand were rare. To quote the abstract of the paper published on Monday in the journal Geology, Bridges, et al,

Prior to Mars Reconnaissance Orbiter data, images of Mars showed no direct evidence for dune and ripple motion. This was consistent with climate models and lander measurements indicating that winds of sufficient intensity to mobilize sand were rare in the low-density atmosphere.

Similarly, the second paper, Silvestro, et al, published on October 22 in Geophysical Research Letters, stated that

results from wind tunnel simulations and atmospheric models show that such strong wind events should be rare in the current Martian atmospheric setting.

Yet, both studies found significant evidence that such winds do occur on Mars, and are moving sand in many different places.
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Catching an avalanche on Mars, as it happens

The Mars Reconnaissance Orbiter team today released this really cool image from Mars, showing an avalanche near the North Pole, in progress. The image looks directly down the cliff face from above. At the base of the cliff we can see the dust cloud from the crash of material billowing out away from the scarp.

What impresses me most about this image is that it was taken by an orbiting spacecraft approximately 200 miles above the planet’s surface, moving at thousands of miles an hour. Yet, the camera not only had the resolution to see the cloud of dust, it could snap the image fast enough to capture the actual fall of material (the white wisps down the side of the cliff that are reminiscent of a waterfall).

Also intriguing is the visible steep face of the cliff face itself. I know a lot of rock climbers who would love to literally get their hands (and chocks) on that rock face. And in Mars’s one-third gravity, rock climbing would surely be different.

avalanche on Mars

The rover Opportunity as seen from Mars orbit

Opportunity on Endeavour Crater rim

The image to the right was taken by Mars Reconnaissance Orbiter, with the white arrow showing the Mars rover Opportunity perched on the rim of Endeavour Crater.

The rover’s scientists hope that the rocks found on the crater rim, dredged up from deep below when the crater impact occurred, will be the oldest rocks so far touched on the Martian surface, and thus give them a peek at ancient Martian geology.

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