During WW2 Germany was making edible fats/margarine out of coal. Similarly, the atmospheric CO2 can be a source of carbon, especially say on Mars.
(another thing back then in Germany - ramjet engine using coal in a metal basket as a fuel. The war does put minds to work - radars/computers/nukes on the Allies side also come to mind.)
(another thing back then in Germany - ramjet engine using coal in a metal basket as a fuel. The war does put minds to work - radars/computers/nukes on the Allies side also come to mind.)