Credit: © Mark Wade. 14,186 bytes. 333 x 180 pixels.
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| Spiral 50-50 - Credit: © Mark Wade. 14,186 bytes. 333 x 180 pixels. |
Mikoyan GKAT OKB-155 began work in 1960 on the Spiral combination aerospace system. In 1965 the advanced project was approved, laying out an ambitious work plan leading to operation of a regular earth-orbit-earth reusable transportation system by the mid-1970's. Go-ahead to actually proceed with development of the manned orbital vehicle was given on 26 June 1966 and Lozino-Lozinsky was selected as project manager.
The Spiral system consisted of three main components:
The project plan for Spiral was as follows:
Technical Description
The GSR reusable hypersonic air-breathing launch aircraft was powered by four turbo-ramjet engines, and two variants were planned. The conservative first variant would use kerosene fuel and accelerate to Mach 4 and 22 to 24 km altitude before releasing the RB+OS. The longer-term second variant would use liquid hydrogen fuel, which would allow it to reach Mach 6 and 28-30 km altitude before releasing the upper stages. The GSR would return to its launch base after completing its mission.
The layout of the GSR was that of a large arrow-shaped flying wing. Vertical stabilisers were mounted at the wingtips. The engine bay was under the fuselage, with high bypass engine inlets. On the top of the wing was the launch pylon for the OS+RB, with the nose and tail portions of the pylon enclosed by ogival fairings for aerodynamic reasons.
The RB rocket that would take the OS from the back of the GSR to orbit consisted of a two-stage rocket. The conservative early version would use Liquid oxygen/kerosene propellants; the later advanced version would use Liquid oxygen/liquid hydrogen.
The OS orbital spacecraft was a flat-bottomed lifting body, triangular in planform, with a large upturned nose that earned it the nickname 'Lapot' (wooden shoe). A unique feature of the OS were the variable dihedral wings. These were set at a 60 degree angle above horizontal during launch, orbit, and re-entry, where they served as vertical stabilisers. After becoming subsonic, dual electric actuators moved them to a horizontal position, where they served as wings, substantially increasing the lift of the spaceplane for air-breathing operations.
The OS would be inserted into an initial 130 km altitude orbit by the RB, where only 2 to 3 revolutions could be maintained before orbital decay. Orbital propulsion consisted of a 1,500 kgf primary engine, with two 40 kgf backup engines. Orbital attitude control and translation were provided by two reaction control system (GDU) pods at the rear of the spaceplane flanking the backup engines. There were a total of six 16 kgf engines for coarse adjustment and ten 1 kgf engines for fine manoeuvres. Fuel tanks for these system were located in the centre of the spaceplane. All engines worked on N2O4/UDMH. After completing its mission the OS would enter the earth's atmosphere at a high angle of attack. After losing most of its velocity, the wings would have been moved to the horizontal lifting position, and the OS would fly to a landing at a conventional airfield.
During the development phase three single-place experimental reusable prototypes of the OS would be built. These would be built in the same configuration as the Spiral OS, but have somewhat smaller dimensions, so that they could be orbited by a Soyuz launch vehicle. For testing the OS in the subsonic terminal approach phase, aircraft-analogues were to be built, powered by a turbojet or rocket and air-launched from a Tu-95 bomber. Two were planned, one to be flown subsonic (article 105-11), and the other up to Mach 6 to 8 (article 105-12). The single reusable orbital manned prototype was designated article 105-13.
An important characteristic of the Spiral was its large usable payload, two to three times greater than that of a conventional launch vehicle of the same mass. Cost per kilogram of payload to orbit would be 3 to 3.5 times less. In addition the system, by using air launch, could reach any orbital inclination, manoeuvre in space, and return, even in adverse weather conditions.
Total Mass: 115,000 kg.
Decree 'On plan of work on Spiral at OKB-155' was issued.
In 1965 the advanced project of the Mikoyan Spiral aerospace system was approved. The ambitious work plan indicted operation of a regular earth-orbit-earth reusable transportation system by the mid-1970's. With Gherman Titov as its head, a Spiral cosmonaut training group was formed (Titov, Dobrovolskiy, Filipchenko, Kuklin, Matinchenko) to train to fly the spaceplane.
The was team now consisted of Titov, Beregovoy, Filipchenko, Kuklin, and Shatalov.
Lozino-Lozinsky was selected as project manager. The Spiral system consisted of three main components: the GSR reusable hypersonic air-breathing launch aircraft; RB expendable two stage rocket; and the OS orbital spaceplane.
A new cosmonaut training group for the Spiral spaceplane was established: Titov, Kizim, Kozelskiy, Lyakhov, Malyshev, Petrushenko.
The EPOS spaceplane made its first flight, taking off from an old dirt airstrip near Moscow, flying straight ahead to an altitude of 560 m, and landing at the Zhukovskii flight test center 19 km away. Pilot was A. G. Festovets.
The first air-drop launch from a Tu-95K (used previously for Kh-20 air to surface missile tests) was made from an altitude of 5,000 m, with landing on skids on a beaten earth air strip.
The eighth and final flight resulted in a hard landing and the writeoff of the aircraft. First and last flights were made by test pilot A. G. Festovets. The eight flights were considered sufficient to characterize the spaceplane's subsonic aerodynamic characteristics and airbreathing systems.