Lenses bend light in useful ways. concave vs convex - convex vs concave lenses for kids, light and lenses. Most devices that control light have one or more lenses in them (some use only mirrors, which can do most of the same things that lenses can do)
But since 1957, optics has also been an important part of the Space Age, starting with ground-based telescopes used to track rockets and satellites. Soon after there were Earth satellites with cameras, telescopes, and other optical instruments, many to look back at Earth, and many more to look at the stars and planets. A little later the US and the then Soviet Union also started to send spacecraft out of Earth orbit to visit the Moon, Venus, Mars, and eventually all the planets except Pluto (a NASA probe is on its way to Pluto now, due to arrive in 2015).
The Hubble Space Telescope is perhaps the most famous space-based optical system, and several engineers at ORA actually worked on the design and other aspects of the repair optics. We even won a NASA Public Service Group Achievement for this and other space-related work). See this website to learn more on how the Hubble works.