Water found on Mars!

[daveboy2000]

Title says it all, source right here: http://www.space.com/22949-mars-water-discovery-curiosity-rover.html

[bigdad84]

Now, it's just up to us, to send humans there.

[Scotius]

And abundance of deuterium too Worth remembering, especially in case Fusion Driven Rocket will eventually fly to Mars.

[czokletmuss]

Gosh damn it to heck!

NASA's Mars rover Curiosity has found that surface soil on the Red Planet contains about 2 percent water by weight. That means astronaut pioneers could extract roughly 2 pints (1 liter) of water out of every cubic foot (0.03 cubic meters) of Martian dirt they dig up, said study lead author Laurie Leshin, of Rensselaer Polytechnic Institute in Troy, N.Y.

Wow. Just wow. This is the most important discovery made by Curiosity so far, maybe even by any Mars lander.

[SargeRho]

the FDR could easily carry enough fuel for a few roundrips.

WATER ON MARS, B****ES.

Wouldn't this mean that a Mars Direct-style mission would be even easier, since no Hydrogen would have to be carried along?

Edited September 26, 2013 by SargeRho

[czokletmuss]

Yup - I bet there will be a big party tonight in Mars Society.

[Anton P. Nym]

Keep in mind this isn't liquid water; some is ice, most is chemically-bound into the soil. So there'll be rejoicing in rocketry circles, but the bio guys are moping a bit and scuffing the dirt with their toes.

-- Steve

[SargeRho]

You can get up to a liter of liquid water out of a cubic meter of soil. I think that's something to rejoice about.

I assume they mean pure water though, so minerals and stuff would need to be added.

[Kerbin Dallas Multipass]

You can get up to a liter of liquid water out of a cubic meter of soil. I think that's something to rejoice about.

Its actually round about 35 liters per m³

[SargeRho]

So yeah, something to rejoice about.

[lajoswinkler]

Wow, space.com, reporting about water on Mars and they use pints and feet, with SI units in brackets.

Anyway, this is a great discovery, but the press and the researchers should be more careful because we've got some bull**** right here.

It says 2% by weight, which means that 1 kg of soil has 20 g (20 ml) of water. OK, that's fine.

But where does the water come from? The rover heated the sample to 835°C. That's destructive heating. Pyrolysis. Granted, some water is in the form of water ice, but how much? If such high temperature was needed to push all water out, then some of it is chemically bonded, therefore Leshin's statement:

"I was really happy when we saw that there's easily accessible water here in the dirt beneath your feet. And it's probably true anywhere you go on Mars."

is totally over the top. Nobody can claim that a total of 2% of water is easily accessible. It seems like future astronauts will just have to shovel some dirt into their habitat units, put it in a funnel with a filter and let it thaw and drip into a beaker. That's not going to happen. Martian regolith is very dry, something like our deserts.

I'm excited abut this discovery, but I resent their hyped tone that leads to disinformation. You can't do that if you're a scientist.

[Kerbin Dallas Multipass]

@lajoswinkler

I'm very uneducated when it comes to chemistry. What does that mean?

What numbers would we get if we ran the same procedure on sahara sand or moondust?

[SargeRho]

It's more easily accessible than being deep under ground. Generating heat is not a difficult task on Mars.

[lajoswinkler]

@lajoswinkler

I'm very uneducated when it comes to chemistry. What does that mean?

What numbers would we get if we ran the same procedure on sahara sand or moondust?

It basically means you have to fry the **** out of the soil to decompose some stuff inside and release water vapor. The fact it will be contaminated with toxic stuff is not accounted for in the article (Mars has perchlorate salts; trace, but enough to be a nuisance).

It's like when you heat calcium carbonate to push out CO2 and you get quicklime in the process. Some of the Martian minerals obviously have bonded water.

Recently, bonded water has been definitely proven to exist in Moon's regolith. Apollo scientists knew about it, but thought it was Earth contamination. Still, Moon regolith contains less water than any Earth soil in existence.

I really don't know the correct numbers. A geologist might be able to find some references. Sahara sand gets into contact with dew every night (animals lick it), so you can imagine there are significant amounts of water in it.

It's more easily accessible than being deep under ground. Generating heat is not a difficult task on Mars.

Generating high temperature is easy. But what about heat? I wouldn't say that's easy at all. If you want a sip of water, you have to put a shovel of regolith in a high temperature furnace (huge RTG?) and collect/condense the vapor, then purify it. People require more than a litre of drinking water each day and you get only 20 ml from a kilo of soil.

[Nibb31]

Wow, space.com, reporting about water on Mars and they use pints and feet, with SI units in brackets.

Space.com is quite rubbish. Its articles always seem to be written for the average American who know nothing about space, so they have a high percentage of fluff and sensationalist approximations.

is totally over the top. Nobody can claim that a total of 2% of water is easily accessible. It seems like future astronauts will just have to shovel some dirt into their habitat units, put it in a funnel with a filter and let it thaw and drip into a beaker. That's not going to happen. Martian regolith is very dry, something like our deserts.

I'm excited abut this discovery, but I resent their hyped tone that leads to disinformation. You can't do that if you're a scientist.

I agree, 2% humidity is really dry. The Sahara desert hardly ever gets below 4%.

To fill a 10 ton tank of liquid hydrogen would require processing thousands of tons of Martian soil. It would potentially require either some very heavy machinery, a huge amount of energy, and a very long time to process.

Edited September 27, 2013 by Nibb31

[bsalis]

People require more than a litre of drinking water each day and you get only 20 ml from a kilo of soil.

True... but any manned mission to Mars will recycle water for human consumption. Extracting water from soil would be to replace any incidental loss and water that cannot be recycled.

Main benefit of water present is to be able to split it into fuel and oxidiser. Powering all that and keeping the liquid hydrogen in the damn tank could be a challenge though. A small LFTR reactor could cover that I suppose.

[karolus10]

Well, I'm very happy that It's not about this:

Water on REAL Mars... so exiting !

[Seret]

The water may be there, but let's just remember that to get it out, you have to heat the soil to several hundred degrees. The energy cost of doing so is quite large, so you need to already have an abundant energy source to get access to the water. Still good news, but it does limit the applications of this water that are practical.

For a rough ballpark figure of how much energy is required, let's take the specific heat capacity of dry earth, since all things considered Martian dirt is pretty dry. So at 1.26kJ kg^-1 K^-1 you're looking at about 560MJ of energy to raise 500kg of dirt by 895K (the 835C plus the average Mars temp of -60C) and extract 1 litre of water. So to produce ten litres per day you need a power plant with an output of at least 3.9MW (assuming no storage losses, etc) plus a bit of energy required to dig up and handle five tons of dirt. That's a large power plant to supply a very small amount of water. You could use the waste heat from a nuclear plant that was somewhat larger again, but you're unlikely to have an electrical demand high enough to make that a particularly efficient option.

Edited September 27, 2013 by Seret
Derp

[ecat]

The water may be there, but let's just remember that to get it out, you have to heat the soil to several hundred degrees. The energy cost of doing so is quite large, so you need to already have an abundant energy source to get access to the water. Still good news, but it does limit the applications of this water that are practical.

For a rough ballpark figure of how much energy is required, let's take the specific heat capacity of dry earth, since all things considered Martian dirt is pretty dry. So at 1.26MJ kg^-1 K^-1 you're looking at about 560GJ of energy to raise 500kg of dirt by 895K (the 835C plus the average Mars temp of -60C) and extract 1 litre of water. So to produce one litre per day you need a power plant with an output of at least 390MW (assuming no storage losses, etc) plus a bit of energy required to dig up and handle half a ton of dirt. That's a very large power plant to supply a very small amount of water. You could use the waste heat from a nuclear plant that was somewhat larger again, but you're unlikely to have an electrical demand high enough to make that a particularly efficient option.

Isn't that kJ in the specific heat capacity of dry earth table?

Also, although the SAM instrument on Curiosity heats the sample to 835degC it does not mean the water is released at 835degC. If much of the water is released at a lower temperature the energy requirements are further reduced.

Thinking about point made earlier in the thread on the storage of hydrogen, how much does the low ambient temperature help?

[Seret]

Isn't that kJ in the specific heat capacity of dry earth table?

Quite right, editted.

Also, although the SAM instrument on Curiosity heats the sample to 835degC it does not mean the water is released at 835degC. If much of the water is released at a lower temperature the energy requirements are further reduced.

Sure, but we are talking about breaking up chemical bonds here, not just vapourising the water. If you drop the temperature the reaction rate will drop. I couldn't tell you if a lower temp would be practical, a chemist might have a better idea.

Thinking about point made earlier in the thread on the storage of hydrogen, how much does the low ambient temperature help?

It might mean that whatever heat engine you were using would run at higher efficiency, since the output side could be in the low 200's kelvin. But it does mean you have to expend a lot of energy warming the dirt.

[Galacticruler]

aside from one or two people, is no body listening to the finding of Perchlorate in the soil?

that is some nasty stuff.

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

[Kryten]

That's not a 'finding', we've known about it since Pheonix. Nice to have confirmation, though.

[Galacticruler]

it is still technically a finding considering that Pheonix only landed somewhere else, I think it was a pole?

[Seret]

It's not news that there's moisture in the soil, it's the amount that had been the surprise. It's enough that extracting it becomes theoretically useful, although not terribly practical for large amounts IMO.

[lajoswinkler]

Also, although the SAM instrument on Curiosity heats the sample to 835degC it does not mean the water is released at 835degC. If much of the water is released at a lower temperature the energy requirements are further reduced.

Thinking about point made earlier in the thread on the storage of hydrogen, how much does the low ambient temperature help?

True, but the bonded water is probably released at several hundred degrees Celsius. Some of the water is just held by hydrogen bonds and will quickly evaporate at ~100°C, but the rest needs to be pushed out by calcination/pyrolysis.

Low ambient temperature will help with LH2 storage, although not a lot. Mars is not very cold in the regions where manned missions are planned.