OPTIMUM MULTIPLE-SKIP TRAJECTORIES

In his classical paper on the ''Schematic Study of Long-Range Semi-Bal listic Trajectories', Pierre Contensou has proposed a type of entry tr ajectory which consists of a series of skip sub-area, intercalating wi th Keplerian sub-arcs in the vacuum. It has been suggested that under favorable conditions, using this trajectory, the range can be extended as compared with the pure atmospheric glide mode. Another possible ap plication of this type of multiple-skip trajectory is to use it for th e rotation of the line of apsides in aeroassisted orbital transfer. In this paper, we shall present the extensive numerical results obtained in the study of the general problem of multiple-skip trajectories wit h specified range. By using a modified set of dimensionless variables- and a new set of adjoint variables, the variational problem consists o f integrating a set of five non-linear differential equations subject to end-constraints. It is found that for low entry speed, the maximum range problem exhibits the typical phugoid motion in pure atmospheric glide, while with high entry speed, a multiple-skip trajectory can be used to extend the range as predicted by Contensou. When the multiple- skip trajectory is used to rotate the line of apsides of elliptic orbi t, the new solution shows significant fuel saving as compared with the case where only one atmospheric passage is considered. (C) 1998 Elsev ier Science Ltd. All rights reserved.