Two long-awaited intercept tests are slated for U.S. terminal and ship-based defenses in the coming months, but the Ground-based Midcourse Defense (GMD) campaign remains stalled for at least another year while engineers sort out a problem with the kill vehicle.

The last successful GMD flight test was December 2008, and two attempts to pit the system against a complex target with countermeasures have since failed. The first was due to an Exoatmospheric Kill Vehicle (EKV) quality issue. In the second test, the EKV flew as expected until its last 20 sec., during what was the longest flight ever for the system, says Missile Defense Agency (MDA) Director Army Lt. Gen. Patrick O'Reilly.

During the annual Space and Missile Defense Conference here, he acknowledged the grounding of the Boeing-led program as the “600-lb. gorilla in the room.” A failure review board has finished its analysis of the latest flight-test flop in December 2010, although he declined to identify the root cause. He says a team is giving the Raytheon EKV Capability Enhancement 2 (CE-2) a second design review, and there is time to conduct a third, if needed, before returning to flight in about a year.

At that point, the MDA will conduct its third attempt at a challenging 90-deg. hit-to-kill intercept, geometry simulating a North Korean launch scenario. EKV production will remain suspended pending the outcome of that flight. CE-2 is a new design that incorporates improvements to mitigate parts obsolescence; O'Reilly says the problem with the EKV will not affect the function of CE-1 vehicles now on Ground-Based Interceptors on alert at Fort Greely, Alaska, and Vandenberg AFB, Calif.

“We fly to learn,” O'Reilly says, acknowledging that the EKV issue could not have been discovered without exposing the system to a long flight in the space environment. “I'm not ready to learn any more right now,” he quips, noting the two successive failures.

Agency officials, meanwhile, are preparing for the first flight of the Raytheon SM-3 IB interceptor, which will incorporate a new two-color infrared seeker and throttleable divert-and-attitude-control system. These features are designed for better discrimination between a warhead and a decoy as well as improved maneuverability in the endgame. The SM-3 IB is slated for use in the European Phased Adaptive Approach (PAA) defense architecture; it will first be deployed on Aegis ships and later move to land-based sites in Romania and Poland to guard Europe from an Iranian attack.

The SM-3 IB will be expected to intercept the Aegis Readiness Assessment Vehicle-B target, likely in the 1,000-km (620-mi.) range, in the upcoming trial.

Shortly thereafter, by October, the MDA hopes to demonstrate another step forward by pitting the Lockheed Martin Terminal High-Altitude Area Defense (Thaad) system against its first-ever “raid.” This will consist of two targets—each flying less than 1,000 km—including an air-launched medium-range target made by Orbital Sciences Corp. and a foreign military asset (an actual threat missile procured from abroad) launched from a mobile sea-based platform.

The goal will be for a single Thaad system—including the AN/TPY-2 radar and one launcher—to detect and intercept both targets, which will be lofted within seconds of one another. This trial is designed to test against what O'Reilly says is a likely “raid” attack, or launch of several missiles dispatched together in an attempt to overwhelm U.S. defenses.

One of these interceptors will be a test unit and another will be pulled from Lockheed Martin's Troy, Ala., production line. The second will include a new optical block switch, a component that encountered design problems last year, delaying deliveries of Thaad missiles to the field. Lockheed is now shipping roughly two missiles per month, with a plan to deliver four monthly in the fall, says Tom McGrath, the company's Thaad vice president. Ninety-eight are on order. The first 11 have been delivered, says O'Reilly.

Technology development and testing work may not be the MDA's biggest challenge, however. As deficit-reduction talks place severe pressure on Pentagon R&D accounts, the $8-10 billion of unclassified MDA spending is not likely to emerge unaltered in the next defense budget request.

Jeff Keuter, president of the George C. Marshall Institute, says lawmakers are increasingly talking about a “cost-to-defend” ratio for technologies, as opposed to the price of a particular missile defense program. “This is a framework that needs to come out more clearly” if Congress is going to begin to use it for budget deliberations.

O'Reilly observes that this is an unprecedented time for U.S. missile defense, in that several systems are being designed at once to operate together to support the different increments of the PAA. This is allowing the agency to make design trades among the systems and to avoid overloading any particular system from requiring more technology—and thus costing more—than necessary.

These forthcoming systems include the Precision Tracking Space Sensor (PTSS) satellites, which are slated to carry infrared sensors for pinpointing cold warheads in their midcourse of flight; and the SM-3 IIB, a yet-to-be-defined next-generation ICBM killer. Though a developmental bonanza may be an advantage for engineers eyeing design trades, the timing could be problematic to jump-start these programs for use in the PAA. Projects that have not yet received contract dollars are typically more vulnerable to delays or terminations than those for which the government has already begun paying.

O'Reilly says he hopes to conduct system-requirements reviews for both programs in the fourth quarter of fiscal 2012. Requests for proposals are slated for release for PTSS in the first quarter of fiscal 2014 and for the SM-3 IIB in the fourth quarter of fiscal 2012.

Contract award for the missile is planned for the first quarter of 2015, with fielding anticipated as soon as 2020.