Design of descent trajectories in atmosphere with respect to engineering constraints

Descent trajectories are relevant to planetary exploration missions as well as to terrestrial missions carried on by means of re-usable vehicles. Moreover, they are interesting for all missions aiming at a full or partial recovery. Analysis of the descent trajectories involves both dynamic and thermal requirements, and due to complex interacting phenomena, as well as to poor knowledge of some of the key parameters, usually requires a numerical analysis. In case a capsule has to be recovered from the descending probes, structural dynamics requirements for its survival should be also considered, posing a limit to tolerable stress. In recent literature, a large effort has been produced to outline the thermal/aerodynamic behavior of re-entering bodies for which the demise or survival prediction only should be given, i.e. for re-entering debris. The aim of the present paper is to enlarge the scope of these analyses, by combining this kind of information with more classical theories concerning re-entry. In such a way, indications for descending trajectories including structural load factor limits can be found. Limits of the approach, which is especially suitable for high entry velocity, are explained. Results are applied to both the cases of Earth re-entry as well as to descent on Mars.