Although very much evolving from allied efforts to stymie the power of Luftwaffe (German Air Force) air defences during the Second World War, the SEAD mission came of age during the Cold War and progenerated an era of NATO dominance in radio frequency combat capabilities. RF capabilities which have now renewed importance in the context of the war in Ukraine and the rise of China. 

On 9 August 2022, the US government confirmed it had supplied Texas Instruments/Raytheon AGM-88B/C High Speed Anti-Radiation Missiles (HARMs) to the Ukrainian Air Force (UAF).

The missiles have been integrated onboard the UAF’s MiG-29 Fulcrum combat aircraft, and have proven effective against Russian ground-based air surveillance and fire control/ground-controlled interception radars. According to the oryxspioenkop.com website cataloguing Russian and Ukrainian equipment losses, the former has lost seven such radars since the war began, some of which will almost certainly have been destroyed by the missiles.

Known as Suppression of Enemy Air Defence, SEAD was refined in the skies above Vietnam. The Soviet Union supplied radar-guided Surface-to-Air Missiles (SAMs) to the government of North Vietnam, and these took their toll on US airpower as the conflict deepened in the mid-1960s. The catalyst was America’s Rolling Thunder air campaign against communist North Vietnam from 2 March 1965.

Rolling Thunder had several motivations: The brainchild of President Lyndon B. Johnson’s administration, it was intended to encourage Hanoi to diminish support for the Viet Cong insurgency in the Republic of Vietnam (RVN), while boosting flagging RVN morale and reducing North Vietnamese air defences were additional motivations. Rolling Thunder would also target North Vietnam’s transportation infrastructure and industrial capability.

The government in Hanoi responded to Rolling Thunder by asking its Soviet allies for SAM systems that could engage targets beyond 16,404ft, then the maximum range of the North Vietnamese Army’s Anti-Aircraft Artillery (AAA). Moscow’s response was to send S-75 Dvina (SA-2 Guideline) SAMs to their allies.

With a maximum engagement altitude of 82,000ft (25,000m) and range of 24.3nm (45km) the SA-2 exceeded the NVA’s needs. And while pilots could fly below the 1,500ft (457m) minimum lethal altitude of the SA-2, this would put them within reach of NVA AAA.

On 24 July 1965 the inevitable occurred. A US Air Force McDonnell Douglas F-4C Phantom was shot down and three more suffered damage, thus the USAF then began the serious business of finding a way to locate and destroy NVA radar-guided SAM sites. The result became known as the Wild Weasel missions.

Commencing in late 1965 from Korat airbase in Thailand, Wild Weasel’s rationale was relatively simple: A fast jet would be adorned with a Radar Warning Receiver (RWR) to detect hostile radar signals from the SAM battery and locate said radar. Wild Weasel crews would head to the SAM site and blast it with conventional ordnance and later, with dedicated Anti-Radiation Missiles (ARMs). The ARMs would detect the offending radar transmissions and use these to home in on the radar before detonating in proximity to it, with the exploding warheads ideally wrecking the radar’s antenna and control equipment.

Wild Weasel proved its worth in Vietnam. In 1965, prior to the mission commencing, the US lost a single aircraft to an SA-2 for every ten missiles fired, but by 1968 this had reduced to just one aircraft for every 48 missiles fired. The Wild Weasel mission had a psychological as much as a destructive impact. NVA radar operators would deactivate their systems if they detected or believed there to be Wild Weasel aircraft in their vicinity so, with the radars deactivated, the efficacy of the SAM battery was significantly degraded.

The Wild Weasel mission not only survived the Vietnam War, but permeated other North Atlantic Treaty Organisation (NATO) air forces, while the end of American involvement in the Southeast Asian conflict from late March 1973 heralded a refocusing of US attention on Europe’s central front.

US experience in the skies above Vietnam was valuable, especially as SAM batteries like the SA-2 would challenge NATO airpower over the Warsaw Pact (WARPAC) and Soviet Union if the Cold War in Europe erupted into open conflict. Likewise, the Israeli experience of Soviet-supplied air defences during the 1967 Six Day and 1973 Yom Kippur Wars was valuable. The result of both conflicts was that Soviet SAM systems, while lethal, were no longer an unknown quantity.

This allowed NATO to develop a SEAD posture by following the US’s lead, and investing in air defence suppression capabilities. Flying over the Inner German Border (IGB) separating West and East Germany would have placed NATO airpower directly in the jaws of Soviet/WARPAC air defences, and NATO fighters would have tangled with their adversaries as part of a prevailing Offensive Counter-Air (OCA) doctrine.

OCA was designed to degrade Soviet/WARPAC airpower from the outset. If NATO was to prevail against the USSR and her satraps, the alliance had to win air superiority and thence air supremacy. The US Department of Defence defines the former as the ability of the red force to sporadically interfere with blue force air operations, while air supremacy is achieved when red air can no longer meaningfully interfere with blue force airpower.

NATO’s Cold War OCA posture would have witnessed a huge effort at the start of any war against Soviet/WARPAC airpower. Fighters would have battled fighters, ground attack aircraft would have hit enemy airbases and physical infrastructure supporting these fighters, and nuclear and conventional surface-to-surface missiles would have hit the industrial base supporting Soviet/WARPAC airpower.

A heavy SEAD effort would have been waged against Soviet/WARPAC integrated air defence systems. These IADSs would have been deployed nationally and would have protected army manoeuvre elements, so NATO’s mastery of the skies was essential to be able to widen the air war to hit hostile tactical, operational, and strategic targets.

The end of the Vietnam War saw the USAF Wild Weasel mission retool with new kit and deploy to Germany, and the F-4C Phantom was adopted by the USAF force as its Wild Weasel platform in 1968. The success of the Wild Weasel mission was not lost on NATO’s European membership, and countries in Europe began investing in similar capabilities, mindful that their air forces would also have to traverse the IGB.

European NATO members procured capabilities from the United States in the guise of the AGM-88B/C HARM, while the Anglo-French Hawker-Siddeley/Matra AS-37 Martel ARM and British Aerospace Corporation ALARM (Air-Launched Anti-Radiation Missile) were also developed. All these efforts provided sovereign SEAD capabilities which could be folded into NATO’s prevailing OCA posture.

MARTEL & ALARM
The AS-37 Martel was one half of a duet of weapons including the television-guided AJ-168 Martel anti-ship missile. The AS-37 was integrated onto the Royal Air Force’s (RAF) Blackburn Buccaneer-S2B combat aircraft, while several Armée de l’Air (ADLA/French Air Force) types could also employ the AS-37 including the SEPECAT Jaguar-E, and Dassault Mirage-III and Mirage-F1 series jets.

The AS-37 was to have originally engaged L-band (1.215GHz to 1.4GHz), S-band (2.3GHz to 2.5GHz/2.7GHz to 3.7GHz), C-band (5.25GHz to 5.925GHz), and X-band (8.5GHz to 10.68GHz) radars. This was later reduced to L-band and S-band, as the RAF felt that radars transmitting in the higher C and X-bands were less of a threat, while development of radar seekers for the missile in these bands also proved difficult.

Crucially for the RAF and the ADLA, this reduced capability still enabled both air forces to hold several Soviet/WARPAC radars at risk, with the AS-37 able to target several Soviet ground-based air surveillance and height finder radars including the PRV-13 (Odd Pair) and PRV-11 (Side Net) height finder systems. Side Net was introduced in circa 1958 equipping the SA-2 long-range, high-altitude SAM system, while Odd Pair entered service in 1967 in support of SA-5 long-range, high-altitude SAM batteries.

As well as hampering the tactical efficacy of a SAM unit by denying its fire control altitude information, SEAD was imperative to preventing SAM batteries discovering targets in the first place. Ground-based air surveillance and early warning radars would continually watch the skies for targets and, once these were discovered, they were handed off to fire control and height-finder radars where these would refine the target’s location so that it could be intercepted by a SAM.

The AS-37 would have been able to target the SA-5’s original 1L117M/P-37 (Bar Lock) S-band radar introduced in 1958. Bar Lock was later replaced by the 5N69 (Big Back) L-band ground-based air surveillance radar from 1975, but this could also be targeted by the AS-37. The missile could also attack the P-40 (Long Track) S-band system accompanying the SA-4 medium-range/medium-to-high altitude SAM system, and would have also been able to target the 5N64S/64N6E/91N6E (Big Bird) ground-based air surveillance radar introduced in 1979 to equip SA-10 high-altitude, long-range SAM batteries.

The AS-37 was used in anger, but not against Soviet/WARPAC targets. The missile went to war with the ADLA in 1986 in Operation Épervier – the codename for France’s military intervention in Chad to contain Libya’s occupation of the north of the country – where it was used on several occasions to attack radars protecting Libya’s bases in northern Chad. It proved successful, particularly against P-15 (Flat Face) ground-based air surveillance radars which provided target information to Libyan SA-6 batteries protecting the airbases in Ouadi-Doum and Faya Largeau.

The AS-37 remained in French service until 1999 when it was formally retired. Apart from its deployment in Libya the weapon does not appear to have been employed to support any further ADLA operations.

Like the AS-37, ALARM was conceived during the Cold War. Ironically, it would earn its spurs being deployed in the post-Cold War world supporting RAF operations in the Gulf, the Balkans, and Libya. The RAF had been looking for a missile to eventually replace the AS-37 since the late 1970s, resulting in Air Staff Requirement 1228 (ASR-1228) which was issued in 1978. ASR-1228 detailed the RAF’s requirement for an anti-radar missile capable of high-speed launch at low altitudes to be employed from the RAF’s Panavia Tornado GR.1 strike aircraft.

ALARM progressed in fits and starts until a final requirement was issued by the air staff in 1982. Two candidate weapons were presented: Texas Instruments and Lucas Aerospace proposed the AGM-88 to answer the requirement, while British Aerospace and Marconi suggested the design which would later become ALARM and which was selected in 1983.

ALARM was a complex weapon. Once launched, it would climb to 40,000ft (12,192m) where its radar seeker could detect targets across an area of 189,633nm² (650,388km²). Frequencies covered by the missile remain classified, but open sources say that it could target S-band and C-band systems among others.  

After reaching altitude the missile would slowly descend beneath a parachute. If a radar’s transmissions were detected the parachute was jettisoned, the missile’s motor would ignite, and the weapon would zoom towards the offending antenna. This flight profile allowed the missile to attack unbriefed radar targets of opportunity, although the ALARM’s radar seeker could also be pre-programmed to listen for specific frequencies or transmissions. Even if the radar operator switched off their equipment in an attempt to escape attack, the missile would ‘remember’ the radar’s location and continue towards it.

ALARM could also be fired to loiter to encourage radar operators to keep their equipment deactivated in a specific area. After launch, the missile would return to Earth using a shallow dive rather than the parachute, and any radar emitting during the dive would be immediately attacked. The missile could also follow a loft trajectory after being launched at low altitude.

ALARM was first used during Operation Desert Storm, the 1991 US-led initiative to evict Iraq from its occupation of Kuwait. Deployments followed in support of air operations in the Balkans during the 1990s and in Libya in 2011, and the missile was retired from service in 2013. Alongside the RAF, ALARM was procured by the Royal Saudi Air Force which is believed to have used the weapon during Saudi Arabia’s recent intervention in Yemen’s civil war.

EUROPEAN COLD WAR SEAD IN CONTEXT
It is of little surprise that European air forces only began to embrace the armed SEAD concept in the latter half of the Cold War. US involvement in Vietnam, and the experience of the Israeli Air Force during that country’s various conflicts involving Soviet/WARPAC-origin air defence underscored the need for this capability but, even then, kinetic SEAD using anti-radar missiles remained a somewhat niche capability. The ADLA and their RAF counterparts blazed a trail with the deployment of the AS-37 and ALARM, West Germany procured the AGM-88 series towards the end of the Cold War in 1987, and Italy followed in 1991.

Russia’s second invasion of Ukraine on 24 February 2022 has once again placed armed SEAD firmly back on the NATO agenda, and investment is flowing into the mission. This is underscored by Germany’s planned acquisition of 15 Eurofighter Typhoon-ECR SEAD aircraft which will be equipped with Northrop Grumman’s AGM-88E Advanced Anti-Radar Guided Missile, while Italy has also procured the AGM-88E and may also procure the Typhoon-ECR to replace the Aeronautica Militare (Italian Air Force) Tornado-ECR SEAD jets.

Forged in the hot furnace of the Cold War, the SEAD mission is moving forward into a new era where kinetic capabilities will be merged with electronic warfare and cyberattack techniques to neutralise hostile IADSs. Inhabited aircraft will also be teamed with avant-garde capabilities like uncrewed systems and loitering munitions. Ukraine will be the theatre in which these SEAD approaches will be developed and defined, influencing NATO’s OCA posture for years to come.