Martian Underground

[rogers_buck]

I'm sure many have seen this SDC article:<br /><br />LINK<br /><br /><br />The upshot is that all of the planned landers/rovers on the books will come up short of digging a hole deep enough to access the liveable layer on mars. Whereas upper limits are good scientific data points, they are somewhat dissapointing when you want to find critters.<br /><br />Perhaps the most promissing of the landing options detailed in the article are fresh gully formations or fresh craters. These might be good for future rover missions, but I'm wondering if there might be a way to salvage the less mobile missions in the pipeline by equiping them with drilling capabilities for the required 8 meters?<br /><br />The ill-fated Mars Polar Lander dropped an impactor that didn't yield any data but must have yielded a nice hole. If the Phoenix mission could do the same and land next to the hole, it would have some really fresh excavations. The technical challenges for such a feat would be truly daunting and likely impractical. By turning the sequence around, however, it may become more possible.<br /><br />If a rover could laser designate an impact point could a "smart bomb" style inertial projectile hit its mark without destroying the rover? The impact would have to be at a safe enough distance so that targeting errors would be within margins of a survivable and useable result. Material thrown out would need to be accessible yet not so close that the rover is shot-gunned to death. Idealy, the impactor would arrive at near the end of the rovers operational life so that a bad result wouldn't compromise all the science.<br /><br />The survivability requirements would likely mean that such a scheme could only work with a rover and it is probably more practical to crawl into an existing hole rather than to make a fresh one. <br /><br /><br /><br />

 

[tom_hobbes]

A very interesting idea. I eagerly await the comments of the tech guys around these parts. <div class="Discussion_UserSignature"> <p><font size="2" color="#339966"> I wish I could remember<br /> But my selective memory<br /> Won't let me</font><font size="2" color="#99cc00"> </font><font size="3" color="#339966"><font size="2">- </font></font><font size="1" color="#339966">Mark Oliver Everett</font></p><p> </p> </div>

 

[rogers_buck]

Not exactly a torrent of interest. I guess nobody would want to be responsible for bombing a $1B rover. )-;<br /><br />It does seem that the tech required for the penetrator with fins would be roughly equivalent to the strap-ons used for making iron bombs into smart bombs. Thermal protection, space hardening, etc., not withstanding. But launching a follow-on mission to boost a 50kg copper penetrator wouldn't require much in the way of boosters and the addition of a laser designator to an instrument boom doesn't seem like much of an engineering challenge. The incremental cost to an existing mission seems pretty low considering that getting down to the critter layer may otherwise out of the question.<br /><br />Granted, we haven't done any aerodynamic hypersonic control surfaces in the martian atmosphere, but it seems that the software for simulating such a thing should be extremely mature. The confidence in the results should be high.<br />

 

[JonClarke]

I have moved this thread to SS&T, a better home for the topic.<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>

 

[JonClarke]

remember this is the results of modelling. All models are wrong (although some are useful). It depends on the basic assumptions used. In this study the assumption is that the shallow susurface is completely frozen so than any organisms are dormant and unable to repair radiation damage. However we know that shallow subsurface water is at least locally and ephemerally present, to form the gullies. Other models also predict ephemeral moisture from melting of frost and snow, and still others predict the persistance of brines to very low temperatures. So the assumptions in this study are questionable.<br /><br />However, even if the predictions of this study are correct, since the forthcoming missions like Phoenix and ExoMars are designed to look for geochemical signatures of life rather than viable organisms, the conclusions should have no impact on the design of those missions. Isotopic ratios will survive the death of the organisms that created them, and organic material may well persist for long peroids, providing they have not been destroyed by strong oxidants.<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>

 

[rogers_buck]

Wondered what happened to this thread...<br /><br />As you say, it isn't an absolute result. However, if an expensive rover mission failed to turn up the goods, the cloud of doubt would hang heavy again for decades. The upper limit would become known, but the ultimate question would remain. If there was some form of leaching through the caustic soils perhaps all remnants of life would be neutralized and carried beyond range. The soil is pretty caustic - I wouldn't mind dumping it in my pool.<br /><br />If a cheap impactor could save the day and produce a fresh excavation on demand, perhaps it would be a good investment as an insurance policy of sorts?<br />

 

[JonClarke]

I doubt if a single mission would resolve the issue, even positive results would be critically reviewed. Perhpas ther instrument was contaminated, or had a systematic error, for example. Positive results from several places would be required.<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>

 

[rogers_buck]

True. And then the final argument, all those rovers you sent to verify the result had seeded it in the first place. I guess we'll wind up sending an HPLC or gel-electrophloresis to actually sequence genes. Then the claim will be all that radiation scrambled the DNA. Finally, a handfull of humans will go there and do some of the same tests all over again, perhaps not as well, and then the result will be accepted. Of course, there will be a greater number who will claim that a negative result was a fabrication by the robots we send as part of a cyber conspiracy.<br /><br />But for the sake of continued exploration, ANY positive result will fuel continued interest and investment. A thoughtfull negative result will add decades to the process. Mars has lived and died many times. It seems to alternate with each new glance. But the glances while dead are much fewer and far between...<br /><br />

 

[rogers_buck]

I imagine those gullie washers will be top candidate for investigations.<br />