Adaptive Sliding Mode for Agile Attitude Tracking in a high-precision modelled VLEO environment

This paper presents a novel Sliding Mode Control (SMC) control formulated on the special orthogonal group SO(3) for spacecraft attitude control in Very Low Earth Orbit (VLEO). The approach addresses nonlinear rotation geometry and environmental disturbances without the singularities or redundancy of traditional attitude representations. A key innovation is the direct adaptive law that dynamically adjusts sliding manifold parameters, reducing reaching time and guiding the system toward desired dynamics once sliding is established. The controller is validated using the high-fidelity high-precision orbit propagator which accounts for the main environmental disturbances. Preliminary results demonstrate accurate attitude tracking performance in realistic maneuvering scenarios, confirming the controller's effectiveness for the challenging VLEO environment.