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 July 7, 2015

News: F-35 loses dogfight to fighter jet from 1980s – A new report alleges that an F-35A was defeated by the very aircraft it is meant to replace.   Business: South Korea selects Airbus for $1.33 billion tanker contract – European aerospace giant Airbus won a $1.33 billion deal June 30 to supply air refueling...
 
 
U.S. Chamber of Commerce photograph

Boeing, Embraer to collaborate on ecoDemonstrator technology tests

U.S. Chamber of Commerce photograph Frederico Curado, president & CEO of Embraer, and Marc Allen, president of Boeing International, at the Brazil-U.S. Business Summit in Washington, D.C. The event occurred during an offici...
 
 
Untitled-2

Tactical reconnaissance vehicle project eyes hoverbike for defense

The U.S. Army Research Laboratory, or ARL, has been exploring the tactical reconnaissance vehicle, or TRV, concept for nearly nine months and is evaluating the hoverbike technology as a way to get Soldiers away from ground thre...
 

 
Air Force photograph by SSgt. William Banton

Upgraded AWACS platform tested at Northern Edge

Air Force photograph by SSgt. William Banton Maintenance crew members prepare an E-3G Sentry (AWACS) for takeoff during exercise Northern Edge June 25, 2015. Roughly 6,000 airmen, soldiers, sailors, Marines and Coast Guardsmen ...
 
 
LM-Legion

Lockheed Martin’s Legion Pod™ takes to skies

Lockheed Martin photograph by Randy Crites Lockheed Martin’s Legion Pod recently completed its first flight test, successfully tracking multiple airborne targets while flying on an F-16 in Fort Worth, Texas. Legion Pod was in...
 
 
Air Force photograph by SSgt. Marleah Robertson

First Marine graduates Air Force’s F-35 intelligence course

Air Force photograph by SSgt. Marleah Robertson Marine Corps 1st Lt. Samuel Winsted, an F-35B Lightning II intelligence officer, provides a mock intelligence briefing to two instructors during the F-35 Intelligence Formal Train...
 




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=""> <s> <strike> <strong>