SSM-A-5 Boojum

The XSSM-A-5 Boojum, also known by the project number MX-775B, was a supersonic cruise missile developed by the Northrop Corporation for the United States Air Force in the late 1940s. Intended to deliver a nuclear warhead over intercontinental range, it was determined to be too ambitious a project given technical difficulties with the SM-62 Snark which it was to follow on from, and was canceled in 1951.

Development
As part of a United States Army Air Forces effort to develop guided missiles for the delivery of nuclear weapons, the Northrop Corporation was awarded a development contract in March 1946 for the design of two long-range cruise missiles. Designated MX-775, the contract called for a subsonic missile, the MX-775A, later designated SSM-A-3 Snark; and a more advanced supersonic missile, MX-775B, which in 1947 was given the name SSM-A-5 Boojum, Northrop naming the missiles after characters from the works of Lewis Carroll.

Given the company designation of N-25B, the design of the Boojum took place over the next several years, and produced a number of different variations on the concept. The finalized design called for a long, slender missile, fitted with delta wings, and powered by a pair of General Electric turbojet engines, mounted in nacelles near the tips of the wing.

The missile was intended to be launched utilizing a rocket sled; air-launch from a Convair B-36 heavy bomber was an alternative that was studied. The missile would climb at subsonic speeds to its operating altitude, then conduct a supersonic dash to the target area, being guided using a celestial navigation system. A "slipper" type drop tank would be jettisoned halfway through the flight. The Boojum was intended to be capable of carrying a warhead weighting up to 5000 lb over a range between 1500 to 5000 mi.

Cancellation
At the end of 1946, the contracts that had been awarded to Northrop were revised; the Snark was canceled, while the Boojum was to be fully developed as an operational system. Northrop lobbied for the reinstatement of the Snark, however; this was successful in getting the program reauthorized during 1947, with the Boojum being deferred to a follow-on project.

Despite the design having been finalized, the United States Air Force (which the USAAF had become in 1948) determined that the project was technologically unfeasible, given continuing development difficulties and technical problems encountered during the Snark's development. Accordingly, in 1951, the Boojum project was canceled, before any prototypes of the missile had been constructed.