At least two dozen nations are developing, have built or bought, or are hosting some type of missile defense system, from Azerbaijan’s Soviet-built SA-10 Grumble/SA-20 Gargoyle to Israel’s Arrow and David’s Sling. In the past 30 years, it is estimated the United States and its allies alone have fielded more than 1,500 missile interceptors and associated support systems and sensors.

Of those, only Israel has used its systems in actual national defense against incoming missiles, demonstrating both the state of the art and the viability of missile defense, although the United States has employed missile defenses outside U.S. territory. As attacks against Israel to date have come from launch sites just across its borders, that nation’s definition of NMD is a bit broader than that of Europe or the United States.

In November 2012, a third Israeli system, Iron Dome, was hailed as the best demonstration of missile defense to date when it successfully intercepted 302 of 840 Hamas rockets fired into Israel from Gaza in a single four-day attack. The majority of those not intercepted were not fired upon, as their trajectories would take them outside populated areas; Israeli Defense Forces claimed the actual kill rate against targeted rockets exceeded 80 percent. While not intended as a defense against ballistic missiles, Iron Dome is considered a vital part of Israel’s multilayer national missile defense system.

Developed and coproduced by Boeing and Israel Aerospace Industries (IAI) as the world’s first operational national missile defense system, the Arrow Weapon System provides a two-tier BMD capability.

The Arrow 2, operational since 2000, uses a fragmentation warhead to destroy short- and medium-range ballistic missiles above the stratosphere, preventing debris from nuclear, chemical, or biological weapons from scattering over Israel. The Arrow 2 Block 4 is the most recent upgrade, providing enhanced midcourse guidance, lethality, and target identification and discrimination. A proposed Block 5 would allow coordinated operations with the next-generation exo-atmospheric Arrow 3 and increase the defended area by up to 50 percent.

The first Arrow 3 was successfully tested in February 2013. Able to be launched earlier and engage threats at greater range and higher altitudes than previous interceptors (during the arc between leaving and re-entering the atmosphere), it also is intended to provide additional defense capability for evolving threats – primarily the possibility of Iranian nuclear-tipped missiles.

David’s Sling, using the Stunner terminal missile defense interceptor jointly developed by Rafael and Raytheon, will add another layer to Israel’s defense against ballistic missiles when it achieves initial operational capability in 2014. The missile has no warhead, instead using an enhanced hit-to-kill (HTK) mechanism to destroy its target.

In November 2012, a third Israeli system, Iron Dome, was hailed as the best demonstration of missile defense to date when it successfully intercepted 302 of 840 Hamas rockets fired into Israel from Gaza in a single four-day attack. The majority of those not intercepted were not fired upon, as their trajectories would take them outside populated areas; Israeli Defense Forces claimed the actual kill rate against targeted rockets exceeded 80 percent. While not intended as a defense against ballistic missiles, Iron Dome is considered a vital part of Israel’s multilayer national missile defense system.

The world’s most widely deployed missile defense system is the U.S. Patriot (originally an acronym for Phased Array Tracking Radar to Intercept on Target), currently operational in a dozen nations, including Israel and two others in the Middle East, four in Europe, and three in Asia. The Raytheon-built system, which got its first battle test defending Israel and Saudi Arabia from Iraqi missiles during the first Gulf War, employs Patriot Advanced Capability 2 (PAC-2) and PAC-3 missiles to engage targets at medium range. Updated numerous times since it was developed in the 1980s, one of the more recent improvements was a more accurate guidance system – Guidance Enhanced Missile-Tactical (GEM-T). The PAC-3 introduced a range of improvements to the system, most significantly a new, more capable, and smaller missile, the MIM-104F. Four of the missiles can be stored in each launch canister versus the PAC-2’s single missile in each canister.

The new GEM-T production model began test firings in March 2012. In addition, it also is being tested with Raytheon’s system of radar-carrying airships, the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS), to enhance its detection range.

“Rather than looking at these systems independently – the GMD to fight the long-range threat and another system that might fight the medium-range one and another that might fight the short-range – let’s try to build them into an interconnecting group of systems that we can refer to as an integrated air and missile defense. The same sensors won’t be able to do it all, but hopefully there will be some connects and shared data, with shared information and shared situational awareness between the sensors. Each of those will help us tie the picture together.”

Not all components of modern missile defense involve hardware, however. In March 2013, DoD released a new “Strategy for Homeland Defense and Defense Support of Civil Authorities,” setting out Pentagon priorities in coordinating its defense programs, including BMD, with those of civil authorities in the United States, Canada, and Mexico through 2020. While not part of an anti-missile program per se, it emphasized the government’s growing concern about defense of the Western Hemisphere and the need for pre- and post-attack cooperation across borders at all levels.

While 34 nations now belong to the Missile Technology Control Regime (MTCR) – formed by Canada, France, Germany, Great Britain, Italy, Japan, and the United States in 1987 to curb the proliferation of ballistic missiles – and 134 have signed the International Code of Conduct (ICoC) against Ballistic Missile Proliferation since 2002, many key players remain apart, including China, India, Iran, Israel, North Korea, Pakistan, and Syria.

For more than a half-century, the United States and Canada have maintained a close watch on all launches into space – currently about a half-dozen every day around the globe – through the North American Aerospace Defense Command (NORAD), looking for potential long-range ballistic missile threats. NORAD’s mission is strictly missile warning, however; should it detect an actual attack, defending North America from a missile strike would fall to the U.S. Northern Command (NORTHCOM), whose current commander, Army Gen. Charles H. Jacoby, Jr., is dual-hatted as commander of NORAD.

That response would call on the U.S. Ballistic Missile Defense System, a system-of-systems network of space- and ground-based sensors able to detect and track missile threats to North America, then link with the Ground-based Midcourse Defense System (GMD). Launching interceptors against any detected threat relies on the Alaska National Guard’s 49th Missile Defense Battalion and the Colorado National Guard’s 100th Missile Defense Brigade, according to Air Force Brig. Gen. Kenneth E. Todorov, NORTHCOM’s deputy operations director.

“These are 300 National Guardsmen defending 300 million citizens of the United States. They are the no-kidding, 24/7 watch – watching for threats and waiting for them to come. And if they come, they are going to shoot them down,” he told DoD’s American Forces Press Service in January 2013, but added more is needed. “We have focused very hard on improving GMD capabilities since it became operational in 2006. But as we go forward as a command, one thing that we will change will be our emphasis and focus on short- and medium-range missile defense of the homeland.

“Rather than looking at these systems independently – the GMD to fight the long-range threat and another system that might fight the medium-range one and another that might fight the short-range – let’s try to build them into an interconnecting group of systems that we can refer to as an integrated air and missile defense. The same sensors won’t be able to do it all, but hopefully there will be some connects and shared data, with shared information and shared situational awareness between the sensors. Each of those will help us tie the picture together.”

The end result, he predicted, would be “cylinders of capability,” fielded as they are developed, hopefully within the next 10 years.

“Then as it develops and matures, I think we will start to knit the capabilities together to strengthen the numbers, if you will, and overlapping sensors from the short-range to the medium-range to the long-range,” Todorov predicted. “With the synergy among all of it, one plus one will equal three.

“We can’t take anything for granted. There are adversaries out there and groups of people and nation states that would like to do us harm.”

This article was first published in Defense: Spring 2013 Edition.