One factor Israel may have considered in agreeing to the recent cease fire with Hamas was a possible shortage of Tamir missiles (used by the Iron Dome system to shoot down rockets). The problem was that Israel was not sure how many long (over 20 kilometers) range rockets (that could reach larger urban areas) Hamas had left. Hamas had managed to fire about a thousand rockets in a week, with most of them hitting unoccupied areas or being intercepted by Tamir missiles. Israeli aircraft had made over a thousand bombing raids on Gaza, hitting hundreds of rocket storage sites. But the rockets appeared to be stored in small quantities all over the place, often in residential areas. Israel won’t say what their count was of Hamas rockets destroyed by air strikes but it was apparently less than the 12,000 rockets Hamas is supposed to have. Thus it was possible Israel faced the possibility of running out of Tamir missiles before Hamas ran out of long range rockets. That would mean dozens, or more, dead Israelis. At that point, Israel would have to send in ground troops to shut down Hamas rocket launches. That would also mean more dead Israelis. So, to be on the safe side….
Each of the five Iron Dome batteries has radar and control equipment and three or four missile launchers (each containing twenty missiles). Each battery costs about $40 million, which includes up to a hundred Tamir missiles (costing $40,000 each). In the two years before the recent conflict Iron Dome had fired nearly 200 Tamir missiles at rockets headed for populated areas. In the last week Iron Dome systems have fired over 400 more Tamir missiles. Israel never said how many Tamir missiles it has stockpiled, but the manufacturer of the Tamir admitted that, for most of November, the missile assembly line has been going round the clock. Now Israel knows how Iron Dome operates under heavy rocket fire and how many Tamir missiles would be needed to deal with a large scale attack. The Tamir production is likely to keep going on overtime for a while yet.
Meanwhile, there are maintenance issues for a large number of Tamir missiles kept in storage for a long time. Each 90 kg (200 pound), three meter (9.8 feet) long, 160mm missile is crammed full of volatile chemicals (the rocket motor), electronics, mechanical devices (to actuate the fins), and batteries. All this stuff goes bad over time and must be monitored. Parts must be replaced when they go bad. Just building several thousands of these missiles is not enough, you need climate controlled storage bunkers, monitoring and test equipment, spare parts, and technicians trained to carry out repairs. Like most missiles Tamir will also undergo upgrades to software and hardware. That will be yet another expense. The latest version of Tamir is believed to cost $90,000 each.