The US military began seeking a substitute for imported mica dielectric during World War II in order to make the U.S. capacitor industry independent of foreign supply. For centuries glass had been recognized as an excellent insulator, and a special composition with dielectric properties similar to those of mica was developed. The first issue was developing a process to form the glass into very thin ribbon, and then manufacturing a capacitor in large quantities using this glass dielectric technology.

Before glass capacitors reached significant production, Germany surrendered and the war had ended. With the threat to the mica supply removed, pressure to expand production diminished until the electrical advantages of glass dielectrics vs. mica was better documented. At the time, the majority of designs that required glass capacitors were military applications. Because mica capacitors were available in tremendous quantities at much lower prices, commercial acceptance of glass capacitors was relatively insignificant, primarily because mica capacitors were available in tremendous quantities at much lower prices.

Additional research and development resulted in the marketing of the CY-style capacitor in 1951. Its stability, low noise characteristics and small size led to immediate and widespread recognition by the electronics industry — military as well as commercial.

Further material and ‘glass fusion process’ development efforts yielded the ultra-reliable CYF series of capacitors.

In less than three years, the CYFR capacitor was being mass-produced with unprecedented reliability. CYFR capacitors displayed high accuracy, reliability, stability, fire control and guidance elements for the major military and commercial programs.

NASA’s space programs have used glass capacitors for many missions over the past 50 years.

When NASA’s Mars Exploration Rover, Spirit and its twin rover Opportunity, landed safely on the planet surface, glass capacitors in the mission critical Rover Lift Mechanism Actuator and Lander Pedal Actuator Circuits allowed the Lander to open and adjust its pedals. This action enabled the Rover lift mechanism to raise the Rover, so that its wheels could be deployed in order to drive on the Martian terrain. Glass capacitors were chosen because of their reliability in an application that was unpowered for years, then instantly required to turn on and function properly (space travel), and the reliability of operating in harsh and severe conditions (Mars). The glass capacitors used in the Mars Rover mission did not experience any aging effects over time or through a variety of environments such as temperature cycling and radiation fields. They behaved in a low noise fashion so sensor circuitry data could be accurately interpreted and acted on.

The Tracking and Data Relay Satellite System (TDRSS) is a communication signal relay system that provides tracking and data acquisition services between low earth orbiting spacecraft and NASA control and/or data processing facilities. The system allows nearly continuous command and telemetry communications between ground control centers and unmanned, automated research and applications spacecraft orbiting thousands of miles above the Earth. The TDRSS permits communications with spacecraft during at least 85 percent of their orbit, without the satellite system acting as a space-based relay, communications with satellites could be accomplished only when the spacecraft are in sight of a ground station, which is only 15 percent of an orbit. The TDRSS relies on glass capacitors for Doppler shift correction in the receiver circuitry. Glass capacitors allow the receiver to have better resolution and accuracy than ceramic capacitors. The stable electrical parameters with total dose radiation coupled with zero aging and lot-to-lot temperature retraceability allowed glass to be an ideal choice for the receiver front-end circuitry. Glass capacitors help enable TDRSS receiver to maintain its center frequency and correct for frequency shift effects due to spacecraft motion.