PULSE MOTOR OPTIMIZATION VIA MISSION CHARTS FOR AN EXOATMOSPHERIC INTERCEPTOR

The selection of the pulse split and the interpulse delay of a two-pul se exoatmospheric midcourse stage for an exoatmospheric interceptor, w hich uses a kinetic kill vehicle (KKV) for a direct hit kill, is exami ned. Mission chart analysis is introduced along with system error tree s and is used to select motor parameters that maximize the complete we apon system performance. In this analysis, the interceptor receives me asured target updates from a weapon system consisting of a track senso r and a link to the interceptor. Location of the weapon system track s ensor is not restricted hy this analysis. The interceptor states may b e measured by the interceptor, by the weapon system track sensor, or b y some combination of these. For specific weapon system and intercepto r errors, the mission charts indicate upper and lower limits on the se cond-pulse burnout time. Ignition of the second pulse anywhere between these bounds leads to a high probability of a successful intercept wi th the earliest ignition time generally producing the highest average speed. These bounds are a function of 1) the KKV divert capability, 2) the weapon system and interceptor errors, 3) the fraction of second-p ulse impulse allotted for midcourse correction divert, and 4) the prop ellant split between the first and second pulse. As the total mission time to intercept increases, the difference between the upper and lowe r bounds decreases until the mission becomes infeasible. The system er rors and the pulse split determine the maximum feasible mission time. For a specific set of errors, there is a pulse split that optimizes th e maximum feasible mission time and intercept range when all system co nstraints are considered. The maximum feasible intercept range is extr emely sensitive to the system errors.