DARPA will launch into geostationary orbit 20-meter telescope membrane

Modern military and commercial satellites involved photographing the Earth, fly into orbit a few hundred kilometers. However, their resolution of up to 50 cm per pixel. Accommodation in low orbits creates a lot of inconvenience - the satellite can not continuous shooting one point, in fact, over the right place at the right time may not be a single satellite. Geostationary orbit is devoid of these shortcomings, but with a height of 35,786 km above sea level, it is impossible to obtain an acceptable resolution images. The higher resolution requirements, the greater should be the diameter of a lens or mirror of the telescope. So much more that bring a bulky telescope into geostationary orbit yet economically unfeasible.

Project DARPA MOIRE ( Membrane Optical Imager for Real-Time Exploitation ) is designed to solve this problem using a radically new design of the telescope. Instead of lenses or mirrors therein are thin transparent membrane with microscopic grooves concentric to focus the rays of light diffraction. The effective diameter of this diffraction lens is 20 meters. When folded, the telescope is compact enough that it can be lifted into orbit launch vehicle class Atlas-5. Resolution membrane telescope will be 2, 5 meters per pixel in a field of 10 to 10 km. The telescope will transmit the image to the ground in real time at 1 frame per second. It can be sent to almost any point visible from orbit of the Earth, there are several of these telescopes will lay virtually the entire surface of the planet.



One of the sections of the prototype telescope MOIRE i>

While the image quality membrane telescope smaller than the refractor or reflector of the same size, this is offset by its small mass. Telescope traditional construction with similar characteristics would weigh about seven times more. MOIRE telescope will be the largest optical telescope in the world. The diameter of the Hubble Space Telescope - 2, 4 meter telescope Джеймс Webb , which is to be launched in 2015, will have a mirror diameter of 6, 5 meters. Even крупнейшие ground-based telescopes have a smaller diameter. Only in 2020 it is planned commissioning of the Giant Magellan Telescope with a mirror diameter of 24, 5 meters.



Size comparison MOIRE with major space and ground-based telescopes. I>

The main contractor of the project are MOIRE US Air Force Academy and the corporation Ball Aerospace & Technologies. Today successfully completed ground testing of the prototype 5-meter telescope. Although the main purpose of MOIRE - military intelligence, it is possible that the experience gained during its creation, and will be used for the construction of telescopes for astronomical observations, because telescopes Кеплер and the James Webb Space Telescope - also the development of Ball Aerospace & Technologies.



Source: habrahabr.ru/company/nordavind/blog/205132/