"Mars landing." . . "Fuel production." . . "Propellants." . . "Sabatier reaction." . . "Oxygen." . . "Carbon dioxide." . . "Mars sample return missions." . . "Hoppers." . . . . "Project Genesis Mars in situ technology demonstrator mission:final report"@en . . . . . . . . . . . . . . . . . . . . . . . . "Extraterrestrial resources." . . "Methane." . . "Mars (Planet)" . . "Unmanned spacecraft." . . "Delta launch vehicle." . . . .