Catalyst

A catalyst is a substance that facilitates a chemical reaction without being consumed by the reaction. Many of the reactions used in hydrocarbon synthesis would be impractical without a catalyst. Catalysts are also required for the Sabatier reaction to produce Methane. Catalysts are often manufactured in shapes that maximize the surface contact area. The quantities of material required are small compared to the volume of production, but catalysts are often fairly rare metals. It probably makes sense to import catalysts from Earth, until the manufacturing base on Mars is sufficient to support a local production market.