Mechanization of Minimum-Energy Automatic Lunar Soft-Landing Systems

Nondimensional parameters are developed and plotted for use in rapid analysis of soft-landing system concepts. With the aid of these charts, optimum soft-landing systems are discussed. The systems automatically control and reduce vehicle energy remaining after main-stage retro-thrust to zero at the landing surface, with an expenditure of a mininum amount of stored energy. Mechanizations of some practical automatic landing systems are presented and compared with an optimum system in terms of energy consumption and ability to tolerate wide ranges of initial vehicle velocities and positions.