Israel already boasts an array of sophisticated missile defences, which were used successfully during the 11-day Gaza war this year.

The High Availability Aerostat System resembles a giant blimp or zeppelin. The Defense Ministry says it’s one of the world’s largest systems of its kind. It was developed in cooperation with a subsidiary of state-owned Israel Aerospace Industries and TCOM, a U.S. aerostat manufacturer.

Israel has moved aggressively in recent years to counter potential threats from Iran, the Hezbollah militant group in Lebanon and Gaza’s militant Hamas rulers, all of which boast large arsenals of rockets capable of hitting major cities.

During the Gaza war, Hamas fired barrages of rockets at Tel Aviv in an attempt to overwhelm Israel’s Iron Dome defense system, but Israeli officials say it shot down around 90% of the projectiles it targeted.

Israel carried out hundreds of airstrikes against what it said were militant targets. The fighting killed more than 250 Palestinians, including 129 civilians, according to the United Nations. There were 13 deaths on the Israeli side.