(May 23 2006)
The Webb Project passed the Systems Definition Review (SDR) in January. Two independent teams reviewed the overall quality and completeness of the system architecture, operational concepts, requirements, performance, and verification plan. Both teams were impressed with the overall quality of the work and indicated that the program was ready to move towards the Preliminary Design Review (PDR). This milestone indicates that the overall design of the observatory is sound and that detailed design can begin.
In several areas, the Webb Project is already engaged in detailed design. Actual construction has commenced on long-lead items. In particular, sixteen of the beryllium primary mirror segments are either being machined or figured at Axsys. Two of the segments are being polished at Tinsley. The science instruments are also considered long-lead items as they must be delivered to NASA more than three years before launch. All of the instrument projects have passed their preliminary design reviews. High-fidelity engineering versions are being constructed and will be used in the initial integration of the science payload and optics tests.
In addition to working on the long-lead items, the Project is focused on demonstrating the technical readiness of the new technologies that enable the Webb design. Two of the technologies, the multi-layer sunshield and the near-infrared detectors have achieved flight-ready status. Ball Aerospace is testing each step of the telescope alignment and wavefront sensing and control with a 1/6th scale model of the telescope. This summer, a team from Northrop Grumman, NASA, and the STScI will test the thermal performance of a backplane segment at cryogenic temperatures with 10 nm accuracy. The mechanical cooler for the mid-infrared instrument is the last technology to be verified in December 2006. The Project will present the results of these tests at a Technical Non-Advocate Review in January 2007. Assuming that this review is successful, the Project will have retired the major technical risks in the Webb development.