Featured Research

from universities, journals, and other organizations

Opportunity on verge of new discovery: Mars rover poised on rock that may yield yet more evidence of a wet Red Planet

Date:
September 17, 2011
Source:
Washington University in St. Louis
Summary:
The Mars rover Opportunity, which was designed to operate for three months and to rove less than a mile, has now journeyed more than seven years crossing more than 21 miles. Today, it is poised at the edge of a heavily eroded impact basin, the possible location of clay minerals formed in low-acid wet conditions on the red planet.

Pancam false color mosaic of the rock target Chester Lake, acquired on sol 2709 (the 2,709th day of Opportunity’s mission). This rock, located on Cape York, on the edge of the Endeavour crater, is a breccia in which various rock fragments have been cemented together in a finer-grained matrix, probably during formation of the Endeavour crater billions of years ago. Opportunity is about to make in-situ measurements of this rock which will determine whether it contains clay minearals formed in the presence of water.

Shortly after Labor Day 2011, the Mars rover Opportunity was poised on the rim of the 22,000 meter-wide Endeavour Crater, preparing to sample a novel rock type. Much older than the sedimentary samples the rover's "tasted" so far, this new sample is flush with the promise of revealing clues to the planet's environment when running rivers coursed the surface.

Related Articles


What was supposed to have been a 90- to 180-day exploration of two distinct regions of the red planet has turned into a saga that has become one of science's most compelling and long-lasting adventures (now into its eighth year), enthralling the public and the science communities alike.

Launched the summer of 2003 and landing in January 2004, the solar-powered Mars Exploration Rovers (MER) Spirit and Opportunity completed their intended basic missions in April 2004. Each continued roving until March 2010, when Spirit, mired in unexpected but scientifically interesting martian sand and pointed in an unfavorable direction to survive the winter dark, gave up the ghost.

Opportunity, on the other hand, remains active, having reached the rim of Endeavour Crater Aug. 9, 2011, knocking at the door of geology different from any it has explored during its first seven-plus years on Mars.

"Opportunity now is in a brand new mission," says Raymond E. Arvidson, PhD, the James S. McDonnell Distinguished University Professor in Arts & Sciences at WUTL, and MER deputy principal investigator. "In late August, we looked at a rock named Tisdale, with a composition unlike any we've seen before. It has an enormous amount of zinc, bromine, phosphorus, chlorine, and sulfur, all elements that are mobile in the presence of water.

"The ancient rim of Endeavour represents a period when there was probably a lot more water on the surface," Arvidson says. "So, we're trying to get the chemical, mineralogical and geological setting to 'back out' those ancient conditions to reconstruct environmental conditions during this earlier time period."

The conditions that formed the sandstones Opportunity has sampled over the past seven years represent a kind of drying-out period of Mars. Occasionally wet but usually dry and wind-blown, the sulphur-rich mineral grains formed vast dune fields that were cemented into sandstone over millions of years by occasional seeping groundwater.

But the terrain Opportunity now is sampling -- largely buried by lake bed sediments -- pops up in places like Endeavour rim and is much older, going back to the earliest days of the planet. That's some 3.5 to 4 billion years ago in the last stages of heavy bombardment, when Mars was sweeping up the last planetessimals -- cosmic dust grains that collided and stuck to each other to form larger bodies. Endeavour is an impact crater produced during that heavy bombardment period.

Arvidson and his WUSTL colleagues also are part of the Compact Imaging Spectrometer for Mars (CRISM) team of the Mars Reconnaissance Orbiter, a craft orbiting Mars with sophisticated instrumentation that helps Arvidson and other NASA scientists determine where Opportunity should try to go next. The CRISM instrument provides spectral information on martian rocks at a super-high resolution that is processed and analyzed at WUSTL.

CRISM spectral data and other orbital data on the part of the Endeavour crater rim named Cape York indicated a good possibility that clay minerals would be found there.

"Clays form in more neutral, less acidic conditions than the sulfate-rich sandstones we've been looking at," Arvidson says. "Our hypothesis is that if there are clay minerals, the water was less acidic and therefore more conducive to life. The presence of zinc, bromine, phosphorus, chlorine, and sulfur in the Tisdale rock is exciting in that it points toward water moving through and altering the rock, although we have no evidence for clay minerals in Tisdale. Further, the Tisdale surfaces were very rough and we were unable to make use of the Rock Abrasion Tool (RAT) to clean off the surfaces to expose fresh materials.

"Thus, we moved on and are now in the thick of the hunt to find these elusive clay minerals by traversing to other rock targets and making detailed measurements, including making chemical and mineralogical observations of natural, brushed, and ground surfaces. The rock Opportunity is sitting over currently is called Chester Lake and will be our first target in which we will use the RAT to progressively expose deeper and deeper surfaces," Arvidson says.

The key Opportunity instrument to verify the presence of what Arvidson thinks are iron-bearing clays is the Mφssbauer spectrometer. This instrument measures the abundance of iron-bearing minerals in martian rocks and soil by probing tiny changes in the energy levels of the iron atomic nucleus in response to its environment. The Mφssbauer spectrometer illuminates a rock with a radioactive source of gamma rays tuned to the energy levels in the iron nucleus and then uses the energies of the returning gamma rays to determine the abundance of iron-bearing minerals in the surface rocks.

Because Opportunity's arm cannot move side to side due to a broken actuator, Arvidson and team members drive the vehicle to a spot where the arm can still place the RAT and in-situ instruments onto the surface.

Opportunity's mast-mounted emission spectrometer is no longer working, and the steering on one of the wheels is rotated in a bit. But Arvidson says the engineering and science teams have met every challenge through diligence and guarded optimism.

"Opportunity is just a really well-made vehicle," Arvidson says. "It's way, way beyond warranty. It was supposed to drive about 600 meters and so far it's gone 33,500 meters in round numbers, and has taken maybe 150,000 pictures by now.

"It's well-made and has a dedicated team that has eked out every ounce of science that we can get from it. Plus, we've been lucky and landed on a terrain that has rocks that contain detailed clues on past environmental conditions," he says.

"Stay tuned, we have a new mission and expect to make yet more exciting discoveries about the red planet."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. The original article was written by Tony Fitzpatrick. Note: Materials may be edited for content and length.


Cite This Page:

Washington University in St. Louis. "Opportunity on verge of new discovery: Mars rover poised on rock that may yield yet more evidence of a wet Red Planet." ScienceDaily. ScienceDaily, 17 September 2011. <www.sciencedaily.com/releases/2011/09/110914171756.htm>.
Washington University in St. Louis. (2011, September 17). Opportunity on verge of new discovery: Mars rover poised on rock that may yield yet more evidence of a wet Red Planet. ScienceDaily. Retrieved November 21, 2014 from www.sciencedaily.com/releases/2011/09/110914171756.htm
Washington University in St. Louis. "Opportunity on verge of new discovery: Mars rover poised on rock that may yield yet more evidence of a wet Red Planet." ScienceDaily. www.sciencedaily.com/releases/2011/09/110914171756.htm (accessed November 21, 2014).

Share This


More From ScienceDaily



More Space & Time News

Friday, November 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Crowdfunded Moon Mission Offers To Store Your Digital Memory

Crowdfunded Moon Mission Offers To Store Your Digital Memory

Newsy (Nov. 19, 2014) — Lunar Mission One is offering to send your digital memory (or even your DNA) to the moon to be stored for a billion years. Video provided by Newsy
Powered by NewsLook.com
Accidents Ignite Debate on US Commercial Space Travel

Accidents Ignite Debate on US Commercial Space Travel

AFP (Nov. 19, 2014) — Serious accidents with two US commercial spacecraft within a week of each-other in October have re-ignited the debate over the place of private corporations in the exploration of space. Duration: 02:08 Video provided by AFP
Powered by NewsLook.com
Lunar Mission One Could Send Your Hair to The Moon

Lunar Mission One Could Send Your Hair to The Moon

Buzz60 (Nov. 19, 2014) — A British-led venture called Lunar Mission One plans to send a module to the moon with keepsakes from Earth. Vanessa Freeman (@VanessaFreeTV) tells you how to get your photos and DNA onboard. Video provided by Buzz60
Powered by NewsLook.com
Why A Russian Object Is Being Called A 'Satellite Killer'

Why A Russian Object Is Being Called A 'Satellite Killer'

Newsy (Nov. 18, 2014) — An unidentified Russian spacecraft is getting some attention, with some saying it could be for research while others say it could be a weapon. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins