With NASA's renewed focus towards a permanent human presence on the moon, comes the development of the Crew Exploration Vehicle. Unforeseen circumstances can induce emergency situations necessitating contingency plans to ensure crew safety. It is therefore desirable to define the feasibility of a direct abort from an outbound translunar trajectory. Thus an astrodynamic model for lunar transfer has been developed to allow for characterization of the abort feasibility envelope for conceivable transfer orbits. In addition the model allows for several trade studies involving differently executed abort options, factoring in fuel margins. Two optimization schemes were utilized; one to expedite return via any fuel in excess of that required for the abort, and one to explore the boundary region of direct abort infeasibility envelope searching for plausible abort trajectories.

The characterization and optimization of translunar abort trajectories for the Crew Exploration Vehicle can ensure increased crew survivability in emergency situations.