GUIDANCE AND ATTITUDE CONTROL LAW FOR THE FINAL PART OF A REENTRY VEHICLE TRAJECTORY - ALTERNATE LAWS FOR THE EXPERIMENTAL VEHICLE HSFD II

Abstract The experimentation part of HSFD-II (High Speed Flight Demonstrator phase II) was conducted under a CNES (French Space Agency) - JAXA (Japaneese Space Agency) cooperation. JAXA provided the instrumented mock-up and CNES provided stratospheric ascending balloons (for mock-up release at up to 30 km in altitude) at the Kiruna-Esrange (Sweden) test falicity. In the terms of the cooperation was included the development of an alternate set of guidance and attitude control laws provided by ONERA. The control law was obtained using a robust polytopic method. The original guidance law of the US Shuttle was used as a baseline, but with significant adaptations, in particular for deep slope angle values (down to -50° in guidance phase versus about -5° for the Shuttle). The article first recalls the Flight Mechanics equations involved along with notations. The principle of the attitude control law is indicated and the guidance law is detailed. Finally the results of worst case simulations are presented.