The Transit-O series of satellites that closely followed the design of Transit 5C-1 were also called “Oscars” (Oscar is the phonetic alphabet for “O”, i. e., operational). They were also called NNS (Navy Navigation Satellite) or shortened NavSat.
Polar OrbitATS 2 (Applications Technology Satellite) was a medium altitude, gravity-gradient-stabilized spacecraft designed to test new concepts in spacecraft design, propulsion, and stabilization, take high-quality cloudcover pictures, provide in situ measurements of the aerospace environment, and test improved communication systems.
Medium Earth Orbit