X3 satellite 'Prospero', 1971.
© Science Museum / Science & Society Picture Library
Flight spare of the X3 satellite, which was named Prospero once it reached orbit. Britain developed the Black Arrow as its national satellite launch vehicle in the late 1960s. After the programme was cancelled, in July 1971, permision was given to fire one last rocket. This launcher, Black Arrow R3, succesfully put the X3 into orbit on 28th October, 1971, which made Britain the sixth country to launch a satellite using its own rocket. Prospero was a pumpkin-shaped, spin-stabilized satellite weighing about 70kg, intended to test basic systems such as solar cells, telemetry systems and thermal coatings.