HUNTSVILLE, Ala. (AP) -- Fritz Mueller, a developer of the gyroscope that helped power spaceflight to the Moon, died Tuesday of congestive heart failure. He was 93.

"Old-timers remember Fritz as a pillar in the evolution of mankind's space traveling ability during the past century," said Ernst Stuhlinger, one of the chief administrators on the von Braun rocket team.

Mueller met von Braun while working in Berlin in 1935, which led to his successful career in the United States.