Editing Blue Steel (missile) (section)

===Delays===
Avro began work proper in 1955, with the assigned [[Rainbow Code]] name of "Blue Steel" which it would keep in service. With Elliots working on the guidance system, [[Armstrong Siddeley]] would develop the liquid fuel engine. The design period was protracted, with various development problems exacerbated by the fact that designers lacked information on the actual size and weight of the proposed Green Bamboo, or its likely thermonuclear successor derived from the Granite series.

The program ran into delays almost immediately. All of the systems - missile, navigation and motor - ran into problems and this resulted in the companies pointing fingers at each other. By the late 1950s it was clear the missiles would not be ready for their 1962 initial operational introduction, leading to significant criticism of Avro on the part of the Ministry of Supply and the Air Ministry.

By this time it was clear that the Soviets were going to install an even more extensive missile system that originally believed, one that would cover the approach routes to the targets and even have sites on the Russian coastline, well outside the range of the missile.

Avro proposed that Blue Steel would evolve over time, subsequent versions increasing speed (to Mach 4.5) and range. The ultimate Blue Steel would be a {{convert|900|nmi|km|abbr=on}} range weapon that could be launched by the supersonic [[Avro 730]] under development. They were told to limit themselves to the specification of OR.1132.<ref name="BSP">{{Harvnb|Gibson|Buttler|2007}}{{page needed|date=April 2023}}</ref> The project was delayed by the need to develop the required [[stainless steel]] fabrication techniques; this would have been gained in building the Avro 730 but that had been cancelled by then. The Elliots guidance system was plagued by accuracy problems, delaying test flights.

As it turned out, neither of the originally-proposed UK-designed warheads were actually fitted, being superseded by [[Red Snow]], an Anglicised variant of the U.S. [[B28 nuclear bomb|W-28 thermonuclear warhead]] of 1.1 Mt yield. Red Snow was smaller and lighter than the earlier warhead proposals. The missile was fitted with a state-of-the-art [[inertial navigation]] unit. This system allowed the missile to strike within 100 metres of its designated target. In addition, the pilots of the [[Avro Vulcan]] or [[Handley Page Victor]] bombers could tie their systems into those of the missile and make use of the guidance system to help plot their own flight plan, since the unit in the missile was more advanced than that in the aircraft.

On launch the rocket engine's first chamber developing {{convert|24000|lbf|kN|abbr=on}} thrust would power the missile along a predetermined course to the target at around [[Mach number|Mach]] 1.5. Once close to the target, the second chamber of the engine (6,000&nbsp;lbf) would accelerate the missile to Mach 3. Over the target the engine would cut out and the missile would free-fall before detonating its warhead as an [[air burst]].

To speed the trials at [[Woomera Test Range|Woomera]], the test rounds were flown there by Victors and Vulcans in Operation Blue Ranger. The trials began in 1960 about the time the original requirement expected the weapon to be in service. The missiles were prepared at the Weapons Research Establishment near Salisbury South Australia, and flown to be launched at the Woomera range from RAAF Edinburgh. A specialist unit, [[No. 4 Joint Services Trials Unit RAF]], was established to carry out preparatory and operational tasks.

Blue Steel finally entered service in February [[1963 in aviation|1963]], carried by Vulcans and Victors, although its limitations were already apparent. The short range of the missile meant that the V bombers were still vulnerable to enemy surface-to-air missiles. A replacement for Blue Steel, the Mark 2, was planned with increased range and a [[ramjet]] engine, but was cancelled in [[1960 in aviation|1960]] to minimise delays to the Mk.1. The UK sought to acquire the much longer-ranged United States AGM-48 Skybolt air-launched ballistic missile and was greatly frustrated when that weapon was cancelled in late [[1962 in aviation|1962]].

[[File:AEC Blue Steel tender.jpg|thumb|AEC Mandator Blue Steel tender at [[Royal Air Force Museum London|RAF Museum, Hendon]]]]
Blue Steel required up to seven hours of launch preparation, and was highly unreliable. The Royal Air Force estimated in 1963 that half the missiles would fail to fire and would have to be dropped over their targets, contradicting their purpose of serving as standoff weapons. Even as it deployed Blue Steel as a high-altitude weapon, that year the government decided that because of anti-aircraft missiles' increasing effectiveness, V bombers would have to convert from high-altitude to low-altitude attacks. These trials were conducted in 1964 and concluded in 1965<ref name="baylis1995">{{cite book | title=Ambiguity and Deterrence: British Nuclear Strategy 1945-1964 | publisher=Clarendon Press | last=Baylis |first= John | year=1995 | location=Oxford | isbn=0-19-828012-2 |pages=349–351}}</ref> With no effective long-range weapon the original Blue Steel served on after a crash programme of minor modifications to permit a low-level launch at {{convert|1000|ft|m|abbr=on}}, even though its usefulness in a hot war was likely limited. A stop-gap weapon ([[WE.177]]B) was quickly produced to extend the life of the V-bomber force in the strategic role until the Polaris missile was deployed. This WE.177 [[Laydown delivery|laydown weapon]] supplemented the remaining modified Blue Steel missiles, using a low-level penetration followed by a pop-up manoeuvre to release the weapon at {{convert|1000|ft|m|abbr=on}}. One live operational round was deployed on each of forty-eight Vulcan and Victor bombers, and a further five live rounds were produced as operational spares. An additional four non-nuclear rounds were produced for various RAF requirements, and there were sixteen other unspecified training rounds.

Blue Steel was officially retired on 31 December 1970, with the United Kingdom's strategic nuclear capacity passing to the [[submarine]] fleet.