How "renewable" is water on mars?

[Elthy]

SpaceX ITS concept will need lots of water for fuel production, also its very likely that any human colony couldnt be a perfect closed cycle. So somehow the colonists would need asteady supply of water.

From what i know there is lots of water burried in the surface, getting it out of there isnt a big problem (just heat to evaporation). But what happens when they have processed most of the soil around the colony, will they have to dig futher away every time? Or does the water redistribute itself over longer timeframes?

[kerbiloid]

Looks that seasonal actions move large amounts water.

Another question: wouldn't they be "large" in Martian terms, like a dust storm in the vacuum.

[Xeorm]

Hard to say exactly. I don't think Mars is the type to have a mature water cycle. Nor do we have detailed analysis of any particular spot to determine how water is redistributed there. Even on Earth that'll be a complex question.

[Nibb31]

We really don't know much about water on Mars. Yet another point where SpaceX is putting the cart before the horse.

[WinkAllKerb'']

renewability of water is either %%inter/inner//proxy@base(s) either a %%@atmo. thingies 2cp of my own" "

[Finox]

We do know that Mars has frost and snow, in limited quantities by Earth standards, but the point is that water does cycle through the air and redistribute itself.   I doubt water will be much of a problem for a colony, from what we know the planet has enough water to cover itself in 30m of the stuff.   Although a large colony wouldn't want to process soil for its water, it would be easier to just drill a well...

[Nathair]

5 hours ago, WinkAllKerb'' said:

renewability of water is either %%inter/inner//proxy@base(s) either a %%@atmo. thingies 2cp of my own" "

Hm?

[insert_name]

On 2/3/2017 at 2:43 AM, kerbiloid said:

Looks that seasonal actions move large amounts water.

Another question: wouldn't they be "large" in Martian terms, like a dust storm in the vacuum.

The changes in the polar ice cap are mostly due to dry ice. However some of the probes we sent have had condensation, and opportunity spotted clouds of water ice in the sky. 

[magnemoe]

On 7.2.2017 at 0:54 AM, Finox said:

We do know that Mars has frost and snow, in limited quantities by Earth standards, but the point is that water does cycle through the air and redistribute itself.   I doubt water will be much of a problem for a colony, from what we know the planet has enough water to cover itself in 30m of the stuff.   Although a large colony wouldn't want to process soil for its water, it would be easier to just drill a well...

Drilling an well would be an good idea, even if water is frozen you could mine it, pump down steam to melt the permafrost and your get water. 
The drill hole would run dry after some time so you would need to drill new or extend the existing. 
This is just an annoyance as its so much water and you just need a few hundred tons. 
 

[kerbiloid]

There is water on Mars

Spoiler

 

[Zerxal]

We don't really know how much water there is on mars. We do have dry ice though at the poles, but that's not exactly water.

 

[magnemoe]

9 hours ago, PhysicsBrain said:

We don't really know how much water there is on mars. We do have dry ice though at the poles, but that's not exactly water.

 

Current estimates of permafrost indicate that its more than enough.  
People overestimates how much water is needed my multiple orders of magnitude, because they think earth and insane large scale use of cheap water. with an mars base. 
Even if we go full out, say 50 people, greenhouses, cracking water to refuel landers for return, just something with water like an small low yield marginal oil field where you use trucks to transport the oil will have enough water for hundreds of years. 
Issue on Mars is only how much gear you need to mine it as this has to be sent from Earth 

[softweir]

The difficult as I see it is the location of the water: most of it is at the poles, where sunlight is least available. It is true that Mars' thin atmosphere means that atmospheric attenuation of sunlight is much reduced compared to on Earth, but the angle of the sun above the horizon is very low, which would make collecting it technically difficult. And if they intend to use water and sunlight to produce fuel then they will need lots of sunlight!

[KerikBalm]

On 3/4/2017 at 1:59 PM, PhysicsBrain said:

We don't really know how much water there is on mars. We do have dry ice though at the poles, but that's not exactly water.

 

There are very large quantities of water ice at each pole. There is a layer of dry ice above the water ice, but this mostly sublimates away during the summer, and reforms during the winter.

https://en.wikipedia.org/wiki/Martian_polar_ice_caps

Quote

The caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, while the south cap has a permanent dry ice cover about 8 m thick.^[4] The northern polar cap has a diameter of about 1000 km during the northern Mars summer,^[5] and contains about 1.6 million cubic km of ice, which if spread evenly on the cap would be 2 km thick.^[6] (This compares to a volume of 2.85 million cubic km (km³) for the Greenland ice sheet.) The southern polar cap has a diameter of 350 km and a thickness of 3 km.^[7] The total volume of ice in the south polar cap plus the adjacent layered deposits has also been estimated at 1.6 million cubic km.

... but I haven't heard of any proposals for colonies near the polar caps, so.... anyway, supply of water at the poles would not be an issue - the issue would be heat and energy (one could go with nuclear reactors rather than solar)

[Green Baron]

We do know that Mars has frost and snow, in limited quantities by Earth standards, but the point is that water does cycle through the air and redistribute itself.   I doubt water will be much of a problem for a colony, from what we know the planet has enough water to cover itself in 30m of the stuff.   Although a large colony wouldn't want to process soil for its water, it would be easier to just drill a well...

 

Quoted from Finox. I still have problems with the forum editor. Or the editor with me.

 

Interesting. Care to provide us with a source ?

 

Edit: could as well be 2700m :-))

Don't cite me ! Just one link you can find when looking for water on mars ... i am trying to say that it might be wise to wait until moar data is available. Never judge an outcrop from afar ! :-)

 

Edited March 5, 2017 by Green Baron