Iron Dome is an Israeli mobile all-weather air defense system developed by Rafael Advanced Defense Systems and Israel Aerospace Industries. It is designed to intercept and destroy short-range rockets and artillery shells fired from distances of 4 kilometers (2.5 miles) to 70 kilometers (43 miles) away and whose trajectory would take them to an Israeli populated area. The system has three central components: Detection & Tracking Radar, Battle Management & Weapon Control, and Missile Firing Unit. The radar system is built by Elta, an Israeli defense company and subsidiary of Israel Aerospace Industries, and by the IDF. The control center is built for Rafael by mPrest Systems, an Israeli software company. The Iron Dome uses radar to track incoming rockets and can determine whether the missiles trajectory poses a threat to a protected area, such as a strategically important site or populated center. If the rocket does pose a threat, a command and control center can respond by launching its own Tamir missile to intercept it. The system is not configured to fire on rockets outside of a protected area, meaning these are ignored and left to land harmlessly elsewhere. The Iron Dome has a 95.6% success rate during a rocket salvo fired by Islamic Jihad in May. The US government has spent over $1.5 billion on the Iron Dome program, and research related to it as well.