Brimstone is a ground or air-launched ground attack missile developed by MBDA UK for the UK's Royal Air Force. It was originally intended for "fire-and-forget" use against mass formations of enemy armour, using a millimetre wave (mmW) active radar homing seeker to ensure accuracy even against moving targets. Experience in Afghanistan led to the addition of laser guidance in the dual-mode Brimstone missile, allowing a "spotter" to pick out specific and the highest priority targets, particularly useful to minimise collateral damage when friendly forces or civilians were in the area. The tandem shaped-charge warhead is much more effective against modern tanks than older similar weapons such as the AGM-65G Maverick missile. The Maverick however carries a 300 lb warhead to make up the difference in design. Three Brimstones are carried on a launcher that occupies a single weapon station, allowing a single aircraft to carry many missiles.
After a protracted development programme, single-mode or "millimetric" Brimstone entered service with RAF Tornado aircraft in 2005, and the dual-mode variant in 2008. The latter was used extensively in Afghanistan and Libya. An improved Brimstone 2 was expected to enter service in October 2012, but problems with the new warhead from TDW and the ROXEL rocket motor put back the planned date to November 2015. MBDA is studying the use of Brimstone on ships, attack helicopters, UAVs, and from surface launchers. However, it will not be integrated on the Lockheed Martin F-35 Lightning II. Germany, Qatar and Saudi Arabia have purchased the missile. The cost per missile has been quoted as £175,000 each in 2015, or "over £100,000".
Development Previous developments There had been a number of British air-to-ground anti-armour concepts developed during the 1970s and 1980s, including the SNEB rocket, the proposed Hawkswing version of Swingfire, and ultimately the BL.755 cluster bomb. There were some alternatives offered during this time, including the 1966 Hawker Siddeley Dynamics (HSD) Cluster Martel proposal that mounted a cluster dispenser on the front of the Martel airframe to provide standoff capability.
AST.1227 BL.755 formed the basis for the Royal Air Force's (RAF) anti-armour air-to-ground strikes for many years, but it was always considered to be "expensive" if it needed to be used against individual targets instead of mass attacks. There were also concerns about the use of such weapons near friendly troops. This led to the late-1970s Air Staff Target 1227 (AST.1227) for a guided weapon to replace BL.755.
One early respondent to the AST.1227 was a modification of the small SRAM missile, which had originally been designed to be carried in pods containing multiple missiles, meaning that in the air-to-ground mode a large number could be carried. However, the Ministry of Technology expressed concerns about using an infrared seeker in the anti-tank role, especially due to the possible use of anti-IR "dazzlers" and other countermeasures.
The next attempt adapted the Rapier airframe to carry a laser seeker, either the Martin Marietta design used on the M712 Copperhead or a similar Swedish RB.83 which was also used in the ground-to-air role. The result was "Sabre", which was expected to have a single-round hit rate of 80% and the ability for a single aircraft to carry up to 10 missiles. It also had the ability to be used on helicopters, not only as a replacement for Hawkswing, but also as an air-to-air weapon against enemy helicopters and low-flying aircraft.
AST.1227 was abandoned in 1981, and Sabre along with it, due to the development of "smart" munitions in the US. This led to the release of AST.1238 the same year, calling for a long-term project to develop a self-guided weapon using a millimetre wavelength (mmW) radar seeker.
AST.1238 The AST. 1238 received eight bids in November 1987, but down-selected to five in February 1988. These included the Hunting Engineering Smart Weapon Anti-Armour, an unpowered dispenser with sixteen submunitions that would be ejected at a pre-selected location and then use mmW seekers. BAe Dynamics proposed two designs, one from Hatfield based on the AGM-65 Maverick airframe with a new warhead and an imaging infrared seeker, and Stevenage had a second concept based on their Merlin anti-armour mortar round. BAE's aircraft division added the DASA (by this point MBB SE) VERBAL system, and ML Aviation and Rheinmetall offered another cluster dispenser. Finally, Marconi and Rockwell offered Brimstone, a version of AGM-114 Hellfire with a mmW seeker. Texas Instruments entered Griffin-38, a small direct-attack weapon, but it was unpowered and lacked the required stand-off range.
The project was officially started in 1988, before the end of Cold War, and the project was cancelled.
Gulf War experience, SR(A).1238 Combat experience in the 1991 Gulf War led to a revaluation of many of the UK's ongoing weapons programmes. The RAF concluded that their low-level attack doctrine had been made far too specialized in its role in performing deep interdiction strikes and anti-airfield attacks. When used in the anti-armour role, their Panavia Tornado aircraft were exposed to ground fire, and they concluded some level of stand-off weapon was needed. AST.1238 was reactivated and became Staff Requirement (Air) SR(A).1238.
SR(A).1238 received five new bids. The Thorn Anti-Armour Weapons System was a powered BL.775. Hunting proposed a small cruise missile based on the German Mehrzweckwaffe-2, a powered version of the German Mehrzweckwaffe-1 cluster bomb dispenser. Known as Smart Weapon Anti-ARMour (SWAARM), it ejected a small number of smart munitions instead of a large number of bombs. Texas Instruments entered the similar Griffin-38, but it was unpowered and lacked the required stand-off range.
This left two designs in the running. BAe Dynamics proposed an updated version of their earlier SRAM-based concept using the newer and larger ASRAAM to produce Typhoon. GEC-Marconi offered their Advanced Anti-Armour Weapon (AAAW), a more refined version of their earlier Hellfire-based concept, using a 9 GHz MMW seeker that was completely fire-and-forget and could be used in all weather. Typhoon did not come close in performance terms, and AAAW won the contest.
GEC-Marconi (whose missile interests now form part of MBDA) was originally awarded the contract on 7 November 1996. Brimstone Contract Announced – November 1996 typhoon.starstreak.net
The first ground firing of the Brimstone missile occurred in August 1999, followed by the first air-launched firing from a Tornado GR4 in September 2000.
Design Brimstone has a tandem shaped-charge warhead employing a smaller initial charge around , designed to initiate reactive armour, followed by a larger, more destructive charge, designed to penetrate and defeat the base armour. It was estimated that Brimstone would be several times more effective than the AGM-65G Maverick against modern tanks, and 20 times more effective than the BL755 cluster bomb. In combat, Brimstone has demonstrated accuracy and reliability "both well above 90 percent" according to the MoD; Air Chief Marshal Sir Stephen Dalton has said that 98.3% to 98.7% of Brimstone fired in Libya "did exactly what we expected".
Targeting and sensors Brimstone is a "fire-and-forget" missile, which is loaded with targeting data by the weapon systems officer (WSO) prior to launch. It is programmable to adapt to particular mission requirements. This capability includes the ability to find targets within a certain area (such as those near friendly forces), and to self-destruct if it is unable to find a target within the designated area.
In addition to the semi-autonomous ability to decide its own targets, the Brimstone has the capacity to determine where on a target to best impact causing the most damage. The missile's advanced sensor package includes its extremely high frequency millimetric wave radar, which allows the weapon to image the target and hence choose a target location. With as many as twenty-four missiles in the air, the missile's targeting system also required an algorithm to ensure that missiles hit their targets in a staggered order, rather than all simultaneously.
Brimstone can be fired in a number of attack profiles; direct or indirect against single targets, a column of targets or against an array of targets. The latter utilises a salvo attack capability for multiple kills per engagement. Once launched, the platform is free to manoeuvre away from the target area or engage other targets.
Launch system
Each launch system carries three missiles on rails. This allows a single aircraft to carry large numbers of missiles; for example, a Typhoon fighter could carry up to six launch systems, which gives a maximum payload of eighteen Brimstone missiles, in addition to a useful air-to-air payload. The missile was carried by the Tornado GR4 aircraft in RAF service. In February 2014 the National Audit Office warned of a possible capability gap under existing plans to fit Brimstone to Typhoon in 2021, two years after the Tornado retired; in June 2014 the MoD announced a study to accelerate this to 2018 and look at a common launcher that could also launch SPEAR Cap 3. MBDA has fired test rounds from an MQ-9 Reaper drone and is studying the use of Brimstone on attack helicopters and from surface launchers.
It was intended that Brimstone would be integrated on the RAF Harrier aircraft fleet under Capability D of the JUMP programme with a scheduled in-service date of 2009. A Harrier GR9 first flew with 12 Brimstones on 14 February 2007. In late 2009 Brimstone was "nearing completion for integration on the Harrier", but in July 2010 it was reported that this would be postponed until the insensitive-munition version of the missile became available in 2012. Brimstone had not been officially cleared for use on the type when the UK Harriers were withdrawn from service in late 2010.
Following the 2022 Russian invasion of Ukraine, Britain decided to supply Ukraine with Brimstone missiles, however Ukraine did not have a suitable aircraft to launch the system. The UK developed a Wolfram armoured vehicle, based on an extended 6x6 Supacat chassis.
Brimstone 3 features surface-to-surface launch capability. A number of vehicle based launching options have been conceptualised for Brimstone such as ARES, a mission module for Boxer, Challenger 2, Supacat HMT, and a number of UGVs.
Operational service
Operational clearance of the missile was delayed by 12 months due to the unavailability of a Tornado trials aircraft, as the RAF chose instead to rush the development of the Storm Shadow air launched cruise missile ahead of the Iraq war, but another delay of 6 months resulted from redesigning the autopilot for safe release at higher speeds. Over 2,000 missiles were produced.
Dual-Mode Brimstone The original Brimstone could not be used in Afghanistan as the rules of engagement required a "man-in-the-loop". Under an Urgent Operational Requirement in 2008, modifications were made to the seeker and software of over 300 existing missiles to create Dual-Mode Brimstone. The new missiles can be laser guided according to the STANAG 3733 standard as well as retaining the millimetre wave seeker; the pilot can select either mode from the cockpit or use both simultaneously. Laser guidance allows specific enemy targets to be picked out in cluttered environments, while the mmW radar ensures accuracy against moving targets.