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Prior to landing of reusable space transportation systems, the vehicle’s landing legs needs to be fully deployed to enable a safe landing and further re-use of the space vehicle. During that phase the deployment system has to overcome harsh and challenging environmental conditions. In this study, a numerical simulator is developed in order to investigate these influences on the landing leg deployment dynamics. By means of an extensive aerodynamic database and a broad approach flight domain, the influence of aerodynamics, exhaust plume, and vehicle’s attitude on the deployment dynamics is analyzed. This study shows on the example of the first stage demonstrator CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss back Operations), that thrust level, vehicle attitude, and the deployment system parameters affect the deployment performance.

This paper addresses the robust control of a micro-launcher. The general framework of this work is a R&D project of the French space agency (CNES) focused on new launchers. The objective was to evaluate the potentialities of Linear Parameter Varying (LPV) techniques for the specific problem of launchers control. As a realistic test case, the microlauncher preliminary research program, supported by the CNES Launcher Directorate, has been considered. First a Linear Fractional Transformation (LFT) based model of the launcher has been established and validated. Then two strategies have been chosen to design a robust controller of the angle of attack: a complete LPV controller has first been developed; then a controller based on an LFT representation of a classical lead phase controller has been considered. Realistic simulations have been conducted to compare both strategies with a more traditional interpolated lead phase controller. Finally, the simulation results exhibit very promising results, allowing a total respect of the performance specifications.

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