For all the futuristic advancements packed into modern space-based telescopes, they all still rely on the same bulky, heavy glass optics that Galileo used centuries ago. But thanks to this DARPA project, future telescopes could eventually use optics as thin as saran wrap to peer into deep space.
Glass optics are heavy, cumbersome, and a real pain to launch into orbit given their propensity for cracking under the massive vibration loads present during liftoff. DARPA hopes to sidestep this limitation with the Membrane Optical Imager for Real-Time Exploitation (MOIRE) program, providing scientists with a potential platform for real-time video and imaging coverage of the Earth from Geosynchronous Earth Orbit (GEO).
Using membranes for space-based telescopes is not a new idea. Instead of reflecting incoming light, they instead refract it — like a Fresnel lens — focusing the light onto the telescope's imaging device. However, the resolving capabilities of conventional membrane optics are far below that of glass and have an overall optical efficiency of barely 30 per cent. MOIRE, on the other hand, hopes to leverage emerging technologies that would not only make orbital telescopes 86 per cent lighter and more cost-effective, but also nearly double their optical efficiency to 55 per cent. That still isn't close to the 90 per cent efficiency produced by glass optics, but it is enough to enable MOIRE to capture images using membrane-optics for the first time ever. Plus, with the weight-savings membrane optics provide, future telescopes could overcome the efficiency deficiency by simply increasing the size of the lens.
"Membrane optics could enable us to fit much larger, higher-resolution telescopes in smaller and lighter packages," said Lt. Col. Larry Gunn, DARPA program manager, in a press statement. "In that respect, we're 'breaking the glass ceiling' that traditional materials impose on optics design. We're hoping our research could also help greatly reduce overall costs and enable more timely deployment using smaller, less expensive launch vehicles."