The Long Road to Missile Defense

March 1, 2011

early since the dawn of the nuclear age, America has sought a reliable defense against the world’s most fearsome weapons: nuclear-armed ballistic missiles. In recent months, the continued determination and resiliency behind that quest, and the elusiveness of the goal, were on clear display.

At its Lisbon Summit on Nov. 19, the NATO Alliance agreed for the first time to cooperate with the US in building a missile defense system to protect Europe, consistent with the Obama Administration’s proposed Phased Adaptive Approach. This system will center on improvements in space-based sensors and land-based radars, and on upgrades of the Navy’s existing Aegis Ballistic Missile Defense System.

On Dec. 15, the Pentagon’s Missile Defense Agency tested the “hit-to-kill” capability of the Ground-Based Midcourse Defense (GMD) system. For this test, an intermediate-range ballistic missile target was launched from Kwajalein Atoll, in the Republic of the Marshall Islands, with Air Force early warning satellites and a Sea-Based X-Band Radar successfully acquiring and tracking the missile. A long-range interceptor missile then launched from Vandenberg AFB, Calif. The Exoatmospheric Kill Vehicle deployed into space, but failed to intercept the target. This latest test of the GMD system was a repeat of a January 2010 exercise, which was also unsuccessful.

A Ground-Based Interceptor is launched from Vandenberg AFB, Calif., during a test in late January 2010. (USAF photo by A1C Anglina Davis)

Then, in late December, the Obama Administration’s signature nonproliferation initiative nearly floundered over the concerns of Senate Republicans that it might inhibit future US missile defenses. Ultimately the New START was ratified by the Senate 71 to 26, but only after Republicans insisted on rewriting the resolution of ratification accompanying the treaty to reaffirm US plans to build a missile defense system in Europe over Russian objections.

Meanwhile in early January, the speaker of Iran’s Parliament, Ali Larijani, publicly declared his country’s plans to boost its program to field more advanced short- and medium-range missiles, even as Iranian leaders continue to ignore international pressure to abandon a suspected nuclear weapons program.

All of those recent milestones reveal fundamental truths about the decades-long US effort to field a viable missile defense system to protect the homeland, allies, and deployed military forces. “Hitting a bullet with a bullet” on a global scale and in the compressed timeline necessary to intercept a missile in flight remains one of the most daunting and expensive challenges the United States has ever undertaken.

A Growing Threat

The Obama Administration’s proposal and NATO’s adoption of a Phased Adaptive Approach built around upgrades of existing technology promises to accelerate the effort to field a layered missile defense system capable of attacking short- and intermediate-range ballistic missiles in all phases of flight, a key goal of the Defense Department’s Missile Defense Agency.

Perhaps most importantly, the continued determination of rogue nations such as Iran and North Korea to pursue nuclear weapons and long-range missiles proves threats are rapidly evolving. The need to counter rogue nations with viable missile defenses is becoming more urgent. The need to defend against the limited arsenals of those countries, however, is also more achievable than realizing President Reagan’s vision of a Cold War shield against the Soviet Union’s thousands of ICBMs.

“Although the US and Russia are reducing their strategic arsenals, North Korea and Iran remain on a dangerous nuclear path,” said Air Force Gen. Kevin P. Chilton, then head of US Strategic Command, the lead combatant command for missile defense integration and advocacy.

Testifying before Congress last year, Chilton noted that Iran’s successful February 2009 satellite launch and North Korea’s similar attempt a few months later moved those countries a step closer to acquiring ICBM capability that could threaten much larger areas of the world.

“The recently completed [Ballistic Missile Defense Review] notes the growing threat of ballistic missiles as they become more flexible, mobile, survivable, reliable, and accurate from greater ranges,” testified Chilton, who retired in February. “Countering the growing desire among many states for such cost-effective weapons and symbols of national power requires sustained and carefully designed missile defense investments.”

Developing the “layered architecture” of a Ballistic Missile Defense System that can target ballistic missiles in all phases of their flight, anywhere US interests are threatened, requires what MDA calls a “complex system of elements.” Key nodes include space-based sensors and ground- and sea-based radars for launch detection and missile tracking; ground- and sea-based interceptor missiles for destroying ballistic missiles in flight; and perhaps most importantly, an integrated command and control battle management and communications network acting as a central nervous system, constantly testing the synapses that link sensors, radars, and interceptor missiles and components from all the individual armed services.

“The Ballistic Missile Defense System is in some ways an almost uniquely joint enterprise, with the Pentagon’s Missile Defense Agency interfacing with the major combatant commands, all of the armed services, and various joint functional component commands to bring all of their capabilities together behind the single mission of missile defense,” said Col. John Kress, chief of the missile warning, missile defense, and surveillance operations division at Air Force Space Command. “I can’t think of another military enterprise of a comparable scale and degree of joint interoperability.”

In August, Iran test-fired its 29-foot-long Fateh ballistic missile. Iran has announced intentions to boost its missile program. (Photo by Vahid Reza Alayi via

Early Warning Evolution

Indeed, to understand the critical role the Air Force plays as the “eyes and ears” in that complex system and throughout its operations, you have to look to the eastern scrub plain of Colorado. On the outskirts of Colorado Springs are Peterson and Schriever Air Force Bases, home to Air Force Space Command, the Missile Defense Agency’s Missile Defense Integration and Operations Center, and US Strategic Command’s Joint Functional Component Command for Integrated Missile Defense. Colorado Springs is also home to US Northern Command, the North American Aerospace Defense Command, and the Cheyenne Mountain Air Force Station, making it as close to a solar plexus for the Ballistic Missile Defense System as exists in any single location.

During the Cold War, the missile warning mission was primarily conducted by 1,200 men and women who toiled in the subterranean city burrowed into Cheyenne Mountain. They routinely prepared for an ICBM attack in an underground complex protected by 27-ton concrete and steel blast doors, floating on a bed of more than 1,000 steel springs, the better to cushion them from a potential thermonuclear blast.

Since the end of the Cold War, the operations center had focused on the more modest threat of a single missile or handful of missiles launched from North Korea and targeting the United States. During frequent drills, AFSPC’s constellation of Defense Support Program early warning satellites detect a missile launch from their geosynchronous orbit 22,000 miles above Earth, using infrared sensors to detect heat from the missile and booster plumes against the cool of the Earth’s background. This data is cross-referenced with a global network of US ground-based radars, including AFSPC’s Ballistic Missile Early Warning System.

After double-checking data and estimating the missile’s flight time and likely impact point, the Cheyenne Mountain operators practice communicating the warning over redundant communications lines to the Pentagon, White House, and US Strategic Command. In fact, practically the only thing the operations center couldn’t do during the roughly 28 minutes it would take a North Korean ICBM to reach the United States is to take any action to stop it.

The Ballistic Missile Defense System now being developed and fielded by MDA is designed to fill that critical gap in defensive capability.

Much of the C2 work once conducted at Cheyenne has now migrated to MDA’s Missile Defense Integration and Operations Center and Strategic Command’s Joint Functional Component Command for Integrated Missile Defense. Both synchronize global US missile defense operations.

Air Force Space Command’s role as the backbone of the early warning and tracking system, however, has not changed dramatically since the Cold War. “From our perspective, we still bring to the table global observation and early warning of missile launch, and then we feed that information into the broader missile defense architecture,” said Kress. Although all of the services operate sensors that feed into the broader BMDS, he notes the Air Force system of DSP satellites and ground-based radars still provides the broadest coverage of potential long-range missile launches.

A Standard Missile-3 is launched from the cruiser Lake Erie during a joint MDA and Navy test. The SM-3 successfully intercepted a threat target minutes later. (US Navy photo)

Critical Constellation

“While DSP satellites are a Cold War system, they have been upgraded over the years to better detect the launch of smaller, shorter range missiles, though they have some limitations in that regard in terms of ‘scan rate’ and infrared spectrum,” said Kress. “That’s why our primary focus is to transition from the DSP to SBIRS [Space Based Infrared System] as soon as possible. … SBIRS will have much better capability in terms of detecting shorter and intermediate-range missiles, and in tracking all missiles more precisely, hopefully right up until the point of intercept.”

Like a number of elements of the BMDS, however, the SBIRS program has been beset by delays, technological problems, and cost overruns. The program was restructured by MDA, for instance, with a lower tier constellation of SBIRS satellite reconfigured as the Space Tracking and Surveillance System. The STSS program launched two demonstrator satellites in 2009 to provide proof of concept. The higher altitude constellation of proposed SBIRS satellites has yet to launch into geosynchronous orbit.

“Sustainment of our early warning radars and fielding of the … SBIRS geosynchronous constellation are essential to maintaining timely threat warning and attribution,” said Chilton in testimony last year. “However, though SBIRS geostationary orbit was originally programmed to launch in 2002 as a replacement for DSP, we have not yet launched a single SBIRS satellite. … [So] we face ongoing challenges to sustaining our missile warning constellation’s long-term health. The SBIRS geostationary orbit satellite constellation is critical to any missile defense architecture.”

Not only is the BMDS designed to give the United States multiple chances to detect, track, and intercept enemy missiles, it will also sow doubt in the mind of any future adversary calculating the chances of a successful attack versus the costs of retaliation. The greater the doubt, the more the calculus is tipped toward deterrence.

“A basic fundamental … about missile defense is [that] it’s not a foolproof shield,” said Army Lt. Gen. Patrick J. O’Reilly, director of the MDA, at a symposium last year. “But the more layers you add, the much better effectiveness you have. … There is not one single system out there that would provide the type of protection that I think any of us would be satisfied with. But when you combine systems, you get to a very high level of protection.”

Technicians work on a SBIRS satellite. The constellation has yet to be launched into geosynchronous orbit. (USAF photo)

If the United States were to become involved in a regional war in the future, he said, a viable missile defense could prevent the conflict from escalating into a strategic conflict by deterring missile attack.

It’s a “fact that the psychological and political objectives of deterring opponents, and reassuring allies, are really built on the precepts that you have a physical and credible deterrence against the use of ballistic missiles,” O’Reilly said.

How an Intercept Would Work

To understand the “complex system of elements” the Missile Defense Agency is constructing to provide a layered defense against missile attack, consider a hypothetical Iranian missile attack on Europe or the United States sometime in the foreseeable future.

Immediately upon launch, the missile will be detected by state-of-the-art infrared sensors aboard the Air Force’s constellation of SBIRS and STSS satellites, and by SPY-1 radars aboard Navy Aegis ballistic missile defense cruisers stationed in the Persian Gulf.

Early detection is critical, because missiles are easiest to detect and most vulnerable in the initial “boost phase” of flight, when missile exhaust is bright and hot and no countermeasure decoys have deployed. The boost phase “window” for engagement closes in five minutes or less, meaning interceptors must be stationed relatively close by.

That’s one reason MDA is increasing the number of Aegis ballistic missile defense cruisers and destroyers to 38 by Fiscal 2015, and focusing on major block upgrades to increase the range and capability of its Standard Missile-3 interceptors. If an Iranian weapon is a short- or intermediate-range missile aimed at installations in Europe and it reaches the midcourse phase of its flight, by 2018, Aegis Ashore interceptor batteries stationed in Romania and Poland will target it.

An ICBM targeting the US will coast in space for as long as 20 minutes in its midcourse phase of flight. During this time, it will be tracked by an advanced network of sensors and radars, including the Air Force’s SBIRS constellation and a Sea-Based X-Band Radar.

The largest X-band radar in the world, the mobile Sea-Based X-Band Radar can provide precise tracking of target missiles of all ranges, and discriminate between actual missiles and countermeasure decoys. This information will then be fed into the ground-based command, control, battle management, and communications system, which will launch interceptors from bases in Alaska and California.

The last chance to intercept the Iranian missile will come in its terminal phase, once it re-enters the atmosphere. A short- or medium-range missile in terminal descent might run a phalanx of interceptors, including the Army’s Terminal High Altitude Area Defense (THAAD), which is now being fielded; the Army’s Patriot Advanced Capability-3 (PAC-3), already deployed worldwide; and the Aegis Sea-Based Terminal Defense System using the SM-2 Block IV missile.

The vision behind this complex, multilayered defense system is that the whole is greater than the sum of its many parts.

James Kitfield is the defense correspondent for National Journal in Washington, D.C. His most recent article for Air Force Magazine, “Rethinking the QDR,” appeared in the October 2010 issue.