An incremental verification approach will be used to reduce risks. Performance parameters are tested incrementally as the observatory is integrated to increase the confidence in the final verification. Institute staff support some tests at the component level (e.g., testing of instrument detectors), but become more involved in I&T starting at the instrument level. Each instrument has its own I&T program, starting with engineering models and then flight models.
These tests occur at the individual instrument sites: FGS and NIRISS at the David Florida Lab in Canada, NIRSpec at the Astrium facility in Germany, MIRI at the Rutherford Appleton Laboratory in England, and NIRCam at the Lockheed Martin Facility in the US. The instruments are then brought together in the Integrated Science Instrument Module (ISIM), which has its own I&T program at Goddard Space Flight Center (GSFC). Once the ISIM and telescope optics are mated, there is an additional I&T program at Johnson Space Center (JSC). Institute staff support the tests at the instrument, ISIM, and ISIM+optics level by direct participation in test planning, test staffing, and data analysis.
The testing of the combined ISIM+optics is particularly impressive, and it occurs in Chamber A at JSC, which was notably used for testing of the Apollo program. This huge chamber will be outfitted with helium shrouds to simulate the thermal environment of the JWST orbit around Sun-Earth Lagrange point 2. A test stand will hold JWST right-side up and provide gravity compensation of the telescope structure. Test equipment at the center of curvature will measure the phasing of the mirrors before and during the thermal vacuum tests. ITT, a Northrop Grumman corporate partner, will oversee the testing. Besides supporting the JSC tests in general, Institute staff are also supporting the development and testing of the multi-wave interferometer used for the center of curvature measurements.
