Transit-O 25 & 31

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. The Transit-O series had one important change: Hysteresis rods were installed on the solar panels to dampen the residual motion after the satellite despin operation in orbit following launch).