Launching the Patriot PAC-3 surface-to-air missile from a Boeing F-15C fighter to intercept a tactical ballistic or cruise missile could be demonstrated within two years, believes Lockheed Martin, which has received a $3 million follow-on contract from the US Missile Defense Agency (MDA) to continue refining the concept.
The Air-Launched Hit-To-Kill design is one of several concepts being studied by the MDA for boost-phase intercept and homeland defence.
Work completed by Lockheed under an initial $2 million contract concluded that launching the PAC-3 from dual-missile canisters under the wing of a tactical fighter was feasible, says Mike Trotsky, vice-president air and missile defence systems.
Lockheed's concept of mounting a PAC-3 on the F-15C is one of several under study to defeat ballistic missiles
There are two possible mission scenarios, says Trotsky. In one, a forward-deployed F-15 on combat air patrol (CAP) would launch the PAC-3 to intercept a ballistic missile in its boost phase.
The homeland defence mission envisages tactical ballistic or cruise missiles being launched from barges. "The aircraft could be on CAP or be scrambled and intercept both types of target," he says.
The F-15's radar would detect and track the target. The aimpoint would be uploaded to the PAC-3 before launch and updated during flight using the fighter's radar as a datalink, with terminal guidance to be provided by the missile's active seeker. "We would not have to do much to the PAC-3. Once it leaves the aircraft, its mission is pretty much the same," says Trotsky.
Raytheon is working on a competing air-launched boost-phase intercept concept under the MDA's Network Centric Airborne Defense Element (NCADE) programme. The company's interceptor combines an AIM-120 AMRAAM air-to-air missile's first stage with an AIM-9X Sidewinder's infrared seeker with a new second stage using hydroxyl ammonium nitrate propellant.
An F-15 test flight is planned for mid-year under a 12-month, $7 million risk-reduction contract awarded last year. Raytheon says NCADE will be the same size as AMRAAM and rail launched, and that F-15 flight tests will involve an interim design using the AIM-9X as its first stage.
Trotsky believes that Lockheed's approach offers lower risk, although the combat-proven PAC-3 has never been integrated with an aircraft. "Although NCADE is based on AMRAAM, and therefore low risk in integration with the aircraft, it is a new missile with no pedigree," he argues.
Lockheed has also looked at arming the F-15 with its new THAAD missile-defence interceptor, which is three times the weight of the 320kg (700lb) PAC-3 and 1m (3.3ft) longer at 6m.