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astronautix.com A9/A10

A9 Engine Shutdown
A9 Engine Shutdown -

Credit: Gary Webster. 13,071 bytes. 216 x 223 pixels.



Family: A4. Country: Germany. Status: Development 1945.

The A9/A10 was the world’s first practical design for a transatlantic ballistic missile. Design of the two stage missile began in 1940 and first flight would have been in 1946. Work on the A9/A10 was prohibited after 1943 when all efforts were to be spent on perfection and production of the A4 as a weapon-in-being. Von Braun managed to continue some development and flight tests of the A9 under the cover name of A4b (i.e. a modification of the A4, and therefore a production-related project). In late 1944 work on the A9/A10 resumed under the code name Projekt Amerika, but no significant hardware development was possible after the last test of the A4b in January 1945.

During the course of development, the vehicle evolved. The first stage, the A10, was first to have used a multi-chamber design: a cluster of 6 A4 combustion chambers feeding into a single expansion nozzle. Later a massive single chamber/single nozzle engine was planned. Test stands were built at Peenemuende for firings of the 200 tonne thrust engine.

The original second stage A9 design was a refined A4 with swept wings. A later version had two fuselage strakes instead of wings. Wind tunnel tests showed that these provided better supersonic lift and solved the problem of transonic shift of centre of lift. A secondary benefit was better packaging of the A9 into the forward interstage of the A10.

Guidance systems of the time were hopelessly inaccurate at the 5000 km range planned for the A9/A10. Therefore it was decided that the A9 would have to be piloted. After cut-off of its engine at 390 km altitude and 3,400 m/s, the A9 would re-enter and begin a long glide to extend the range. The pilot was to be guided by radio beacons on surfaced German submarines in the Atlantic Ocean. After reaching the target the pilot would lock in the target in an optical sight, then eject. Death or internment as a prisoner of war would follow.

Work on the A9/A10 was prohibited after 1943 when all efforts were to be spent on perfection and production of the A4 as a weapon-in-being. Von Braun managed to continue some development and flight tests of the A9 under the cover name of A4b (i.e. a modification of the A4, and therefore a production-related project). In late 1944 work on the A9/A10 resumed under the code name Projekt Amerika, but no significant hardware development was possible after the last test of the A4b in January 1945.


Comparison of A9/A10Comparison of A9/A10 - Comparison of A9/A10 Versions

Credit: © Mark Wade. 6,010 bytes. 484 x 354 pixels.


Designs beyond the A9/A10 were sketched out as well. Adding an A11 stage would have resulted in a satellite launcher. An additional A12 stage would result in a four stage vehicle with the A9 being a manned orbital space shuttle.

Post-war refinement of the intercontinental missile concept in America and Russia went down two paths. On the one hand, it was found that it would be much more efficient for the A9 second stage to use a ramjet to extend the range to the 10,000 km true intercontinental range needed for the post-war adversaries to attack each other. This path led to the American Navaho and Soviet Buran and Burya missiles. On the other hand, improvements in rocket structures and engine efficiencies made it possible to design pure ballistic vehicles with cut-off velocities over twice as high as the A9/A10 and 10,000 km ranges. In the end, these faster, uninterceptable designs won out.



A9/A10 CutawayA9/A10 Cutaway

Credit: Gary Webster. 13,619 bytes. 144 x 382 pixels.


Specifications

Payload: 1,000 kg. to a: 5,000 km range trajectory. Liftoff Thrust: 200,000 kgf. Total Mass: 85,300 kg. Core Diameter: 4.1 m. Total Length: 41.0 m.


A9/A10 Chronology


- 1940 -

A-9 2 ViewA-9 2 View

Credit: Gary Webster. 18,179 bytes. 363 x 222 pixels.


- 1943 -
- 1944 November -

Bibliography:



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Last update 12 March 2001.
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