Planar Aeroassisted Attainability Domain

Abstract

The purpose is to study the general problem of aerodynamic maneuvers at low altitudes while at orbital speed. The spacecraft’ s trajectory changes are generated by the applied lift and drag aerodynamic forces. Employing an adequate model of the aerodynamic forces function of the angleof attack, the unbounded angle of attack is used as the control variable. To perform a general analysis of spacecraft trajectories when employing aerodynamic forces, the aeroassisted attainability domain is studied. Specie cally, given the initial position and velocity of the vehicle at atmospheric entry, the region in state space that can be attained by the vehicle at atmospheric exit when using all of the possible controls at its disposal is determined. The set of trajectories belonging to the boundary of the attainability domain is obtained through the variation of a single parameter, namely, the initial value of angle of attack at atmospheric entry. The trajectories are obtained by a forward integration of the state and adjoint equations of motion. Representative results of the attainability domain for given initial conditions and vehicle characteristics are presented.