The RP-318 was the Soviet Union's first rocket-powered aircraft. Built in 1936 by Sergei Korolev as an adaptation of his SK-9 glider, it was originally to have been used to flight test an early rocket engine designed by Glushko. When both Korolev and Glushko were arrested and sent to the Gulag in 1938, development of the RP-318 was continued by others, culminating in the first powered flight on February 28, 1940. Test pilot V. P. Fedorov was towed to 2,600 m and cast off at 80 km/ before firing the rocket engine and accelerating the aircraft to 140 m/s and an altitude of 2,900 m. In all, the RP-318 flew nine times before World War II ended the work.