Attitude Dynamics and Control of Drag-Balance CubeSats

The article examines the system stability, obtaining upper bounds for the mass unbalance to verify the applicability of magnetic control laws valid for rigid bodies to the drag-balance CubeSat two-body system. The rod is connected to the satellite body by two flexural springs. The spin axis is orthogonal to the rod, exposing the plates to the incoming atmosphere flux at the spin rate and generating a relative displacement between the DBI and the satellite. The spin frequency component of this displacement is therefore related to the atmospheric drag force and can be evaluated by measuring the displacement itself and isolating the spin frequency content. Single-, double-, and triple-unit CubeSat implementations of the DBI concept are possible. The drag-balance CubeSat attitude control system must provide for attitude acquisition, spin axis orbit normal pointing, spin rate estimation, and regulation.