* Astronomy

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RE: Mars Dust Devil

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Research Helps Scientists Understand Dust Devils on Mars and Earth

"It's a bit of an art - learning how to drive across dry lake beds at great speed. And it can be quite hairy as well" - Matt Balme

During the next three years, Balme will spend a lot of time careening across playas and other open, desert areas to better understand dust devils on Mars - how much dust they lift into the atmosphere and how this affects the Martian climate.

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The University of Arizona-based High Resolution Imaging Experiment (HiRISE) group this week released a good look at a dust devil on Mars. This is not the storm bedeviling NASA's Mars Exploration Rovers, Spirit and Opportunity.
The HiRISE camera captured the dust twister by chance in its photographic swath of a region in the southern hemisphere near Hellas Planitia during a Martian mid-afternoon early last month. The HiRISE camera is orbiting the Red Planet on NASA's Mars Reconnaissance Orbiter.

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Credit NASA

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This image of a Dust devil on Gusev plain was taken by the Spirit rover on April 15th, 2007 (Sol 1166).

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Credit NASA

The left image was taken 188 seconds before the right image was taken. A Martian moon seems to be visible in both images.

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Global warming has hit Mars, but the planet's shifting winds and swirling dust devils that power climate changes there bear no relation to the heat-trapping gases that now concern the people of Planet Earth.
Researchers studying images of the Martian surface taken by generations of orbiting spacecraft have found that the planet's most prominent features have darkened and lightened in recent decades, altering the way sunlight reflects from its sandy soils, its rocky heights and its deep craters.
The result, say the scientists, is that the average global ground temperatures on Mars have risen by more than 1.5 degrees Fahrenheit during the past two decades, while the surface air temperature has risen by a little more than a degree in the same period.

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Martian Dust

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Martian dust may be hazardous

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RE: Mars Dust Devil

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The ambitious Viking missions to Mars, dispatched in the 1970s to search for life on the Red Planet, left a few puzzles for researchers to ponder, including a soil experiment that showed unmistakable signs of chemical activity.

Followup studies determined the triggering agent was, disappointingly, not organic matter. The mystery lay dormant for 30 years until recently when a team of scientists found proof of another interloper: Martian dust devils.
Whipped by strong winds, mini-cyclones of swirling dust regularly dance across the face of Mars, generating fields of static electricity as particles rub against each other and cast off positive and negative charges.
Scientists believe the electricity may produce reactive chemicals that build up in the Martian soil, a theory that would explain Viking's puzzling results.

"Our calculations indicate that once these electric fields are produced by dust storms on Mars, they free more electrons from atoms and molecules in the thin Martian atmosphere. These electrons then collide with and break apart molecules such as water and carbon dioxide, creating new chemical products that continue to react with other constituents in Mars' atmosphere" - Gregory Delory, a senior fellow at the University of California Berkeley Space Science Laboratory.

Delory and his colleagues then calculated how the broken molecules would recombine into reactive chemicals, such as hydrogen peroxide and ozone.
Over time, hydrogen peroxide would become so abundant that it would fall like snow onto the ground, permeating the soil, the researchers said.
The study, which appears in the current issue of Astrobiology, was based on field and laboratory experiments conducted over the past five years.

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The US space agency's rovers will get a software upgrade to allow them to make "intelligent" decisions in the study of Martian clouds and dust devils.

The new algorithms will give the robots' computers the onboard ability to search through their images to find pictures that feature these phenomena.
Only the most significant data will then be sent to Earth, maximising the scientific return from the missions.
Nasa says its robotic craft will become increasingly autonomous in the future.

"An instrument can acquire considerably more data than can be down-linked - this is a recurring theme on all spacecraft" - Rebecca Castano, from the agency's Jet Propulsion Laboratory (JPL).

"In the future, the capability will be there not just to patch flight software but to completely re-write it" - Ralph Lorenz, University of Arizona.

"The idea now is to collect as much data as the instrument can, analyse them onboard for features of specific interest, and then down-link only the data that have the highest priority" - Rebecca Castano.

Currently, the rovers are allocated time to look for clouds and dust devils, which may or may not appear - they are naturally transient events. And getting humans to sift the images is time consuming.
The software upgrade, due to take place in the next month, will make the whole process much more efficient.

"Clouds typically occur in 8-20% of the data collected right now If we could look for a much more extended time and select only those images with clouds then we could increase our understanding of how and when these phenomena form. Similarly with the dust devils" - Rebecca Castano.

Leaving the robots to "get on with it" - to do the decision-making - is the way ahead, Nasa believes.
The agency's Mars Odyssey orbiter, which has been mapping the Red Planet since 2001, will get new autonomous flight software later this year.
This will give the satellite the ability to react to sudden changes on the Martian surface. It will be "tuned" to look for temperature anomalies, rapid changes in the polar caps, the emergence of dust storms and the formation of water-ice clouds.
If its algorithms mark an event of interest, the spacecraft will be able to break into its routine and take more images, without waiting for commands from Earth.
Scientists say this will capture short-lived, but highly significant, events that might otherwise have been missed.
The approach has been pioneered on Nasa's Earth Observing-1 satellite, which has now made thousands of autonomous data collects since 2003.
A classic example was an eruption on Antarctica's Mt Erebus volcano in 2004. Typically, it could take several weeks to learn such a remote volcano had gone into an active phase; but as soon as EO-1 detected heat from the lava lake at the mountain's summit, it reprogrammed its camera to take more pictures.
The spacecraft also sent a rapid alert to volcanologists on the mission's science team.
So successful has EO-1's Autonomous Sciencecraft Experiment software been that it is now running the satellite's main science operations.

"This has helped us reduce the operations cost of this mission from $3.6m to $1.6m a year - over half that reduction was directly attributed to the onboard automation that we're talking about. That was critical in getting the mission extended. The approach has shown its worth and it is applicable to a wide range of future missions" - Steve Chien, principal investigator for autonomous sciencecraft at JPL.

Ralph Lorenz, from the University of Arizona, Tucson, works on the current Cassini-Huygens mission to Saturn and its moons. He was thrilled by the performance of the Huygens lander, which touched down on the ringed planet's largest satellite, Titan, in January 2005; and he is already thinking about a return flight some time in the next decade.
He said self-reliant spacecraft would open up new science opportunities on far-distant missions, where probes might be out of contact with Earth for hours or even days at a time.
Lorenz envisages the next craft on Titan to be a blimp that could fly itself around the moon and select the most interesting locations to set down to do investigations.

"It's important to note also that launch dates will no longer limit technological capabilities. We've seen how the Mars rovers are constantly being updated. To get to Titan, it will take about seven years, during which time we can improve and finesse the type of autonomous software we might apply. In the future, the capability will be there not just to patch flight software but to completely re-write it" - Ralph Lorenz.

Castano, Chien and Lorenz were explaining the latest developments in autonomous spacecraft operations here at the American Geophysical Union Joint Assembly.

Source BBC