Among those on the ground at Peenemunde were Walter Dornberger, noted rocket expert Werner von Braun, and Nazi female test pilot Hanna Reitsch, who later claimed to have slept through the raid. Some markers were dropped too far south, and ultimately a number of buildings remained undamaged, while tragically many bombs hit the forced labour camps, killing between 5-600 prisoners. Sufficient damage was caused to delay the V-weapons programme for some months however, and the senior engineer Dr Walter Thiel was among the dead.