DARPA's Ultra-Light, Foldable Satellites Can See 40 percent of Earth's Surface at Once [Video]

DARPA is designing satellites with telescopes made of ultra-thin, super-light, foldable membranes. These advanced telescopes could help in many fields, from weather forecasting, disaster management to spying on the enemy.

The Defense Advanced Research Projects Agency (DARPA) advanced telescope would unfold into a gigantic eye in the space, relaying real-time images of earth from a distance from some 22,000 miles above the surface.

DARPA's Membrane Optical Imager for Real-Time Exploitation (MOIRE) has demonstrated that it is possible to create large telescopes using polymer membrane. From Geosynchronous Earth Orbit (GEO), a satellite with the latest telescope system could scan about 40 percent of the Earth's surface at once. The satellite could focus 6.2 miles by 6.2 miles at a resolution of about 1 meter, providing a real-time video of the area under scrutiny at 1 frame per second, the agency said.

Telescopes have had many changes in designs, but they still use glass and lenses. However, one can go only so far in making large-diameter glass mirrors to get a good quality image. The program plans to take the telescope design to next-level by 'breaking this glass ceiling.'

Each membrane is as thick as a household plastic wrap and works like a Fresnel lens- with hundreds of microscopic grooves of varying thickness. The membrane diffracts light and focuses it on a sensor. This pattern in then translated into an image by the satellite.

The MOIRE's latest system will have many such membranes that are packed in the form of thin petals. The entire system during launch will be only about 20 feet in diameter. Once in space, these petals will unfold, creating a multi-lens system that would be about 20 meters (about 68 feet). According to DARPA, the new telescope will be larger than any other glass-based telescope.

"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, according to a news release. "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."

Note that these membranes are quite inefficient when compared with glass. Recently, MOIRE managed to increase the membrane's efficiency from 30 percent to 55 percent.

 However, unlike glass, membranes are light and cheap to produce, meaning that scientists could create large-diameter lenses without worrying about its weight. Also, these thin telescopes would reduce rockets' payload, making launches easier and feasible.

Ball Aerospace & Technologies Corp, the prime contractor for the MOIRE program recently constructed a telescope based on the MOIRE design and tested its working ability.

"This is the first design to use transparent membranes on a large scale," said Aaron Seltzer, director of Advanced Development for Ball Aerospace's National Defense business unit, in a press release. "The result is a telescope with exceptionally low mass per unit of collecting area."