Author Topic: Mars HSF landing sites?  (Read 17123 times)

Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #40 on: 05/30/2015 11:37 am »
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Also, what sort of robotic mission would give us maximum confidence short of actually digging down tens of meters?
Good question. I don'y know the answer, but it seems reasonable that if we can detect water from orbit we should be able to detect it with more confidence from the ground surface.
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Online Russel

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Re: Mars HSF landing sites?
« Reply #41 on: 05/30/2015 11:44 am »
Who has that map of inferred water percentage?

Edit: Oh never mind, I Googled this..

http://www.astrobio.net/articles/images/mars_water_mosaic.jpg

Anyhow, what that map says to me is that first of all we don't know about anything deeper than a metre. But that in that top metre there plenty of soils with over 3% water equivalent (measured by hydrogen content). I'm tempted to be a bit more favorable towards processing soil. But, only where there is loose soil. the kind you can brush, sweep or vacuum up.

Also, the patches on this map that are of interest (near the equator) seem to lie in a spot close to 180 East/180 West and around 20 degrees East.

Now how much of those areas intersects with at least 1Km below MOLA? Sorry about the scale on that map.
« Last Edit: 05/30/2015 12:02 pm by Russel »

Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #42 on: 05/30/2015 03:16 pm »
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Before you guys go any further, remember that '10 or 10s of meters' was me guessing from the thickness of a line from a diagram I may not have read right. Go and look at it and you will see what I mean. I was really asking if anyone had real info about it.
Done and done, but I have nothing to add. We need a specialist!
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Offline guckyfan

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Re: Mars HSF landing sites?
« Reply #43 on: 05/30/2015 03:24 pm »
OK first we would need to establish, how deep the ice really is. A sonar can do that easily. The reflective properties of ice is extremely different to regolith.

Digging down there? A small bulldozer can dig a trench in a few weeks, not a problem at all. And then there is pure water ice. A glacier will in all likelihood contain pure drinking water. Maybe not a task for a 4 man 4 week mission. But a very minor thing for anything larger than that.

Offline nadreck

Re: Mars HSF landing sites?
« Reply #44 on: 05/30/2015 05:08 pm »
OK first we would need to establish, how deep the ice really is. A sonar can do that easily. The reflective properties of ice is extremely different to regolith.

Digging down there? A small bulldozer can dig a trench in a few weeks, not a problem at all. And then there is pure water ice. A glacier will in all likelihood contain pure drinking water. Maybe not a task for a 4 man 4 week mission. But a very minor thing for anything larger than that.

Rather than strip mining the water and allowing quite a bit (more and more after time) to sublime away, I would suggest drilling down to it initially, tunnelling down later and probably making use of space in the ice, I think habitats could be more easily built in that space than regolith.  Also I don't see that ice that built up over time in a glacier would not be as much as 10% suspended particles. If this is glacier, the surface that isolates it from the atmosphere it would sublime into is probably the sediment from the top layers subliming away.
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #45 on: 05/30/2015 10:38 pm »
OK first we would need to establish, how deep the ice really is. A sonar can do that easily. The reflective properties of ice is extremely different to regolith.

Digging down there? A small bulldozer can dig a trench in a few weeks, not a problem at all. And then there is pure water ice. A glacier will in all likelihood contain pure drinking water. Maybe not a task for a 4 man 4 week mission. But a very minor thing for anything larger than that.
A small correction: I think you meant indifferent to regolith, which is very informative.

I actually have experience in operating construction equipment. In theory a  bulldozer might work to dig a trench, but in practice you frequently run into boulders or hard ground that requires a narrow bucket with teeth. I mostly used a loader/backhoe to dig a trench. The depth was limited by the length of the backhoe arm, about 2-1/2 to 3 m.

If we need to reach down 5 to100 meters I would trade in this equipment for a well driller of the same mass. On Earth we routinely drill water wells down to 400 m or so and IMO it could work on Mars. When we decide to use the water ice we would insert a well casing down into the zone of ice. Then we would drop down a heat source to melt the ice, a well pump and a flexible pipe to bring water to the surface, We would have to continuously warm the water to maintain its liquid state.

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Offline KelvinZero

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Re: Mars HSF landing sites?
« Reply #46 on: 05/31/2015 02:34 am »
A small correction: I think you meant indifferent to regolith, which is very informative.
Im confused whether you are saying sonar will not work, or it will work even if the ice is mixed with regolith. Remember Poe's Law! I can't detect satire without smilies... like this: ;)

Online Russel

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Re: Mars HSF landing sites?
« Reply #47 on: 05/31/2015 03:23 am »
I hate to be no-fun but so far we have absolutely zero direct evidence of there being something-like-ice close to the surface anywhere on Mars anywhere within 30 degrees of the equator. We have some theories and suppositions that there almost certainly is some shallow ice in some circumstances but so far we don't have any actual locations. And my suggestion is that such deposits of something-like-ice anywhere near the equator have to be actually found and characterized.

Added to your misery is that when you do actually discover subsurface ice on Mars (I'm certain we will) then you'll run into practical issues. You may find the layer of ice is thin (even just a few inches) and when you do try to drill/extract it the overlying strata subsides and you lose flow. You may find that the heat you try to use is ineffective because melt water may find other paths or the veiny nature of the ice means you have to heat a prohibitively large volume of soil/rock.

In short what you really need is a thick deposit of ice, many meters deep. You'll need to accurately characterise the "ore" body just as they do on Earth, which involves landing instrumentation and doing a field survey at many points at once. Space based instruments probably aren't going to see far enough below the surface.

And I'd bet you lunch and dinner that such easy to mine deposits will show up but they will be fairly rare at any useful latitude. Meaning you could send a robotic mission to do this kind of detailed geological survey but it will be hit and miss.

Also, if you mine a hole inside a large deposit of ice and try to call it a shelter, please count me out. that would be so unstable. I'd rather just blow a hole in a cliff face.

Offline guckyfan

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Re: Mars HSF landing sites?
« Reply #48 on: 05/31/2015 07:20 am »
In short what you really need is a thick deposit of ice, many meters deep. You'll need to accurately characterise the "ore" body just as they do on Earth, which involves landing instrumentation and doing a field survey at many points at once. Space based instruments probably aren't going to see far enough below the surface.

I see a deposit of 100 1 million km³ qualifying as "a thick deposit of ice, many meters deep".

Corrected wrong number but the argument is still true. ;)

I am also surprised that you are so much better informed than the University of Nantes and the Institute of Planetary Research of DLR  in Berlin, Germany. They do not give 100% certainty but a very high confidence of their finding. That is why I suggested that sonar probes at the surface would be needed before a mission relies on that water.

And I mean different reaction of regolith vs. ice to sonar to find the depth of that ice.
« Last Edit: 05/31/2015 05:35 pm by guckyfan »

Offline guckyfan

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Re: Mars HSF landing sites?
« Reply #49 on: 05/31/2015 07:29 am »
It has been argued that those radar readings are ambiguous and may not point to water, because they identify hydrogen, not water. That may be a valid concern. Maybe it is oil deposits rather than water? But I don't really think so. ;)

About that glacier study. There is vast experience on plastic flow of ice and the geologic traces it gives. It is a very valid assessment that there is water in the identified area Vallis Marineris.

Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #50 on: 05/31/2015 08:45 am »
A small correction: I think you meant indifferent to regolith, which is very informative.
Im confused whether you are saying sonar will not work, or it will work even if the ice is mixed with regolith. Remember Poe's Law! I can't detect satire without smilies... like this: ;)I
It is very possible that I misunderstood. I thought you meant that sonar could reflect off ice effectively despite the presence of regolith overburden, therefore being indifferent to its presence. I am open to correction. (??)

If sonar is effective then sonar needs to be aboard the 2020 rover that is being planned. From info on this thread, we may agree that we need to employ it to verify the presence of glacial ice beneath Vallis Marineris.

I hope someone on this thread can attend the workshop. I cannot.
« Last Edit: 05/31/2015 09:09 am by Ionmars »
Could a Mars pole-vaulter set a new record? Not in a space suit. (smiley)

Offline guckyfan

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Re: Mars HSF landing sites?
« Reply #51 on: 05/31/2015 09:11 am »
It is very possible that I misunderstood. I thought you meant that sonar could reflect off ice effectively despite the presence of regolith overburden, therefore being indifferent to its presence. I am open to correction. (??)

Sonar can find boundaries within the underground. Propagation of sound is different in different materials and there will be reflection on a boundary of different materials. So they can determine how deep the ice is. That is what I was trying to say.

Offline KelvinZero

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Re: Mars HSF landing sites?
« Reply #52 on: 05/31/2015 09:20 am »
Btw I started a thread on excavation with impactors in advanced topics here..
Found this page that can allow a much more easily quantifiable discussion:
..and concluded that you could dig a 17 meter deep hole (and about 5m wide at bottom) with two impacts. It seemed to be easily within ARRM scales.

Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #53 on: 05/31/2015 09:34 am »



Sonar can find boundaries within the underground. Propagation of sound is different in different materials and there will be reflection on a boundary of different materials. So they can determine how deep the ice is. That is what I was trying to say.

Info received and appreciated. Now let's get sonar aboard the 2020 rover.
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Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #54 on: 05/31/2015 10:06 am »
Btw I started a thread on excavation with impactors in advanced topics here..
Found this page that can allow a much more easily quantifiable discussion:
..and concluded that you could dig a 17 meter deep hole (and about 5m wide at bottom) with two impacts. It seemed to be easily within ARRM scales.
Nice thread. I'm going there to respond so I won't go OT here.
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Offline Ionmars

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Re: Mars HSF landing sites?
« Reply #55 on: 05/31/2015 12:06 pm »
OK, here’s my report on the subject assigned to me by me in Reply #40:  “Mawrth Vallis as a Landing Site for HSF.”

Mawrth Vallis is a valley on Mars at 22.3°N, 343.5°E with an elevation approximately two kilometers below datum. It is an ancient water outflow channel and one of the oldest valleys on Mars (1).

Mawrth Vallis is located in the middle of a mysterious region on the boundary between the southern highlands and northern lowlands of Mars. At this line the entire planet suddenly drops in elevation. It is also conveniently near a hazard-free landing zone. The Mars Science Laboratory science team would use the 2020 rover to piece together the history of this puzzling site (2).

This region also holds special interest to science because of the presence of clay minerals (phyllosilicates) that form only if water is available. Some of the clays are montmorillonite, kaolinite and nontronite. On Earth such clays occur in weathered volcanic rocks or in hydrothermal systems where volcanic activity and water interact. Such clay minerals preserve microscopic life, so traces of ancient life might be found at Mawrth (1).

[Image 1 below]


Evaluation as a HSF landing site:

(a) Proximity to nearest surface ice:    unknown (poor)   
(b) Atmospheric pressure/elevation:   -2000 km (good)
(c) Temperature range:          unknown
(d) Latitude:         22.3 degrees N (Fair for L/L)
(e) Small crater or hillock available: Yes, the tiny crater just north of the 24-mile wide crater may be about the right size.

[Image 2 below]

(f) Flat hard area within the crater: unknown

Conclusion: Among the sites being studied for the 2020 rover mission there is no doubt that some are outstanding candidates for an HSF landing site. This is not one of them.

References
(1)   http://en.wikipedia.org/wiki/Mawrth_Vallis
(2)   http://mars.nasa.gov/msl/mission/timeline/prelaunch/landingsiteselection/mawrthvallis2/
« Last Edit: 05/31/2015 12:22 pm by Ionmars »
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Online Russel

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Re: Mars HSF landing sites?
« Reply #56 on: 05/31/2015 12:07 pm »
In short what you really need is a thick deposit of ice, many meters deep. You'll need to accurately characterise the "ore" body just as they do on Earth, which involves landing instrumentation and doing a field survey at many points at once. Space based instruments probably aren't going to see far enough below the surface.

I see a deposit of 100 million km³ qualifying as "a thick deposit of ice, many meters deep".

I am also surprised that you are so much better informed than the University of Nantes and the Institute of Planetary Research of DLR  in Berlin, Germany. They do not give 100% certainty but a very high confidence of their finding. That is why I suggested that sonar probes at the surface would be needed before a mission relies on that water.

And I mean different reaction of regolith vs. ice to sonar to find the depth of that ice.

That thick deposit of ice is near the equator?

Online Russel

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Re: Mars HSF landing sites?
« Reply #57 on: 05/31/2015 12:13 pm »
It has been argued that those radar readings are ambiguous and may not point to water, because they identify hydrogen, not water. That may be a valid concern. Maybe it is oil deposits rather than water? But I don't really think so. ;)

About that glacier study. There is vast experience on plastic flow of ice and the geologic traces it gives. It is a very valid assessment that there is water in the identified area Vallis Marineris.

I'm quite happy to believe that hydrogen signature is hydrated minerals. But if you're basing a landing site on mining water from soil then you're going to be steered towards area with a lot of loose surface soil and areas that have higher concentrations of water.

The questions I keep groping at are these.

In the areas where you have easily mined soils (deep and loose) is there a correlation or an anti-correlation between that desirable property and water content.

In the areas of the planet that have shown up as having higher concentrations of water in the top metre of soil (again we're talking about the equatorial zone) is there any correlation between these areas and areas of scientific interest and areas that are below "sea level". From the maps I linked earlier I think there's only a few small areas that are both high in water and below "sea level".

Also I might add that deep loose soil isn't necessarily a good thing for a landing site.

Offline guckyfan

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Re: Mars HSF landing sites?
« Reply #58 on: 05/31/2015 12:22 pm »
That thick deposit of ice is near the equator?

http://www.dmzone.org/papers/Gourroncetal2014_VM.pdf

Yes the Vallis Marineris according to that paper.

Online Russel

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Re: Mars HSF landing sites?
« Reply #59 on: 05/31/2015 12:47 pm »
That thick deposit of ice is near the equator?

http://www.dmzone.org/papers/Gourroncetal2014_VM.pdf

Yes the Vallis Marineris according to that paper.

Ok, I'm not a geologist but my reading of that paper is that its worth looking for. Here are the most important paragraphs..

Quote
6.2. Ice preservation
Surface ice is currently not stable at the Martian equator (Fanale
et al., 1986; Baker, 2001). However, field observations in ice disintegration
landscapes on Earth and theoretical calculations demonstrate that
mantling of relict ice bodies by debris layers as thin as a few decimeters
is enough to significantly inhibit rates of ice disintegration by melting
(Ostrem, 1959; Mattson et al., 1993) or by sublimation (Marchant
et al., 2002; Kowalewski et al., 2006, 2011). The development of
protecting ablation tills during the first stages of glacial disintegration
can thus explain the preservation until the present day of huge volumes
of ancient ice on Valles Marineris chasma floors, as it does at higher
latitudes on Mars (Squyres, 1978, 1979; Shean et al., 2005; Milkovich
et al., 2006; Holt et al., 2008). In addition, rock debris produced by
periglacial weathering at high elevations along valley walls and around
basement massifs can have accumulated on the ice surface during
the glaciation and favored later preservation of stratified benches and
lateral banks. Paraglacial mass movements also are able to provide a
large amount of debris during deglaciation and thus contribute to ice
preservation.]

and

Quote
7. Conclusion
Self-consistent landform assemblages indicate that Valles Marineris,
the giant valley system that stretches along the Martian equator, was
entirely glaciated during late Noachian to early Hesperian times and
still contains huge volumes of fossil ice inherited from this ancient
glaciation. Alternative nonglacial interpretations may be tentatively
proposed for the individual significance of each landform described
here. However, a glacial interpretation is supported by the fact that
these individual landforms collectively compose an elegant and selfconsistent
assemblage typical of a relict glaciated valley landsystem.
Fig. 13 shows our favored scenario for the history of this glacial fill.
The Valles Marineris glacial system comprised wet-based glaciers
that were able to flow and slide over their beds at some time of their
history at least. It was most probably fed by ice accumulating at low
elevations directly from the atmosphere onto chasma floors and valley
walls, with only minor contributions from tributary glaciers flowing
down from higher elevations. Similar fossil glacial landsystems dating
back from the early Martian history are to be expected in many other
low-latitude troughs such as chasmata, chaos, valleys, impact craters,
and other basins.

They're not exactly making a claim about how much fossil ice exists although they are making a strong claim that it can be preserved and probably does exist in some places. They're also saying at one point that ice can survive a long time under relatively think layers of cover.

So the bottom line for me is you can't expect to strike it lucky the first go you drill. Its still a huge area. What I need more convincing of (and again I'm not a geologist) is whether the sort of ice that is preserved in this sort of situation is likely to be found in deep layers. Its a real possibility I guess, but you'd need to both find it (robotic mission) and then characterise it (another mission).

That being said it would be a real cool place to have a first human landing.

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