Stability of Guided Parachute-Payload Systems for Planetary Descent

A key requirement for enabling manned Mars missions is the capability to land a payload within 100 m from its nominal target. State of the art technology, however, is still far from reaching this objective. A possible solution for improving the landing accuracy on Mars is the development of a guidance system that exploits thrusters installed on the backshell of the descent vehicle to control its position during the parachute descent. The research summarised here aims at evaluating how the introduction of the guidance system influences the stability properties of the parachute-payload spacecraft and what performance the resulting closed-loop system can achieve. To do this, first the dynamics of the vehicle, modelled as a rigid body, has been investigated analytically and then its response to different external perturbations was simulated by means of a multibody model. The results are encouraging and prove that the parachute descent guidance system could efficiently contribute to improving the landing accuracy on Mars.