An Anomaly in Intercept Time for Short Range Ballistic Re-Entry Vehicles

This paper documents an anomaly in intercept time of a ballistic re-entry vehicle (RV) by a ballistic interceptor. Intuitively, it is expected that as soon as an incoming RV is detected, the defense will launch an interceptor. However, we show that under some conditions (short range, lofted RV trajectory and an interceptor that is slower than the RV) it is best to delay the launch of the interceptor so that the intercept time is minimal. This is important since by minimizing the intercept time, the interceptor can intercept the RV earlier, further away from the defense location and therefore safer for the defense. In addition, with minimal intercept times, the defense may maximize the number of engagement opportunities. This will allow the defense to improve the probability of raid negation. That is, the probability of neutralizing all incoming RVs is greater with more engagement opportunities. We will show how to minimize the intercept time using analysis in the phase space (velocities of the RV and the interceptor) and validate the results using MANA (Map-Aware Non-uniform Automata).