ON TUESDAY 19 JUNE the whole of Fedden’s team, including the pilots and crew, travelled to Nordhausen in the mountainous Harz region. Some of them went with the two Dakotas direct to the landing strip outside Nordhausen, while the others travelled the 50 or so miles (80km) by road from Stassfurt where they had inspected the BMW jet engine plant the previous day. It must have been a very pleasant journey as the Harz is an exceptionally scenic area, where the thickly wooded slopes are dissected by rocky gorges and valleys of rich farming land. The regional capital, Halberstadt, had been severely damaged by air raids but for the most part there was little of the widespread devastation they had experienced in the industrial areas to the north. Fedden noted that it was ‘a very hot and brilliantly fine summer’s day’. However, the British team had little time to enjoy the mountain scenery for they were about to descend into what can only be described as a man-made vision of hell:

    The Mission had been told that at Nordhausen there was a large underground factory, and that they would see extraordinary production methods, but they had no idea that they would be brought face to face with such an undertaking. Although members of the Mission had read a good deal about the concentration camps of Germany, Nordhausen was not officially regarded as such, but as one of the most modern production factories. The reaction of the Mission to this visit to Nordhausen was one of the utmost revulsion and disgust. Such a place must be visited to be believed, and it is hoped that nothing can compare with it elsewhere in the world.

Although Fedden refers to it as Nordhausen, taking the name from the nearest town, the subterranean factory tunnelled under the Kohnstein mountain was officially known as the Mittelwerk, meaning middle or central works. The site, including the nearby concentration camps which housed the workforce, was uncovered by the advancing American troops of the 3rd Armored Division on 11 April 1945. US Army Intelligence knew that there was something unusual in the area. It was only with the discovery of the thousands of dead and sick prisoners in the outlying camps and barracks that they began to grasp the true scale of what they had stumbled upon.

The Mittelwerk was the largest and most notorious of the German subterranean arms factories. Its chief function was the assembly of the main elements of Hitler’s much vaunted Vergeltungwaffen, the vengeance or retaliation weapons, principally the V-1 flying bomb and the V-2 (A4) rocket. There was also a third and lesser-known V weapon, the V-3 super-gun, although this had no connection with the Mittelwerk as it was of necessity constructed at a fixed site near the Channel. The V-3 was a long-range cannon with a series of propellent charges spaced along the barrel’s length which were fired in sequence to maximise the finned projectile’s velocity. Under the German codename Tausendfussler (‘millipede’) – because of the gun’s appearance with the charge chambers sticking out like legs on the long barrel – work had commenced in the autumn of 1943 to construct up to five V-3 guns in quarries located near Mimoyecques in the Pas de Calais. The 490ft (150m) barrels were placed within sloping tunnels aimed directly at London. Some test firings had been conducted at the Hillerben artillery proving ground near Magdeburg, but the Mimoyecques guns had yet to fire in anger when they were put out of commission on 6 July 1944 by Tallboy deep-penetration bombs delivered by the RAF’s 617 Dambuster Squadron.

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American personnel in front of the camouflaged south entrance to the Mittelwerk weapons factory concealed beneath the Kohnstein mountain near Nordhausen. (NARA)

In contrast to the V-3, the other two V weapons, the V-1 and V-2 (A4), were more flexible in their deployment and consequently they proved to be far more deadly and difficult to defend against.


The first to be deployed, but by only a matter of months, was the V-1 flying bomb. Developed by the Luftwaffe, as opposed to the V-2 (A4) rocket which was regarded as a long-range artillery weapon and hence the province of the army, this was the precursor to the modern cruise missile. Back in November 1939 the RLM had issued a requirement for a remote-controlled aircraft capable of carrying a payload of 2,200lb (1,000kg) over a distance of 310 miles (500km). In other words far enough if launched from occupied Europe to reach Britain, in particular London. Fritz Gosslau of the Argus Motoren company had already conducted some work on a remote-controlled surveillance aircraft, the AS 292, and Argus combined with Lorentz AG and Arado to produce a joint design for such a flying bomb. In April 1940 Gosslau presented the plans to the RLM as Project P35 ‘Erfurt’ (the name of the capital city of Thuringia). The Air Ministry decided not to go with this design because of concerns about the viability of the remote-control aspects as they feared it might prove vulnerable to electronic jamming.

Nonetheless, Gosslau pressed ahead with his developmental work, abandoning the remote-control system in favour of an autonomous pilot-less aircraft. For expertise in designing a fuselage Heinrich Koppenburg, the head of Argus, recruited the assistance of Robert Lusser, who was a chief designer with Heinkel and had taken up a position with the Fieseler aircraft company. Lusser simplified and improved Gosslau’s design, principally making it into a single instead of twin-engined craft, and the revised project was re-submitted to the technical department of the RLM in June 1942. It was approved by Ernst Udet and the Fieseler company was appointed as the main contractor to build the Fiseler Fi 103, as the project was now designated.

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Around 25,000 inmates died at the notorious Mittelbau Dora camp built to house slave workers for the Mittelwerk. Many were killed by the fleeing SS guards and as the result of an Allied air raid. (NARA)

The Fi 103 was a pilot-less aircraft with a wingspan of 17.6ft (5.37m) and measuring just over 27ft (8.3m) from nose to tail. The fuselage was of welded sheet steel while the wings were constructed from plywood and slotted on to a main metal spar extending from the fuselage. The payload, a not inconsiderable 1,900lb (850kg) of Amatol-39 explosive, was contained within the warhead, and propulsion was via a single pipe or tube-like engine supported at the rear of the fuselage by a small tail. This was the Argus pulsejet, a type of engine sometimes referred to as a resonant jet. In flight, fuel was drawn past hinged flaps at the front of the pipe by the aircraft’s forward motion. Initial ignition was by an automotive spark-plug, but otherwise it required no source of ignition once it got going as each pulse of fuel, coming at a rate of fifty per minute, was ignited by the heat of the previous one. Each combustion shut the flaps at the front, forcing the exhaust to be expelled out of the back of the tube to create thrust, and the cycle recommenced. This meant that the pulsejet engines were extremely simple devices with very few moving parts. They were also light in weight and could run on a low-grade petroleum fuel. Furthermore, in comparison with the later V-2 rockets, they were relatively cheap to produce.

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V-1 assembly line at Nordhausen. The flying bombs lack their wings and nose cones at this stage. The wings would be slotted on to the circular spars. (NARA)

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Cutaway diagram of the Fieseler Fi-103 V-1 with Argus As 014 pulsejet. (USAF)

Because of the apparent advantages of the pulsejet concept, tests were also conducted to investigate their potential as propulsion units for conventional aircraft, as well as for road vehicles and even on an experimental high-speed attack boat, but the excessive vibration and high noise levels made them unsuitable for more sustained use. Even for the unmanned V-1 the Argus As 014 engine suffered a drawback in that it did not generate sufficient thrust for the missile’s stubby wings to attain take-off speed. The V-1 had a stall speed of around 130mph (200km/h), and accordingly they were launched on an inclined ‘ski ramp’. The missile was mounted on a trolley launched by a piston-driven steam catapult, although this is something of a misnomer as they actually used T-Stoff and Z-Stoff fuels consisting of hydrogen peroxide and potassium permanganate.

In flight the V-1s attained an airspeed of around 400mph (640km/h), cruised at between 2,000 and 3,000ft (600-900m), and had an operational range of about 160 miles (250km). Their altitude was regulated by a weighted pendulum and gyroscopic system to control pitch, while a gyrocompass controlled the yaw and roll via a linkage to the small rudder in the tail. An odometer activated by an anemometer – a wind gauge driven by a tiny pair of propeller blades located on the tip of the nose – determined when the missile had travelled the predetermined distance to its intended target. The odometer could be adjusted to take account of the wind speeds on a particular day, and some V-1s were also fitted with radio transmitters for position verification.

By the end of 1943 around 100 V-1 ski ramp launch sites were under construction along the northern coast of France. It was the presence of these conspicuous ramps, pointing straight at London, that alerted the Allies to the threat of the V-1s and RAF Bomber Command initiated a series of intensive bombing raids to knock them out. In response the Germans abandoned the sites – an action unknown to the Allies who kept pounding away – and opted instead for less permanent and better concealed launch facilities.

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The Allies obtained detailed information on the V-1 flying bombs from examples which fell to earth intact near the launching sites. (CMcC)

The first V-1 attack on London took place on 12 June 1944, just a few days after the D-Day landings at Normandy. The notion of vengeance weapons suddenly became far more than a matter of propaganda or rhetoric and Hitler saw them as an effective act of retaliation against the Allies. The attacks soon intensified and at the height of their deployment more than a hundred V-1s were hurtling across the Channel every day. At the receiving end people living in London and the south-east of England quickly came to recognise and dread the distinctive sound generated by the pulsejets. Described as being like the throb of a noisy motorbike it inspired the British nicknames of Buzz-bombs or Doodlebugs, the latter being a general term for a buzzing insect. (The Germans had their own names including Kirschkern, ‘cherrystone’, and the Maikäfer, ‘maybug’.) But the worst sound of all was the terrifying silence that followed the moment when a V-1’s engine cut-out, signalling its imminent descent. The cut-out was not intentional as the missile was designed to strike the ground in a powered dive, but the sudden tilt caused by the automatic release of two spoilers on the elevator resulted in a momentary starvation of fuel in the pipelines. This fault was rectified on later models.

To deal with this new form of aerial bombardment the British developed a number of countermeasures. These began with detachments of the Royal Observer Corps stationed along the Channel coast to provide the earliest possible identification of the incoming missiles. Next in line came the anti-aircraft batteries, although in practice the gunners found the small, fast-moving targets extremely difficult to hit at first. The introduction of proximity fuses raised their success rate enormously and by the end of August 1944 around 80 per cent of the V-1s were being destroyed. To back up the AA guns, an inner barrage of 2,000 balloons was deployed to the south-east of London to entangle the intruders in a curtain of wires, and around 300 V-1s were accounted for in this fashion. For the balloon crews Doodlebug catching was a hazardous activity as a snagged V-1 was liable to fall to the ground close to the balloon winch.

The other defence was to scramble fighter aircraft to intercept the missiles. Only thirty Hawker Tempests – one of the few aircraft capable of sufficient low-altitude speeds fast enough to catch them – were assigned to the task initially, but they were later joined by P-51 Mustangs, Supermarine Spitfire Mk XIVs and, during the night in particular, by de Havilland Mosquitoes. In addition the new British jet, the twin-engined Gloster Meteor, was rushed into service, but although it had the speed to catch the V-1s its cannon were prone to jamming and only thirteen kills were attributed to the world’s first jet-on-pulsejet encounters. Shooting a V-1 out of the sky was always potentially dangerous for the pilots, and often failed anyway, so an alternative tactic was to chase a missile and manoeuvre into a position with one of the aircraft’s wing tips just inches above the V-1’s wing, using the airflow to tip it upwards to override the gyros and send it off into a dive. (Not, as sometimes suggested, by physically flipping its wings.) More than 1,000 V-1s were brought down by the aircraft interceptors.

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V-1 being wheeled tail first out from a concrete storage bunker. The wings were fitted on site prior to launching. (CMcC)

The British had one final card up their sleeve. If they couldn’t destroy all of the flying bombs then they would lead them astray through deception. By misleading the Germans regarding the locations of V-1 impacts they caused them to adjust the settings, which had the effect of making the missiles come down in less densely populated areas. This was achieved in part by a news black-out on the identification of specific impact sites and, more significantly, by feeding false intelligence back to Berlin via a number of turned German agents. To add a degree of authenticity information on some of the location of undeniable and well-known V-1 impact sites was included in these reports. By this late stage in the war it had become virtually impossible for the Luftwaffe to carry out reconnaissance flights over England to verify the information, so these reports were largely taken at face value.

Approximately 9,500 of the V-1 missiles were launched against London and south-east England before the various launch sites in France had been overrun by Allied ground forces in October 1944. Further attacks continued on a reduced scale with the missiles either air-launched from beneath bomber aircraft flying over the North Sea or, during February and March 1945, several hundred longer-range F-1 variants were launched from sites in Holland. The final V-1 to fall on English soil came down at Datchworth, Hertfordshire, on 29 March 1945. By then almost 23,000 people had lost their lives in the V-1 attacks, and over a million homes had been destroyed. It is estimated that without the policy of deliberately diverting the missiles away from central London the casualty figures might have been much higher, possibly by as much as another 50 per cent.


The V-2 was not a successor to the V-1; it was developed entirely separately and its origins go back to the 1920s when the imagination of a young man named Wernher von Braun was captivated by Hermann Oberth’s book Die Rakete zu den Planetenräumen – The Rocket into Interplanetary Space. From 1930 von Braun attended the Technical University of Berlin where he assisted Oberth in the development of liquid-fuelled rocket motors. Walter Dörnberger, an artillery captain in the German Army, recognised the potential of the rocket as a weapon of war and arranged an Ordnance Department grant for von Braun to work within the army’s fledgling rocket programme at the Kummersdorf testing site. By late 1934 von Braun and Dörnberger’s group had successfully launched two liquid-fuelled rockets, the A1 and A2, which attained heights of 7,200 and 11,500ft (2,195 and 3,500m) respectively. These were the first in the series of the ‘A’ or Aggregat rockets, the German term referring to a mechanism or mechanical system. The next step on the evolutionary ladder was the A3, a much bigger rocket with an engine that burned oxygen and alcohol to generate 3,300lb (1,500kg) of thrust for a duration of forty-five seconds. A triple-gyroscope was devised to control its trajectory by deflecting the jet vanes. By late 1937 test firings were being undertaken at the army’s new rocket development and test centre at Peenemünde, a remote site on the island of Usedom, off Germany’s Baltic coast. (The Luftwaffe shared part of the test site.) The first launches suffered from a variety of teething problems, including premature parachute deployment and engine failures, and the rockets crashed soon after launching. The most likely cause was identified as being the guidance system and work on the A3 rocket was abandoned in favour of the full-scale A4 and also the A5 which was a smaller test version of the A4.

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A V-1 launch ramp at Belloy-sur-Somme. (CMcC)

The A4 had been developed specifically as a ballistic weapon with a range of about 109 miles (175km) and a payload of 2,200lb (1,000kg) of Amatol explosives. In order to achieve this goal the A3’s troublesome motor was redesigned by Walter Thiel, and following an extensive series of test firings of the A5 version the first successful launch of the A4 took place on 3 October 1942. The rocket performed flawlessly this time and came down 120 miles (193km) away after attaining a height of 260,000ft (80,000m); it was the first man-made artefact to penetrate the edge of space. After watching the pencil-thin plume of flame disappear into the heavens, Walter Dornberger proclaimed the day as ‘the first of a new era in space transportation, that of space travel’. With stars in their eyes the missile’s proponents were more than happy to ignore its destructive nature and the dreadful cost in human misery to achieve it.

Having previously experienced indifference from Adolf Hitler, who believed that such a weapon was not needed as the war would be concluded very swiftly, the A4 programme was suddenly accorded the highest priority. The V-2 – as it was christened by Joseph Goebbels’ Reichsministerium für Volksaufklärung und Propaganda (the Reich Ministry for Public Enlightenment and Propaganda) – stood almost 46ft (14m) high. At the tip was the warhead, next came the automatic gyroscopic control systems, then the fuel tanks – which accounted for the bulk of the missile’s volume and weight with an upper tank holding a 75 per cent ethanol/water mixture and in the lower tank liquid oxygen – and at the base there was the rocket motor, exhausts and the four control fins. Despite its deadly intent the V-2 had an undeniably pleasing aerodynamic profile. It was, in essence, the shape of the future.

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Once the land-based V-1 launch sites in France had been overrun by the Allies in October 1944 the missiles were air-launched from modified Heinkel He 111 bombers over the North Sea.

From the moment of launch the rocket was propelled for up to sixty-five seconds under its own power before continuing on a free-fall trajectory to its target. It was guided automatically by rudders located on the trailing edge of the tail fins, and by four internal vanes directing the exhaust gasses. Its LEV-3 guidance system consisted of two free gyroscopes – one for vertical and one for horizontal guidance – and an accelerometer to control the engine cut-off at a pre-determined velocity.

An assembly line had been set up at Peenemünde by mid-July 1943 but barely a month later, on the night of 17/18 August 1943, the RAF unleashed Operation Hydra as the first strike in the Allies’ Operation Crossbow strategic bombing campaign, aimed specifically at destroying the V-weapon programme. An armada of 596 heavy bombers pounded the research centre at Peenemünde. Although the deputy director Walter Thiel (the engineer who had also designed the motor for the Wasserfall anti-aircraft missile) was killed in the attack, along with hundreds of civilian workers, Hydra failed in its objective as the V-2 programme was set back by about only six to eight weeks. Ironically its main outcome was to accelerate the drive to disperse and protect V-2 production underground.

The initial intention was to launch the V-2 rockets from a number of fixed bases in northern France, and processing and launch facilities were constructed in the Pas de Calais for this purpose. At Watten a massive blockhaus (‘bunker’) was constructed in the form of a concrete box 302ft (92m) long and 92ft (28m) high. The facility included a liquid oxygen plant and the rockets would be delivered by train for final assembly, fuelling and arming, with an anticipated launch rate from the site of up to thirty-six per day. Constructed by the Organisation Todt with walls of reinforced concrete up to 23ft (7m) thick the blockhaus was considered impregnable, but the Allies struck with Barnes Wallis’s Tallboy earthquake bombs before the construction work was completed and the concrete had had a chance to fully harden. The blockhaus was put out of action, and obviously it had become too conspicuous to fulfil its intended role. But just as the pyramids outlived the Pharaohs this massive structure will remain as a relic of the Third Reich for hundreds if not for thousands of years to come. Likewise the nearby ‘Coupole’ V-2 facility at Wizernes, constructed within a disused chalk quarry and capped by a shallow concrete dome 276ft (84m) across, also fell victim to the Crossbow raids before becoming operational.

With the large static sites attracting too much attention the Germans changed to individual mobile launch batteries which were known as Meillerwagens after the trailer vehicles used to transport the missiles. The V-2 had been designed with transportation on the existing railway system in mind, which meant that they could be sent to any number of locations very easily and then transferred to the Meillerwagens to be launched from the cover of wooded areas. Painted in camouflage colours, or dark olive green, and given the transient nature of the mobile launch pads, the V-2s were virtually immune from observation and attack by Allied aircraft.

On the receiving end the V-2s were both undetectable and unstoppable. They fell to earth at 2,200mph (3,550km/h) – approximately four times the speed of sound. There were no warnings, no air-raid sirens, and for the victims on the ground it was as if the explosion was instantaneous. The only defence was to repeat the policy of falsifying information on the impact locations and to conduct an all-out bombing campaign against the V-2 installations, although the Mittelwerk remained unknown to Allied intelligence and as it was located deep beneath the Kohnstein mountain it was virtually impregnable anyway.

Apart from the issue of its impunity from defensive measures, the value of the V-2 as a strategic weapon is highly questionable. Starting in September 1944 more than 3,000 V-2s were launched, with about half that number targeting London while the bulk of the remainder fell on Allied-occupied Antwerp, with a further seventy-six in France and eleven launched against the advancing Allied forces at Remagen within Germany itself in the final stages of the war. It is estimated that around 2,750 civilians lost their lives in the attacks on London and another 6,500 were injured. Set against this the weapon was extremely expensive to construct and consumed significant quantities of increasingly scarce materials and resources. The V-2 programme is said to have cost Germany more than the Americans invested in the Manhattan Project to develop the atomic bomb. Individually each V-2 missile cost around twenty-five times more than a V-1 but only delivered a comparable payload. Furthermore the V-2’s warhead did not have a proximity fuse and the missile’s incredibly high rate of descent meant that it exploded when already embedded into the ground with much of its destructive energy being dissipated. As a vengeance weapon it clearly had a devastating effect on its victims. However, it wasn’t until 10 November 1944 that Winston Churchill announced in Parliament that England had been under attack from the rockets ‘for the last few weeks’ as he put it. By that time the war was clearly moving in the Allies favour and its end was in sight. There was absolutely no possibility that the V-2 campaign could have changed the outcome.

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General Dornberger shakes the hand of Gerneral Hjanssen on the occasion of General Fellgiebel’s visit to Peenemunde in October 1944. Fellgiebel is between the two officers and beside Wernher von Braun who is wearing a dark suit. (NARA)


In September 1943, only a couple of months after the RAF’s Operation Hydra raids on Peenemünde, the Mittelwerk had been incorporated as a private company and a contract for the construction of 12,000 V-2 (A4) missiles was awarded on 19 October 1943. The immediate task was to significantly extend the existing tunnel network, making it suitable as a full-scale arms factory.

Some tunnelling had commenced back in August 1936, before the outbreak of war, working from an Anhydrite mine on the north side of the mountain. Ostensibly this was to create a bomb-proof store for chemicals, oil and gasoline, although some sources also suggest that the intention was to store chemical weapons or poisonous gases here. The firm responsible for that construction work had been a government company called Wissenschattliche Forschungsgesellschaft, also known as WIFO. For its new role as a weapons factory a second phase of extensive excavation was started in 1943 to create an overall floor area almost 6,500,000ft2 (600,000m2) once completed. According to post-war Allied intelligence reports only 1,780,000ft2 (165,000m2) was actually in use by the time the Mittelwerk was overrun in April 1945. The layout consisted of two main parallel tunnels, known as ‘A’ and ‘B’, each large enough to accommodate double railway tracks running their length. These main tunnels were connected at regular intervals by a series of parallel transverse tunnels to form what looked in plan form like a shallow S-shaped ladder. A 1945 CIOS report on underground factories in Germany provides further details:

    The general layout and production arrangements were based on two main tunnels, each about a mile long and 30ft [9m] wide, extending from one side of the hill to the other, thus giving double entry on both sides. These two main tunnels were connected via forty-six cross-galleries, known as Halls or Kammer, each one about 520ft [160m] long and 30ft [9m] wide. The two primary tunnels were used for main and inter-bay transport. Prepared roads giving access to the four main entrances permitted the use of road transport both to and throughout the main tunnels.

Constructing the tunnels was reasonably straightforward from an engineering point of view as the anhydrite had a particularly fine-grain crystalline structure well suited to tunnelling and it could stand unsupported over widths of 30 or 40ft (9 or 12m). In spite of occasional rock falls the galleries were unlined, although steel supports and cross beams were placed to strengthen particular areas where the roof was weaker. To provide ventilation eight vertical shafts led upwards to the surface. Once the tunnels were operational a system of air heater batteries positioned within the ventilation system provided heating, the warmth being circulated by the movement of the air. To prevent the air from becoming stale a system of extractors ensured that fresh air was supplied at a rate of about 33,550,000ft3 (950,000m3), which roughly equates to one complete change of air every hour.

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Photograph of the V-2 rocket engine assembly line at the Mittelwerk, taken from the mission report.

Transverse tunnels numbered 1 to 17, starting at the northern end of the complex, had been completed in 1937. A second phase of excavations saw the remaining ones constructed in two stages, with numbers 18 to 36, and later 37 to 46, finished by March 1944. All of this work took a vast labour force consisting of concentration camp inmates who were overseen by the SS under the command of General Hans Kammler. According to the Nazis’ war productions minister, Albert Speer, the use of prisoners for the work was considered to be a reliable means of ensuring that the Mittelwerk remained secret from the rest of the world. Initially the workforce came from the Buchenwald concentration camp and it was made up of a variety of nationalities, including large contingents from Russia and Poland. Many were Jewish, but not all. There were also a number of political prisoners, including members of the French Resistance for example. At first these Häftlinge, meaning ‘detainees’ or ‘inmates’, worked, ate and slept in the freezing unheated tunnels for weeks on end without respite, digging and clearing the works. Throughout this process the atmosphere was thick with gypsum dust and blast fumes, and many hundreds, possibly thousands, of the workers never saw daylight again.

Once the excavation work had been completed the prisoners were rehoused in a new camp built close to the mouth of the tunnels and known as Dora. Its name was later changed to Mittelbau-Dora. Until the new camp opened in November 1944 with its own incinerators, the bodies of those who perished were transported back to Buchenwald for disposal. At Mittelbau-Dora there were around fifty-eight barracks on the main site, and in addition there were up to forty or more sub-camps scattered in the area around the mountains. Once the tunnelling work had been completed the inmates were reassigned to build the V weapons. In July 1944 the Nordwerk, or ‘north works’, occupying transverse tunnels 1 to 20 were allocated to Junkers for jet and piston engine production and this appears to have been run independently, without SS involvement. Meanwhile, the V-1 flying bomb assembly commenced in October 1944 in the tunnels vacated by the excavation teams at the southern end of tunnel A. At the end of January 1945, fifty-one V-1s were shipped from one of the Fieseler factories to Nordhausen for completion and by February the Mittelwerk had become the sole factory producing the flying bombs. In the final months of the war Taifun anti-aircraft missiles were also being produced at the site. But the main product to emerge from the Mittelwerk remained the V-2 rocket and it is estimated that around 4,575 were completed in the six months between August 1944 and March 1945.

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Another Mittelwerk image from the mission report, this time of an unfinished V-2 rocket.

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The rear section of a V-2 stranded on a train near Bronkirchen, 5 April 1945. (NARA)

The tunnels were organised as a vast production line with Tunnel A used to bring in and transport the components and materials to where they were needed, while the main assembly took place in Tunnel B, running from north to south. The transverse tunnels were used for the more detailed work, checking and installing components, as well as for storage. Each missile was mounted on a railway bogey for its journey on the production line principle. At the south end of the tunnel system Hall 41 had been excavated up to 50ft (15.2m) in height to allow for each missile to be raised into the vertical position for final testing of the gyroscopes and guidance systems.

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The massive ‘blockhaus’ at Watten in the Pas de Calais was intended as an impregnable launch facility for the V-2 rockets. (JC)

It was a colossal undertaking and according to the CIOS data the labour force at any one time was in the region of 12,000 people, of whom three-quarters were foreign or slave workers, and an estimated 2,000 were free workers. Working in two shifts of twelve hours straight, they were supervised by German engineers under the ever-present scrutiny of SS guards. The type of task each man was assigned depended very much on his skills. Those with any sort of engineering or technical background were selected to inspect parts, sub-assemblies or conduct tests, and in many cases these workers were from among the better educated French prisoners. The less skilled, notably the Russians and Poles, were assigned to the more physical duties such as transporting and moving the components and materials. This was particularly back-breaking work and it is said that these prisoners were treated far more harshly by the guards and consequently they were ‘used up’ very rapidly.

Aware that the rockets were intended to kill Allied personnel or civilians, some prisoners attempted to sabotage them. This might involve accepting sub-standard parts for example, or perhaps making inadequate welds that would result in the missile failing. But it was a desperately dangerous game to play. Prisoners involved in electrical assembly were required to identify their work by inserting slips of paper and if a component failed it could be traced back to them. The penalty for sabotage was death, not just for the perpetrator but often for the rest of their immediate group of co-workers. Group hangings were common and usually conducted in full view of the others. Sometimes they were carried out using the rocket hoists in Hall 41 with the condemned men slowly raised into the air to suffer a lingering and painful death. Their bodies would be then left dangling from the hoist for several days as a deterrent to the others.

It is estimated that as many as 60,000 people passed through Mittelbau-Dora and the associated sub-camps. Of these around 25,000 inmates died, either from malnutrition, disease, exhaustion or from the vicious beatings inflicted by the guards and the executions. As the Allies advanced towards the area, in early April 1945, many prisoners were also killed by the SS in their panic to evacuate the camps, and others died as the result of RAF bombing raids between 1-4 April after the rows of huts were mistaken for factory or military facilities. Some of the most enduring and pitiful images of concentration camp inmates and the rows of emaciated corpses come from Mittelbau-Dora.

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Cutaway revealing the V-2’s complex rocket engine. This preserved example is displayed at the Imperial War Museum, London. (JC)

When the Fedden Mission arrived at the Mittelwerk it was only a couple of days before the area was scheduled to be handed over to the Russians. The site was occupied by a handful of US army personnel, but otherwise it was unguarded. The area surrounding the main entrance into the tunnel complex was littered with V-2 components, fuselage rear sections, complete with their fins, lying sideways on wooden frames ready to be transported, plus rows of combustion chambers and nozzles standing upright, slightly taller than a man. The entrance itself was disguised by crude wooden scaffolding covered by camouflage netting. On entering the tunnel it took several minutes for the visitors’ eyes to adjust from the harsh sunlight outside to the deep gloom within, but once inside they found that the production areas were surprisingly well lit by overhead electric lights. When the American troops first discovered the tunnels they had found them abandoned, but left as if ready for the next shift with the lights and ventilation systems still running.

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Drawing of three members of the Aggregat rocket family. The Aggregat 4, the V-2, is shown alongside the proposed Aggregat 9, or A4B, which was to be a longer-range version of the A4. In the centre is the A10 intercontinental missile intended to attack the USA.

The Mittelwerk tunnel system is so vast that Fedden’s team could only explore a part of it:

    Its extent and area were such that it was impossible to gain anything but a very rough idea of its size and capacity, and there was nobody to explain the details, except one of the directors of the BMW factory, who had only been there on one or two occasions before.

In the southernmost tunnels there were hundreds of wingless V-1 missiles. The wings would only have been attached once they had been transported to the launch sites. A little further into the tunnels they came across the stores of unused V-2 components, including the liquid oxygen tanks, and in Tunnel B they found examples of the completed rockets. On one the Americans had scrawled ‘Hands off don’t move’, although who the message was intended for is hard to say. In the ten weeks or so since its discovery the Allies, particularly the Americans, had been busy stripping this technological Aladdin’s cave of its contents before the area came under Russian control. It is estimated that they transported around 300 rail-car loads of V-2 hardware and components back to the USA, not all of it from the Mittelwerk as many V-2s were also captured intact, having been stranded in transit by the devastating disruption caused by the intensive bombing of the German railway system. Moving through the interconnecting tunnels Fedden also saw some of the production lines where the more intricate components had been assembled by the enforced workers. Some of the halls housed huge machine tools which had been brought from Peenemünde and these included Weingarten hydraulic presses more than 20ft (6.1m) tall. At first Fedden was true to the remit of his mission and wrote of his experience in the Mittelwerk purely as an engineer:

    It is difficult to explain in writing the impressions the Mission received, coming in from brilliant sunshine and beautiful country, having been through this enormous labyrinth, containing the most expensive equipment and tooling for making these various aircraft munitions on an unparalleled production basis, as regards fool-proof slave labour production. To go from store to store, which had been looted by the slave workers and the soldiers, and to find the most up-to-date and brand new equipment lying strewn about the floor in hundreds, such things as micrometers, gauges, very expensive precision equipment, Bosch fuel pumps, electric starters, etc. in the utmost confusion – must be seen to be appreciated.

Nonetheless he and his team were not immune to the human tragedy they were witnessing: ‘This factory is the epitome of megalomaniac production and robot efficiency and layout. Everything was ruthlessly executed with utter disregard for humanitarian conditions.’ They also saw for themselves something of the conditions in the Mittelbau-Dora concentration camp:

    The record of Nordhausen is a most unenviable one, and we were told that 250 of the slave workers perished every day, due to overwork and malnutrition. Some of the Mission visited a slave workers’ encampment, talked to a Dutch doctor who had been there throughout the war, and saw many of the wretched inmates who were in an appalling state, although receiving every medical attention now. They also saw stretchers heavily saturated in blood, a room in which there was a slab on which the bodies were drained of blood, and the incinerators in which they were burnt. These are all facts which require to be seen to be fully appreciated.

Undeniably the V-2 had set in motion a leap in technological development that has gone on to shape post-war history and our modern world. Yet the German rocket programme came at an inconceivably high price in terms of the loss of life. The story of the Mittelwerk is one written in human suffering and misery and the mathematics reveal a chilling statistic. Each V-2 missile came at the price of six human lives. In fact more people died in building the V-2 weapons than were killed by their deployment and it has been suggested that the main product to come from tunnels of Mittelwerk was not the V weapons, it was death itself. Naturally the Fedden team was in sombre mood after its descent into the darker regions of human depravity. In the Final Report Fedden wrote: ‘This terrible and devilish place has now passed into Russian hands and it is sincerely hoped that our Allies will deal with it in a proper and adequate manner.’

They did just that. As with the other Allies before them the Russians took whatever technology was of value. Then in 1948 the south portal to Tunnel A was blown up and the Mittelwerk and its dark history lay largely forgotten for several decades. In 1991 the tunnel complex was designated by the Germans as an historic site to protect it from further damage by surface mining in the area. There is now a small museum area in the southern part of tunnel A, with access via a transverse tunnel. Many parts of the underground site remain inaccessible and some chambers, including Hall 41, are partially or completely submerged under water. A memorial to the thousands who died has been created at the site of the Mittelbau-Dora camp, but the legacy of the Mittelwerk does not rest there. The on-going story of the post-war exploitation of the secret Nazi rocket technology and the competition between the former Allies to grab the best of the German scientists, and their involvement in the use and treatment of a slave workforce, is continued in Chapter 12.

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