 This mirror is about 70 centimetres in diameter and it's curved to a very particular shape within fractions of a wavelength and that allows it to form an image of the right place for our instruments. So a lot of the optical instrumentation work that we do here is from astronomy telescopes where we build instruments for the largest telescopes in the world, you know, 8, 10 metre telescopes and the next generation 25 up to 40 metres in diameter. So the glass in here is used as mirrors and it's not the kind of mirror that you have in your bathroom. We actually coat the first surface of the mirror. In this instance it's coated with silver. You can also use aluminium or gold. The glass that is used here is almost similar to what you might bake with at home. It's very similar properties and it's curved to a very particular shape within fractions of a wavelength and that allows it to form an image of the right place for our instruments. This telescope is going to be an optical ground station for laser communication research. That's where you use light and lasers from space to send information back to the ground. You can do that at very high speed and with great security. The value to everyone that's able to access what we have in space, you know, GPS, that goes straight to your phone. You've got earth observation data that look for flood and fire events, satellite imagery that people use all the time. So the value that ground stations like this provide is immense. So the particular glass that we use is really important because we need to match the thermal properties so it doesn't expand or contract too differently to the rest of the structure and so that it holds its shape. And it needs to be a material that you can polish so that you can get literally all the scratches out of it so that you have very good reflectivity from the surface of the mirror. Glass is definitely one of the things that makes all this technology possible. In order to achieve an optical system you need something that's transparent that you can shape very precisely and so glasses really fit that field very well.