Show notes
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 into clock accuracy improvements for space use and how he initially doubted such improvements were possible—until he realized it required different physics principles. When asked about using GPS on the Moon and Mars, both Peter and Lee explained the limitations. While GPS signals can be detected on the Moon, a local positioning system might be more practical. On Mars, environmental challenges like dust storms complicate signal transmission. Later, Peter discussed the Clementine mission, which mapped the Moon using cameras initially developed for the Strategic Defense Initiative. Lee noted how Clementine’s data later supported encryption and high-speed networks in education and defense. They also addressed early GPS launches—Peter developed a cost-effective launch solution using surplus ICBMs, and Lee praised Peter’s innovative "bow and arrow" launch method.
Peter and Lee described the technical precision required for GPS accuracy, including clock modulation and carrier frequency synchronization. Applications like tectonic plate monitoring were among the early uses. Concerns were raised about GPS vulnerability in nuclear environments and its role in nuclear targeting. Peter expressed alarm over the potential for nations like North Korea to disrupt GPS via high-altitude nuclear detonations. We ended with a discussion on hypersonic weapons and the challenges of tracking them due to plasma interference with electromagnetic signals.
The program concluded with a listener question about whether today’s education system can produce the kind of innovation seen in early satellite development. All three guests expressed concerns, citing the need for more emphasis on freedom to explore and pursue self-education. Don’t miss all of their comments on this important question.
Listeners, feel free to post comments on this program and for our guests on both TSS blog page but also using the comments on our Substack page, doctorspace.substack.com.
The audio only version of this program is here:
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