ATTITUDE DYNAMICS INVESTIGATION OF THE OEDIPUS-A TETHERED ROCKET PAYLOAD

The OEDIPUS-A tethered rocket payload consisted of two spinning subpay loads each with a pair of flexible radial booms and connected by a con ductive tether, This first flight of a spinning tethered two-body syst em achieved a tether deployment of 958 m, which at that time was the l ongest space tether ever flown. Although the approximately 15-min miss ion was generally very successful, unexpected dynamic behavior was obs erved in one of the subpayloads. This paper reviews the attitude dynam ics investigation that was undertaken following the flight in an attem pt to understand what may have caused this dynamics anomaly, The formu lation of a general mathematical model is described that consists of a rigid central body undergoing targe rotations with three orthogonal p airs of flexible booms. Tether interaction with the central body is mo deled as a forcing term, caused by the tether tension, to the free-bod y equations. Results of a parametric study are presented, which show t hat the interaction of the tether with the payload, which was assumed to be negligible prior to the night, is the likely cause of the unexpe cted dynamic behavior. Two mechanisms associated with the tether inter action have been identified: one is a forcing term on the payload, whi ch causes a precession of the payload angular momentum vector, and the other is additional energy dissipation in the payload.