Arnold Theodore Nordsieck (5 January 1911 – 18 January 1971) was an American theoretical physicist. He is best known for his work with Felix Bloch on the infrared problem in quantum electrodynamics. He developed the inertial electrostatic gyroscope (ESG) used as part of the inertial navigation system of nuclear submarines that allows them to remain underwater without having to surface to ascertain their location.
https://en.wikipedia.org/wiki/Arnold_Nordsieck