Likewise, the solution to dealing with massive numbers of warheads was to use faster computers and automated radars, allowing many interceptors to be in flight simultaneously. Zeus was being developed just as digital computers were experiencing a massive improvement in performance through parallel processing. Radar systems were likewise introducing the first phased array radar (Passive electronically scanned array) systems. Combining the two would allow hundreds of warheads and interceptors to be tracked and controlled at once. As long as the interceptor missile was not significantly more expensive than the ICBM, which was likely given their relative sizes, overwhelming such a system would not be feasible in a weapons system.