Mars Rover Spirit Mission Update Thread

[centsworth_II]

<i>"Parna (wind blown silt) deposits are seeming more and more attractive."</i> -- JonClarke<br /><br />Are you talking about fossil dunes? <br /><br />The rounded, curved surfaces of the 'soft rocks' on West Spur are very intriguing. Are they due to : The original shape of the rocks? The way in which these rocks fracture? Or the way in which they weather? <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Hi centsworth<br /><br />It's good to be back. With respect to your question, parna is wind blown silt to sandy silt. it can form dunes close to source 9source bordering dunes) but more typically mantles the landscape. It is formed by dust blown off dry lakes and flood plains in arid or semi arid environments. Parna is composed of clays, oxides, carbonates, and quartz Loess is similar, except that loess is derived from glaical material and therefore is composed of fresh rather than weathered minerals.<br /><br />Yes, Clovis look like rock, but is so soft that even pressure from the arm forms impressions. This suggests to me that the material is essentially unindurated but cohesive, like parna or silty sand, or loess or volcanic ash. The cohesiveness can come either from interlocking shapes (as in ash) or electrostatically (as in parna or loess). Such materials are cohesive enough to form cliffs but soft enough to be excavated with a spade (in China people have even cut houses into loess, as have people in the altered ash of Capadocia in Turkey).<br />There are standard engineering tests which define the choesiveness of soils etc. by the amount of power needed to form an indentation of knwon size. whether the rover arm is sufficiently calibrated to determine this I don't know. A similar calculation could probably be calculated from how the wheels crust the rock as well.<br /><br /><br />Cheers<br /><br />Jon<br /><br /><br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[centsworth_II]

<i>"Parna is composed of clays, oxides, carbonates, and quartz..."</i> -- JonClarke<br /><br />Two of the four materials you mention, clay and carbonates, would be an exciting find indeed. I'm not holding my breath though. But the questions remain, where is the clay, where is the carbonate?<br /><br />From this U.S. Geological Survey archive article (not based on MER data):<br /><br /><i> "Mars Mystery: Where's the Clay? <br /><br /> Scientists at the U.S. Geological Survey are saying "Where's the clay?" as they examine new data on the mineral composition of Mars. The amount of clay minerals on the surface of Mars is much lower than expected... no more than 2 percent of the amounts found on Earth.<br />Some scientists believe that clays are important to the formation of life.... If clays never formed in abundance on Mars, life may not have been able to develop. <br /><br />Since iron oxides and clay are common products of the weathering process on Earth, they were assumed to be equally common on Mars."</i><br /><br /><br />I can't wait to find out what those 'soft rocks' are made of. There's also the salt story: How does the salt content in the hills compare to that on the plains, and what does it mean.<br /> <div class="Discussion_UserSignature"> </div>

 

[fangsheath]

Spirit is moving forward in a generally easterly direction, utilizing the north-facing (south) edge of the "ravine." No surprise there. I'm guessing that either they do not intend a very long traverse or they are trying to get a better look at outcrops in this swale before they commit to traversing flat or south-facing ground.

 

[radarredux]

> <i><font color="yellow">This Ebenezer guy looks softer than goat cheese</font>/i><br /><br />What amazes me is how smooth the upper-right section of the circle is. Reminds me of ice.<br /><br />Now if NASA goes forward with bringing in investor money for space efforts, instead of the little clover leaf pattern in the circle (see smooth section on the right) I can imagine a little "IBM" logo or something pressed into the soil for each test <img src="/images/icons/smile.gif" /></i>

 

[JonClarke]

Hi centsworth<br /><br />Nice link and an interesting question. I suppose there are several levels of answer.<br /><br />First, what do we mean by "clay" ? There are three meanings to clay: a mineralogical definition (a family of hydrated layer silicate minerals), a sedimentary definition (particles of any composition smaller than 4 microns), and popular (sticky stuff on a farmer's boots). The popular definition illustrates a key prioperty of clay, its cohesiveness. particles of any composition small enough to be called clay are generally cohesive because of electrostatic forces are able to exert significantly on that scale. Mineralogical clays (which also happen to be composed of particles less than 4 microns) are also cohesive because there mineral structure allows the formation of electrostatic bonds between particles, especially when wet. Thus any granular material that contains even a couple of percent of particles less than 4 microns, especially if those particles are of mineralogical clay, with be quite cohesive, even if unlithfied. The "clay" glues the particles together. <br /><br />Second, the only direct information we have on the mineralogy of the surface of Mars so far is from SNC meteorites, IR spectrometers on orbiters and landers. Clays are present in trace amounts in the meteroites, but then clay rich lithologies are not likely to survive the ejection process from Mars. We have indirect information from the Mossbauer spectrometers and mass balance data from the Viking analyses. The problem with spectometers is that, although a reasonable instrument for detecting the presence of a mineral, it is a blunt instrument for dtermining the quantity. Sepctrometry is also strongly dependent on factors such as scale, surface roughness, absorbtion bands in the amosphere, obscuration by clouds and aerosols etc. So I think there is a crying need for a more quantitative instrument to determine mineralogy like XRD on future Mars landers.<br /><br />The conclusi <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[thechemist]

<i> <font color="yellow">I can imagine a little "IBM" logo or something pressed into the soil for each test </font></i><br /><br />Well, at the center right one can see at least the two circular marks left by the Mossbauer ring (if I remember well). <br />A clue about the softness of Ebenezer might be the way the bottom has been deformed, maybe during one of the instrument heads retraction.<br /><br /><i> <font color="yellow">Reminds me of ice </font></i><br /><br />Well, it reminds me of fresh cement <img src="/images/icons/smile.gif" /><br /><br /><i> Hint: fresh cement is not known to be completely dry <i> <img src="/images/icons/smile.gif" /><br /></i></i> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[fangsheath]

According to today's flight director's update, they had a specific target in mind, and I think we are there. This is where they intend to spend the period of conjunction.

 

[centsworth_II]

Re: Identifying clays on Mars:<br /><br /><br /><i> "...I think there is a crying need for a more quantitative instrument to determine mineralogy like XRD on future Mars landers. <br /> The conclusion is I would be very cautious of any attempt to quantify the amount of any mineral phase from spectral data alone."</i> -- JonClarke<br /><br /><br />You may not get your XRD instument on the upcoming Mars Science Laboratory rover, but the Atomic Force Microscope, which I recall you are not enthusiastic about, could possibly identify clays, at least from a particle morphology perspective.<br /><br />Oh, well, the MERs are giving us plenty to think about as it is. Always the same story -- the more questions answered, the more raised.<br /><br />Thanks for helping this geologically challanged individual understand a little better.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

<i>"According to today's flight director's update, they had a specific target in mind..."</i> -- fangsheath<br /><br /><br /><i>"The planned gap in sending daily plans runs for about 12 days....<b>The rovers will be instructed ahead of time to continue</b> doing atmospheric operations and <b>Moessbauer spectrometer readings</b> daily during that period. No movements of the wheels or the robotic arms are in the conjunction-period plans...."</i> -- NASA press release<br /><br /><br />Given that the resolution of the Moessbauer data improves with the length of time the instrument rests on a target, and the instrument arm will not be moved for several days, this could be the <b>Mother of All Moessbauer</b> readings! With this in mind, I wonder what special target they've chosen. <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Morphology would certainly help, but it would be good to get composition also. I know that BSE and EDX in an SEM can give add compositional data to morphology. Can the AFM do the same (or similar)?<br /><br />Cheers <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[centsworth_II]

<i>"I know that BSE and EDX in an SEM can give add compositional data to morphology. Can the AFM do the same (or similar)?"</i><br /><br />I hope that's a rhetorical question.<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

I've never used AFM, so was hoping that someone could enlighten me <img src="/images/icons/smile.gif" /><br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mikehoward]

<blockquote><font class="small">In reply to:</font><hr /><p>With this in mind, I wonder what special target they've chosen.<p><hr /></p></p></blockquote><br /><br />It looks like Spirit has rolled into the little "ravine"; I bet that's where they'll stay for the long integration. I can't wait until they put together the Navcam images from the present position.

 

[fangsheath]

The rover has pulled up to the rock at lower right, it is only inches from the right front wheel. Although it may appear to have been moved by the vehicle, it quite definitely has not been. Notice the rock formation at the top of the image, which seems to combine surface features of Pot of Gold and Clovis.

 

[anoolios]

Looks like another chunk has stuck to the moessbauer spectrometer shoe. <br /><br />http://qt.exploratorium.edu/mars/spirit/micro_imager/2004-09-05/2M147677607EFF8800P2956M2M1.JPG<br /><br />The stuck chunk can be seen on the shoe in some of the navcam views. Wonder if it would compromise the spectrometer readings? Seems odd that stuff is so sticky, the metal shoe looks smooth.<br /><br />http://qt.exploratorium.edu/mars/spirit/navcam/2004-09-05/2N147680901EFF8800P1938R0M1.JPG<br /><br />

 

[silylene old]

<i>Why aren't we sending a fleet of MERs (say, four) as our next step in Mars exploration?</i><br /><br />I have been advocating this for a while. I bet MERs could be mass-produced and launched for under perhaps $100M each. I do think a fleet of 10 MERs would accomplish more science than several other proposed billion-dollar missions. This would be a good subject to debate in another thread. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[rybanis]

Oi vey, in those navcam pics you can see how much dust is collecting on the solar panels <img src="/images/icons/frown.gif" /> <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Hi Silylene<br /><br />I am all for it. But I think the cultural expectation is that each mission pushes the envelope with respect to technology and science goals. However historically a succession of near identical spacecraft have often proved very successful - Ranger (the later ones), Surveyor, Lunar Orbier, Luna (all series), Venera....<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[earth_bound_misfit]

Yes indeed. The MER's need a "go gadget" like hand with a feather duster <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p> </p><p> </p><p>----------------------------------------------------------------- </p><p>Wanna see this site looking like the old SDC uplink?</p><p>Go here to see how: <strong>SDC Eye saver </strong>  </p> </div>

 

[arizonast]

The softness of certain rocks encountered by both rovers to date could be a function of their mineralogy, but some component of their hardness could be an artifact of the impact event at the respective crater, e.g., Gusev, Endurance, Eagle. A good analogy is a surficial carbonate surrounding Berringer Crater in Arizona, where under hi-T and P the water within the rock was volatilzed, vaporized etc, leaving behind a dehydrated reduced sponge-like, soft carbonate matrix. There has been a tendency to forget or overlook what high temps and pressures can do to a rock at an impact site, which may mask sedimentary structure.

 

[thechemist]

The "silent" period started for Spirit (Sol 244).<br /><br />One can tell by the way the last PanCam images look like :<br /><br />http://qt.exploratorium.edu/mars/spirit/pancam/2004-09-08/2P147763935EFF8800P2290R1M1.JPG<br /><br />Hopefully more focus on existing data analysis will be given. <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[centsworth_II]

<i>"Hopefully more focus on existing data analysis will be given."</i><br /><br />I'll be dissapointed if there is no press briefing bringing us up to date on what has been found concerning the composition of the rocks that Spirit has been studying on West Spur. This would be a good time to do that. <br /> <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

Earlier I was wondering what special target would be chosen for the super long, super high resolution Mossbauer analysis over solar conjunction. Well....<br /><br /><i>"For the conjunction period, the rover team has placed the Mössbauer spectrometer on one of the two magnets on the rover deck. Spirit will activate the Mössbauer instrument every day during conjunction in order to characterize the dust that has collected on the magnet."</i> -- From this update.<br /><br />I never thought of <i>that</i>! Of course the mossbauer being for characterizing iron compounds and the magnets exclusively collecting iron compounds, I guess it would make sense to do the highest resolution iron compound analysis on the purest iron compound sample. Which would be found on the magnets. <div class="Discussion_UserSignature"> </div>

 

[mikehoward]

Actually, it looks like there are still some pictures trickling in. Who knows how long it will last, though.<br /><br />http://qt.exploratorium.edu/mars/spirit/pancam/2004-09-09/2P147765091EFF8800P2290R1M1.JPG<br /><br />Check out the eroded rocks at the bottom of this one:<br />http://qt.exploratorium.edu/mars/spirit/pancam/2004-09-09/2P147765642EFF8800P2290L7M1.JPG