Mars Rover Spirit Unearths Surprise Evidence of Wetter Past Options

[Guest_AlexBlackwell_*]

Mars Rover Spirit Unearths Surprise Evidence of Wetter Past
NASA/JPL
May 21, 2007

[CosmicRocker]

As much as I am drooling over the thought of MSL on Mars, I sure would feel better if there were two of them. I think there is some merit in the multi-MER concept. They are dynamite little explorers that have proven themselves and their EDL concept, but I think you run into a problem budgeting the large crew needed to keep many of them operating and exploring efficiently.

Getting back on topic...

Are we to assume that this silica is in its anhydrous form or could it contain some water of crystallisation?

That's an interesting question. If this silica is truly amorphous or non-crystalline, there can't be any water of crystallization. Besides, I am not aware of any crystalline form of silica that holds water. But opal is an amorphous form of silica that does contain variable amounts of water.

I don't know how they know that this silica is non-crystalline. Which instrument tells them that, or how do they infer it? I would suspect that if this material was not anhydrous, that fact would be widely advertised as further proof of water once on Mars. I think the mini-TES can see water wherever it may be.

[tglotch]

As much as I am drooling over the thought of MSL on Mars, I sure would feel better if there were two of them. I think there is some merit in the multi-MER concept. They are dynamite little explorers that have proven themselves and their EDL concept, but I think you run into a problem budgeting the large crew needed to keep many of them operating and exploring efficiently.

Getting back on topic...

That's an interesting question. If this silica is truly amorphous or non-crystalline, there can't be any water of crystallization. Besides, I am not aware of any crystalline form of silica that holds water. But opal is an amorphous form of silica that does contain variable amounts of water.

I don't know how they know that this silica is non-crystalline. Which instrument tells them that, or how do they infer it? I would suspect that if this material was not anhydrous, that fact would be widely advertised as further proof of water once on Mars. I think the mini-TES can see water wherever it may be.

The Mini-TES is the instrument that determined that the silica is amorphous. The spectral character of amorphous or opaline silica looks quite different from quartz or one of the other crystalline polymorphs of SiO2.

As for water, the Mini-TES can qualitatively assess hydration state of soils by looking for a spectral feature near 6 microns. As far as I know (and I'm not positive), this white, silica-rich soil does not have a strong 6 micron feature, implying low or no water content in the silica.