Agency to modify anti-air warfare missile and mid-course system following cancellation of Raytheon programme

The US Missile Defence Agency is hoping to fill part of the gap in its future sea-based missile defence coverage created when the Raytheon Standard SM-2 Block IVA Navy Area system was cancelled. It plans to improve the SM-2 ER anti-air warfare (AAW) missile and modify the complementary upper-tier SM-3 mid-course missile defence system.

"We found that through improvements in the Navy Mid-Course System, the so-called upper tier, which is performing quite well, and some improvements in the existing Block IV Standard missile, we can achieve much of the capabilities lost as a result of the removal of Navy Area," says Pete Aldridge, US defence undersecretary for acquisitions, logistics and technology. As a result there will be no dedicated replacement of the SM-2 Block IVA cancelled late last year after cost overruns.

Raytheon is considering design changes to the recently flight tested SM-3 to intercept ballistic missiles at lower exo-atmospheric altitudes. The system has been designed to operate above 60km, incorporating a kinetic warhead and a two-pulse third-stage rocket motor. By burning only one pulse or none of the third stage, the missile is not accelerated as fast and can intercept incoming targets at a lower height.

SM-2 Block IVA, as with SM-3, was a development of the baseline Block IV AAW missile, incorporating a side-mounted imaging infrared (IR) seeker and a nose-mounted fuze for endo-atmospheric interceptions below 60km. The Pentagon and Raytheon are looking at incorporating the Block IVA's modified autopilot software into the Block IV to improve its kinematic capabilities to intercept ballistic missiles without changes to the existing semi-active seeker and side-mounted fuze.

"It doesn't have as good a kill probability as the Block IVA would, but we think we can get the kill probability up. If we can do that it will absorb a lot of the shorter-range capability that was lost," says Aldridge. This will require modifications to the shipboard Lockheed Martin Aegis weapons system and radar, and while it will not offer the same small wavelength detection capabilities of an IR seeker, the system could be ready early next year, says a source.


Source: Flight International