Mars rover uncovers hints of water activity

Newscientist ^ | 20 February 04 | David L Chandler

[Dog]

Mars rover uncovers hints of water activity

Shiny, polished pebbles were unearthed in a trench (Image: NASA)

The latest close-up inspections of Martian soil and rock by the NASA rovers Spirit and Opportunity continue to provide tantalising and unexpected results. A rock that had looked sedimentary proved to be volcanic, while a freshly-dug trench is showing what may be hints of some recent water activity.

Opportunity has now completed a full set of microscopic imaging and two kinds of spectroscopy inside a trench that it dug earlier this week. By spinning one wheel while locking the other five, the rover gouged out a furrow 50 centimetre long and 10 centimetre deep in the soft, powdery soil.

On Thursday, it placed its instrument arm on six different locations on the side and bottom of the trench. The sides of some tiny spheres were spotted embedded in the soil in the trench side - similar to those seen earlier on the soil and in an outcrop of bedrock.

But the ones in the trench appear shiny and polished. This could indicate sedimentary origins, with the stones becoming buffed gently as they rolled at the bottom of shallow water.

Also, the sand-grain or smaller particles in the soil seem to be clumped or cemented together, says science team member Albert Yen. The clumping suggests salts which can migrate with water vapour through the soil "providing a weak cement," he says.

The team is now looking for evidence of salts in the data just received from the Mossbauer spectrometer and the Alpha-Proton X-ray Spectrometer taken inside the trench.

Distance record

Opportunity is now heading toward a section of the outcrop, called El Capitan, which seems to include the full suite of layers that is seen in different parts of the outcrop, says team leader Steven Squyres. "There's different kinds of material here" in the bedrock, as revealed by its different rates of weathering, he says.

By going to El Capitan, "from a single rover parking spot, we can reach both parts of the unit" with the robotic arm, according to Squyres.

Meanwhile, on the other side of Mars, the twin rover Spirit has officially reset the record for total distance travelled on Mars. The previous record-holder was the tiny 1997 rover Sojourner which journeyed 102 metres.

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Freeze-thaw cycles

Spirit has now gone more than 110 metres from its landing spot and is about halfway to the rim of a crater called Bonneville. The sheer crater rim is expected to provide a window into deeper layers of the soil in this region, which may have once been a lakebed.

There are already some intriguing features being seen there, says David DesMarais, a science team member from NASA's Ames Center. Tiny geometric indentations in the soil there resemble the cracking seen in some soils as they go through periodic freeze-thaw cycles or moistening and drying, either of which could mean the recent presence of some water in the Gusev site's soil, he says.

But one rock that had tantalised the scientists this week turned out to be quite ordinary. Spirit had spotted a rock that looked flaky, resembling the finely-layered rocks seen by Opportunity in its very different location. But closer examination showed this rock to be just ordinary basalt.

[Dog]

Very interesting.

[Dog]

fyi..

[Miss Marple]

Thanks, Dog! I am babysitting today so I can't catch all the news. I really am fascinated by the Mars Rovers.

[Crazieman]

I'm sure Richard Hoaxland will think its some sort of conspiracy to destroy evidence.

[Dog]

So am I Jane..

[Sacajaweau]

btt

[JennysCool]

That reminds me that there was a "sensitive" type caller on George Noory last night, saying he hoped Spirit and Opportunity weren't adversely affecting the Martian environment. Yeesh.

[BykrBayb]

They must have read my post a few days ago and followed up on it. I told them! http://www.freerepublic.com/focus/f-news/1079392/posts?page=81#81

[Dog]

Way to go you called it..:-)

[BykrBayb]

No applause necessary. Just throw money.

[RightWhale]

There has been a pallet load of 'dry Mars' articles on the space news websites lately. The question probably won't be finally resolved until the Mars driller is sent in the next few years, but the Dry Martinis may be having their last binge.

[Two Thirds Vote Aye]

Hey Dog! As it turns out, I worked on the fuel tank on Mars Global Surveyor back in the 90's, so I have a bit of an involvement in this. In addition, one of the managers in my division is on the science team (I don't know him real well.....he works other stuff generally). He emailed us from JPL earlier this week and said that he had won an argument to investigate the sidewalls of the trench in addition to the bottom. They originally were only going to look at the bottom. I'm glad he won the argument!

You will also be interested to know that I worked on the fuel tanks on Cassini. We launched it in 1997. Took 7 years to get to Saturn. Saturn orbit insertion burn is July 1, 2004.

[Dog]

Cool Thirds.....very cool!

[Two Thirds Vote Aye]

It's definitely very exciting! Even as we speak, I am RIGHT NOW, and have been for a couple of years, working on the fuel tank on Mars Reconnaissance Orbiter. The core structure for this spacecraft sits in a cleanroom about 3 floors below me. The fuel tank is sitting there, too, and will be installed in the core structure. Needless to say, I specialize in fuel tanks. I perform structural analysis on them. We launch this beauty in 2005.

[RightWhale]

Cassini.

What do you think of the news that the Cassini lander 'Huygens' experiment is still being designed even though Cassini is nearly at its destination? The ESA Huygens probe will be dropped off eventually at Titan.

[bruin66]

I worked on the fuel tank on Mars Global Surveyor back in the 90's

I, unfortunately, predate you. I worked on the Mariner Mars '64 project while at JPL. Regards...

[Texans]

Reading it for the first time, but I think the trenching could have caused the smoothing of the rock ?

[RightWhale]

I think if they adjust the gamma correction of the image processor, the range of brightness contrast won't be so great. That is, the brightness is probably artificial to a degree.

[Two Thirds Vote Aye]

I presume what they are talking about is what they are going to do with the data, or how they are going to obtain it; i.e., where they plan to drop it or what they are going to command it to do once it arrives. Just like the Mars rovers, they might have some options of what data to obtain, etc. and they are trying to decide. I'm not for certain, but I think it's a fixed probe; no mobility. I'm not real familiar with how much control they have over it when it arrives on Titan.

[Two Thirds Vote Aye]

Excellent bruin66! Regards to you!