SM-2-IV

American surface-to-air missile. Extended-range surface-to-air missile for use by AEGIS naval vessels. A version with lower tier anti-missile capability against tactical ballistic missiles was tested but not put into production.

The requirement for the Standard Missile SM-2ER Block IV was to provide an extended-range surface-to-air missiles that could be launched from Navy AEGIS ships equipped with the new MK 41 Vertical Launch System. The original Standard ER missile could only be launched from the rail-type launchers that equipped older US vessels. In order to fit into the VLS launch tubes, the SM-2ER Block IV used a new, shorter but fatter MK 72 booster motor, and dispensed with the control fins on the original missile. Instead the missile used thrust-vector control. The missile was upgraded to include the MK 45 MOD 10 Target Detection Device, for improved performance against high-performance, stealthy targets even under severe jamming environments. The Block IV eventually evolved into the Block IVA Navy Area Theater Ballistic Missile Defense missile.

Problems with MK 72 booster delayed the program. The first launch in December 1992 was 18 months behind schedule. Priority given to development of the anti-missile version further delayed the program, and Initial Operational Capability for the Block IV was only certified in August 1999.

The Block IVA retained all anti-air warfare capabilities of the A model but added an anti-missile capability through use of a dual-mode RF/IIR seeker, an upgraded MK 125 warhead package, and an enhanced autopilot. Flight tests began in 1994, and in January 1997, a Lance tactical missile was shot down for the first time. The missile was to have been part of a two-tier ABM system, with the more capable Standard SM-3 as the upper tier. However the decision was taken to proceed with the SM-3 alone in December 2001 and the Block IVA program was cancelled.

Maximum range: 240 km (140 mi). Boost Propulsion: Solid rocket. Cruise engine: MK 104. Maximum speed: 4,000 kph (2,400 mph). Initial Operational Capability: 1999.