Building the A4

By the summer of 1936, Nazi Germany was preparing for war. A new test rocket, the A3, was in development, but the pressure to produce a practical missile for warfare was growing. The result was an outline for the A4, a massive rocket that would scale up all their existing systems. Dornberger suggested that it should be able to carry a 100-kg (220-lb) explosive warhead over more than 260km (160 miles).

Tests of the A3 began in late 1937. This was a much more powerful rocket than its predecessors, developing 1,500kg (3,300lb) of thrust at launch and capable of burning for up to 45 seconds. A small tank of liquid nitrogen, heated so it evaporated into high-pressure gas, was used to force propellant into the engine at high speed. The A3 also incorporated a guidance system of gyroscopes and accelerometers. Although this had practical problems, the theory was sound - the first use of a technique still in use today.

The A4's gestation was a long one - and fortunately for the Allies, its debut was partly delayed by Germany's own military hierarchy. The success of the Blitzkrieg attacks of 1939 and 1940 made the Army so convinced of its superiority that it opted to cut back on funding to Dornberger's project. But building an engine with a thrust of 25,000kg (55,1251b) was also a massive technical challenge. The

PEENEMÜNDE RAID

Their suspicions aroused by aerial photographs and Polish resistance reports, the Allies launched air raids against Peenemünde in August 1943.

main problem for the scientists was how to force fuel into the combustion chamber at a fast enough rate to produce the required thrust. The solution was a high-speed turbopump, powered by the fierce chemical reaction of hydrogen peroxide and potassium permanganate. In the meantime, other systems were tested on a new research rocket, called the A5. By the time the first A4 successfully launched, on 3 October 1942, Germany's hopes for a swift war had been dashed and much was expected of the new weapon. This was soon to have a new name.

THE FIRST MISSILE

The A4 is the ancestor of all other liquid-fuelled rockets, including most modern ballistic missiles and space launch vehicles. To this day, rocket technology still follows the same principles set out by the A4 team.

TESTING KIT

This box of electronics was used for pre-launch tests on A4 rockets. Generally the launch sequence was triggered from inside an armoured vehicle or blockhouse close to the launch site, with all other personnel kept back at a safe distance.

explosive warhead oxygen container automatic gyroscopic guidance hydrogen peroxide container aerodynamic rudder

container for alcohol-water guidance beam and radio control apparautus fuel turbopumps explosive warhead container for alcohol-water oxygen container main combustion chamber graphite steering vane automatic gyroscopic guidance guidance beam and radio control apparautus hydrogen peroxide container fuel turbopumps aerodynamic rudder

GUIDANCE GYROSCOPES

The later A-series rockets used several gyroscopes and accelerometers to calculate the rocket's precise trajectory, speed, and distance travelled, so that it could be guided using steering vanes that deflected the exhaust.

GUIDANCE GYROSCOPES

The later A-series rockets used several gyroscopes and accelerometers to calculate the rocket's precise trajectory, speed, and distance travelled, so that it could be guided using steering vanes that deflected the exhaust.

MOBILE LAUNCHER

One reason for delays to the V-2 entering service was the need to develop a transport system for it. The rockets had to be fuelled and transported from Nordhousen to forward units via the rail network before they came within range of the enemy cities.

The missile goes to war

Although the first successful A4 launches occurred in late 1942, it took almost two more years before the missile was ready to enter service. By that time, it had acquired a more infamous pseudonym - the V-2.

As the A4 edged closer to mass production, it was increasingly dear that Peenemünde was not well-suited to large-scale manufacturing or perhaps even continued testing. The devastating Allied raids of August 1943 proved the final straw - among the casualties was Walter Thiel, the ingenious designer of the A4's high-performance engine. The decision was made to move much of the flight testing to Blizna in southern Poland, while large-scale manufacture of the missiles would begin in the huge Mittelwerk tunnel complex under the Kohnstein mountain near the town of Nordhausen in central Germany. The main focus of those remaining at Peenemünde would be research and development.

At the insistence of Joseph Goebbels's propaganda ministry, the A4 was henceforth to be called the Vergeltungswaffe-2 (Reprisal Weapon 2), or V-2 for short. The name V-1 had been given to the Luftwaffe's jet-propelled "flying bomb", tested alongside the V-2 at Peenemünde and also manufactured at the Mittelwerk. To provide a slave workforce for the huge underground factories, concentration camps at nearby Mittelbau-Dora were expanded.

By the end of 1943, thousands of prisoners were being worked to death in appalling conditions beneath the mountain.

Even with these massive resources, production did not go smoothly - von Braun's team at Peenemünde was still refining the rocket, and every modification resulted in lost time and lost lives among the labourers. Meanwhile, construction of infrastructure for the new weapons was under way. While the V-1 flying bombs required long concrete "ski ramps" to assist their take-off, the V-2 was designed for rapid deployment on mobile launchers. Nevertheless, the German military began planning a number of bunkers along the French coast that it intended to use for V-2 launches, but the Allied air forces subjected these to such heavy bombing that they were eventually abandoned.

By mid-1944, shortly after the D-day landings that started the liberation of mainland Europe, the Allies had a good idea of what was coming - parts of crashed V-2s had been smuggled to London from both Poland and Sweden, and aerial reconnaissance missions had given intelligence analysts an insight of the rocket's dimensions and capabilities.

MOBILE LAUNCHER

One reason for delays to the V-2 entering service was the need to develop a transport system for it. The rockets had to be fuelled and transported from Nordhousen to forward units via the rail network before they came within range of the enemy cities.

HIT AND RUN

A standard V-2 battery would consist of about 30 vehicles - Meillerwagens, mobile generators, fire trucks, tow trucks, and troop transporters. They became proficient at moving into forest cleorings or tree-lined lanes, setting up, and launching within just a few hours.

The Soviet Union Building

SCENE OF DEVASTATION

When a V-2 struck the corner of Smith field Market in central London, early on the morning of 8 March 1945, it killed 110 people. However, this was one of the last missiles to reach Britain - within weeks the V-2 launchers had been driven back out of range.

... they travelled faster than the speed of sound ... The first you knew was the explosion."

Eyewitness to a V-2 attack, London, 1944

them from their Meillerwagen launch platforms became a hit-and-run operation. A practised V-2 crew could set up, launch a missile, and depart within two hours usually moving too quickly for the launcher to be spotted and destroyed on the ground. Ultimately the V-2 attacks were only brought to an end as the German Army was driven into retreat and the target cities fell out of range. The bombardment finally ceased in March 1945.

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