Missile Divert System Operating Phenomenonology

摘要

The Atmospheric Interceptor Technologies (AIT) missile airframe uses a solid propellant Divert and Attitude Control System (DACS) to maneuver the interceptor and close with the target. Precise knowledge of the aerodynamic forces and moments is required to insure hit-to-kill (HTK) aim point accuracies required for successful operation of the interceptor. The accuracy of missile interceptors is critically dependent on the fidelity of the DACS system. The fidelity of the DACS is dependent on the accuracy of the force amplification factor due to the flow separation caused by the divert jet interacting with the free stream flow. Predictions of the behavior of a DACS system at medium altitude (45-50 km) endo-atmospheric operating conditions has shown a very large separated region flow field upstream of the divert jet, a massive separated extent of the flow field around the missile, and very large transient changes in the behavior of this separated region. This behavior has been corroborated with tests of full-scale missile hardware at duplicated flight conditions in Aero-Thermal/Aero-Optics Evaluation Center (AAEC) tests. Surprisingly, lower altitude operations of the DACS (30-35km altitude) has led to the conclusion that jet induced flow separation is an inherently unsteady event at both altitudes, resulting in a variable amplification factor. Comparisons between experiments run in a shock tunnel at duplicated run conditions using a real solid propellant thruster as well as computational fluid dynamic predictions of a powered missile in flight with plume induced flow separation support the conclusions reached above.