Surveyor program
In 1966 at Hughes Aircraft Company (HAC) in El Segundo, California, Frimtzis was the assistant manager of the Trajectory Analysis Department on the Surveyor program. The department developed the trajectories for all Surveyor spacecraft flights. Additionally, he managed the Liftoff and Translation experiment. It proved that spacecraft engines can be reignited on the lunar surface, a task which was not a Surveyor technical requirement. The Surveyor was the first unmanned spacecraft to soft land on the moon. In addition to collecting and analyzing lunar samples, and photographing the surface of the moon, it proved the principle of soft landing a spacecraft on the lunar surface, and selected the landing corridor for the future Apollo manned flights.