MiG-105 EPOS Analog 105.11Photographed on 24 August 2009 at the Russian Air Force Museum, Monino, near Moscow.
EPOS = Experimental Passenger Orbital Aircraft.
Atmospheric flight test version of the Spiral OS manned spaceplane. The 105-11 incorporated the airframe and some of the systems of the planned orbital version.
After the decision to proceed with the Buran space shuttle, all that was left of the Spiral manned orbital vehicle project was a subsonic aerodynamic test vehicle, now designated EPOS (Experimental Passenger Orbital Aircraft) and flown by Air Force test pilots. On 11 October 1976 this 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 Zhukovskiy flight test center 19 km away. One year later, on November 27, 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 was made in September 1978, resulting in a hard landing and the write-off of the aircraft. The first and last flights were made by test pilot A. G. Festovets.
The vehicle consists of a flat-bottomed lifting body with a large upturned nose that earned it the nickname 'Lapot' (wooden shoe). The nose design was found to greatly reduce afterbody heating during reentry and was adopted by NASA in its HL-20 proposal of the 1980's. The load-bearing structure, like that of the US X-20, consisted of a network of struts and longerons. The outer skin was articulated to permit thermal expansion during reentry. A unique feature of the spaceplane 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 stabilizers. 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 airbreathing operations. The main body of the spaceplane had a sweepback angle of 78 degrees, and the wings, 55 degrees. The large vertical stabilizer had a sweepback of 60 degrees. Aerodynamic controls consisted of the vertical rudder, elevons in the wings, and air brakes mounted at the top rear of the fuselage. Landing gear normally consisted of four skids, in a tail-dragging configuration, the long frontal skids deploying in a complex manner from landing gear bays mounted on the sides of the spaceplane above the heat shield.
Air-breathing propulsion consisted of a Koliesov RD-36-35K turbojet of 2,350 kgf with 500 kg of fuel, which amounted to 10 minutes of cruise at full thrust. This was used, with wheels attached to the forward skids, for takeoffs from unpaved airstrips. In the orbital version, it would give the spaceplane a chance to 'go around' or divert to a secondary airfield in the event of bad weather or a missed approach (the US Shuttle was originally to have such engines, but they were dropped for weight reasons). The 176 kg engine was fed from a dorsal intake at the base of the fin. This intake was covered during launch and orbital operations; an actuator opened the housing once the spaceplane reached subsonic speed.
Orbital propulsion used 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 maneuvers. Fuel tanks for these systems were located in the centre of the vehicle.
Picture added on 14 September 2009 at 07:52
Added by Lambert Arnaud on 28 July 2010.