Use of Lunar Produced Propellants for Manned Mars Missions

Manned Mars Mission departures from low lunar orbit (LLO), L2, and low Earth orbit (LEO), using oxygen or oxygen and hydrogen produced on the Lunar surface; or Phobos produced propellants; are compared to departures from LEO using Earth produced propellants. The economy of a given scheme is a function of the ratio of Earth launch to lunar launch costs per unit mass. To achieve savings on the order of 40% of total Earth launch costs for steady state operations requires the availability of both oxygen and hydrogen on the Moon and launch per unit mass costs of lunar surface to LLO in the range of 25% of Earth to LEO costs.