ALARM (Air Launched Anti-Radiation Missile) is a British anti-radiation missile designed primarily to destroy enemy radars for the purpose of Suppression of Enemy Air Defense (SEAD). It was used by the RAF and is still used by the Royal Saudi Air Force. The weapon was retired by the UK at the end of 2013.
ALARM under the wing of a RAF Tornado GR4
|Type||Air-to-surface anti-radar missile|
|Used by||See operators|
|Wars||Gulf War, Kosovo War, Iraq War, Libyan Civil War, Yemeni Civil War (2015-present), Saudi Arabian-led intervention in Yemen|
|Manufacturer||BAe Dynamics (1982–1999)|
MBDA (UK) Ltd (since 1999)
|Mass||268 kilograms (591 lb)|
|Length||4.24 metres (13.9 ft)|
|Diameter||230 millimetres (9.1 in)|
|Warhead||Proximity fused high-explosive|
|Engine||Bayern Chemie two stage solid-fuel rocket motors|
|Wingspan||0.73 metres (2.4 ft)|
|93 kilometres (58 mi)|
|Speed||2,455 kilometres per hour (1,525 mph) (supersonic)|
|Pre-programmed/passive radar seeker|
|Tornado GR.4, Tornado F3, J22 Orao|
The Ministry of Defence received bids for a new anti-radiation missile in late 1982; British Aerospace Dynamics offered ALARM while Texas Instruments teamed with Lucas Aerospace offered its HARM missile. Defence Secretary Michael Heseltine announced the selection of ALARM on 29 July 1983. The initial order was 750 missiles for the RAF. The selection process was controversial; the battle between the contractors was bitter, the Ministry of Defence favoured ALARM to retain UK industrial capabilities while the Treasury favoured the cheaper and proven HARM.
In early 1986, BAe recognised that Royal Ordnance was having difficulties delivering the missile's motor, named Nuthatch, and began to consider alternatives. Royal Ordnance's solution to the required burn-loiter-burn characteristic of the engine was complex. In July 1987, BAe, by then the owner of Royal Ordnance, replaced the Nuthatch motor with a lower risk motor designed by Bayern-Chemie. BAe's GB£200 million contract for the missile was renegotiated with the price increased to GB£400 million and delivery pushed back from 1988 to 1990.
ALARM is a fire-and-forget system, with an added loiter capability. In loiter mode, ALARM will, when launched, climb to an altitude of 13 km. If the target radar shuts down, the missile will deploy a parachute and descend slowly until the radar lights up. The missile will then fire a secondary motor to attack the target.
ALARM has been used in the following conflicts:
- Primary Function: Suppression of Enemy Air Defence
- Contractor: MBDA
- Power Plant: Bayern Chemie two stage solid propellant rocket motors
- Length: 4.24 m
- Diameter: 23 cm
- Wing Span: 73 cm
- Launch Weight: 268 kg
- Speed: 2455 km/h (supersonic)
- Warhead: Proximity fused high-explosive
- Range: 93 km
- Fuse: Laser Proximity
- Guidance system: Pre-programmed/passive radar seeker
- Unit Cost: undisclosed
- Date Deployed: 1990
- User: UK (RAF)
- Tornado GR.4
- Tornado F3: fitted in time for 2003 Gulf War, receiving designation Tornado EF3
- Weapon has been "fit checked" on other RAF aircraft, such as the Jaguar. Due to its relatively large weight it is not suited to the entire RAF fleet.
- Also was expected to be usable on the Eurofighter Typhoon, but this requirement was deleted.
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- Major Projects Report 2008, page 149(155) Archived 5 February 2011 at the Wayback Machine. UK Ministry of Defence, 2008.