Manned Mars mission transfer from Mars parking orbit to Phobos or Deimos

The problem of orbit transfers from a Mars parking orbit with an inclination of 165 degrees to the Mars Moon is addressed. The transfer can be accomplished using a three impulse transfer. The current 1999 baseline manned Mars mission requires a Mars parking orbit with an inclination of 165 degrees. This orbit inclination is necessary due to the direction of the Mars arrival and departure asymptotes of the interplanetary trajectory. The selection of this inclination for the parking orbit minimized the delta velocity requirements at Mars arrival and departure. This presents a problem in making transfer from this orbit to either Phobos or Deimos since it is a retrograde orbit. It is possible to make this transfer efficiently using a three impulse transfer and an intermediate transfer orbit with a very large apogee altitude. How the intermediate transfer orbit apogee can be determined based on a preselected transfer time, the delta velocities required as a function of transfer time, and the propellant required at a function of mission module weight for a transfer time of 5 days is shown. The data presented is specifically for the 1999 opposition class mission but the methods outlined are applicable to any other mission which requires a high inclination parking orbit.