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"If you think about a cubic foot of this dirt and you just heat it a little bit - a few hundred degrees - you'll actually get off about two pints of water - lik

"If you think about a cubic foot of this dirt and you just heat it a little bit - a few hundred degrees - you'll actually get off about two pints of water - like two water bottles you'd take to the gym," Dr Leshin explained. This is huge for Mars exploration by humans. 1. We can send unmanned expeditions to stockpile large tanks of water. 2. This would allow us to literally 3D print structures on the surface and allow us to significantly decrease the amount of materials we need to transport to the surface in order to build a habitat. Edit: 3. And ALICE rocket fuel could be created using this water and the aluminum found in the Martian soil.

JumpCrisscross 13y ago
Water doubles as a source of propellant. A human Mars trip may now only need to carry a one way load of propellant.
deleted 13y ago
[deleted]
- IvarRafn 13y ago
  Well a flame of a candle burns at around ~1500°C so it's not that much if you think about it.
elements 13y ago
Since people have been hopeful about finding water there for a while, are there any good estimates for how much exploration mission costs would be reduced by if water were found?
- bfe 13y ago
  One of the central costs of a round trip to Mars is the fuel for the return flight. With enough water at Mars we can manufacture all the methane/oxygen rocket fuel we need on site. The Mars Direct mission architecture and the NASA Johnson Space Center's Design Reference Mission derived from Mars Direct both assume we send hydrogen from Earth to manufacture rocket fuel for the return trip at Mars, combining it with atmospheric carbon dioxide into methane and oxygen, and saving 95% of the mass of the fuel versus bringing it all from Earth. They are estimated at $20-30 billion and $50 billion respectively (spread over ten to twenty years), compared with the earlier $450 billion price tag of the Space Exploration Initiative announced by President Bush 1, which was based on bringing all our fuel for the round trip with us from Earth. Not even having to send hydrogen from Earth would cut the cost further. Methane/oxygen rockets have been rare outside of Russia, but Pratt & Whitney demonstrated a working model of a modded RL10 rocket engine running on methane/oxygen. More to the point in the context of Mars missions, SpaceX is switching to methane/oxygen for their new Raptor engine.
  - kposehn 13y ago
    Are there benefits to methane/oxygen outside what you referenced?
    - bfe 13y ago
      Liquid hydrogen has what Elon Musk calls the pain-in-the-ass factor. It requires much higher volume tank at much lower temperature, adding lots of mass to the rocket, and it's impossible to effectively seal. RP-1 kerosene has the inconvenience of requiring your planet to have been covered with life a hundred million years ago. So, methane is the liquid fuel of choice for future martians.
    - jccooper 13y ago
      Methane, while less dense (thus requiring bigger tanks) has a higher specific energy than kerosene, and thus has a higher ISP (rocket efficiency). Methane is also less sooty and should have better cooling as its a "mild cryogenic" like liquid oxygen. Basically, it's between LH2 (hydrogen: high ISP, very low density, very very cold) and RP-1 (kerosene: lower ISP, high density, room temp) and may be a good compromise. And its derivable on Mars. Downside is there's very little flight heritage for a methane engine, so most of this is theoretical. EDIT: Paper: http://thehuwaldtfamily.org/jtrl/research/Propulsion/Rocket%20Propulsion/Propellants/DLR,%20Comparative%20Study%20of%20Kerosene%20and%20Methane%20Engines.pdf http://thehuwaldtfamily.org/jtrl/research/Propulsion/Rocket%...
bfe 13y ago
We can also electrolyze the water into oxygen and hydrogen for oxygen to breathe, and mix the hydrogen with carbon dioxide from the air to make methane, and use the methane and oxygen (or hydrogen and oxygen) for rocket fuel.
alex_stoddard 13y ago
In situ return journey propellant production has been a key element of Robert Zubrin's "Mars Direct" proposal: http://en.wikipedia.org/wiki/Mars_Direct http://en.wikipedia.org/wiki/Mars_Direct
jlgreco 13y ago
ALICE is Aluminum+Water Ice in case anybody is wondering. You basically make a slurry of very fine Aluminum powder and water, then freeze it. Very cool stuff.
xbryanx 13y ago
Aluminium Nano-thermites like ALICE are certainly cool, and certainly scary. Could you make a explosive more powerful than small atomic bombs? http://en.wikipedia.org/wiki/Nano-thermite http://en.wikipedia.org/wiki/Nano-thermite
- varjag 13y ago
  My physics is rusty, but I don't think any chemical reaction can approach the energy yield of fission or fusion.
warfangle 13y ago
They also suggest that one of the main components is perchlorate -- which, if turned into lithium perchlorate can be used for oxygen generation, and if turned into ammonium perchlorate can be used for solid rocket fuel.
- jonnathanson 13y ago
  The perchlorate hypothesis seems to be getting a lot of confirming evidence: http://www.sciencedaily.com/releases/2013/09/130926143246.htm http://www.sciencedaily.com/releases/2013/09/130926143246.ht... While the science dailies are pitching the perchlorate finding as a "setback" (because it complicates the search for organic molecules), it's indeed promising for fuel usage.
loceng 13y ago
Transporting material to Mars isn't going to be an issue with SpaceX's reusable rockets. Though 3D printing structures is a good idea and option to consider. And preemptively capturing water for use is smart.
zokier 13y ago
>2. This would allow us to literally 3D print structures on the surface and allow us to significantly decrease the amount of materials we need to transport to the surface in order to build a habitat. Could you explain the connection here? What does water have to do with 3D-printing?
- narfquat 13y ago
  I think he is using 3D printing synonymously with on-site fabrication of components. Not quite the same, but similar.
  - madaxe 13y ago
    Or he means literally 3D-print structures using water, which will freeze in the Martian atmosphere to form water ice - which is actually a pretty great structural material if used appropriately.
    - Filligree 13y ago
      Unfortunately, exposed ice will sublimate pretty quickly. You could possibly use it as a bulk structural material when covered, and certainly for radiation shielding.
      - bfe 13y ago
        You can also use water for holding your pressurized structures together: bolt some pipes to your structure, bury them, pour liquid water through the pipes and into the soil, let it freeze, and you've got anchors made of ice.
      - madaxe 13y ago
        Aye, true that. Well, cover it in mylar, and it was rads I was thinking of predominantly. You could potentially make something like http://en.wikipedia.org/wiki/Pykrete http://en.wikipedia.org/wiki/Pykrete using martian topsoil.
    - varjag 13y ago
InclinedPlane 13y ago
ALICE is unlikely to be the best idea for rocket fuel produced on Mars. We already know that it is easy to produce propellant on Mars using the sabatier reaction and the Martian atmosphere as the primary ingredient (to produce liquid methane and O2). Not only is this a high grade rocket propellant but also the vast majority of the mass comes from the atmosphere. Of the mass of the propellant only 1/4 of it would be methane and of that only 1/4 would be Hydrogen (1/16th of the total mass). This makes it feasible to ship over the Hydrogen feedstock from Earth and generate the remaining 94% of the mass of propellant using Martian resources. However, the easier it is to get water on Mars the easier it is to produce propellant in this way. However, we already know that substantial amounts of water ice underlie most of the Martian surface, materials that are as much as half water by mass only a meter or so below ground. This new information only means that it will take much less equipment to get at small quantities of water nearer the surface.

JumpCrisscross 13y ago

Water doubles as a source of propellant. A human Mars trip may now only need to carry a one way load of propellant.

deleted 13y ago

[deleted]

IvarRafn 13y ago
Well a flame of a candle burns at around ~1500°C so it's not that much if you think about it.

elements 13y ago

Since people have been hopeful about finding water there for a while, are there any good estimates for how much exploration mission costs would be reduced by if water were found?

bfe 13y ago
One of the central costs of a round trip to Mars is the fuel for the return flight. With enough water at Mars we can manufacture all the methane/oxygen rocket fuel we need on site. The Mars Direct mission architecture and the NASA Johnson Space Center's Design Reference Mission derived from Mars Direct both assume we send hydrogen from Earth to manufacture rocket fuel for the return trip at Mars, combining it with atmospheric carbon dioxide into methane and oxygen, and saving 95% of the mass of the fuel versus bringing it all from Earth. They are estimated at $20-30 billion and $50 billion respectively (spread over ten to twenty years), compared with the earlier $450 billion price tag of the Space Exploration Initiative announced by President Bush 1, which was based on bringing all our fuel for the round trip with us from Earth. Not even having to send hydrogen from Earth would cut the cost further. Methane/oxygen rockets have been rare outside of Russia, but Pratt & Whitney demonstrated a working model of a modded RL10 rocket engine running on methane/oxygen. More to the point in the context of Mars missions, SpaceX is switching to methane/oxygen for their new Raptor engine.
- kposehn 13y ago
  Are there benefits to methane/oxygen outside what you referenced?
  - bfe 13y ago
    Liquid hydrogen has what Elon Musk calls the pain-in-the-ass factor. It requires much higher volume tank at much lower temperature, adding lots of mass to the rocket, and it's impossible to effectively seal. RP-1 kerosene has the inconvenience of requiring your planet to have been covered with life a hundred million years ago. So, methane is the liquid fuel of choice for future martians.
  - jccooper 13y ago
    Methane, while less dense (thus requiring bigger tanks) has a higher specific energy than kerosene, and thus has a higher ISP (rocket efficiency). Methane is also less sooty and should have better cooling as its a "mild cryogenic" like liquid oxygen. Basically, it's between LH2 (hydrogen: high ISP, very low density, very very cold) and RP-1 (kerosene: lower ISP, high density, room temp) and may be a good compromise. And its derivable on Mars. Downside is there's very little flight heritage for a methane engine, so most of this is theoretical. EDIT: Paper: http://thehuwaldtfamily.org/jtrl/research/Propulsion/Rocket%20Propulsion/Propellants/DLR,%20Comparative%20Study%20of%20Kerosene%20and%20Methane%20Engines.pdf http://thehuwaldtfamily.org/jtrl/research/Propulsion/Rocket%...

bfe 13y ago

We can also electrolyze the water into oxygen and hydrogen for oxygen to breathe, and mix the hydrogen with carbon dioxide from the air to make methane, and use the methane and oxygen (or hydrogen and oxygen) for rocket fuel.

alex_stoddard 13y ago

In situ return journey propellant production has been a key element of Robert Zubrin's "Mars Direct" proposal: http://en.wikipedia.org/wiki/Mars_Direct http://en.wikipedia.org/wiki/Mars_Direct

jlgreco 13y ago

ALICE is Aluminum+Water Ice in case anybody is wondering. You basically make a slurry of very fine Aluminum powder and water, then freeze it. Very cool stuff.

xbryanx 13y ago

Aluminium Nano-thermites like ALICE are certainly cool, and certainly scary. Could you make a explosive more powerful than small atomic bombs? http://en.wikipedia.org/wiki/Nano-thermite http://en.wikipedia.org/wiki/Nano-thermite

varjag 13y ago
My physics is rusty, but I don't think any chemical reaction can approach the energy yield of fission or fusion.

warfangle 13y ago

They also suggest that one of the main components is perchlorate -- which, if turned into lithium perchlorate can be used for oxygen generation, and if turned into ammonium perchlorate can be used for solid rocket fuel.

jonnathanson 13y ago
The perchlorate hypothesis seems to be getting a lot of confirming evidence: http://www.sciencedaily.com/releases/2013/09/130926143246.htm http://www.sciencedaily.com/releases/2013/09/130926143246.ht... While the science dailies are pitching the perchlorate finding as a "setback" (because it complicates the search for organic molecules), it's indeed promising for fuel usage.

loceng 13y ago

Transporting material to Mars isn't going to be an issue with SpaceX's reusable rockets. Though 3D printing structures is a good idea and option to consider. And preemptively capturing water for use is smart.

zokier 13y ago

>2. This would allow us to literally 3D print structures on the surface and allow us to significantly decrease the amount of materials we need to transport to the surface in order to build a habitat. Could you explain the connection here? What does water have to do with 3D-printing?

narfquat 13y ago
I think he is using 3D printing synonymously with on-site fabrication of components. Not quite the same, but similar.
- madaxe 13y ago
  Or he means literally 3D-print structures using water, which will freeze in the Martian atmosphere to form water ice - which is actually a pretty great structural material if used appropriately.
  - Filligree 13y ago
    Unfortunately, exposed ice will sublimate pretty quickly. You could possibly use it as a bulk structural material when covered, and certainly for radiation shielding.
    - bfe 13y ago
      You can also use water for holding your pressurized structures together: bolt some pipes to your structure, bury them, pour liquid water through the pipes and into the soil, let it freeze, and you've got anchors made of ice.
    - madaxe 13y ago
      Aye, true that. Well, cover it in mylar, and it was rads I was thinking of predominantly. You could potentially make something like http://en.wikipedia.org/wiki/Pykrete http://en.wikipedia.org/wiki/Pykrete using martian topsoil.
  - varjag 13y ago

InclinedPlane 13y ago

ALICE is unlikely to be the best idea for rocket fuel produced on Mars. We already know that it is easy to produce propellant on Mars using the sabatier reaction and the Martian atmosphere as the primary ingredient (to produce liquid methane and O2). Not only is this a high grade rocket propellant but also the vast majority of the mass comes from the atmosphere. Of the mass of the propellant only 1/4 of it would be methane and of that only 1/4 would be Hydrogen (1/16th of the total mass). This makes it feasible to ship over the Hydrogen feedstock from Earth and generate the remaining 94% of the mass of propellant using Martian resources. However, the easier it is to get water on Mars the easier it is to produce propellant in this way. However, we already know that substantial amounts of water ice underlie most of the Martian surface, materials that are as much as half water by mass only a meter or so below ground. This new information only means that it will take much less equipment to get at small quantities of water nearer the surface.