Transporting Water to Mars

[Dominatus]

I'm currently working on a project, and was curious as to how to transport a few tons of water to mars.(or any other planet). So I was wondering if it would be more fuel and cost efficient to carry it as vapor, ice, or as liquid... Maybe a few launches and rendezvous to the interplanetary stage in orbit, a little at a time... I don't know. Be nice to hear what some other bright minds think.

[sal_vager]

If it's just a few tons needed you can probably find it on Mars already, we know there is water there now, might as well find ways to extract it

[Krevsin]

The mass is the same in any given case, but plain water requires the least amount of messing around with the cooling systems and requires a relatively small amount of space (1 cubic meter for 1 ton, can't get more straightforward than that) to be ferried around with.

But I agree, it is easier to just mine the thing. Or you could just send hydrogen there and use the Oxygen present in Mars's Carbon Dioxide atmosphere. It'd require some chemical equipment, but I think the overall tonnage of Hydrogen plus the equipment would be lower than just ferrying water there.

Edited November 9, 2013 by Krevsin

[Scotius]

Why would you transport water to Mars? Mars soil contains about 2% of chemically tied water. Haul refinery and nuclear reactor there, and you will have constant supply of water. And it's not accounting for water that probably is frozen at Mars poles. But if you insist - carrying water from Earth is horribly cost prohibitive. You would be better off finding an asteroid containing water (dead comet perhaps) and transporting it to Mars.

[Ralathon]

The thing that really matters when transporting stuff throughout the solar system is mass. More mass = bigger payload fraction = less delta V.

So when transporting water the state only influences what container it needs. A ton of water weighs the same whether its gas or solid after all. This means storing it as steam is completely out of the question, that means you need a huge (And therefore heavy) container with powerful heating equipment.

The solid - liquid difference is a bit harder to determine. If you transport it from earth to mars liquid is probably best. Liquid water is denser than ice so you can fit more in the same tank. If you go out farther it probably shifts in the favor of ice. That's because ice is stable in a vacuum if it's colder than -55 degrees Celsius (or something in that order, going from memory here). This means that you don't need a container at all as long as you stay far away from the sun. Just glue a engine to a block of ice and push it around.

As for sending it all up at once vs multiple launches. It is best to send it all at once. This is because rocket engines are single use and really expensive, if you send up the water in 5 launches it'll take the same amount of fuel but 5 times the engines. Besides, a few tons isn't that much in terms of payload.

[lajoswinkler]

Until humans find a way to extract extremely low amounts of water in Martian soil (we've already discussed it at length, it is drier than Sahara sand), water will have to be carried along, and it will be quite some time before such need vanishes.

Liquid water is the best because its density is greater than ice.

[Vaebn]

Nuke a comet into a collision cource with it, simples.

Edited November 9, 2013 by Vaebn

[bradley101]

Until humans find a way to extract extremely low amounts of water in Martian soil (we've already discussed it at length, it is drier than Sahara sand), water will have to be carried along, and it will be quite some time before such need vanishes.

Liquid water is the best because its density is greater than ice.

Have you read any data? http://www.space.com/22949-mars-water-discovery-curiosity-rover.html A liter of water per cubic foot. Use a inflatable green house that uses he natural sunlight to extract the water into vapor. Then you condense is simple. No power needed light weight to bring to mars.

[Kryten]

Yes, he did-that's hydrated minerals, it's not like we're talking about wet sand here. A greenhouse is going to do absolutely nothing.

[bradley101]

Yes, he did-that's hydrated minerals, it's not like we're talking about wet sand here. A greenhouse is going to do absolutely nothing.

But still is higher concentration of water ie permafrost with maybe as low as 10-15% concentrations the greenhouse affect could work. Under the right conditions it could be a low maintainence water extraction system move it from place to place so you don't use up all the water one area. Make the top of the dome like a lens to increase the effect. Even if you have the water locked in chemicals if you base is running off nuclear power use the vast waste heat of the reactor to bake the water out cheap and easy as your utillizing your resources to the max.

[lajoswinkler]

Unfortunatelly it's not that simple. It will not work. To purge water you'd need a nuclear reactor to heat it to several hundred °C.

Given the average progress of space exploration, humans will need to carry their own water for a long, long time.

[Scotius]

Not if we find big enough deposits of ice on site. We know there is ice near Moon's poles. And possibly there are frozen lakes buried under layer of Mars soil. If we locate them, getting water is just a question of digging deep enough. And then purifying the stuff

[lajoswinkler]

Yeah, if.

This subject has been beaten to death on KSP forum, I don't have much more to say about it...

[JebidiahsBigSister]

If you carry it as liquid or ice then you can use it as radiation shielding