Review and Analysis of Single-thruster Attitude Control Techniques for Spinning Spacecraft

The attitude dynamics and manoeuvre survey in this paper is performed for a mission scenario involving a penetrator-type spacecraft, a semi-rigid axisymmetric prolate spacecraft spinning around its minor axis of inertia, requested to perform a 90° spin axis reorientation manoeuvre. In contrast to most existing spacecraft only one attitude control torque is available, perpendicular to the spin axis. Having only one attitude thruster on a spinning spacecraft could be preferred for spacecraft simplicity (less mass, less power consumption etc.), or it could be imposed in case of redundancy/contingency operations; the proposed Japanese Lunar-A penetrator spacecraft had been designed in this way. This constraint does yield restrictions on the thruster timings, previously unanalysed, depending on the ratio of minor to major moments of inertia. The attitude dynamics of a spinning rigid body are first investigated analytically, then expanded for the specific case of a prolate, axisymmetric, semi-rigid body. Next two well-known techniques for manoeuvring a spin-stabilised spacecraft, the Half-cone/Multiple Half-cone and the Rhumb line slew, are compared with two newer techniques, one developed by Astrium Satellites and one developed at Surrey Space Centre. Each technique is introduced and characterised by means of simulation results and illustrations for the penetrator mission scenario and the relative benefits of each slew are discussed in terms of slew accuracy, energy (fuel) efficiency and time efficiency. For example, a sequence of half-cone manoeuvres (a multi-cone manoeuvre) tends to be more energy-efficient than one half-cone for the same final slew angle, but more time-consuming. As another example, the new techniques are designed to overcome the specific restriction on slew angle attainable by a half-cone manoeuvre, giving one additional degree of freedom for designers to fine-tune.