Propulsion requirements for the supply of lunar-derived oxygen for a manned Mars mission

The use of lunar-derived liquid oxygen with hydrogen for robust manned explorations beyond earth is discussed. The propellant mixture ratio for optimal performance is near the current design point of r = 6. The results of NASA-sponsored studies of missions using cryogenic bipropellant H2-O2 for most functions reveal the potential benefits from a propellant terminal in cis-lunar space. The main propulsion technologies associated with Mars mission case studies include: in-space fluid transfer, zero-g ignition, oxygen-enriched propellant mixtures, throttling of main engines, and H2-O2 based auxiliary propulsion.