Over 2,000 U.S. and Israeli troops have conducted their largest joint air-defense training exercise ever. The objective was to see how effective U.S. and Israeli anti-missile systems would be in jointly defending against missile attacks from Iran, Syria and Lebanon. The exercise involved real or simulated use of Israeli Arrow, plus U.S. Thaad, Aegis SM-3, plus Patriot and Hawk missile defense systems from both countries.
About half the $2 billion cost of developing Arrow came from the United States. In addition, American firms have done some of the development work, or contributed technology. The U.S. has been threatening to cut the several hundred million dollars it would be spending on future Arrow development, in order to save money, and allocate more resources to U.S. anti-missile systems (Aegis SM-3, THAAD and GBI). American support of Arrow was originally sort of an insurance policy, in case similar U.S. effort didn't work out. But Israel sees Arrow as its main defense against Iranian missiles. Thus the recent exercise, and the U.S. offer of Thaad and Aegis systems.
Israel has two batteries of Arrow, and over a hundred missiles available. An Arrow battery has 4-8 launchers, and each launcher carries a six missiles in containers. The Arrow was developed to knock down Scud type missiles fired from Syria, Saudi Arabia or Iraq. The two ton Arrow I is being replaced with the 1.3 ton Arrow II, which can shoot down longer range ballistic missiles fired from Iran. Israel is currently developing and testing an upgraded Arrow II.
The U.S. has provided Israel with a mobile X-band radar that enables it to detect incoming ballistic missiles father away. Currently, the Israeli Green Pine radar can only detect a ballistic missile fired from Iran when the missile warhead is about two minutes from hitting a target in Israel. The X-band radar would allow the Iranian missile to be spotted when it was 5-6 minutes away, enabling the Israeli Arrow anti-missile missile to hit the Iranian warhead farther away and with greater certainty. Israel also wants to buy a land based version of the Aegis anti-missile missile.