Will Fiber-Optic Cables Get Made in Orbit? Maybe

Flawless Photonics and Adelaide University tested whether microgravity can improve ZBLAN, a fluoride glass that could transmit light with far less loss than silica across a broad range of wavelengths. On the International Space Station, a suitcase-sized machine drew 11.8 kilometers of fiber, including a continuous 1.1-kilometer strand. Tests found that space-made step-index fiber had lower optical loss and was 80 percent stronger than comparable Earth-made fiber. Single-index samples were slightly stronger in space but showed no measurable optical improvement. The findings support the idea that reduced gravity suppresses crystallization, which weakens glass and scatters light, but show that gravity is only part of the problem.

Even the best space-made fiber achieved only about a twofold reduction in signal loss, far short of ZBLAN’s theoretical potential of roughly 100 times less loss than silica. Bubbles and defects in the glass preforms scatter light, while trace metal impurities absorb it; neither issue is solved by manufacturing in orbit. Researchers say substantially purer ingredients are essential, and that purification will be difficult and costly. The business case also depends on scaling production and automating it: the ISS is due to retire in 2030, while private or automated orbital facilities remain alternatives. Rocket soot and possible ozone damage add environmental costs. Flawless plans another ISS experiment for 2027, testing improved preforms and processing methods.