Tsybin's design was called the gliding spacecraft (PKA). The draft project, undertaken in co-operation with Korolev's OKB-1, was signed by Tsybin on 17 May 1959.The piloted PKA would be inserted into a 300 km altitude orbit by a Vostok launch vehicle. After 24 to 27 hours of flight the spacecraft would brake from orbit, gliding through the dense layers of the earth's atmosphere. At the beginning of the descent, in the zone of most intense heating, the spacecraft would take advantage of a hull of original shape (called 'Lapotok' by Korolev after the Russian wooden shoes that it resembled). After braking to 500 to 600 m/s at an altitude of 20 km, the PKA would glide to a runway landing on deployable wings, which would move to a horizontal position from a stowed vertical position over the back of the spacecraft. Control of the PKA in flight was by rocket jets or aerodynamic surfaces, depending on the phase of flight.

The Tsybin bureau was closed down shortly after the draft project was completed. Tsybin and his staff transferred to the Myasishchev bureau in October 1959 (which had its own on-going VKA-23 winged spacecraft project). The Myasishchev bureau was then in turn closed and the staff transferred to Filial 1 of Chelomei's OKB-52 bureau in 1960. Tsybin's work on the PKA was passed to the Mikoyan bureau and formed the starting point for the design of the Spiral spaceplane.