Potential game-changer for propellant generation on Mars

[Exoscientist]

 

Potential Game-Changer for Generating Propellant on Mars.

https://https://exoscientist.blogspot.com/2023/07/potential-game-changer-for-generating.html

 

  Rather than needing football fields of solar cells to generate propellant, by instead collecting free O2 and CO in Mars atmosphere the process can actually *generate* power.

 

 If the gas separation of O2 and CO out of the CO2 of the Martian atmosphere can be done at low energy, it is possible it could even be done at sufficiently low cost to profitably ship the hydrogen to Earth.

 

  Robert Clark

 

[magnemoe]

Interesting idea but does Mars has enough oxygen to this to be viable? I assume oxygen is an trace gas there like co2 is on Earth. 
And always thought the extract co2 from earth atmosphere plans as very stupid as its an trace element so you get it from the exhaust of the gas turbine. 
Extracting co2 from atmosphere I would use plants, yes it could work if you had an gas turbine near the gas field, extract the 10% something co2 and inject back into the well for back pressure. 
Today you mostly use water coming up from the well, its cheaper to re inject than clean it enough to release. 

[darthgently]

49 minutes ago, magnemoe said:

Interesting idea but does Mars has enough oxygen to this to be viable? I assume oxygen is an trace gas there like co2 is on Earth. 
And always thought the extract co2 from earth atmosphere plans as very stupid as its an trace element so you get it from the exhaust of the gas turbine. 
Extracting co2 from atmosphere I would use plants, yes it could work if you had an gas turbine near the gas field, extract the 10% something co2 and inject back into the well for back pressure. 
Today you mostly use water coming up from the well, its cheaper to re inject than clean it enough to release. 

Well, in addition to the free oxygen the CO2 does have 2 oxygens per carbon.  (Maybe exoscientist meant CO2 when he typed CO?)

https://www.sciencedaily.com/releases/2017/06/170605110809.htm

[intelliCom]

On 7/19/2023 at 8:42 AM, magnemoe said:

Interesting idea but does Mars has enough oxygen to this to be viable? I assume oxygen is an trace gas there like co2 is on Earth. 
And always thought the extract co2 from earth atmosphere plans as very stupid as its an trace element so you get it from the exhaust of the gas turbine. 
Extracting co2 from atmosphere I would use plants, yes it could work if you had an gas turbine near the gas field, extract the 10% something co2 and inject back into the well for back pressure. 
Today you mostly use water coming up from the well, its cheaper to re inject than clean it enough to release. 

Electrolysis, maybe?

[magnemoe]

On 7/19/2023 at 1:37 AM, darthgently said:

Well, in addition to the free oxygen the CO2 does have 2 oxygens per carbon.  (Maybe exoscientist meant CO2 when he typed CO?)

https://www.sciencedaily.com/releases/2017/06/170605110809.htm

You are obviously correct, the problem is getting hydrogen not oxygen. Yes its ice on Mars but you need to drill after it and melt it. 

[mikegarrison]

The problem is that the O2 and CO in the Martian atmosphere is not "free" in the sense of "easily obtainable". You would have to process a massive amount of Martian atmosphere, and then you would have to separate out the O2 and CO.

These processes will require energy. I recognize that you discuss this in your blog post, but it all seems kind of hand-wavy.

The disadvantage to mining ice is that you then have to break apart the O2 and H2, but the advantage to it is that the ice is concentrated. (That is, assuming you can find some where you want to find it.) You are trading one energy-intensive problem for another one.

Edited July 24, 2023 by mikegarrison

[Exoscientist]

On 7/18/2023 at 7:37 PM, darthgently said:

Well, in addition to the free oxygen the CO2 does have 2 oxygens per carbon.  (Maybe exoscientist meant CO2 when he typed CO?)

https://www.sciencedaily.com/releases/2017/06/170605110809.htm

 

 No, the issue is of energy. It takes a large amount of energy to split CO2 or H2O by electrolysis, which explains why you get so much energy out when you run the process in reverse for combustion. 

 Robert Zubrin has written because of the Starships large size it will take 10 football fields of solar panels or perhaps even an entire nuclear power plant shipped to Mars to provide the power needed for generating the propellant on Mars for a Starship return flight.

 But instead of that we can get both oxygen(O2) and carbon monoxide(CO) that exist as free gases in  Mars predominantly CO2 atmosphere.  The problem now is they are at such low concentration at about 1 part per thousand. Then the issue is separating these gases out when they are at such low concentrations in a low power fashion.

 Filtering out the O2 that exists freely in the Mars atmosphere was done in a simulated experiment here on Earth by a process called by the researchers TSSD. This took 1/10th the power of the MOXIE instrument sent to Mars on the Perseverance rover that does it by electrolysis. (Google “TSSD”, “MOXE”, and “Mars”).

 However, I’m betting the filtration process can be done by another order of magnitude reduction in the power needs. 

 If so, then instead of producing propellant on Mars requiring megawatts of power input, it could be production of propellant on Mars generates megawatts of power output.

   Robert Clark

[Nuke]

better off using the hydrogen as remass in nuclear engines to help power the interplanetary logistics that a mars colony will require. 

Edited July 24, 2023 by Nuke