Self Testing and Repairing Computer STAR

In 1960 he joined the Spacecraft Computers section of the Jet Propulsion Laboratory (JPL), California Institute of Technology, and initiated research on reliability of computing systems that originated the concept of "fault tolerance", first described in a paper presented at the 1967 Fall Joint Computer Conference.

He organized and directed the JPL STAR research project from 1961 to 1972. This effort resulted in the construction and evaluation of the experimental JPL STAR (Self-Testing-And-Repairing) computer, for which, he received U.S. Patent No. 3, 517, 171, "Self-Testing and Repairing Computer" granted on June 23, 1970 and assigned to NASA. A paper that described the JPL STAR computer won the Best Paper selection of the IEEE Transactions on Computers in 1971.

In 1969, JPL began designing a Thermoelectric Outer Planet Spacecraft, or TOPS (Voyager1 and Voyager2 missions). Outer planet missions ranged so far from the sun that solar cells would be inadequate. TOPS would carry radioisotope thermoelectric generators to provide electrical power. STAR was considered as the on-board computer for TOPS. Components built to STAR specifications later found their way into the NASA Standard Spacecraft Computer 1 (NSSC-1).