Ice Within Craters

Palomar · 2005-07-21 05:54:14

http://antwrp.gsfc.nasa.gov/apod/ap050720.html

*That was posted yesterday in "Mars Express." I'm bringing it over here with a specific question. The crater walls average 300 meters in height. The ice pocket might be 200 meters thick. Crater itself is 35 km wide.

What would be the most efficient way for Martian colonists to harvest such ice?

--Cindy

C M Edwards · 2005-07-21 14:46:40

http://antwrp.gsfc.nasa.gov/apod/ap050720.html
What would be the most efficient way for Martian colonists to harvest such ice?
--Cindy

First off, cool picture! 8)

Now, if I wanted that ice...

The biggest deposit is at the bottom of a three hundred meter dropoff with what looks like a very uneven bottom (notice the steep lip around the ice and the offcenter pile of rock on one end?). So, getting down there is going to be risky. Solution: Send in the probes! A small rover equipped with a rudimentary seismograph could find a nice spot that is both flat enough and solid enough to land on and set up shop.

If I couldn't do that, then please note that this photograph doesn't show just one ice deposit. There are several small deposits all around the rim of the crater. If Endurance crater is any indication, an off-center impact crater is likely to have a layer of deeply broken rock around its upper rim, and this will hold both dust and ice in the gaps between the boulders. That ice can be extracted, and the broken rock and tailings can be discarded right into the crater.

If I couldn't do that either, given the probable structure of the crater rim there is still bound to be extractable ice in it. Subliming that ice will bring water vapor up through those cracks in the rock. I would heat the surrounding soil and try to collect the gas as it came out. This can be done with a power source or by brushing off the top layers of dust and letting the sun do the work for you. It might even already be occuring quite naturally. We could easily find the first gas wells on Mars just sitting there waiting to be capped off.

The caption says that the ice is still there because the sun angle doesn't reach to the bottom of the crater, but that's consistent with neither the fact that there are ice deposits all over the top of the crater where the sun shines every day of the year, nor the fact that we can actually see the bottom of the crater quite clearly. I wouldn't put much stock in that explanation, except to say that the sun at 70 degrees north latitude might not give enough heat to mine the ice, particularly in the very bottom of the crater.

All three methods require mining equipment, but not all methods require the same equipment. There's bound to be a cost effective method to go after at least one of those ice deposits.

Mace · 2005-07-21 20:38:50

How about this giant project? First we dig a little ditch around the entire thing. Then we cover the entire thing with clear plastic. Finally we get our orbiting spacecraft to deflect a laser from Earth and ZAP and poof the ice becomes a gas. Then as it cools it becomes a liquid and slids down the plastic into the ditch which flows right to our containment unit. A bit grand scale but the plastic could always be reused for the colonies after the water is collected.

Or we could just build the colony on the ice sheet.

C M Edwards · 2005-07-22 10:04:10

Or we could just build the colony on the ice sheet.

Now you're talking!

I know we've all been holding out for that special tropical garden spot on Mars. But, with the construction of a suitable road (the crater walls are probably not steep enough to require a tunnel), something like this polar crater could be the next best thing.

Shaun Barrett · 2005-07-26 00:17:03

Spectacular picture!
I wonder how the ice came to be there?

Did groundwater flow into the crater and freeze?
Did it snow heavily in the past and leave this crater full of ice?
Do any neighbouring craters have ice deposits also, perhaps hidden under dust?
:?:

Incidentally, if those crater walls are 300 metres high, the ice looks too shallow to be up to 200 metres deep - at least to me (?)
:?

Palomar · 2005-07-26 05:10:52

Spectacular picture!
I wonder how the ice came to be there?
Did groundwater flow into the crater and freeze?
Did it snow heavily in the past and leave this crater full of ice?
Do any neighbouring craters have ice deposits also, perhaps hidden under dust?

*Yeah, those are really good questions. I've had similar questions in mind. It's quite a concentration of ice, no?

--Cindy

Commodore · 2005-07-26 08:06:11

How bout a giant dome over the whole crater, and gradually line the bottom in concrete. Then the ice is melted, soil is trucked in, atmosphere is provided.

And we have the first lakeside resort on Mars.

Shaun Barrett · 2005-07-26 22:20:54

Cindy:-

It's quite a concentration of ice, no?

It's quite a concentration of ice .. YES!

And it just underlines the huge difference between the Moon and Mars when it comes to readily available resources. With Luna, we're scratching around looking for theoretical ice deposits in shadowed polar craters, while on Mars we have plentiful water ice for sure .. as well as unlimited carbon, hydrogen, nitrogen and all the other elements necessary for a thriving colony.

God! I hope we don't spend too long faffing around on the Moon. I want to get on with the Mars thing!

Palomar · 2005-07-27 05:07:54

Cindy:-
It's quite a concentration of ice, no?
It's quite a concentration of ice .. YES!
And it just underlines the huge difference between the Moon and Mars when it comes to readily available resources. With Luna, we're scratching around looking for theoretical ice deposits in shadowed polar craters, while on Mars we have plentiful water ice for sure .. as well as unlimited carbon, hydrogen, nitrogen and all the other elements necessary for a thriving colony.
God! I hope we don't spend too long faffing around on the Moon. I want to get on with the Mars thing!

*This'll come as no surprise: Of course I agree with you. At least Mars has an atmosphere and its gravity is stronger than Luna's.

Honestly, I don't get the fascination with Luna. Robotic exploration, yes. Probes, yes. But manned? It just seems so danged impractical.

We've been faffing around in LEO for the past 30 years, so I'm not holding my breath. Recently saw a certain current vehicle referred to as "NASA's pride." I felt like sticking my finger down my throat when I read that...LOL.

IMO, too many people in "the business" willing to settle for 2nd best. Well that ain't me.

--Cindy

BWhite · 2005-07-28 19:30:49

Cindy:-
It's quite a concentration of ice, no?
It's quite a concentration of ice .. YES!
And it just underlines the huge difference between the Moon and Mars when it comes to readily available resources. With Luna, we're scratching around looking for theoretical ice deposits in shadowed polar craters, while on Mars we have plentiful water ice for sure .. as well as unlimited carbon, hydrogen, nitrogen and all the other elements necessary for a thriving colony.
God! I hope we don't spend too long faffing around on the Moon. I want to get on with the Mars thing!

Shaun, next time you argue with a lunatic about lunar ice, cite NASA scientist Wendell Mendell. At Return to the Moon he was very critical of the lunar polar ice theory. He says the stuff just ain't there.

Maybe I will google some links and edit, when I get bored of politics. :?

DonPanic · 2005-07-29 01:53:24

LO

Spectacular picture!
I wonder how the ice came to be there?

Can suppose that it's summer remains of larger CO2 and water ice winter condensation deposit, no ?

Anyhow, ESA tells that by September, we'll know more about underground Mars water.

Shaun Barrett · 2005-07-29 20:17:22

DonPanic:-

Can suppose that it's summer remains of larger CO2 and water ice winter condensation deposit, no ?

If so, shouldn't all the shadowed craters at those latitudes have ice remnants in them? :?:

Shaun Barrett · 2005-07-29 21:26:49

Getting back to the point of this thread, which I confess I was partly responsible for side-tracking [ :oops: ], here's Cindy's original question again:-

What would be the most efficient way for Martian colonists to harvest such ice?

I think it depends on the size of the colony to some extent, and whether the colonists want the ice just for their immediate needs, like drinking, washing, and perhaps splitting off the oxygen for breathing, or whether they want to set up a large propellant factory.

Many scientists believe the icy polar regions of Mars may be the best place to look for life because they're the latitudes where the existence of water, albeit in the solid phase, is an established fact (as a brilliant photo like this one demonstrates so well). It's conceivable some of the first crewed missions might be sent to regions like this for precisely those reasons - the certainty of finding water and the possibility of detecting life.
If so, initially the astronauts may be content to cut out chunks of the ice and carry them back into the Hab through the airlock, where it can be melted into containers. i.e. The simple low-tech solution!

-- If you want a larger industrial method of utilizing the ice, the ideal way would be to seal off a large area of the ice deposit under a pressurized dome. But raising the pressure too high under that dome brings problems with the very large forces exerted, which tend to rip the dome from its foundations. Fortunately, you wouldn't have to raise the pressure very high under the dome to allow the ice to melt and remain liquid - perhaps only 15 millibars above ambient would be plenty. This translates into about 150 kgs per sq. metre of ice surface enclosed. If your dome is, say, 20 metres across, the amount of upward force on the dome would only be some 47 tonnes.
-- With a perimeter of about 628 metres, that means each metre of the dome skirt would only need to resist an upward force of about 75 kilograms. I think this could be achieved by melting the skirt into the ice using a localized heat source and then allowing the intense Martian cold to re-freeze it.
-- Under the dome, astronauts in spacesuits could use solar energy to melt the surface ice, creating pools, and pump the precious liquid through insulated pipes into holding tanks inside the colony, or to wherever else it's required.

Tholzel · 2005-07-30 12:13:03

If so, initially the astronauts may be content to cut out chunks of the ice and carry them back into the Hab through the airlock, where it can be melted into containers. i.e. The simple low-tech solution!

On Everest we would leave the tent each mid day and hack out clunkers of water ice and carry it back. there, we had a full time stove just to melt it down for the day's drinking and cooking water. Low tech, high success rate.

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#1 2005-07-21 05:54:14

Re: Ice Within Craters

#2 2005-07-21 14:46:40

Re: Ice Within Craters

#3 2005-07-21 20:38:50

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#4 2005-07-22 10:04:10

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#5 2005-07-26 00:17:03

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#6 2005-07-26 05:10:52

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#7 2005-07-26 08:06:11

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#8 2005-07-26 22:20:54

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#9 2005-07-27 05:07:54

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#10 2005-07-28 19:30:49

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#12 2005-07-29 20:17:22

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