discussions with aerojet of california usa took place aimed at exploiting the varied rocket-making skills of the two companies, and in 1959 the banwell works became bristol aerojet (baj), with a board chaired by sir reginald verdon-smith of bristol aeroplane company, with dan kimball leading the aerojet representation. co-operation began with the blue water lorry-launched battlefield nuclear missile, but the blue water project was cancelled in 1962, and so the mos had no application for the polyurethane propellant which was promoted by aerojet. baj banwell concentrated on development of improved rocket motor cases and their materials, and here aerojet assistance was valuable. a contract was executed for 5,500 motor cases for the martin 'bullpup' missile for nato. gosling (for bloodhound), retriever (sea slug), 3000 sealyham (sea cat), and troy (rapier) motor cases were built under the design authority of the rocket propulsion establishment westcott, a ministry of supply establishment. with the next project, blackcap, baj became design authority, and its manufacture featured electron beam welding allowing assembly of fully machined components. at the end of the sixties baj developed the waxwing apogee-stage motor for the black arrow rocket which was used to put the prospero telecommunications satellite in orbit in 1971