Following a baffling test in September, Israel’s Arrow II missile defense system has undergone a series of upgrades and improvements, the defense establishment announced this week. During the earlier test, the interceptor reached its target, but failed to neutralize it.

Israel Hayom reported Wednesday that Israel Aerospace Industries, which is developing the system, and Defense Ministry experts were confounded by the test results. A special team, which included even retired engineers, took until December to pinpoint the problem which caused the misfire.

The weakness detected in the system “has no effect on the Arrow II’s operational abilities,” a statement by the defense establishment said. Nonetheless, improvements to the system controls will be introduced to serve as a ‘safety net’ should the problem repeat itself.

The Arrow defense system is part of a multi-tiered program. The Arrow II is designed to protect the population against short- and medium-range ballistic missiles, with the Arrow III intercepting long-range missiles

The Defense Ministry also noted that a planned test of the Arrow III in December was cancelled on account of a malfunction in the target missile, and is therefore considered “no test” rather than a failure, since the Arrow III was never launched.

Despite the setbacks, officials maintain the development of the David’s Sling missile defense system, designed to deal with medium- to long-range rockets and cruise missiles, is progressing as planned. Pending the success of several tests, the system is set to be operational by the end of 2015,

Additionally, according to defense officials, the Iron Dome success rate during this past summer’s Operation Protective Edge was 90 percent. The system is credited with enabling Israel to prolong the operation and increase its success. Recent upgrades to the system have also expanded its original range, which was effective on projectiles fired from distances of between 4 kilometers (2.5 miles) and 70 kilometers (43 miles).