Spin-Down and Active Nutation Controller /SDANC/ for the Galileo projectThe Spin-Down and Active Nutation Controller stabilizes the Galileo spacecraft during spin-down from approximately 70 to 1 rpm. Angular motion of the spacecraft is sensed through a pair of accelerometers and a sun sensor which is needed only at low spin rates. Spin and nutation information is derived by a set of 'loosely coupled' spin and transverse rate estimators. Spin rate is reduced by two spin-down thrusters. The transverse angular rate is compared with a variable threshold; exceeding the threshold activates axial thrusters which impart appropriate transverse torque to reduce the nutation. The scheme was verified by extensive computer simulations and has been demonstrated over a wide range of initial conditions.
Document ID
19800061361
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Lin, H. S. (California Institute of Technology, Jet Propulsion Laboratory, Pasadena Calif., United States)