Full size Black Arrow rocket third stage booster, code named 'Waxwing', plus satellite turntable and base

The Waxwing rocket motor, named after the bird of the same name, was the first of its kind in British rocketry. its near-spherical form enabled the smallest amount of steel casing to be used for a given amount of solid propellant. Its nozzle was also gently arced in a near 'Rau' design, not previously used in Britain, to improve its performance.

The Black Arrow R3 rocket's third stage comprised a Waxwing, a turnatable and the X3 satellite. Small Imp rocket motors set the turntable and satellite spinning at 3 revolutions per minute. This would help stabilize the satellite in space. Shortly after separation from the second stage of Black Arrow the Waxwing ignited and burned for just under one minute. This boosted the third stage to a velocity of a little under 8 km/s at an altitude of almost 620 km. When spent the Waxwing and turntable were separated from the satellite which, now in orbit, was re-named Prospero after the magician in William Shakespeare's play The Tempest.