“Punching above…..”
MBDA’s AIM-132 ASRAAM(Advanced Short Range Airto-Air Missile) entered service with the Indian Air Force (IAF) as a ‘fireand-forget’ Close Combat Missile (CCM) for self defence of IAF-operated Jaguar strike fighters, in the process progressively replacing the earlier R.550 Magic. As the Jaguar is essentially a low-flying aircraft, the threat is projected to come from higher altitudes, so two missiles are carried on the Jaguar’s over wing stations. Over wing pylons require quick missile separation and ASRAAM being the fastest, lowest drag CCM weapon extant, inherently provides safe separation, unmatched “snap-up” capability, plus guaranteeing “first shot first kill” to avoid getting involved in an unnecessary dogfight.
MBDA’s ASRAAM is presently also in service with the RAF and RAAF, which is an optimum solution given its ability to passively provide short to medium rangeprotection. Reportedly, much impressed by its performance, the IAF have initiated proceedings to integrate the missile with its Sukhoi Su-30MKI and Tejas LCA fleet as well. It should be noted that although labelled as a CCM, the AIM-132 ASRAAM actually qualifies as a Near Beyond Visual Range Air-to-Air Missile (NBVRAAM) with its range exceeding 25 km.
The 2.9 metre-long, 88 kg missile is optimised for best possible pre-merge performance, following the dictum that whoever gets the first shot off is likely to win the encounter. Therefore the missile is built from the outset to acquire an opponent and successfully engage it at maximum range. Still, should the first shot not succeed, the missile will then provide close-in performance to destroy the target aircraft at close quarters.
Key to the missile’s acquisition range performance and high 90 degrees off boresight lock-on capability is its 128x128 element Focal Plane Array (FPA) Indium Antimonite Imaging Infra-Red (IIR) seeker mounted on a two axis gimbal. The device is manufactured as a single Indium-Antimonite die and in effect is a single chip low resolution thermal imager sensitive in the 0.5 to 5.4 micron band. FPA dramatically increases sensitivity because it continuously “stares” at the target, thus exposing a much larger detector area for much longer to the target’s emissions. Moreover, because it uses a television style scan, rather than conical reticule scan, it is for all practical purposes immune to flares as well as blinking Infra-Red (IR) jammers.
ASRAAM on the Jaguar
The only robust countermeasure is a laser with sufficient power to blind or burn it out. Because in effect the FPA produces a TV picture of the target scene, it is virtually impossible to break lock by violent manoeuvres at any range, also since the gimbal mechanism will adjust line of sight of the FPA. The target airframe is tracked using contrast lock techniques similar in concept to those used by the AGM-65 Maverick ASM, and therefore escape from seeker coverage is geometrically impossible – providing the airframe can sustain this. The ASRAAM warhead is a compact DASA-built blast fragmentation design, fired by a Thorn-EMI laser proximity fuse, with a backup impact fuse. This highly accurate ASRAAM is in effect a “hittile” as the warhead serves the purpose of guaranteeing the otherwise almost certain kill produced by a direct hit with a high velocity missile airframe.
The selection of AIM-132 ASRAAM for a considerable proportion of IAF platforms is indicative of the fact that enhanced situational awareness in modern air warfare has resulted in the probability of majority of aerial duels taking place in near beyond visual range, where a combination of Active Radar Homing (ARH) Beyond Visual Range Air-to-Air Missile (BVRAAM) and IIR homing NBVRAAM is likely to dominate the proceedings.
Sayan Majumdar