The long-range, high-altitude Arrow-II system, which has been operational since 2000, is designed to knock out ballistic missiles, with Iran being the primary threat in that sector.
The third layer, to counter intermediate-range missiles, is still being developed. This system, known as David's Sling, is at least two years from deployment.
The first Iron Dome battery, which will be deployed in the south to counter Hamas' rocket fire, will be delivered to the Israeli air force in about six weeks. It is expected to be operational by May. Others will be sited in the north later this year.
"Making Iron Dome operational will transform Israel's political and security situation on the northern and southern fronts," said Pinchas Buchris, director general of the Defense Ministry.
Iron Dome, developed over the last two years at a cost of $200 million by state-owned Rafael Advanced Defense Systems Ltd., uses small guided missiles to destroy short-range rockets used by Hezbollah and Hamas.
The number of batteries that will be required and the cost remains a troubling question.
It is generally accepted that the military would need about 20 batteries to defend the entire northern and southern borders from Hezbullah and Hamas bombardment. Each battery costs $14 million. The high operational costs are also causing some consternation.
Each interception of Hamas' Gaza-manufactured Qassam rockets, which cost around $200 apiece, would cost around $100,000.
All this "will require either diverting substantial funds from other defense projects or significantly increasing the defense budget," the Haaretz daily noted.
The deployment of Iron Dome, when completed, will provide for the first time a defense against Hezbollah and Hamas rockets that have plagued Israel for years. The barrages inflicted few casualties and little damage, although the political and psychological impact was considerable.
Iraqi leader Saddam Hussein fired some 309 Scud ballistic missiles at Israel during the 1991 Gulf War, the first time the Jewish state's population centers had come under bombardment. These were largely ineffective.
But Hezbollah's relentless rocket bombardment of northern Israel during the 34-day war in July and August of 2006 changed that. The Iranian-backed Hezbollah unleashed some 4,000 rockets of various calibers -- an average of 150-200 per day right up to the final minutes of the conflict.
Northern Israel was paralyzed. Some 50 people were killed. Israelis understood that missile bombardment was the shape of things to come.
The Iron Dome project emerged from the 2006 crisis to meet that security threat.
Iran now has Shehab-3 ballistic missiles capable of hitting anywhere in Israel. These are targets for the long-range, high-altitude Arrow-II missiles developed by state-owned Israel Aerospace Industries and the Boeing Co. with U.S. funding.
Hezbollah is now reported to have in excess of 42,000 Syrian and Iranian rockets -- around three times the number it had in 2006. These will now be countered by Iron Dome.
The military and geopolitical implication of the advent of Arrow, Iron Dome and David's Sling being developed by Rafael and Raytheon of the United States, are considerable. When all three interlocking systems are in place Israel will be in a position, to a large extent, to counter every type of missile and rocket its enemies possess.
Doubtless it will not be able stop every missile if they are fired en masse but the Jewish state will have greater protection than any other state on the planet.
The Arab News, published in the Gulf, noted in an editorial Friday that Iron Dome "represents a change of strategic balance in the same way that the Russians believe that the U.S. missile shield affects the global balance of nuclear weaponry …
"Israel will soon apparently have cover against rocket assault from anywhere in the Middle East.
"Moscow fears that the proposed U.S. missile shield will allow Washington to launch a strategic atomic strike and then defend itself against retaliation," Arab News said.
"Precisely the same analysis must be applied to Israel with its undeclared and illegal nuclear arsenal."