Israel has successfully tested its newest missile defense system, the military said, a step toward making the third leg of what Israel calls its \"multi-layer missile defense\" operational.  The \"David s Sling\" system is designed to stop mid-range missiles, with ranges of up to 300 kilometers. It passed its test, shooting down its first missile in a drill Sunday in southern Israel, the military said.  Israel has also deployed Arrow systems for longer-range threats from Iran. The Iron Dome protects against short-range rockets fired by militants in the Gaza Strip and Hezbollah guerrillas in Lebanon. Iron Dome shot down hundreds of rockets from Gaza in this month s round of fighting.  Israeli Defense Minister Ehud Barak said the success of Iron Dome highlighted the \"immense importance\" of such systems.  \"David s Sling,\" also known \"Magic Wand,\" is developed by Israel s Rafael Advanced Defense Systems and US-based Raytheon Co. The military said the program, which is on schedule for deployment in 2014, would \"provide an additional layer of defense against ballistic missiles.\"  The next generation of the Arrow, now in the development stage, is set to be deployed in 2016. Called the Arrow 3, it is designed to strike its target outside the atmosphere, intercepting missiles closer to their launch sites. Together, the two Arrow systems would provide two chances to strike down incoming missiles.  Israel also uses US-made Patriot missile defense batteries against mid-range missiles, though these failed to hit any of the 39 Scud missiles fired at Israel from Iraq In the first Gulf War 20 years ago. Manufacturers say the Patriot system has been improved since then.