Operation Hydra was a Royal Air Force attack on the Peenemünde Army Research Center on the night of 17/18 August 1943. It was the first time a master bomber was used for the main force. Group Captain John Searby, CO of 83 Squadron, commanded the operation. It began the Operation Crossbowstrategic bombing campaign against Nazi Germany's V-weapon programme. 215 British aircrew members and 40 bombers were lost, and hundreds of civilians were killed in a nearby concentration camp. The air raid killed two V-2 rocket scientists and delayed V-2 rocket test launches for seven weeks.