 These fluctuations peaked at the end of the Martian summer at 0.6 parts per billion.Methane has been proposed as a possible rocket propellant on future Mars missions due in part to the possibility of synthesizing it on the planet by in situ resource utilization.An adaptation of the Sabatier methanation reaction may be used with a mixed catalyst bed and a reverse water-gas shift in a single reactor to produce methane from the raw materials available on Mars, utilizing water from the Martian subsoil and carbon dioxide in the Martian atmosphere.