We developed pressurised window requirements, designs, and verification methodology for manned spacecraft. We were required to improve and extend structural verification and fracture establishing a feasible structural integrity approach for design, verification and acceptance of critical pressurized glass window panes. An initial crack could lead to larger fractures and the larger the pane of glass the more likely such flaws are to be present.
The study developed a rigorous test system including numerical modelling, bending tests with applied pressure and acceptance test where the candidate pane was scrutinised for cracks.
We were required to generate a structural verification guide for pressurised windows, incorporating best practice and lesson learned about window verification methodology. We reviewed existing requirements and current state-of-the-art in spacecraft window design, following detailed procedures prescribing the analysis, inspection and testing of windows. Design work included an experimental programme to assess and refine the verification and mechanical characterisation methods at material level. Results of the material characterisation testing were applied to the design of a breadboard window assembly and development of a test campaign. The breadboard window was subjected to analysis, inspection and a test campaign – comprising qualification and acceptance tests on two glass panes. We produced a structural verification guide; benefitting all future window developments.
We have improved and extended structural verification and fracture control methodologies and requirements for the verification and acceptance of manned spacecraft windows. The project has been completed successfully with expertise having been developed in the areas of glass characterisation, inspection and testing.