V-2 rocket offensive began on 8 September 1944, when "Lehr- und Versuchsbatterie No. 444" () launched a single rocket guided by a radio beam directed at Paris. Wreckage of combat V-2s occasionally contained the transponder for velocity and fuel cutoff. The painting of the operational V-2s was mostly a ragged-edged pattern with several variations, but at the end of the war a plain olive green rocket also appeared. During tests, the rocket was painted in a characteristic black-and-white chessboard pattern, which aided in determining if the rocket was spinning around its longitudinal axis. The original German designation of the rocket was "V2",
Mittelbau-Dora concentration camp prisoners, but also with foreign forced labourers, POWs and drafted Germans. On 8 September 1944, the first V-2 built at Mittelbau was successfully launched at London. That month, production hit 600 units, a pace that was kept up until February 1945. Besides the main camp Dora, housing an average of 15,000 prisoners, the main subcamps were "Lager Ellrich" (established 2 May 1944, averaging around 8,000 prisoners), "Lager Harzungen" (1 April 1944, 4,000 prisoners), "Lager Rottleberode" (13 March 1944, 1,000 prisoners) and the SS construction units III and IV (totaling around 3,000 prisoners, distributed among several small camps along a newly