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, the project was determined to be too ambitious given technical difficulties with the SM-62 Snark which it was planned to follow, and it was canceled in 1951.

[1] Northrop named the missiles after characters from the works of Lewis Carroll, with Boojum coming from the final line of The Hunting of the Snark.

[1] The missile would climb at subsonic speed to its operating altitude, then conduct a supersonic dash to the target area, guided by a celestial navigation system.

[4] 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.