Mars Rover Yielding New Clues While Lodged in Martian Soil

Jun 25, 2009
Soft soil exposed when wheels of NASA's Mars Exploration Rover Spirit dug into a patch of ground.

(PhysOrg.com) -- NASA's Mars rover Spirit, lodged in Martian soil that is causing traction trouble, is taking advantage of the situation by learning more about the Red Planet's environmental history.

In April, Spirit entered an area composed of three or more layers of soil with differing pastel hues hiding beneath a darker sand blanket. Scientists dubbed the site "Troy." Spirit's rotating wheels dug themselves more than hub deep at the site. The rover team has spent weeks studying Spirit's situation and preparing a simulation of this Martian driving dilemma to test escape maneuvers using an engineering test rover at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

A rock seen beneath Spirit in images from the camera on the end of the rover's arm may be touching Spirit's belly. Scientists believe it appears to be a loose rock not bearing the rover's weight. While Spirit awaits extraction instructions, the rover is keeping busy examining Troy, which is next to a low plateau called Home Plate, approximately 3.2 kilometers (2 miles) southeast of where Spirit landed in January 2004.

"By serendipity, Troy is one of the most interesting places Spirit has been," said Ray Arvidson of Washington University in St. Louis. Arvidson is deputy principal investigator for the science payloads on Spirit and its twin rover, Opportunity. "We are able here to study each layer, each different color of the interesting soils exposed by the wheels."

One of the rover's wheels tore into the site, exposing colored sandy materials and a miniature cliff of cemented sands. Some disturbed material cascaded down, evidence of the looseness that will be a challenge for getting Spirit out. But at the edge of the disturbed patch, the soil is cohesive enough to hold its shape as a steep cross-section.

Spirit has been using tools on its to examine tan, yellow, white and dark-red sandy soil at Troy. Stretched-color images from the panoramic camera show the tints best.

"The layers have basaltic sand, sulfate-rich sand and areas with the addition of silica-rich materials, possibly sorted by wind and cemented by the action of thin films of water. We're still at a stage of multiple working hypotheses," said Arvidson. "This may be evidence of much more recent processes than the formation of Home Plate...or is Home Plate being slowly stripped back by wind, and we happened to stir up a deposit from billions of years ago before the wind got to it?"

Team members from NASA's Johnson Space Center in Houston feel initial readings suggest that iron is mostly present in an oxidized form as ferric sulfate and that some of the differences in tints at Troy observed by the panoramic camera may come from differences in the hydration states of iron sulfates.

While extraction plans for the rover are developed and tested during the coming weeks, the team plans to have Spirit further analyze the soil from different depths. This research benefits from having time and power. In April and May, winds blew away most of the dust that had accumulated on Spirit's solar panels.

"The exceptional amount of power available from cleaning of Spirit's solar arrays by the wind enables full use of all of the rover's science instruments," said Richard Moddis of the Johnson team. "If your rover is going to get bogged down, it's nice to have it be at a location so scientifically interesting."

The rover team has developed a soil mix for testing purposes that has physical properties similar to those of the soil under Spirit at Troy. This soil recipe combines diatomaceous earth, powdered clay and play sand. A crew is shaping a few tons of that mix this week into contours matching Troy's. The test rover will be commanded through various combinations of maneuvers during the next few weeks to validate the safest way to proceed on .

Spirit's right-front wheel has been immobile for more than three years, magnifying the challenge. While acknowledging a possibility that Spirit might not be able to leave Troy, the rover team remains optimistic. Diagnostic tests on Spirit in early June provided encouragement that the left-middle wheel remains useable despite an earlier stall.

"With the improved power situation, we have the time to explore all the possibilities to get Spirit out," said JPL's John Callas, project manager for Spirit and Opportunity. "We are optimistic. The last time Spirit spun its wheels, it was still making progress. The ground testing will help us avoid doing things that could make Spirit's situation worse."

Provided by JPL/ (news : web)

Explore further: Full lunar eclipse delights Americas, first of year

add to favorites email to friend print save as pdf

Related Stories

Spirit rover's wheels stuck in soft Martian dirt

May 12, 2009

(PhysOrg.com) -- The five wheels that still rotate on NASA's Mars Exploration Rover Spirit have been slipping severely in soft soil during recent attempts to drive, sinking the wheels about halfway into the ...

Spirit Wiggles Into Position

Oct 17, 2005

NASA's Mars Exploration Rover Spirit completed a difficult, rocky ascent en route to reaching a captivating rock outcrop nicknamed "Hillary" at the summit of "Husband Hill."

Spirit Completes Studies Of Arad, Moves On

Feb 03, 2006

Spirit is healthy and continues to pursue the short-term goal of driving to 'Home Plate.' Results from scientific instruments on the rover's robotic arm indicate that the white soil target called 'Arad' has a salty chemistry ...

Spirit Examines Light Tones Halley Formation

Jul 04, 2006

Stretching along a formation mission team members have named Low Ridge, lying in front of the Martian winter haven for NASA's Spirit rover, are several continuous rock layers that make up the ridge.

Spirit Resumes Driving

Feb 03, 2009

(PhysOrg.com) -- NASA's Mars Exploration Rover Spirit resumed driving Saturday after engineers gained confidence from diagnostic activities earlier in the week evaluating how well the rover senses its orientation.

Recommended for you

Vegetables on Mars within ten years?

20 hours ago

The soil on Mars may be suitable for cultivating food crops – this is the prognosis of a study by plant ecologist Wieger Wamelink of Wageningen UR. This would prove highly practical if we ever decide to ...

NASA Cassini images may reveal birth of a Saturn moon

21 hours ago

(Phys.org) —NASA's Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon, and may also provide clues to the formation of the planet's known ...

Meteorite studies suggest hidden water on Mars

21 hours ago

Geochemical calculations by researchers at Tokyo Institute of Technology to determine how the water content of Mars has changed over the past 4.5 billion years suggest as yet unidentified reservoirs of water ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

docknowledge
5 / 5 (1) Jun 25, 2009
Lol. Thankfully, Ray Arvidson used the nicely precise word "serendipity".

Rather than...wait for it..."fortuitously" -- a word that has entered the Pantheon of doublespeak. "Fortunately" and "by accident" do not mean the same thing.

More news stories

Astronomers: 'Tilt-a-worlds' could harbor life

A fluctuating tilt in a planet's orbit does not preclude the possibility of life, according to new research by astronomers at the University of Washington, Utah's Weber State University and NASA. In fact, ...

NASA Cassini images may reveal birth of a Saturn moon

(Phys.org) —NASA's Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon, and may also provide clues to the formation of the planet's known ...

Vegetables on Mars within ten years?

The soil on Mars may be suitable for cultivating food crops – this is the prognosis of a study by plant ecologist Wieger Wamelink of Wageningen UR. This would prove highly practical if we ever decide to ...

Tech giants look to skies to spread Internet

The shortest path to the Internet for some remote corners of the world may be through the skies. That is the message from US tech giants seeking to spread the online gospel to hard-to-reach regions.

Patent talk: Google sharpens contact lens vision

(Phys.org) —A report from Patent Bolt brings us one step closer to what Google may have in mind in developing smart contact lenses. According to the discussion Google is interested in the concept of contact ...

Wireless industry makes anti-theft commitment

A trade group for wireless providers said Tuesday that the biggest mobile device manufacturers and carriers will soon put anti-theft tools on the gadgets to try to deter rampant smartphone theft.