Trajectories for Direct Vehicle Transfer from Moon to Earth

Abstract

An investigation of possible direct ballistic transfer of transport vehicles from the Moon to landing areas on Earth, with particular attention to the sensitivity of initial condition errors, indicates the required conditions to successfully accomplish such transfers. The importance of such parameters as location of launch site, location of landing area, and departure velocity are discussed. The results indicate that very little control of the velocity vector in both magnitude and direction will be required for the early attempts of return flight from the Moon where the objective will be the landing of an instrumented capsule anywhere on the Earth’s surface. However, later manned return flights, where the objectives will be to land on a particular area of the Earth, such as a spaceport, will require guidance systems of a high degree of accuracy during the powered phase to properly control the velocity vector.