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 28 February 1940. Test pilot V. P. Fedorov was towed to 2,600 meters and cast off at 80 kilometers per second before firing the rocket engine and accelerating the aircraft to 140 meters per second and an altitude of 2,900 meters. In all, the RP-318 flew nine times before World War II ended the work.