AM-21 Standoff ARM
Range: Direct mode: 80km, standoff mode: 180km
Speed: up to mach 5.5
Warhead: 71kg directed fragmentation
Guidance: active Millimetric wave radar, passive radar seeker and INS/GPS
Propulsion: Variable Flow Ducted Rocket with additional booster
The AM-21 is a large multi role anti radiation missile designed to be launched as either a defensive measure or as part of a preplanned Suppression/Destruction of Enemy Air Defences(S/DEAD) operation.
The missile itself starts off as a fairly standard cylindrical body with 2 air intakes for the variable flow ducted rocket propulsion system jutting out to the lower left and right hand sides. The nose is very finely shaped to reduce the drag experienced during very high supersonic/ hypersonic flight. The aft of the missile body from the air intakes back is shaped to provide a lifting surface and 2 very small wings can be deployed from a pod in the dorsal position. These wings are designed to provide extra lift during reduced speed/extended range engagements. Other than the wings the only external surfaces are 6 small fins around the aft exhaust nozzle.
Power for the missile comes from a variable flow ducted rocket that is designed to propel the missile at up to mach 5.5 for a short duration or mach 3.5 with a much larger endurance. The main rocket is ignited on launch by a booster rocket with its own jettisonable nozzle. Once the launch booster ahs fired and its nozzle jettisoned the main ducted rocket takes over and this exhausts through a thrust vectoring nozzle that provides the main directional control. Thrust vectoring control was chosen to reduce the drag caused by aerodynamic surfaces and thus boost range. The throttle system is slightly more complex than that found in other variable flow rockets and is capable of fully shutting down the main motor as part of the missile “loiter” capability. Engine restart is achieved by a small secondary booster motor.
Due to the extremely high speeds the missile will encounter during use most of the body is constructed from titanium and stainless steel.
In terms of guidance the AM-21 uses a multi function package. The first part of the guidance package is the passive radar seeker designed to detect and home in enemy radar emissions and should it be require other radio emissions such as data links and jamming systems. Secondary to this is an active millimetric terminal engagement radar that allows the missile to prosecute an attack on a variety of non emitting enemy targets in all weathers. Finally supporting and complementing these sensors is an onboard inertial and satellite navigation package that allows the missile to navigate to a specific location, be it a way point, the last know position of an active emitter or the real time location of a target that has been provided by the launch aircraft via the missile’s 2 way data link.
In use the AM-21 has two main operating modes:
The first is the direct mode. This is primarily a defensive mode where by the launch aircraft detects a threatening emission either using its own onboard defensive aides systems or by using the AM-21 own passive system. In response to the threat the AM-21 is launched toward the direct of the source of the threat along the shortest possible path and at maximum speed. Should the threat cease to emit a number of options are available depending on the mission parameters pre programmed by the user and the availability of support measures on the launch aircraft. The three main options are: The missile will continue on its course at max speed and attempt to engage using its terminal radar guidance; the missile will perform a pull up manoeuvre, throttle back its engine and deploy its wings before entering loiter mode or if the launch aircraft was able to geolocate the emitter before it turned off the missile will use its navigation system to fly to last known geolocation and engage.
The second operating mode is known as the Standoff mode. This is designed to be used as part of coordinated offensive S/DEAD operation. In this mode the missile is launched from close to max range and immediately throttles back the engine and deploys its wings. The missile will then flies towards a predetermined location, following any required way points. Once it reaches its destination the missile can immediately attack any suitable targets its sensors can locate or enter loiter mode and await a target of opportunity to present itself. Using the 2 way data link the launch aircraft, or any other platform its can hand off weapons control to, can retask the missile, provide it with up to date coordinates of a likely threat or even cue it to attack a particular target.
Loiter mode is a special option that allows the missile to remain in close proximity to a suspected emitter location an engage any emitter that turns itself on. In this mode the missile climbs to approximately 15,000m, throttles back its motor to its minimum sustainable output and begins flying a holding/search pattern. Should no target present itself before the missile is down to a minimum level of fuel the engine is shut off and a parachute deployed to slow the missile’s descent. Should a target be identified during the descent the secondary booster fires and relights the main motor to allow the missile to engage the new target. Duration of the loiter mode can depend on a number of factors including the amount of fuel remaining and weather conditions but generally once loiter mode has been entered the missile can maintain it for approximately 25-30 minutes with at least 15 minutes of that being in the parachute descent stage.
Regardless of attack mode the AM-21 will always attempt to use the same terminal engagement profile. The basic engagement profile is if flying towards the target the missile will pitch up before diving vertically onto the target or if attacking from loiter mode by simply diving onto the target. The Millimetric wave radar enables the missile to accurate recognise what type of emitter is being targeted and this permits the main warhead to be detonated at exactly the right height to take out the main antenna, be it mast mounted or not and inflict maximum damage against any other vehicles or equipment within the blast area.
Price: $570,000 per missile