Abstract: The estimation and compensation of fixed, but unknown uncertainties of a thruster (22) for improving satellite attitude estimation and control as well as eliminating the need for nutation damping devices is disclosed. A thruster (22) is fired and an attitude state is estimated using an estimator (116). A commanded rate change (122) is calculated, which is modified using a compensating feedforward command (126) as updated by a fixed uncertainty estimator (124) unless an estimated rate is less than an absolute value of a threshold rate. The modified commanded rate change (130) is used to incrementally adjust thruster fire on-time (104) until a predetermined satellite trajectory is reached.