The Double Spectre is a dual-chambered, variable thrust liquid fuel rocket engine, developed by Britain's De Havilland Engine Company, Ltd. Both chambers used high test hydrogen peroxide (HTP) as the oxidizer and kerosene as the fuel and produced a thrust range of 800-16,000 pounds.
The Double Spectre was developed from late 1957 by De Havilland under contract to Britain's Ministry of Supply. In 1958, the Double Spectre was fitted to the test version of the 200-mile range Blue Steel air-to-surface missile, also known as a "standoff bomb" which was comparable to the U.S.'s Hound Dog missile. By 1961, the Double Spectre was replaced by the higher thrust, longer duration Bristol Siddley Stentor. The missile entered service in 1962 but was gradually withdrawn from service during 1973-1975.
Rolls-Royce Ltd. donated this Double Spectre to the Smithsonian in 1970.
Gift of Rolls-Royce Ltd.