SpaceX Mars presentation: IAC 2017

[DocM]

The Sabatier process is not new, being developed a century ago. Currently its used on ISS. It's just massively underutilized elsewhere. 

 

And it's not as if the catalysts are expensive; nickel, aluminium oxide etc.  Use solar to split water to get H2, add CO2 from anywhere + startup heat and methane comes out the other end. Lots of it.

 

High school chemistry.

[FloatingFatMan]

20 minutes ago, DocM said:

The Sabatier process is not new, being developed a century ago. Currently its used on ISS. It's just massively underutilized elsewhere. 

 

And it's not as if the catalysts are expensive; nickel, aluminium oxide etc.  Use solar to split water to get H2, add CO2 from anywhere + startup heat and methane comes out the other end. Lots of it.

 

High school chemistry.

Which leads me back to my earlier question as to why it's not used on an industrial scale already...

[DocM]

Because extracting methane from natural gas, which is extremely common and easy to get especially in the US, is easier. Chill LNG and the impurities either float to the top or sink to the bottom. Tap the center of the vessel and POOF!, seriously pure methane comes out.

 

That said, Musk said during IAC that the ISRU system for BFR is already very far along. Expect more from them wrt ISRU, especially for methane.

[FloatingFatMan]

The US is not the only country on the planet, and quite a few of the others don't have such easy access to sources of natural gas, so I ask again.. Why has NO ONE done this previously if it's as simple as said?

 

[DocM]

In no small part, because it's easier and cheaper to import LNG, or produce coal gas, than to use the Sabatier process

 

It also depends on having enough fresh water to make the hydrogen for Sabatier to produce methane. 

 

Now that ISRU is being developed big time for the space agencies and other uses we may see a change in economics and minds.

[FloatingFatMan]

24 minutes ago, DocM said:

In no small part, because it's easier and cheaper to import LNG, or produce coal gas, than to use the Sabatier process

 

It also depends on having enough fresh water to make the hydrogen for Sabatier to produce methane. 

 

Now that ISRU is being developed big time for the space agencies and other uses we may see a change in economics and minds.

So basically, it's not been used much before primarily due to economics. Right. Thank you. That's what I figured too but I wanted to confirm.

 

Of course, off Earth economics matter less and you use what you have to use, but still, I want to see a functioning model that gives the yield they need with the resources they'll have on Mars.  That means they also need equipment to extract the fresh water they need... Which is?

[DocM]

Mining bots. Ice is a meter or so  under Mars' surface over much of the planet, and immediately subsurface in other locales. The Sabatier or reactor heat can melt it and solar electrolysis or catalysts can split it into H2 and O2.

 

Another source is Mars' atmosphere. It has water vapor, and simply blowing it over zeolyte beds will extract it. Once the zeolyte is  saturated excess heat from a reactor or Sabatier can distill if out, then the zeolyte bed gets reused.  Multiple zeolyte beds cycled through the extractor keeps it going continuously. Now split the water as with Sabatier

 

NASA built a subscale prototype zeolyte extractor and exposed it to a simulated Martian atmosphere. It extracted prodigious amounts of water.

Edited October 18, 2017 by DocM

[FloatingFatMan]

1 hour ago, DocM said:

Mining bots. Ice is a meter or so  under Mars' surface over much of the planet, and immediately subsurface in other locales. The Sabatier or reactor heat can melt it and solar electrolysis or catalysts can split it into H2 and O2.

 

Another source is Mars' atmosphere. It has water vapor, and simply blowing it over zeolyte beds will extract it. Once the zeolyte is  saturated excess heat from a reactor or Sabatier can distill if out, then the zeolyte bed gets reused.  Multiple zeolyte beds cycled through the extractor keeps it going continuously. Now split the water as with Sabatier

 

NASA built a subscale prototype zeolyte extractor and exposed it to a simulated Martian atmosphere. It extracted prodigious amounts of water.

Thank you. I'd never heard of zeolite before, but your mention of it led me on a google hunt, which led to the following PDF.

 

https://www.lpi.usra.edu/publications/reports/CB-955/washington.pdf

 

Fascinating stuff. Around 3.3kg of water per sol in a 7.5m habitat for about 16kW power use (5% of reference mission power availability). I love science.  

[Unobscured Vision]

Yep. The solar panels on the ship and some modest gear feeding the H2O into the tanks can do that job. Don't have to really put anything into it at that end other than the electricity and setting up the equipment and fine-tuning it. The whole process can be automated too.

[DocM]

Someone could make a career just doing zeolite research. Amazing stuff, and the Thomsonite variant, beautiful examples are found around the upper Great Lakes, is a  gemstone.

 

[Unobscured Vision]

 Love those stones. Find them regularly on/in Lake Michigan.

[DocM]

58 minutes ago, Unobscured Vision said:

 Love those stones. Find them regularly on/in Lake Michigan.

We found some nice ones near  the Tahquamenon Falls State Park, my woodland second home

[Unobscured Vision]

Lots of them up in the Porcupine Mountain area. The river to the south and east has them. Find 'em a lot when we go exploring.

 

[EDIT] Bit of placer gold too, if one can be troubled to bring their panning stuff.