Could pre-integration tests have revealed the initial G10 truss failure mode?

Determine whether any feasible pre-integration mechanical validation procedure conducted outside the cryostat—specifically one that replicates the asymmetric vacuum plate deflection under atmospheric pressure and differential radial contraction—can reliably identify the epoxy joint failure mechanism in the initial G10 vacuum/PTC1/PTC2 mechanical truss prior to multiple thermal cycles, so as to prevent cascading truss failure in the Simons Observatory Small Aperture Telescope receiver.

Background

During early testing, the initial G10 vacuum/PTC1/PTC2 truss design—using G10 tabs epoxied between aluminum feet—experienced failure after nine thermal cycles. Subsequent analysis revealed that asymmetric vacuum plate deflection and differential radial contraction imposed higher-than-anticipated stresses at epoxy joints, leading to cascading failure.

The authors note uncertainty about whether the validation procedures performed (including LN2 dunking and hang tests) could have identified this failure mode, because those tests did not replicate the particular vacuum plate deflection present only when assembled in the cryostat.