Satellite Missions

Abstract

Transit is a US Navy first generation satellite radio navigation system (the world's first), designed and built by JHU/APL - the entire development program (S/C hardware, ground support network, user equipment, etc.) was conducted within APL at Laurel, MD, USA; RCA (later named: GE Astro Space, now Lockheed Martin) was the satellite integrator starting with Oscar-18 (Transit-O-18). The program was initiated by Frank T. McClure in the spring of 1958, based on JHU/APL's Doppler tracking discoveries by William H. Guier and George C. Weiffenbach (the Sputnik orbit could be determined from RF Doppler data) and the realization of the “navigation problem” (it states: if the position of the satellite were accurately known, then Doppler data could tell an observer on the ground his unknown position). The Transit demonstration program was sponsored by DARPA (Defense Advanced Research Projects Agency) and officially begun in 1959.