Episode Details

This was a special 2-hour, 16-minute Zoom program.On The Space Show website, the program is available in the audio-only format. Both video and audio are available on this Substack page.

Our discussion focused on the development and evolution of GPS and the recently declassified PARCAE satellite technology. We explored their origins, technical challenges, historical context, and how they interconnected with agencies like the NRO, NRL, and broader advances in computing and satellite technologies. The conversation covered early proposals, the declassification process, and the crucial role of timekeeping, atomic clocks, and Einstein's relativity in enabling this groundbreaking work. Our guests also shared perspectives on future applications, innovation “back in the day,” system resilience, and the shift from strategic to tactical intelligence using satellites like GRAB and POPPY.

After introductions, Richard provided an in-depth overview of our special guests and the PARCAE project. Lee began by referencing a 1957 Naval Research Laboratory (NRL) document that proposed two major satellite programs, one of which was PARCAE. He also shared that he is currently writing a book on the evolution of these systems, including GRAB, POPPY, and PARCAE.

We examined how GPS and PARCAE—two closely linked programs—emerged. GPS, which began development in the late 1950s, utilized passive ranging for uniform accuracy across satellite constellations. PARCAE evolved from early reconnaissance satellites and focused on collecting radar signals globally, especially from the Soviet Union. GPS’s ability to provide accurate geolocation greatly enhanced PARCAE’s capabilities. Lee emphasized the importance of 3D mapping and global time synchronization in improving satellite positioning accuracy. We also discussed the difficulties of orbital prediction, relativistic corrections, and the eventual declassification of GPS for civilian use. Note what our guests said about getting so much data that they were overwhelmed and the early computers could not really handle.

On the military front, we addressed how GPS was used for targeting and precision strikes. In response to a listener question, Lee explained that as early as 1966, the goal was to accurately know the location of both the user and the target to direct weapons effectively. The challenges included creating precise maps and compensating for Earth’s motion. The GPS system reached full operational capability in 1995, evolving from 15-foot accuracy in 1977 to today's much finer resolution. The conversation also covered the complexity of GPS—its integration across organizations, multiple technologies, and the development of similar systems by other nations. Our guests discussed the foundational work of pioneers like Roger Easton (Richard’s father), John Foster, Alexander Flax, Alan Berman, John McLucas, David Packard, and others.

Later, a listener asked the guests to share their educational and career backgrounds. Lee spoke about earning his bachelor’s in electrical engineering from Penn State, where he gained early experience in transistor design. His career took off when he was recruited by Singer and later the NRL after his work during the Cuban Missile Crisis. Peter, an EE graduate from Purdue, also found his way to NRL. Richard shared his own background as well. All three emphasized the importance of self-education and the freedom they had to explore ideas across disciplines—something they felt was essential to their success.

Peter reflected on GPS evolution and expressed regret about abandoning UHF transmissions, which might have enhanced performance in forested areas. Lee emphasized the need for cost reduction in future GPS upgrades and the importance of cross-disciplinary exposure for young minds. Peter recounted how Roger Easton proposed passive ranging and how Alan Berman’s expertise in atomic clocks was instrumental in advancing GPS. Peter also shared insights