Mittelwerk (; German for "Central Works") was a German World War II factory built underground in the Kohnstein to avoid Allied bombing. It used slave labor from the Mittelbau-Dora concentration camp to produce V-2 ballistic missiles, V-1 flying bombs, and other weapons.
Mittelwerk GmbH
On the night of 17/18 August 1943, RAF bombers carried out Operation Hydra against the Peenemünde Army Research Center where V-2 development and production was being carried out.
On 19 October 1943, the German limited company Mittelwerk GmbH was issued War Contract No. 0011-5565/43 by General Emil Leeb, head of the Army Weapons Office, for 12,000 A-4 missiles at 40,000 Reichsmarks each.
Mittelwerk GmbH also headed sites for V-2 rocket development and testing at Schlier (Project Zement) and Lehesten. Beginning in May 1944, Georg Rickhey was the Mittelwerk general manager, Albin Sawatzki was the Mittelwerk technical director over both Arthur Rudolph's Technical Division (with deputy Karl Seidenstuecker) and Hans Lindenberg's 50 engineers of the quality control group located at Ilfeld. Other Mittelwerk/Ilfield engineers included Magnus von Braun in turbopump production, Guenther Haukohl who supervised V-2 production after helping design the assembly line, Eric Ball (assembly line), Hans Fridrich, Hans Palaoro and Rudolph Schlidt. The facility had a communications staff under Captain Dr Kühle, an Administrative Division run by Börner under Mittelwerk board member Otto Karl Bersch, and a Prisoner Labor Supply office (Brozsat). Hannelore Bannasch was Sawatzki's secretary. Wernher von Braun, who was involved in the planning of the facility, initially remained in Peenemunde but was in charge of quality control at the Mittelwerk. He worked closely with both Sawatski and Rudolph, and by his own admission visited the Mittelwerk "10 or 15 times" including an extended stay during the hellish construction period in the fall of 1943.
Other projects
In July 1944, Hans Kammler ordered the North Works (Nordwerke) to use cross-tunnels 1–20 for a Junkers jet and piston engine factory, leaving cross-tunnels 21–46 for Mittelwerk GmbH. During February–April 1945, the Nordhausen plant built Taifun anti-aircraft missiles and Heinkel He 162 jet fighters and put into operation a liquid oxygen plant. The plant was the Eber project and used equipment evacuated from the Watten bunker and elsewhere to build Heylandt liquid oxygen generators; the 15 generators were nearly complete when the site was captured. The Mittelwerk also contained equipment for producing jet fuel, and in an emergency 1944 decentralization program (named Geilenbergprogramm after Edmund Geilenberg) started the "Cuckoo" project, an underground oil plant to be "carved out of the Himmelsburg" North of the Mittelwerk. In early February 1945, Wernher von Braun and his team moved from Peenemunde to Bleicherode where, under Hans Kammler's orders, he was responsible for weapons production at multiple underground sites, some operational and others still on the drawing board. Most were never completed. For example, plans for V-2 rocket plants (the Southern Works near Friedrichshafen and the Eastern Works near Riga) were never fulfilled.
V-1 flying bomb assembly began during October/November 1944 in the South end of tunnel A. At the end of January 1945, 51 V-1s were shipped from a dispersed Fieseler factory in Upper Bavaria (code name Cham) to the Nordhausen plant for completion. After a second V-1 factory at Burg was closed, the Mittelwerk Werk II in February 1945 was the only factory producing V-1 flying bombs, and a total of 2,275 V-1s were built by Werk II from September 1944 until April 1945.
Although there has long been speculation about other "exotic" weaponry being constructed or stored at Mittelwerk, evidence of this is scarce. For example, Richard Overy notes in The Bombing War - Europe 1939-1945 (2013): "There is some evidence that small spherical bombs containing radioactive waste were stored in the Mittelbau-Dora works [...], but it is not conclusive."