Dynamics of interstage separation for a DMSP spacecraft - Hypothesis testing of a flight anomaly

This paper examines the dynamics of separation between the second and third stages of a DMSP spacecraft. This study is motivated by the need to critically scrutinize and systematically evaluate the plausibility of a two-stage hang-on scenario via the interstage electrical connectors and their cabling, which has been hypothesized as the initiating cause of failure of the recent F5 flight. The gyro data during this separation process are first presented, together with a postulated scenario to explain the vehicle dynamics. Three versions of this scenario have been carefully selected, modeled, and simulated, and the results have been compared with the flight data. For this 10.5 sec period, it is concluded that: (1) nominal separation can offer a simple explanation for the three observed gyro histories, (2) the complex behavior resulting from a three-connector hang-on scenario can also match the same data reasonably well. From a dynamics point of view, these results suggest that this connector hang-on scenario is plausible.