Nearly two years ago, Defense Secretary Robert Gates unveiled a new incremental strategy to protect much of Europe and the Eastern U.S. from an Iranian ballistic missile attack. The so-called Phased Adaptive Approach (PAA) was designed with increments, each deploying new technologies in 2011, 2015 and 2018, and—eventually—the final phase would provide coverage from intercontinental ballistic missile threats from Iran in 2020.

The rationale for scrapping a plan to put 10 two-stage Ground-Based Interceptors (GBIs) in Poland for coverage from the PAA was that the threat from “raids,” or high numbers, of short- and medium-range missiles was greater than that from an ICBM attack from the Middle East. Earlier estimates predicted that Iran could deploy an ICBM as early as 2015, but these projections slipped to later in the decade. The Defense Intelligence Agency still argues that 2015 is possible, industry sources say, pushing some to suggest that a GBI solution for the Eastern U.S. and Europe is still needed.

But questions loom as to whether the technology, funding and programmatic approach to achieve ICBM coverage and early intercept, which is described by some government officials as “limited” at best, in 2020 are sufficient. To understand these questions, it is critical to outline the underpinnings of the PAA. The plan in 2009 was to embark on a strategy to achieve early intercept of ballistic missiles in 2020, thus nullifying the need to address the highly complex challenge of differentiating a warhead from decoys in space.

When asked what the Pentagon's plan is for countermeasures if early intercept does not materialize with the IIB in 2020, Missile Defense Agency (MDA) officials simply state: “We fully expect to have a viable early-intercept capability with the SM-3 Block IIB in the 2020 time period.” The MDA declined interview requests for this article and instead provided comments in writing.

With early intercept—defined by U.S. Army Lt. Gen. Patrick O'Reilly, MDA director, as occurring before apogee—a missile is ideally destroyed before it can deploy its payload. Another benefit is the ability to “shoot-look-shoot,” a doctrine that calls for taking a second shot at an incoming missile if the first misses. Time is available for only a second shot, however, if the first is very early in flight.

To embark on the PAA and early-intercept strategies, the Pentagon terminated the Multiple Kill Vehicle (MKV) program and canceled plans to base in Poland 10 GBIs, which are part of the Ground-Based Midcourse Defense (GMD) system now deployed to protect the U.S. from a North Korean attack (see p. 49).

The plan is to incrementally improve the interceptor, software and sensor technologies with the Aegis ballistic missile defense (BMD) system through the four phases. Early intercept is a challenge because sensors must be in the right place at the right time to detect a launch and interceptors must also be able to fly at long range and achieve high velocity to reach a target prior to apogee.

At issue today is whether the architecture as envisioned is achievable; and the piece most critics question is the plan to achieve early intercept and protect the Eastern U.S. from an Iranian ICBM attack.

USAF Gen. (ret.) Lester Lyles, who led the MDA when it was called the Ballistic Missile Defense Organization, is co-chairing a Defense Science Board task force review of the early-intercept strategy with Adm. (ret.) William Fallon, who headed U.S. Pacific Command. The report is being written and will likely be briefed to Pentagon leaders in the fall.

Lyles declines to discuss his findings until they are briefed to the Pentagon. Industry and government sources familiar with the study have different views on what the findings will be. Some say the task force questions the ability to achieve early intercept with the time and money available. Others say the report will outline what can be achieved with the current strategy.

Whatever the outcome, the results are likely to influence the SM-3 IIB program, whether it moves forward and, if it does, what the missile will look like. The IIB is the notional long-range missile killer that will be fielded in Phase IV by 2020 for early intercept to fulfill the promise of protecting the Eastern U.S. and most of Europe from an Iranian ICBM attack.

The MDA has issued 32-month study contracts to three companies—Boeing, Lockheed Martin and Raytheon—to explore concepts for this missile, which is also sometimes referred to as the Next-Generation Aegis Missile.

The goal with the IIB program is to build a missile that has a high velocity at burnout—meaning the booster has a high speed when it detaches from the kill vehicle. This, coupled with sophisticated thrusting and divert systems on the kill vehicle, would give the kill vehicle more momentum and thus a larger defended space. “Range doesn't always get you there in missile defense. It really is your velocity at burnout,” says one industry official. “The agency needs, rather than to rush the IIB development, to take the time and get it right so that they've got the interceptor that will do this early- intercept job.”

Capability tradeoffs for the IIB are open now, though there are a few boundaries that are surfacing. To make use of the MK 41 vertical launch systems on Aegis ships today, the missile's diameter must fit. The weapon will also likely use solid fuel. Should liquid fuel be required, the Navy is unlikely to support the program because the service does not allow it on ships, and the program would crater without Navy support. And the weapon must be deployed by 2020. Industry sources suggest that O'Reilly is in favor of a 27-in.-dia. booster, which is the largest size that can be accommodated by the MK 41. This has not been issued as a requirement, however.

Two schools of thought are emerging on how to tackle the IIB design. One, pushed by Raytheon, which built the Standard Missile family of interceptors, is to incrementally build upon the SM-3 product line, optimized for sea-based exoatmospheric kills, to achieve the IIB capability. Initially, the SM-3 IIB moniker indicated an assumption on the part of the Pentagon that Raytheon would build the missile as an upgrade to its SM-3 IIA, a cooperative development with Japan to build a larger missile designed to protect Japan from North Korean attack with fewer ships. However, objections from competitors prompted the MDA to consider a competition. One Raytheon official declared: SM-3 “has been one of Raytheon's most important programs, and now we are competing for it.”

Another view of the IIB, pushed by the company's competitors, is that a totally clean-sheet approach is needed to achieve the requirements. Lockheed Martin wants a foothold in the long-range interceptor market; the company already builds the Patriot interceptor family and Terminal High-Altitude Area Defense missiles.

Boeing's interest, by contrast, is twofold. If the IIB concept fails and is terminated, Boeing's GBI is the likely choice to quickly provide protection, at least, of the Eastern U.S. (emplacement in Europe could prove too disruptive to relations with Russia for a European defense). If the IIB does survive, a Boeing win would maintain the company's grip on the long-range interceptor market.

Raytheon's argument, however, is that the SM-3 family has been able to exceed expectations, achieving intercepts beyond its design specifications. And, company officials say, it is possible that continuing to develop the system could pay off with a capability in 2020. Some industry officials suggest a clean-sheet design could be far riskier than evolving the SM-3 owing to schedule and funding constraints.

Raytheon officials point to the most recent flight test of an SM-3 IA. During the exercise, called Stellar Charon, an Aegis-launched SM-3 IA intercepted its longest-range target to date, a Lockheed Martin LV-2 intermediate-range ballistic missile (IRBM) launched from 3,700 km (2,294 mi.) away at Meck Island in the Kwajalein Atoll. Also new for this test was to prove a “launch-on-remote” capability, which means the Aegis, near Kauai, Hawaii, fired the SM-3 based on a missile track provided by an AN/TPY-2 X-band, ground-based radar at Wake Island rather than waiting for the ship to generate an “organic” S-band radar track from its onboard AN/SPY-1 radar.

Launch on remote is a step forward for Aegis, because it allows for the interceptors to be part of a larger network of sensors deployed by MDA, rather than forcing a commander to wait for a threat to cross the ship's radar footprint prior to launching an interceptor. “Near the end of the missile time of flight is when the organic track of the ship took over,” says Wes Kremer, Raytheon's SM-3 program manager. “Most of the time of flight of the missile was the early part of the flight that wouldn't have been possible without the launch-on-remote capability.” SM-3 outstrips the range of the Aegis's AN/SPY-1, so allowing for launch on remote takes advantage of more of the missile's range. Also during the flight test, two Space Tracking and Surveillance System (STSS) satellites tracked the LV-2 target using mid- and long-wave infrared sensors. MDA officials say it is possible that Aegis could have launched the interceptor on the STSS track alone.

“Earlier they used to characterize the Aegis BMD early-deployment capability as short- and medium-range ballistic missiles,” says Ed Miyashiro, vice president of Raytheon Missile Systems in Tucson, Ariz. “Now we include intermediate-range type missiles, which are much longer range.”

The Stellar Charon test took place with a PAA Phase I capability—the Aegis 3.6.1 software and an SM-3 IA missile. Raytheon officials point out that the capability was proven early; it is planned for use with the Aegis 4.0.1 software (designed for a more robust launch-on-remote capability) and the SM-3 IB, which features an improved two-color seeker (optimized for target discrimination from countermeasures) and throttleable divert and attitude control.

With Stellar Charon, “we essentially took a Phase III threat, the intermediate-range ballistic missile [and] used the Phase I architecture—with some expanded things such as the launch on remote—to engage,” Kremer says. “It really is demonstrating how all of the pieces are coming together.” Though planned for the 2015 Phase II deployment, the IRBM kill demonstrated during Stellar Charon “has direct applicability to the USS Monterey right now,” says Frank Wyatt, Raytheon's vice president of naval weapons.

Another goal for the system is to achieve an “engage-on-remote” capability, which means the interceptor uses only offboard sensors (tracks from remote sensors) to destroy a threat. In contrast, with launch on remote, an organic track is provided to the interceptor late in its flight. This engage-on-remote is slated, according to MDA's plans, for Phase III, which deploys in 2018 and includes the larger SM-3 IIA missile as well as the Aegis 5.1 software update.

Raytheon officials emphasize that they are mindful of the collective benefit behind designing a solution that draws on the capabilities of these remote sensors and command-and-control features as they study options for the IIB solution. Miyashiro describes this process as understanding which “knobs,” or elements, of the system can be turned to produce various results; a less capable interceptor, for example, would require more capable sensors.

“Everybody recognizes that there are lots of knobs you can be turning [but] they need to be balanced within the bounds of reality,” he says. “The problem that has been posed to the community is to give me the system architecture solution that includes not only the missile solution but also the other elements of the architecture and balance it in a way that provides me with the best opportunity to do the mission quickest and cheapest.” Included in these other elements is the fielding of an Airborne Infrared (ABIR) unmanned aerial system and the Precision Tracking Space System, a follow-on to the STSS demo satellites. These sensors are needed to provide early tracking data for boosting ballistic missiles.

Raytheon acknowledges that the MDA is leaning toward a 27-in. booster. The MK 41 launcher can accommodate five 27-in. boosters versus eight of today's SM-3 IAs. The SM-3 IA/Bs are 13.5 in. in diameter, with the IIA planned as an upgrade to a 21-in. frame. Raytheon is leaving the door open to a IIA upgrade for the IIB design because of what company officials say is a track record of SM-3s exceeding capability.

“We always envisioned that the kinematics were robust enough to engage a wide array of threats,” Miyashiro says of the SM-3 family. However, this would require adapting a system designed to protect against shorter-range missiles to one optimized against ICBM-range threats.

Tory Bruno, president of strategic and missile defense systems at Lockheed Martin, says sorting through the tradeoffs between sensor, booster and kill vehicle design for a IIB is a “great systems engineering problem” and “one of the most fun problems we will have any time soon.” He suggests that unlike the Kinetic-Energy Interceptor high-speed, boost-phase missile killer that was terminated in 2009, the IIB would not require an entirely new propellant formulation. “That is good, because that is expensive,” he says. Lockheed Martin is aiming to marry a new booster with some communications technologies and lightweight structures that it was developing for the MKV program. The MKV was crafted to place many small kill vehicles atop a single booster to allow for multiple kills per booster.

Boeing has been mum about its IIB strategy. However, company officials continue to emphasize that the GBI force structure could be expanded as a “hedge” against any technical problems that might arise in developing a IIB or in the event the Pentagon decides to scrap the IIB effort altogether. GBI is, however, not suitable for an early-intercept strategy.

A former senior defense official says that while the PAA does protect the Eastern U.S., it comes at a higher risk than the strategy to place 10 two-stage GBIs in Poland. Those interceptors were planned for deployment as early as 2015; and this official notes that, at the earliest, PAA will provide ICBM coverage in 2020. O'Reilly has told Congress that an intercept test for the two-stage GBI, scheduled in fiscal 2012, has been shifted to 2014.

This official says that the decision by the White House to favor PAA over the GBI plan was a political gesture to placate Russia, which argued that the GBIs in Poland represented a threat. “They made a political decision and then they gave it to the agency and said, 'You have to justify this technically.'”

GMD advocates point to the option of placing interceptors at Fort Drum, N.Y., to provide a deeper magazine and coverage for the Eastern U.S. The MDA is already investing in an East Coast In-Flight Interceptor Communications System. This would provide a communications link for updated information on the whereabouts of the threat as well as a downlink on interceptor progress for commanders. The Eastern data system could function with existing interceptors as well as those that could be placed in New York.

The question of whether a IIB missile can achieve early intercept, and how to do it, is likely be to sorted out this summer. The Defense Science Board will report its findings, and the MDA is likely to request funding for the IIB strategy in the fiscal 2013 budget proposal that is due to Congress next February.