Space

June 12, 2013

Marks on Martian dunes may reveal tracks of dry ice Sleds

nasa-mars
NASA research indicates† hunks of frozen carbon dioxide — dry ice — may glide down some Martian sand dunes on cushions of gas similar to miniature hovercraft, plowing furrows as they go.

Researchers deduced† this process could explain one enigmatic class of gullies seen on Martian sand dunes by examining images from NASA’s Mars Reconnaissance Orbiter and performing experiments on sand dunes in Utah and California.

“I have always dreamed of going to Mars,” said Serina Diniega, a planetary scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and lead author of a report published online by the journal Icarus. “Now I dream of snowboarding down a Martian sand dune on a block of dry ice.”

The hillside grooves on Mars, called linear gullies, show relatively constant width – up to a few yards or meters across – with raised banks or levees along the sides. Unlike gullies caused by waterflows on Earth and possibly on Mars, they do not have aprons of debris at the downhill end of the gully. Instead, many have pits at the downhill end.

“In debris flows, you have water carrying sediment downhill, and the material eroded from the top is carried to the bottom and deposited as a fan-shaped apron,” said Diniega. “In the linear gullies, you’re not transporting material. You’re carving out a groove, pushing material to the sides.”

Images from MRO’s High Resolution Imaging Science Experiment camera show sand dunes with linear gullies covered by carbon dioxide frost during the Martian winter. The location of the linear gullies is on dunes that spend the Martian winter covered by carbon dioxide frost. The grooves are formed during early spring, researchers determined by comparing before-and-after images from different seasons. Some images have even caught bright objects in the gullies.

Scientists theorize the bright objects are pieces of dry ice that have broken away from points higher on the slope. According to the new hypothesis, the pits could result from the blocks of dry ice completely sublimating away into carbon-dioxide gas after they have stopped traveling.

“Linear gullies don’t look like gullies on Earth or other gullies on Mars, and this process wouldn’t happen on Earth,” said Diniega. “You don’t get blocks of dry ice on Earth unless you go buy them.”

That is exactly what report co-author Candice Hansen, of the Planetary Science Institute in Tucson, Ariz., did. Hansen has studied other effects of seasonal carbon-dioxide ice on Mars, such as spider-shaped features that result from explosive release of carbon-dioxide gas trapped beneath a sheet of dry ice as the underside of the sheet thaws in spring. She suspected a role for dry ice in forming linear gullies, so she bought some slabs of dry ice at a supermarket and slid them down sand dunes.

That day and in several later experiments, gaseous carbon dioxide from the thawing ice maintained a lubricating layer under the slab and also pushed sand aside into small levees as the slabs glided down even low-angle slopes.

The outdoor tests did not simulate Martian temperature and pressure, but calculations indicate the dry ice would act similarly in early Martian spring where the linear gullies form. Although water ice, too, can sublimate directly to gas under some Martian conditions, it would stay frozen at the temperatures at which these gullies form, the researchers calculate.

“MRO is showing that Mars is a very active planet,” Hansen said. “Some of the processes we see on Mars are like processes on Earth, but this one is in the category of uniquely Martian.”

Hansen also noted the process could be unique to the linear gullies described on Martian sand dunes.

“There are a variety of different types of features on Mars that sometimes get lumped together as ‘gullies,’ but they are formed by different processes,” she said. “Just because this dry ice hypothesis looks like a good explanation for one type doesn’t mean it applies to others.”

The University of Arizona Lunar and Planetary Laboratory operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colo. JPL manages MRO for NASA’s Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver built the orbiter.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines October 20, 2014

News: Navy grounds ‘Top Guns’ - The F/A-18s needs spare parts and in too many cases they’re being taken from brand new jets. This is a risk to national security and pilots’ lives.   Business: Boeing seeks revised schedule for U.S. aerial tanker - Boeing is revising its master schedule for developing the new U.S. Air Force...
 
 

News Briefs October 20, 2014

New military medical team to help with Ebola in U.S. Defense Secretary Chuck Hagel has ordered the military to prepare and train a 30-member medical support team that could provide short-term help to civilian health professionals if there are more Ebola cases in the United States. His spokesman, Rear Adm. John Kirby, says the team...
 
 

Dragon ‘fires up’ for flight

The Air Force and NATO are undergoing a cooperative development effort to upgrade the avionics and cockpit displays of AWACS aircraft belonging to the 552nd Air Control Wing at Tinker Air Force Base, Okla., and the NATO E-3 Sentrys from Geilenkirchen, Germany. The Diminishing Manufacturing Sources Replacement of Avionics for Global Operations and Navigation, otherwise...
 

 
Boeing photographs

Boeing-built X-37B successfully completes third flight

Unmanned spacecraft concludes record-setting 674-day mission   Boeing photograph A third mission of the Boeing-built X-37B Orbital Test Vehicle was completed on Oct. 17, 2014, when it landed and was recovered at Vandenberg...
 
 

Boeing concludes commercial crew space act agreement for CST-100/Atlas V

Boeing has successfully completed the final milestone of its Commercial Crew Integrated Capability Space Act Agreement with NASA. The work and testing completed under the agreement resulted in significant maturation of Boeing’s crew transportation system, including the CST-100 spacecraft and Atlas V rocket. NASA in July approved the Critical Design Review Board milestone for Boeing’...
 
 

AF to release small business research solicitations

The Air Force Small Business Innovation Research and Small Business Technology Transfer program office is set to release its fiscal year 2015 list of topics Oct. 22, on the SBIR/STTR website.  Small businesses and research institutions with expertise to address the topics’ technology challenges are encouraged to submit proposals. During 2014, the Defense Department SBIR...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>