The de Havilland Propellers Blue Streak was a British medium-range ballistic missile (MRBM), and later the first stage of the Europa satellite launch vehicle. Blue Streak was cancelled without entering full production.^[4]

The project was intended to maintain an independent British nuclear deterrent, replacing the V bomber fleet which would become obsolete by 1965. The operational requirement for the missile was issued in 1955 and the design was complete by 1957. During development it became clear that the missile system was too expensive and too vulnerable to a pre-emptive strike. The missile project was cancelled in 1960, with US-led Skybolt the preferred replacement.

Partly to avoid political embarrassment from the cancellation, the UK Government proposed that the rocket be used as the first stage of a civilian satellite launcher called Black Prince. As the cost was thought to be too great for the UK alone international collaboration was sought. This led to the formation of the European Launcher Development Organisation (ELDO), with Blue Streak used as the first stage of a carrier rocket named Europa.

Europa was tested at Woomera Test Range, Australia, and later at Kourou in French Guiana. Following launch failures, the ELDO project was cancelled in 1972 and development of Blue Streak was halted.

Post-war Britain's nuclear weapons armament was initially based on free-fall bombs delivered by the V bomber force. It soon became clear that if Britain wanted to have a credible nuclear deterrent threat, a ballistic missile was essential. There was a political need for an independent deterrent, so that Britain could remain a major world power. Britain was unable to purchase American weapons wholesale due to the restrictions of the Atomic Energy Act of 1946.

In April 1954 the Americans proposed a joint development programme for ballistic missiles. The United States would develop an intercontinental ballistic missile (ICBM) of 5,000-nautical-mile (9,300 km) range (SM-65 Atlas), while the United Kingdom with United States support would develop a medium-range ballistic missile (MRBM) of 2,000-nautical-mile (3,700 km) range. The proposal was accepted as part of the Wilson-Sandys Agreement of August 1954, which provided for collaboration, exchange of information, and mutual planning of development programmes. The decision to develop was influenced by what could be learnt about missile design and development in the US. Initial requirements for the booster were made by the Royal Aircraft Establishment at Farnborough with input on the rocket engine design from the Rocket Propulsion Establishment at Westcott. British Operational Requirement 1139 demanded a rocket of at least 1500 n.m. range and the initially proposed rocket would have just reached that threshold.

The de Havilland Propellers company won the contract to build the missile, which was to be powered by an uprated liquid-fuelled Rocketdyne S3D engine, developed by Rolls-Royce, called RZ.2. Two variants of this engine were developed: the first provided a static thrust of 137,000 lbf (610 kN) and the second (intended for the three stage satellite launch vehicle) 150,000 lbf (670 kN). The engines were unique at that time in that they could be vectored by seven degrees in flight and could therefore be used to guide the vehicle. This configuration, however, put considerable pressure on the autopilot which had to cope with the problem of a vehicle whose weight was diminishing rapidly and that was steered by large engines whose thrust remained more or less constant. Vibration was also a problem, particularly at engine cut-off, and the later development of the autopilot for the satellite launcher was, in itself, a considerable achievement.

Subcontractors included the Sperry Gyroscope Company who produced the missile guidance system whilst the nuclear warhead was designed by the Atomic Weapons Research Establishment at Aldermaston.

The missiles used liquid oxygen and kerosene propellants. Whilst the vehicle could be left fully laden with over 20 tonnes of kerosene, the 60 tonnes of liquid oxygen had to be loaded immediately before launch or icing became a problem. Due to this, fuelling the rocket took 4.5 minutes, which would have made it useless as a rapid response to an attack. The missile was vulnerable to a pre-emptive nuclear strike, launched without warning or in the absence of any heightening of tension sufficient to warrant readying the missile. To negate this problem de Havilland created a stand-by feature. A missile could be held at 30 seconds' notice to launch for ten hours. As the missiles were to be deployed in pairs and it took ten hours for one missile to be prepared for stand-by, one of the two missiles could always be ready for rapid launch.

To protect the missiles against a pre-emptive strike while being fuelled, the idea of siting the missiles in underground launchers was developed. These would have been designed to withstand a one megaton blast at a distance of half a mile (800 m) and were a British innovation, subsequently exported to the United States. Finding sites for these silos proved extremely difficult. RAF Spadeadam in Cumberland (now Cumbria) was the only site where construction was started on a full scale underground launcher, although test borings were undertaken at a number of other locations. The remains of this test silo, known as U1, were rediscovered by tree felling at Spadeadam. This was also the site where the RZ.2 rocket engines and also the complete Blue Streak missile were tested. The best sites for silo construction were the more stable rock strata in parts of southern and north-east England and eastern Scotland, but the construction of many underground silos in the countryside carried enormous economic, social, and political costs. Development of the underground launchers presented a major technical challenge. 1/60th and 1/6th scale models based on a ‘U’ shaped design were constructed and tested at RPE Westcott. Three alternative designs were drawn up with one chosen as the prototype, designated K11. RAF Upavon would appear to have been the preferred location for the prototype operational launcher with the former RNAS at Crail as the likely first operational site.

In 1955-1956, the rocket motors were test fired at The Needles Batteries on the Isle of Wight.^[5] As no site in Britain provided enough space for test flights, a test site was established at Woomera, South Australia.

Doubts arose as the cost escalated from the first tentative figure of £50 million submitted to the Treasury in early 1955, to £300 million in late 1959. Its detractors in the civil service claimed that the programme was crawling along when compared with the speed of development in the US and the Soviet Union.

Estimates within the Civil Service for completion of the project ranged from a total spend of £550 million to £1.3 billion, as different ministers were set on either abandoning or continuing the project.

The project was unexpectedly cancelled in April 1960.^[6] Whitehall opposition grew, and it was cancelled on the ostensible grounds that it would be too vulnerable to a first-strike attack. Admiral of the Fleet Lord Mountbatten had spent considerable effort arguing that the project should be cancelled at once in favour of the Navy being armed with nuclear weapons, capable of pre-emptive strike.

Some considered the cancellation of Blue Streak to be not only a blow to British military-industrial efforts, but also to Commonwealth ally Australia, which had its own vested interest in the project.

The British military transferred its hopes for a strategic nuclear delivery system to the Anglo-American Skybolt missile, before the project's cancellation by the United States as its ICBM programme reached maturity. The British instead purchased the Polaris system from the Americans, carried in British-built submarines.

After the cancellation as a military project, there was reluctance to cancel the project because of the huge cost incurred. Blue Streak would have become the first stage of a projected all British satellite launcher known as "Black Prince": the second stage was derived from the Black Knight test vehicle, and the orbital injection stage was a small hydrogen peroxide/kerosene motor.

Black Prince proved too expensive for the UK, and the European Launcher Development Organisation (ELDO) was set up. This used Blue Streak as the first stage, with French and German second and third stages. The Blue Streak first stage was successfully tested three times at the Woomera test range in Australia as part of the ELDO programme.

In 1959, a year before the cancellation of the Blue Streak as a missile, the government requested that the RAE and Saunders-Roe design a carrier rocket based on Blue Streak and Black Knight. This design used Blue Streak as a first stage and a 54-inch (137 centimetre) second stage based on the Black Knight.^[7] Several different third stages would be available, depending on the required payload and orbit.

The cost of developing Black Prince was estimated to be £35 million.

It was planned that Black Prince would be a Commonwealth project. As the government of John Diefenbaker in Canada was already spending more money than publicly acknowledged on Alouette and Australia was not interested in the project, these two countries were unwilling to contribute. South Africa was no longer a member of the Commonwealth. New Zealand was only likely to make "modest" contributions.^[8]

The UK instead proposed a collaboration with other European countries to build a three-stage launcher capable of placing a one-ton payload into low Earth orbit. The European Launcher Development Organisation consisted of Belgium, Britain, France, West Germany, Italy and the Netherlands, with Australia as an associate member.

Preliminary work began in 1962 and ELDO was formally signed into existence in 1964.

With Blue Streak, the UK became the first stage of the European launch vehicle with France providing the Coralie second stage and Germany the third. Italy worked on the satellite project, the Netherlands and Belgium concentrated on tracking and telemetry systems and Australia supplied the launch site.

The combined launcher was named Europa.

After ten test launches, the Woomera launch site was not suitable for putting satellites into geosynchronous orbit, and in 1966 it was decided to move to the French site of Kourou in South America. F11 was fired from here in November 1971, but the failure of the autopilot caused the vehicle to break up. The launch of F12 was postponed whilst a project review was carried out, which led to the decision to abandon the Europa design.

ELDO was merged with the European Space Research Organisation to form the European Space Agency.

(Taken from the "Europa SLV Historiograph", produced by HSD Ltd)

Aside from Black Prince, a range of other proposals was made between 1959 and 1972 for a carrier rocket based on Blue Streak,^[9] but none of these were ever built in full and today only exist in design.

In 1959 de Havilland suggested solving the problem of the Blue Streak/Black Knight geometry by compressing the 10 by 1 metre (30 by 3 foot) Black Knight into a 10-foot-diameter (3.0 m) sphere. Although this seemed logical, the development costs proved to be too high for the limited budget of the programme.^[10]

Following its merger with Saunders Roe, Westland Helicopters developed the three-stage Black Arrow satellite carrier rocket, derived from the Black Knight test vehicle. The first stage of Black Arrow was given the same diameter as the French Coralie (the second stage of Europa) in order to make it compatible with Blue Streak. Using Blue Streak as an additional stage would have increased Black Arrow's payload capacity. To maintain this compatibility, the first stage diameter was given in metres, although the rest of the rocket was defined in imperial units.

Black Arrow carried out four test launches (without an additional Blue Streak stage) from Woomera between 1969 and 1971, with the final launch carrying the satellite Prospero X-3 into orbit. The United Kingdom remains the only country to have successfully developed and then abandoned a satellite launch capability.

In 1972, Hawker Siddeley Dynamics (HSD) produced a brochure for a design using Blue Streak as the first stage of a two-stage to orbit rocket, with an American Centaur upper stage. The Centaur second stage would have either been built in the UK under licence or imported directly from the USA. Both the Centaur and Blue Streak had proved to be very reliable up to this point, and since they were both already designed development costs would have been low. Furthermore, it had a payload of 870–920 kg to a geosynchronous orbit with, and 650–700 kg without the use of additional booster rockets.^[11]

Following the cancellation of the Blue Streak project some of the remaining rockets were preserved at:

A section of the propulsion bay, engines and equipment can be found at the Solway Aviation Museum, Carlisle Lake District Airport. Only a few miles from the Spadeadam testing site, the museum carries many exhibits, photographs and models of the Blue Streak programme, having inherited the original Spadeadam collection that used to be displayed on site.

RZ.2 engines are on display at National Space Centre a pair on cradles alongside the Blue Streak rocket, and at the Armagh Planetarium, Northern Ireland and The Euro Space Center in Redu, Belgium.

Footage from the Blue Streak launch was briefly incorporated into The Prisoner's final episode, "Fall Out". A part of the Blue Streak rocket launched on 5 June 1964 from Woomera, Australia, found 50 km SE of Giles in 1980 (c.1000 km) is on display at Giles Weather Station. Another piece was located in 2006, but its exact location has been kept secret by the finders. The titanium structure of a German third stage was, for some time, sited on the edge of a gravel pit in Gloucestershire. Images of the Blue Streak 1 are incorporated in the 1997 film Contact.