By Georgina TorbetJanuary 9, 2021 12:02PM PST
One of the biggest limitations to space missions is weight. The more mass that is added to a rocket, the harder it is to get that payload to where it needs to go. So future crewed missions to Mars have a challenge in terms of how to transport essential but heavy resources like the fuel needed for the return journey to Earth. One approach to this problem is to say we shouldn’t carry fuel to Mars — instead, we should produce fuel from the resources that are available there.
Now, scientists at the University of California, Irvine have come up with a way to make methane-based rocket fuel from resources available on the Martian surface.
The method revolves around the use of a zinc catalyst used in a reaction called the Sabatier process. The zinc acts as a catalyst for carbon dioxide, which reacts with hydrogen to produce methane and water. While this process is well known and is used in current space missions like the life support system on the International Space Station, it has previously required large facilities to operate. The breakthrough use of the catalyst allows the process to be performed on a much smaller scale.
“The process we developed bypasses the water-to-hydrogen process, and instead efficiently converts CO2 [carbon dioxide] into methane with high selectivity,” lead author Houlin Xin, an assistant professor in physics & astronomy, said in a statement.
Carbon dioxide is plentifully available on Mars, as it makes up the majority of the martian atmosphere. And while this method would require astronauts to bring some of the catalyst with them, it would be a much smaller amount than the fuel it can make. It is also easy to transport: “The zinc is fundamentally a great catalyst,” Xin said. “It has time, selectivity, and portability — a big plus for space travel.”
Most rockets currently use hydrogen-based fuel, but there is research being performed into using methane-based fuel in the future. The SpaceX Raptor engine, which will be used in the company’s upcoming heavy launch vehicle Starship, uses methane-based fuel.
But there is still much research to be done into the creation and use of methane fuel before this technique can be used on Mars. “Lots of engineering and research is needed before this can be fully implemented,” Xin said. “But the results are very promising.”