Mirror for James Webb Space Telescope approved Sep 11, 2003 ( taken from SpaceFlightNow )

NASA today announced a major milestone in the development of the James Webb Space Telescope (JWST), the selection of a beryllium-based mirror technology for the telescope's 6.5-meter primary mirror.

An artist's concept of the James Webb Space Telescope. Credit: ESA

The JWST prime contractor, Northrop Grumman, Redondo Beach,Calif., recommended to NASA the mirror technology, suppliedby Ball Aerospace & Technologies Corporation, Boulder,Colo., be selected for the JWST primary mirror.

Northrop Grumman made the recommendation following adetailed process that took advantage of insights from apanel of experts representing the contractor team, NASA andthe science community. Two mirror technologies, berylliumand ultra low-expansion glass, were tested, and theirimplementation plans were thoroughly reviewed during a six-month evaluation. Technical performance, manufacturingschedule, facilities, staffing, and cost were factors takeninto consideration.

"We selected beryllium because the review panel rated it as the highest-performing, lowest-technical-risk solution," said David Shuckstes, Northrop Grumman Space Technology JWST program manager. "Beryllium also has demonstrated an impressive track record operating at cryogenic temperatures on space-based telescopes. This selection of beryllium positions the program for successful initiation of optic development."

Review panel member Matt Mountain, director of the Gemini Observatory in Hawaii and Chile and the JWST Science Working Group's representative, said, "The review process has resulted in a very rigorous and transparent examination of the key issues, encompassing performance, vendor capabilities, schedule and cost risks. I think the selection will ensure the Observatory's primary segments will be capable of great scientific performance at the L2 Lagrange point."

Mirror production will begin within the next few months. The mirrors will be incorporated into optical assemblies, mounted onto the telescope structure and then subjected to a series of tests at cryogenic temperatures, individually and as an integrated system. 

The Observatory design features a 6.5-meter aperture primarymirror, comprised of 18 hexagonal shaped segments. Thetelescope will be 2.5 times the diameter, yet weigh onlyone-third as much, as the mirror on the Hubble SpaceTelescope. JWST will be orders of magnitude more sensitivethan ground-based infrared telescopes.

A technician is shown mounting an alignment fiducial on a hexagonal beryllium mirror segment, developed under the Advanced Mirror System Demonstrator program, which is approximately as large as the JWST flight mirror. Credit: Northrop Grumman

After launch in 2011, JWST will peer into the infrared atgreat distances to see the first stars and galaxies formedin the universe billions of years ago. A flagship mission inNASA's Origins Program, JWST will search for answers toastronomers' fundamental questions about the birth andevolution of galaxies, the size and shape of the universe,and the mysterious life cycle of matter.

NASA's Goddard Space Flight Center, Greenbelt, Md., managesthe JWST project for NASA Headquarters Office of SpaceScience, Washington. The project consists of aninternational team involving NASA, the European SpaceAgency, Canadian Space Agency, industry and academia.

Northrop Grumman is prime contractor leading a teamincluding Ball Aerospace, Eastman Kodak Company, Rochester,N.Y.; and Alliant Techsystems, Magna, Utah. The majorberyllium mirror subcontractors to Ball Aerospace areTinsley Laboratories, Richmond, Calif.; Axsys Technologies,Cullman, Ala.; and Brush Wellman Inc., Elmore, Ohio.