Fritz K. Mueller was a German engineer

Engineer

An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...

.

Mueller was hired by Kreiselgeräte Company in 1933. He developed the PIGA accelerometer. and worked on gyroscope

Gyroscope

A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. In essence, a mechanical gyroscope is a spinning wheel or disk whose axle is free to take any orientation...

s for the German Navy. Later on, he worked on the guidance and control system for the A3 test rocket, the A5, and the A4 (V-2

V-2 rocket

The V-2 rocket , technical name Aggregat-4 , was a ballistic missile that was developed at the beginning of the Second World War in Germany, specifically targeted at London and later Antwerp. The liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known...

) ballistic missile.

Under Project Paperclip, Mueller emigrated to the United States on 16 November 1945 with the Argentina group. There, he worked on developing guidance systems for the PGM-11 Redstone, PGM-19 Jupiter, MGM-31 Pershing, and the Saturn I

Saturn I

The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...

 missiles.
In 1960 Mueller left NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

for private industry.