Fault-Tolerant Control of Spacecraft Attitude with Prescribed Performance

This paper proposes a spacecraft attitude control scheme under time-invariant actuator faults with substantial efficiency degradation. A prescribed performance fault observer is developed, where adaptive laws are constructed to simultaneously estimate constant efficiency loss and fault bias signals. Building upon this observer, a fault-tolerant control framework is established that imposes no structural constraints on controller design, requiring only nominal closed-loop stability in fault-free scenarios. Numerical simulations validate the asymptotic convergence of both observer errors and adaptive estimation parameters, while demonstrating the framework's strong robustness against abrupt fault injections.