“The completion of the program will be a significant layer for Israel’s multi-tiered anti-missile defense system,” Defense Minister Ehud Barak said in a statement

Iron Dome is the lowest of the tiers, tackling the guerrilla rockets of Gaza and Hezbollah. It was originally meant to handle ranges of up to 70 km (45 miles), but designers say this is being expanded to some 250 km (155 miles).

The top-most tier is Israel’s Arrow ballistic interceptor, designed to shoot down long-range Iranian and Syrian missiles at atmospheric altitudes – high enough so that any non-conventional warheads they might carry would be safely destroyed.