Top Secret - Rocket Testing at the Needles

In the 1950s and '60s hundreds of scientists and engineers on the Isle of Wight successfully built, assembled and tested "perhaps the most economical and powerful space missile of its time - the Black Knight."

The concrete bones of the Needles rocket site are one of the few reminders of the successful, but short-lived, British space programme. The headland is now run by the National Trust who have excavated the underground rooms and opened them to the public to commemorate the 50th anniversary of the first test firing of Black Knight rocket.

Here's the story behind this once top-secret facility

In the 1950s Britain was still a "great power" with a large empire and quickly followed the new "superpowers" the USA and USSR in developing the atomic and hydrogen bomb, testing them in Australia.

These weapons now needed a delivery system. The British government ordered the invention and construction of an inter-continental ballistic missile, code named "Blue Streak". The job fell to the Royal Aircraft Establishment at Farnborough. They began an intense effort to research, marshal and consolidate the required technology. Their findings particularly drew their gaze to engine-makers Armstrong Siddley and Island based aircraft designers Saunders Roe of Cowes.

The Blue Streak would be preceded by a smaller prototype rocket that used the same complex liquid propellants but employed hardware and techniques that were immediately available. This rocket was Black Knight. In 1955 Saunders Roe of Cowes were commissioned to develop the air-frame and to carry out the assembly and testing of the missile. They were developing a mixed power-plant fighter aircraft, the Sr53. This employed a rocket motor which ran on kerosene and high-test peroxide.

With engine makers Armstrong Siddley, Saunders Roe adapted this motor for space operations and evolved special methods to fabricate the large, lightweight tanks needed to hold the propellant which made up some 90% of the rocket's total mass. Of special concern was the need to maintain cleanliness and chemical purity when dealing with high-test peroxide which reacts rapidly with most substances by violently separating into very high temperature steam and oxygen. The high-test hydrogen peroxide (H3O2) ignited instantly on contact with kerosene into super-heated steam that could propel the missile faster than the speed of sound, but with an almost invisible flame wake.

The role of the Isle of Wight test site

To assemble and test each rocket before shipment to the Australian launch site at Woomera, Saunders Roe required a local test site. The former artillery battery on the Needles Headland offered a secure location with underground accommodation. In 1955 the High Down site was leased from the Ministry of War. Here, from April 1956, the engines were assembled, tethered and fired, with different levels of fuel to measure the thrust, flight control systems and the consumption of the fuel.

The Needles Headland was transformed into something like a James Bond film set. A complex of specialised buildings was constructed over the New Battery, and underground control and instrumentation rooms were converted from the old magazines. There were 2,200 square feet of control rooms and underground stores, 4,260 square feet of laboratories and offices and 3,080 square feet of workshops and smaller machine shops. The dining rooms catered for 80 people at a time. In all there was space enough for the 240 people who worked there at the peak of operations in the early 1960s.

The 60-foot-long rockets were assembled in the workshops. Then they were towed down the newly built road along the cliff top above Scratchells Bay to one of the two 80-foot-high test gantries. These stood at each side of the natural bowl in the cliff formation above Sun Corner. The rockets were erected inside the steel and aluminium towers by men dressed in protective suits with glass fronted helmets, operating one and a half ton mobile hoists.

During an engine firing test all activities followed at a strict time sequence, initially co-ordinated by large clocks placed at all manned positions. At any point the process could be aborted by the press of a button from several monitoring positions. As the black hands ticked towards the red section of the clock face, the clocks bleeped every ten seconds to warn the workers to get underground. There the scientists stared into an array of "huge grey instrument panels, covered with flickering lights, cathode ray tubes and multi-coloured switches and plugs."

In addition to manual observations, an array of cameras, tape recorders and specialised devices automatically logged data from several hundred instrumentation sensors placed within the engine and other rocket systems to assess their performance.

On ignition the four jet rocket motors fired into steel "exhaust buckets," cooled by a torrent of water from a specially built 60,000-gallon reservoir, at a rate of 3,000 gallons per minute. The exhaust emerged at right angles from the cliff as "a fountain of steam" as the late Vera Attewell recalled, seeing it from the sea, but it only sounded "like a wet squib." At this point the only thing stopping the missile flying through the roof of the gantry was a steel golf-ball coupling in the engine structure clamped to the test bed. The local population were warned of the firings and the downs were closed to the public, "as far back as Tennyson's Monument at least once to my knowledge" recalls Derek Mack, who worked on the project throughout.

With the missile successfully tested a team of engineers accompanied it to the top security missile launch-site at Woomera in Australia. In 1958, after just three years’ work, they released the first Black Knight into the atmosphere. In all 22 were launched into moonless night skies, up to 500 miles above the Earth, falling back to land 80-100 miles down-range of the launch site.

Despite this success Britain eventually gave up on Blue Streak and acquired Polaris missiles from the USA. Black Knight became a tool for research into the upper atmosphere, flying payloads for government agencies and universities. This work suggested the need for Britain to develop a capacity to launch satellites, which led to the next stage of the space programme.

The Space Satellite Programme

In 1965 the Needles team started work on Black Arrow, an 18 ton, almost 44 foot, three-stage space-rocket designed to put a 300-kilogram satellite into a circular 300-mile orbit. The first two stages were designed to reach the right orbital height; the third blasted the satellite at right angles to the Earth's surface, with sufficient velocity to put it into an orbit of continuous free-fall.

Six Black Arrows were built and four launched into space, the first in 1968. The project culminated in October 1971 with the launch of the first, and only, all-British satellite put into space by a British rocket. The experimental satellite Prospero achieved a near perfect orbit and carried out short term data collection on micro-meteorites and space erosion.

Having achieved its peak, the British space programme suddenly ended in a lack of political will and scientific consensus on how to use the rocket. The Needles rocket site was closed, and the buildings dismantled. In 1979 the Woomera station was demilitarised.

The last Black Arrow now resides at the British Science Museum. Another reminder is Prospero, which still functions when contacted from Earth, and will continue to orbit us for another 220 years.

This article is reproduced courtesy of Coach House Publications. The full story is recounted in the book 'Alum Bay & the Needles'.

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6 July 2016

By Jo Macaulay in Articles