The Myasishchev M-55 (NATO reporting name: Mystic-B) is a high-altitude reconnaissance aircraft developed by OKB Myasishchev in the Soviet Union, similar in mission to the Lockheed ER-2, but with a twin boom fuselage and tail surface design. It is a twin-engined development of the Myasishchev M-17 Stratosphera with a higher maximum take-off weight.