Food production spaces and equipment. Propellant production equipment, generally thought to be hydrogen and methane through the Sabatier reaction[63] for fuel—with oxygen oxidizer—for chemical rocket engines Fuels or other energy source for use with surface transportation. Carbon monoxide/oxygen (CO/O2) engines have been suggested for early surface transportation use as both carbon monoxide and oxygen can be straightforwardly produced by zirconium dioxide electrolysis from the Martian atmosphere without requiring use of any of the Martian water resources to obtain hydrogen.[64] Communication equipment Equipment for moving over the surface - Mars suit, crewed rovers and possibly even Mars aircraft.