4 ms·

Maybe not Mars, but if you're willing to go to Titan there are literal lakes of methane: https://en.wikipedia.org/wiki/Lakes_of_Titan https://en.wikipedia.org/

Maybe not Mars, but if you're willing to go to Titan there are literal lakes of methane: https://en.wikipedia.org/wiki/Lakes_of_Titan https://en.wikipedia.org/wiki/Lakes_of_Titan https://en.wikipedia.org/wiki/Atmosphere_of_Titan https://en.wikipedia.org/wiki/Atmosphere_of_Titan

actionfromafar 3y ago
But then you'd have to bring the oxygen instead. To manufacture anything resembling normal rocket fuel you need at least oxygen + hydrogen. Preferrably oxygen, hydrogen and carbon, so you don't have to deal with cryogenic storage of hydrogen.
- kwhitefoot 3y ago
  There is water on other satellites.
  - gus_massa 3y ago
    But you need a lot of energy to split water. You can get a few bubbles with a battery, but to fill the rocket with oxygen you need a huge solar farm or something similar to power the electrolisis plant. Oxygen atoms are easy to find, sand and rust (and water) have a lot of them. The problem is isolating them to produce molecular oxygen that can be used to burn the fuel.
    - kwhitefoot 3y ago
      > a huge solar farm or something similar to power the electrolisis plant. Eventually it should be possible to build such things in space and then they can be huge. There are already semi-serious proposals to solve the Earth's energy problems with space based solar collectors. Of course they would have to a lot bigger further out. Perhaps Jupiter's flux tubes could be tapped.
gus_massa 3y ago
It's weird to think about Titan. Fuel is free as air here, but to drive a ICE car ypu need to pay to fill the oxygen tanks of your car.
- anticensor 3y ago
  And oxidiser injectors and fuel turbochargers.
- anticensor 3y ago
  For a more technical answer on that specific point, see my question on SE: https://worldbuilding.stackexchange.com/questions/181254/feasibility-of-sourcing-fuel-from-air https://worldbuilding.stackexchange.com/questions/181254/fea...

actionfromafar 3y ago

But then you'd have to bring the oxygen instead. To manufacture anything resembling normal rocket fuel you need at least oxygen + hydrogen. Preferrably oxygen, hydrogen and carbon, so you don't have to deal with cryogenic storage of hydrogen.

kwhitefoot 3y ago
There is water on other satellites.
- gus_massa 3y ago
  But you need a lot of energy to split water. You can get a few bubbles with a battery, but to fill the rocket with oxygen you need a huge solar farm or something similar to power the electrolisis plant. Oxygen atoms are easy to find, sand and rust (and water) have a lot of them. The problem is isolating them to produce molecular oxygen that can be used to burn the fuel.
  - kwhitefoot 3y ago
    > a huge solar farm or something similar to power the electrolisis plant. Eventually it should be possible to build such things in space and then they can be huge. There are already semi-serious proposals to solve the Earth's energy problems with space based solar collectors. Of course they would have to a lot bigger further out. Perhaps Jupiter's flux tubes could be tapped.

gus_massa 3y ago

It's weird to think about Titan. Fuel is free as air here, but to drive a ICE car ypu need to pay to fill the oxygen tanks of your car.

anticensor 3y ago
And oxidiser injectors and fuel turbochargers.
anticensor 3y ago
For a more technical answer on that specific point, see my question on SE: https://worldbuilding.stackexchange.com/questions/181254/feasibility-of-sourcing-fuel-from-air https://worldbuilding.stackexchange.com/questions/181254/fea...