The application of depot transfer/rendezvous in space based cyclic orbit missions

Mission planning for future national space programs will seek means to abate the high dollar cost of mass delivery. To meet the fiscal objectives of these programs requires the development of improved transportation logistics, both in the primary Earth-to-Low Earth Orbit (LEO) and secondary orbit-to-orbit space transportation segments for delivery of construction materials, scientific payloads, and personnel. The deployment of space-based orbit transfer vehicles (OTV's) and development of innovative orbit transfer methodologies that reduce secondary cyclic mission support mass requirements (e.g. propellants) is a crucial step in meeting program budgetary goals. The research performed in this thesis has developed an improved efficiency cyclic orbit transfer method, based on non-traditional optimization criteria, through the use of intermediate propellant depot orbits and rendezvous transfer. The technique was optimized for a reference cyclic transfer between LEO and Geostationary Earth Orbit (GEO) in the presence of realistic mission affects including the following: (1) non-planar transfers; (2) perturbed (non-Keplerian) orbit motions; and (3) mission transfer risk mitigation techniques. A semianalytic model was developed to optimize the depot orbit selection and sizing for LEO/GEO cyclic missions for three NASA reference OTV mission payload profiles. The results demonstrated significant reductions in cyclic mission propellant requirements, when compared to current NASA aerobrake OTV missions, for durations of up to one week in GEO. The magnitude of the propellant mass savings was found to depend on GEO on-orbit durations, mission risk strategies, and payload profiles, with maximum propellant savings amounting to approximately 11 metric tons/mission. A first-order cost benefit analysis showed a recurring dollar savings from the use of the depot transfer/rendezvous method ranging from 5 to 83 million dollars per mission.