High-altitude pseudo satellite control

A flight control system capable of restoring flight control authority and desired wing shape for fixed wing High Altitude Pseudo Satellite (HAPS) aircraft comprising:

• at least one aeroelastic fixed wing that is span loaded when flying, an aspect ratio greater than 15 and wing loading less than 6 kg/m2;
• the at least one aeroelastic fixed wing having a plurality of spoilers distributed across the span of the at least one aeroelastic fixed wing, each spoiler being chordwise located approximately above an aerodynamic center and elastic or torsional axis of the at least one aeroelastic fixed wing such that there is no substantial effect on wing pitching moment and longitudinal stability resulting from their actuation and above or near a torsional elastic axis of the at least one aeroelastic fixed wing, such that there is no substantial effect on wing pitching moment and longitudinal stability;
• a control system for controlling the spoilers;
• a spanwise distributed system of attitude sensors which measure
• the pitch and roll at points or regions along the wing span so as to allow determination of wing shape, rate of change of wing shape and its degree of deformation from a pre-defined shape;
• the spoiler being activatable with no substantial effect on wing pitching moment, to modify the spanwise lift distribution to either maintain or reduce the divergence from the pre-defined wing shape in response to the quantities determined by the control system.