FOR HOW LONG WILL IRON DOME SHIELD ISRAEL FROM HAMAS MISSILES? AND WHAT YOU MUST KNOW ABOUT THE NEW DEFENSE TECHNOLOGY CALLED IRON DOME

Israel's Iron Dome missile defense system is figuring prominently in the unfolding aerial conflict with Hamas' military wing in Gaza.

Iron Dome is being credited with protecting Tel Aviv and other Israeli cities by blocking some of the rockets fired from Gaza.

Over the past three days, 737 rockets from Gaza were fired upon Israel: 492 landed, but 245 were intercepted by the system, Israel Defense Forces said Saturday.

 The name Iron Dome evokes an image of a protective
bubble over a city. In practice, Iron Dome is a defense against short-range rockets and mortar shells: the system targets incoming rockets and fires an interceptor missile to destroy them midair.

Each battery has a firing-control radar to identify targets and a portable missile launcher. The system is easily transportable, with just a few hours needed to relocate and set up.

The missile is highly maneuverable. It is three meters, or almost 10 feet, long; has a diameter of about six inches; and weighs 90 kilograms, or 198 pounds, according to the security analysis group IHS Jane's.

The warhead is believed to carry 11 kilograms, or 24 pounds, of high explosives, IHS Jane's said. Its range is from 4 kilometers to 70 kilometers -- or 2.5 miles to 43 miles.

What are the origins of Iron Dome?

Israel began developing the ground-based system in 2007.

After a series of test flights in 2008 and 2009, the first deployment of a battery occurred in southern Israel in 2011, according to IHS Jane's and the IDF. The Israel Air Force reported an interception success rate of 70% in 2011, IHS Jane's said.

Israel credits "breakthrough technology" and the system's radar. Iron Dome confronts multiple threats simultaneously, in all weather conditions, the Israeli military said.

"The radar detects a rocket launch and passes information regarding its path to the control center, which calculates the predicted point of impact," the IDF said. "If this location justifies an interception, a missile is fired to intercept the rocket. The payload of the interceptor missile explodes near the rocket, in a place that is not expected to cause injuries."

Each Iron Dome battery costs $50 million, IHS Jane's said. A missile costs at least $62,000, Israeli officials said.