Recent milestones in the Webb project include final delivery of all four science instruments to the Goddard Space Flight Center (GSFC). The NIRSpec and NIRCam instruments joined MIRI and FGS/NIRISS in the fall of 2013 at GSFC. The instruments have become part of the Integrated Science Instrument Module (ISIM) and are undergoing a series of cryogenic vacuum testing there. The chamber in which the ISIM sits simulates the cold vacuum of deep space; the testing sends commands to and from the different instruments to assess the behavior of the integrated system (instruments, electronics, structure) under these conditions. As of July 2014 the second test is underway; this is the first time all the ISIM systems have been tested together. A third and final test of this configuration is planned in 2015.
Preparations are currently underway for the next phases of integration and testing. Once the ISIM tests at Goddard are completed, the next testing step involving the instruments is to integrate the ISIM with the mirror components and test the Optical Telescope Element and Integrated Science (OTIS). All 18 of the JWST primary mirror segments have been completed and delivered to Goddard; the last three arrived in December 2013. Chamber A at Johnson Space Center (JSC) must be readied for these OTIS tests (planned for 2017): modifications to the chamber are necessary to accommodate the temperatures and vacuum conditions for the test and avoid stray background light that would interfere with the testing.
Other parts of the observatory are coming together.The sunshield on JWST serves the important role of reducing the thermal background and scattered light that the mirrors and instruments will experience, to enable high sensitivity astronomical observations. Full-scale engineering versions of these membranes have been constructed as of Fall 2013, and testing of the tennis court-sized, five layered sunshield is currently being done to confirm that it can withstand launch and deployment in space and retain its expected shape. The Primary Mirror Backplane Support Structure (PMBSS) is the structure that supports the 18 primary mirror segments and instruments; its assembly has also been completed and it underwent testing at Marshall Space Flight Center (MSFC) in Alabama in 2013. It is the largest single structure on the observatory. Testing the assembly of the components that make up the spacecraft bus, which provides many of the support functions to the observatory, are also underway at Northrop Grumman Aerospace Systems (NGAS) facilities in Redondo Beach, CA.
The project has created a new web page with an on-line table that summarizes recent accomplishments. The project will update this web site approximately once per month.
Please follow the Project History link if you want more detailed information on the history of the conception and development of JWST.