The JWST backplane stability test article: a critical technology demonstration

The unprecedented stability requirements of JWST structures can only be conclusively verified by a combination of analysis and ground test. Given the order of magnitude of the expected motions of the backplane due to thermal distortion and the high level of confidence required on such a large and important project, the demonstration of the ability to verify the thermal distortion analysis to the levels required is a critical need for the program. The demonstration of these analysis tools, in process metrology and manufacturing processes increases the technology readiness level of the backplane to required levels. To develop this critical technology, the Backplane Stability Test Article (BSTA) was added to the JWST program. The BSTA is a representative substructure for the full flight backplane, manufactured using the same resources, materials and processes. The BSTA will be subject to environmental testing and its deformation and damping properties measured. The thermally induced deformation will be compared with predicted deformations to demonstrate the ability to predict thermal deformation to the levels required. This paper will review the key features and requirements of the BSTA and its analysis, the test, measurement and data collection plans.