The Avro Blue Steel was a British air-launched, rocket-propelled nuclear stand-off missile, built to arm the V bomber force. It was the primary British nuclear deterrent weapon until the Royal Navy started operating Polaris missile armed nuclear submarines.
Blue Steel was the result of a Ministry of Supply memorandum from 5 November 1954 that predicted that by 1960 Soviet air defences would make it prohibitively dangerous for V bombers to attack with nuclear gravity bombs. The answer was for a rocket-powered, supersonic missile capable of carrying a large nuclear (or projected thermonuclear) warhead with a range of at least 50 miles (80 km). This would keep the bombers out of range of Soviet ground-based defences installed around the target area, allowing the warhead to "dash" in at high speed.
There would have to be a balance between the size of the warhead (Orange Herald or Green Bamboo as developed by the AWRE) and the need for it to be carried by any of the three V-bomber types in use, and that it should be able to reach Mach 3. The Air Staff issued this requirement for a Stand-off bomb as OR.1132 in September 1954.
The Ministry of Supply selected Avro out of the British manufacturers though it had no previous experience in working on guided weapons other than some private venture work; Handley Page had suggested a 500 nmi missile but the Elliots gyro based guidance system was inaccurate beyond 100 nmi. 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. Its 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 boosted-fission warhead Green Bamboo, or its likely thermonuclear successor derived from the Granite series. The large girth of Blue Steel was determined by the 45 inches (1.1 m) implosion sphere diameter of Green Bamboo.
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 900 nmi 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. The project was delayed by the need to develop the stainless steel fabrication techniques; this would have been gained in building the Avro 730 but that had been cancelled by then. Elliots guidance system was plagued by accuracy problems delaying test flights.
Full article ▸