Venus-swingby mission mode and its role in the manned exploration ofMars

Abstract

The present study offers a systematic, thorough analysis of all Venus-swingby opportunities over the extended period of time during which such missions seem most relevant; accurate plots of the speed requirements for these trips; and a critical interpretation of the Venusswingby mode as it affects the various direct-mode choices previously treated by many analysts. The data are plotted in a manner compatible with the direct flight mission charts presented in the NASA Planetary Flight Handbook,, SP-35. Generally speaking, swingby mission opportunities are governed by a basic 6.4-yr syzygistic cycle involving Earth, Mars, and Venus. Within each such cycle, three groups of outbound swingby missions and three homebound groups are worthy of consideration. Study reveals that of these six, two groups are never worthwhile, two always favorable, and two occasionally so. Treating the Venusswingby mode within the totality of possible trajectory types, it is possible to attempt a general philosophy of approach to a long-term Mars exploration program which views this mode in perspective within the total mission spectrum.