December 16, 2009
Successful Design Reviews, Risk Reduction and Flight Hardware Manufacturing Continue to Move Program Forward
REDONDO BEACH, Calif. -- NASA's James Webb Space Telescope reached some notable milestones in several important areas in 2009, making steady progress towards its expected 2014 launch date. The Observatory is being designed and developed by Northrop Grumman Corporation (NYSE:NOC) under contract to NASA Goddard Space Flight Center.
The telescope capped its 2009 achievements with the first primary mirror segment meeting flight specifications at ambient temperatures, the result of a manufacturing process begun six years ago. The mirror segment was successfully polished to an accuracy of less than 20 nanometers, or smaller than a millionth of an inch. This ensures that when the mirror cools to cryogenic temperatures it will change its shape into the exact optical prescription needed. The test was completed within three days of the original schedule.
The mirror segment is an engineering development unit that paves the way for the polishing and testing of the A1 flight mirror and the rest of the 18 segments, which will comprise the giant 6.5-meter (21.3 ft.) hexagonal mirror. After polishing, the segments will be sent
to the X-ray and Cryogenic Facility at the Marshall Space Flight Center in Huntsville, Ala., for verification.
Another significant milestone came in October, when the Optical Telescope Element (OTE), the eye of the Observatory, passed its critical design review, which verified that it will perform as planned. The OTE now is ready to move to the manufacturing phase and integration
of all subsystems.
Observatory manufacturing and testing have progressed steadily this year. The OTE subsystems that are in full production include the secondary mirror assemblies and aft optical assembly, which contains the tertiary mirror and fine steering mirror. The primary mirror segment assemblies also are in full production. The backbone of the telescope, which supports all of the telescope subsystems, is in the early stages of production.
In May, testing was completed on a model of the Observatory's "core" section to validate its sophisticated thermal modeling and design. The core test article was cooled passively to as low as -414 degrees Fahrenheit (slightly above absolute zero) and met test objectives. The core model is a thermal facsimile of the Webb Telescope's central region and consists of the top portion of the spacecraft bus, deployable tower, a truncated but fully tensioned five-layer sunshield, optical telescope element backplane support frame, integrated science instrument module (ISIM) compartment, cable trays, thermal management systems, and ISIM electronics compartment.
The membrane management system for the Observatory's five-layer, tennis-court-sized sunshield passed a preliminary design review in February. Cryotesting on a one-third scale model began in November. Other notable achievements include the primary mirror backplane support structure and ISIM both successfully completing critical design reviews. The spacecraft passed a preliminary design review and completed thruster flight acceptance tests.
Also built this year at Northrop Grumman's Redondo Beach, Calif. space systems manufacturing facility was a full-scale simulator, a key element in the company's extensive test and verification program. The simulator, consisting of the telescope's primary backplane assembly and the sunshield's integrated validation article, was built to develop
the Webb Telescope's hardware design and to give technicians experience handling large elements in advance of working with the actual flight hardware.
The simulator relies on incremental verification, testing, and the use of crosschecks to ensure that the final end-to-end Observatory test is a confirmation of the expected results. Northrop Grumman's approach emulates its highly successful Chandra X-ray Observatory test and verification program.
The James Webb Space Telescope is the next-generation premier space observatory, exploring deep space phenomena from distant galaxies to nearby planets and stars. The Webb Telescope will give scientists clues about the formation of the universe and the evolution of our own
solar system, from the first light after the Big Bang to the formation of star systems capable of supporting life on planets like Earth. Expected to launch in 2014, the telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.
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