Igniter Housing Failure - July 28th–29th, 2023
An integrated igniter test was performed while preparing GAR-E and Spender for the Launch Canada campaign.
Failure
The results were inconsistent because grain size, shape and placement varied between assemblies. In the failed unit, the grain was not seated against the epoxy stop and left excessive empty volume below it. Pressure accumulated in that volume, the body acted as a small pressure vessel and the complete head separated.
Corrective actions
The next revision standardized grain dimensions and added an internal backstop or lip to hold the grain within 1–2 mm of its intended position. The thermocouple was to be epoxied rather than taped, the cap legs were to be positively retained, and the exact flight configuration was to be retested under a written assembly procedure. Additional thermocouple testing was deferred until the ignition controller was integrated because the existing firings had already established the required temperature range.
