Keldysh Bomber - Credit: Mark Wade. 6,546 bytes. 350 x 178 pixels.

Among the advanced designs seized by Soviet forces as they overran Germany was the Saenger-Bredt Antipodal Bomber. This manned spaceplane particularly fascinated Stalin, to the extent that he instructed the NKVD to attempt to kidnap Saenger from his post-war exile in Paris. This did not come to past, but in the immediate post-war period development of a Soviet version of this project was given the highest priority.

On 29 November 1946 the NII-1 NKAP research institute was formed with Mstislav Vsevolodovich Keldysh as its head to investigate and develop the Saenger-Bredt design. Through 1947 studies revealed that the high fuel consumption of Saenger's pure rocket design made the concept unworkable in the near term. Using engines thought to be available in the near term, 95% of the winged vehicle's lift-off mass would have to be propellant. However use of ramjets during the acceleration process would allow the spacecraft to have a more reasonable 22% dead weight fraction and still achieve the 5 km/sec cut-off velocity required for the 12,000 km intercontinental range.

It was clear from the preliminary study that an immense amount of work needed to be done before even a draft project of a feasible design could be prepared. However this would be accomplished by the mid-1950's. The Keldysh design would lead through the EKR and MKR to the Buran and Burya Mach 3 intercontinental ramjet missiles.

The Keldysh Bomber had a length of 28 m, a wingspan of 15 m, and a fuselage cross section of 3.6 m x 1.8 m. Wing area was 126 sq. m which allowed a landing speed of 200 km/hr. The 100 tonne vehicle lift-off mass included: 70.5 tonnes of propellant; 7.5 tonnes for two ramjets; 9.0 tonnes wings and structure; 2.5 tonne rocket engine; 2.5 tonnes propellant tanks; and 8.0 tonnes payload and equipment.

The mission profile for the Keldysh Bomber differed in detail from that of the Saenger.

• The 100 tonne vehicle was accelerated to 500 m/s using a rocket sled equipped with five to six RKDS-100 rocket engines of 600 tonnes total thrust. The sled track would be 3 km long, and the separation velocity would be reached in 11 seconds from ignition.
• The bomber would then separate and climb using its main RKDS-100 rocket engine supplemented by wingtip-mounted ramjets equipped with a supersonic diffuser. These would accelerate the bomber to 20 km altitude and a speed over Mach 3.
• The ramjets would flame out at altitude but the rocket motor would conitnue working. This had a specific impulse of 285 seconds, a thrust of 100 tonnes, and used Lox/Kerosene propellants.

• Development of high-performance, high-thrust Lox/Kerosene rocket engines
• Development of theoretical and experimental data on the aerodynamics of supersonic flight and re-entry
• Development of sled technology capable of 500 m/s speeds
• Light and reliable aircraft construction techniques allowing the unprecedented required mass fraction
• Development of heat shield materials, able to withstand external equilibrium temperatures of 560 degrees Centigrade, for which no known solution was immediately available
• Development of automatic stellar navigation technologies to allow guidance of the bomber to the target with the necessary precision

It was clear from the preliminary study that an immense amount of work needed to be done before even a draft project of a feasible design could be prepared. During the rest of the 1940's much progress was made. Bondaryuk began development of Soviet ramjet engines for missile applications; German rocket engines were upgraded and improved for the R-2 missile. In December 1949, in the review of the Korolev R-3 project, the conclusion was reached that the necessary research was still not available for winged rockets. But by December of the following year, with flight tests of the Bisnovat supersonic rocketplane completed, the way was open for further development.

Payload: 8,000 kg. to a: 5 km/s, 12,000 km range trajectory. Liftoff Thrust: 90,000 kgf. Total Mass: 100,000 kg. Core Diameter: 3.6 m. Total Length: 28.0 m.

• Stage Number: 0. 1 x Keldysh Sled Gross Mass: 50,000 kg. Empty Mass: 25,000 kg. Thrust (vac): 600,000 kgf. Isp: 285 sec. Burn time: 11 sec. Isp(sl): 252 sec. Diameter: 3.6 m. Span: 3.6 m. Length: 14.0 m. Propellants: Lox/Kerosene No Engines: 6. RKDS-100

• Stage Number: 1. 1 x Keldysh Bomber Gross Mass: 100,000 kg. Empty Mass: 29,500 kg. Thrust (vac): 100,000 kgf. Isp: 285 sec. Burn time: 180 sec. Isp(sl): 252 sec. Diameter: 3.6 m. Span: 15.0 m. Length: 28.0 m. Propellants: Lox/Kerosene No Engines: 1. RKDS-100

• Keldysh Space Bomber authorised

  The NII-1 NKAP research institute was formed with Mstislav Vsevolodovich Keldysh as its head to investigate and develop the German Saenger-Bredt design. It was clear from the preliminary study that an immense amount of work needed to be done before a draft project of a feasible design could be prepared - it would take until the mid-1950's.

• 456 - Yevstafyev, M D, Dolgiy put k 'Burye', Vyzovskaya kniga, Moscow, 1996..