Glass has played a central role in space exploration since Galileo fashioned his first telescope in the early 1600s — and in so doing, opened up a world of limitless discovery.
Having learned that the layering of curved glass pieces greatly magnified a distant image, the Italian physicist devised a method for grinding convex and concave lenses and created a wooden tube to hold them in place. His subsequent studies of the nighttime sky led to the birth of modern observational astronomy, and an ever-deepening understanding of the Earth’s role in our complex solar system.
More than 400 years later, glass remains at the heart of humankind’s growing understanding of space and of the Earth itself.
The highly sophisticated telescopes in launched satellites or earthbound observatories depend on large, curved glass mirrors to reflect light and funnel it to the observer’s eye — whether that observer is a ground-based astronomer or a complex digital camera and analytics system in space. The larger the mirror, the more light the telescope can collect; and the smoother the surface, the more accurate the image of the far-away object.
Glass, when manufactured in some of today’s complex processes, has another property not found in any other material: Extreme thermal stability.
All materials have a tendency to change in volume when exposed to temperature changes. Ordinary glass does, too. But a process known as vapor deposition — the formation of glass by depositing layer after layer of thin film on a growing surface, rather than cooling a molten liquid — enables the creation of a titania-doped glass that avoids these expansions and contractions to a remarkable degree.