SPIRAL Project

In accordance to the quinquenal plan of the air forces, the project of a 2 stage launcher plane began in 1965 and was entrusted to OKB-155 A.I.Mikojan whose chief of the engineering and design department was Lozino Lozinsky (55 years). The project received the name of SPIRAL and was to prepare the Soviet Union to the war in space.

Although the project goes back to several decades the ideas which are stated there are quite simply impressive. In accordance with the requirements of the customer the system included a supersonic horizontal launcher (GSR), an orbital space-plane (OS), and an auxiliary rocket. The departure was envisaged into horizontal position like a plane (1), then at an altitude of 28-30 km the orbital space-plane and its rocket were detached from the launcher (the engines worked with F2 H2) (2), the plane launcher then return to its base. When the fighter arrive at an altitude of 120-130 km it separated from its auxiliary rocket (3) and could make up to 2 revolutions to reach (a satellite) or to fly over its objective (to shoot photographs) (4), when the mission was accomplished it started its re-entry in the atmosphere, protected by an abrasive heat shield, moreover the cold part of the fuselage was assembled on special fixings to enable him to become deformed under heat. When the atmosphere was rather dense the wings of the plane were spread, then towards the end of the flight the pilot lit his turbojet to facilitate the landing (on 4 skis) and the final approach.

An important advantage of the SPIRAL launcher was its great payload capacity, 2 or 3 times higher than a traditional system of the same mass. The cost of the put into orbit per kilogram was 3 to 3.5 times inferior. Moreover, by using the principle of a plane launcher the SPIRAL could reach any orbit, make operations in space and turn back to the ground even under difficult climatic conditions.

The SPIRAL system was finally abandoned at the end of the 70's to the profit of the Buran-Energia system, because the program accumulated the delays moreover an important amount of money had been introduced into the project whereas the setting in production would not be done before several years. But the principle of putting into orbit a space shuttle by a horizontal launcher went on and risen in the MAKS project in the 80's, whose plane launcher was the Mriya.

The project of the orbital space-plane (related to SPIRAL) was finally re-orientated in a simple tests plane. New designation was EPOS (Experimental Piloted Orbital Aircraft), and could be controlled by pilots of the Soviet Air Force. In 1976 the project was stopped (the Buran project had just started) except for the tests of model 105.11. Some EPOS pilots joined the test team of Buran (Igor Volk).

Although SPIRAL was stopped, some derived projects appeared in the 80's. It had been decided to use the orbital space-plane placed on a rocket Zenit or to use a larger version of this space-plane combined with the launcher Energia (Ouragan project).

SPIRAL launcher with the orbital space-plane

Orbital space-plane