Violet Friend
Violet Friend was the Ministry of Supply rainbow code for an anti-ballistic missile (ABM) system developed in the United Kingdom.
As they approached the UK, track information from the FPS-16 would direct an AMES Type 86 fire control radar to begin illuminating each selected target.
The Bloodhound would at first fly under direct radio control from the ground while the warhead was still too far to be illuminated, and would then do a "jerk" manoeuvre onto the target trajectory once the Type 86 picked it up.
Protecting the silos required a new ABM with improved performance, but the cancellation of the Blue Streak in 1960 ended much of the system's raison d'être.
Ongoing concerns about the size of the Soviet missile fleet and the use of radar decoys led to serious questions about any system's effectiveness.
[1] At the time, some consideration was given to attacking them with huge barrages of anti-aircraft artillery fire, but some calculations suggested that dud rounds falling back to the ground presented a greater threat than the missile warheads.
They noted that the existing Chain Home radars, then undergoing refits as part of the ROTOR system, could provide two to three minutes warning of an attack from a short-range weapon like the V-2.
They also re-considered the topic of AA-guns against missiles, suggesting that modern radars might reduce the number of rounds required to kill a warhead from as much as 1.5 million to as "few" as 18,000.
[5] In May 1952, as part of a wide review by the Chief of the Air Staff and their counterparts in the British Army, it was agreed that the RAF would be responsible for providing early warning of ballistic missiles.
A short time later, the DRPC's Guided Weapons Sub-committee was asked to consider "a GW for defence against V.2 type of attack."
The only real solution seen is to seize, and maintain, the technical lead in strategic offensive weapons as the only effective deterrent against attack.
[9] A major report by the Air Defence Committee (ADC) in January 1955 stated that short-range missiles were already available to the Soviets and that the UK would come within range of longer-ranged weapons by about 1960.
These were apparently references to the 1,200 kilometres (750 mi) range R-5 Pobeda (SS-3 Shyster) which was based in East Germany starting in 1956 and was known by British intelligence to be equipped with chemical weapons and aimed at London.
They were additionally aware of the ongoing development of the medium-range R-12 Dvina (SS-4 Sandal) which could reach the UK from western Soviet areas.
An advanced draft of the OR was sent to Canada, who issued the Canadian General Air Staff Target written along the same lines but aimed only at ICBMs.
"[13] This basic idea would become a serious concern in the future, when it would be formalized as the cost-exchange ratio, and was ultimately one of the major arguments against a national-scale ABM system being deployed in the US.
Additional comments suggested that the limited defensive role being envisioned was of no use and that every warhead approaching the UK needed to be attacked.
[23] In the case of OR.1135, the cost-exchange argument began to swing the decision in favour of a basic system re-using as much existing hardware as possible, as opposed to a dedicated ABM with higher performance.
Blue Streak was cancelled in April 1960,[25] largely because they felt it would not represent a credible deterrent once Soviet missiles could attack the silos directly.
A new report by the Ministry of Aviation following the cancellation noted: Blue Streak was abandoned largely because it was adjudged vulnerable to attack by 300 rockets arriving on the UK within a period of a minute...it would appear reasonable to take that scale of attack as at least a broad indicator of what an anti ballistic missile defence would have to cope with.
[25]Active defence remained an area of study for the next few years, although little funding was provided for anything outside early warning systems.
[27] The Penley Report's conclusions were much the same as Powell's, noting that operating against warheads appeared a solved problem, but "in the face of decoys, discrimination becomes well nigh impossible.
"[26] A final note was offered by the Air Ministry while commenting on the Penley report: "The overall policy of nuclear deterrence is based on the main assumption that a viable defence against ballistic missile attack is not possible now, nor can be foreseen to be possible at any given future date".
[1] As the interceptor missile had to be launched shortly after detection and had to place itself relatively close to the ultimate intercept location, detailed tracking information was required as early as possible.
To arrange this, radars would be forward deployed in the Netherlands at two sites, one in the south near Terneuzen and the second in the north on the island of Terschelling.
This was originally designed as an instrumentation radar used at missile testing sites to provide highly accurate information for performance measurements.
It was an early monopulse radar design, using this technique to achieve higher accuracy than earlier conical scanning systems.
[1] When the early tracking information was achieved, the interceptor missile was launched as soon as could be, on a course that would take it as close to the estimated location of the warhead as possible.
[1] At the time Violet Friend was first being considered, the Bloodhound missile was still in development and known by its rainbow code Red Duster.
[30] The larger engines from the Blue Envoy allowed the weight to be increased, which was put to use by extending the fuselage to add more fuel tanks.
