Zeus, with a new 400,000 lbf (1.78 MN) thrust solid-fuel booster, was first test launched during August 1959 and demonstrated a top speed of 8,000 mph (12,875 km/h). The Nike Zeus system utilized the ground-based Zeus Acquisition Radar (ZAR), a significant improvement over the Nike Hercules HIPAR guidance system. Shaped like a pyramid, the ZAR featured a Luneburg lens receiver aerial weighing about 1,000 tons. The first successful intercept of an ICBM by Zeus was in 1962, at Kwajalein in the Marshall Islands. Despite its technological advancements, the Department of Defense terminated Zeus development in 1963. The Zeus system, which cost an estimated $15 billion, still suffered from several technical flaws that were believed to be uneconomical to overcome.