High-altitude pseudo satellite control

A method of controlling the flight of a High Altitude Pseudo Satellite (HAPS) aircraft, the aircraft having at least one aeroelastic span loaded fixed wing, an aspect ratio greater than 15 and wing loading less than 6 kg/m2 comprising the steps of

• sensing a quantity from which lift at points or regions along the wing, and/or local pitch and roll attitude, and/or local bending and torsional strain can be determined
• detecting relative differences in the lift, and/or pitch and roll attitude that would cause or account for an adverse deformation in the optimal wing shape
• activating a spoiler on the wing proximal to the where the relative elevated lift is occurring so as to reduce or eliminate the deformation that would otherwise occur.

A method of controlling the flight of a High Altitude Pseudo Satellite (HAPS) aircraft, the aircraft having at least one aeroelastic span loaded fixed wing, an aspect ratio greater than 15 and wing loading less than 6 kg/m2 comprising the step of activating one or more spoilers to reduce the lift of the HAPS when the HAPS is descending through the troposphere.