One of the many challenges of going to Mars is to have enough rocket fuel for the return journey. Shipping all the fuel from the earth becomes too expensive so the fuel must somehow be produced on Mars. One idea, which SpaceX, among others, advocates, is to produce methane on Mars and use it as fuel, and now researchers have found a method to make that idea even more realistic .
The basic idea is to use electricity from solar panels to produce carbon dioxide via electrolysis. The carbon dioxide is then mixed in a second step with water to obtain methane. This is called the Sabatier method and it is already used on the International Space Station, but then to produce water and oxygen.
The problem is that the Sabatier process is a two-step process that requires large facilities if one is to produce such large amounts of methane that it is enough to fill the tank of a Mars rocket. The researchers at the University of California Irvine, UCI, have developed a method that can do the same thing in one step.
What makes this possible is a new zinc-based catalyst that initiates the process.
- Our process skips the water-to-hydrogen part of the process and instead converts carbon dioxide to methane directly, says Houlin Xin, assistant professor of physics and astronomy at UIC and one of the researchers behind the idea.
So far, researchers have only created a small model that works in the laboratory. They will now continue the work of developing a full-scale system that works on Mars. Then, of course, rockets that use methane as fuel are also required.
Today, rockets normally use liquid hydrogen or kerosene together with liquid oxygen. But SpaceX is now testing a new engine, the Raptor, which uses methane instead of hydrogen or kerosene. Raptor, will power the SpaceX Super Heavy rocket, which in the future will hopefully power Starship spacecraft that travel to Mars and back.