Design of fast earth-return trajectories from a lunar base

Abstract

The Apollo Lunar Program utilized efficient, i.e., Earth-return, transearth trajectories which employed parking orbits in order to minimize energy requirements. This thesis concentrates on a different type of transearth trajectory. These are direct-ascent hyperbolic trajectories which omit the parking orbits in order to achieve short flight times to and from a lunar base. The object of this thesis is the development of a three-dimensional transearth trajectory model and associated computer program for exploring trade-offs between flight-time and energy, given various mission constraints. The program also targets the Moon with a hyperbolic trajectory, which can with a time-reversed trajectory, be used for targeting Earth impact points. The first-order model is based on an Earth-centered conic and a massless spherical Moon, using Mathcad version 3.0 This model is intended as the basis for future patched-conic formulation for the design of fast Earth-return trajectories. Applications include placing nuclear-deterrent arsenals on the Moon, various space support related activities and finally protection against Earth-threatening asteroids and comets using lunar bases.