I found this article in Science Daily describing a new low temperature process for producing Methane from CO2 developed at Waseda University by a team led by Professor Yasushi Sekine. It might be a better way then the Sabatier process since it works at 100 degrees C instead of at 300 to 400 degrees C.The line that caught my interest was: "Additionally, operation at low temperatures was demonstrated to be favorable to improve carbon dioxide conversion and increase the amount of methane produced."https://www.sciencedaily.com/releases/2020/02/200227114523.htm
There are several efforts afoot to produce rocket fuel in a more environmentally friendly way. Energy startup Green Hydrogen International is developing a green hydrogen project in South Texas. Researchers at the German Aerospace Center are working on a fuel that only produces nitrogen, oxygen, and water when heated. Canadian company Hyox is developing technology for production of net-zero aviation fuel and rocket propellants that will use low-cost solar power and electrolysis to produce methane and kerosene, both of which can propel rockets into space.
