ble values of m and n for values of m up to 20, was reported as progress through August 1953 [167], [168]. In later works by other researchers, these PN sequences were called shift-register sequences or linear-recurring sequences as a reminder of their particularly convenient method of gener- ation, and were also termed m-sequences since their period is maximal. On January 18, 1954, a JPL PN radio system was operated over a 100-yard link and two independent commands were communicated. Initial synchro- nization was achieved with the aid of a land line which was disconnected after sync acquisition. The system was able to withstand jammer-to-signal power ratios of 15-20 dB before losing lock, against a wide variety of jam- ming threats. This test was the assurance that JPL engineers needed regard- ing the practicality of SR-SS communications. At this point, work on the command system was temporarily dropped and a major effort was begun to optimize a pure ranging system, called the Scrambled Continuous Wave (SCW) system, which consisted of a "very narrow-band CW system scrambled externally by a PN sequence." On July 27, 1954, Corporal round 1276-83 carrying an SCW transponder was launched at White Sands Proving Ground. The transponder operated suc- cessfully from takeoff to near impact seventy miles away, providing range and range rate without loss of lock in the synchronization circuitry. Rechtin, engineer Walter Victor, and Lehan (who left JPL in 1954) later filed an invention disclosure based on the SCW system results from this test, and called the system a COded DOppler RAdar Command (CODORAC) system. This acronym was used to describe the radio guid- ance systems developed for the Sergeant and later the Jupiter missiles in the 1954-58 time frame. Throughout this period one of the major problems in establishing one-way communication to a missile was to make the PN generator tough enough to withstand high temperatures and vibrations as well as small and light enough to fit into the missile design. A variety of devi