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This was a ground test of the Hermes Pathfinder rocket. It occurred on Field A at 3:45 PM on November 10, 2017. It was the first use of the Pyrotechnic Piston to separate the rocket. The piston contained 1g of 4F black powder. The tender descender contained .2g of black powder. The shear pins used were not documented but were likely 2x 6-32 nylon pins and 1x 4-40 nylon pin. The rocket successfully separated, and the tender descender released the main parachute appropriately. After de-integration it was found that the Avionics Bulkhead was seriously deformed. This prevented the planned flight on November 11, 2017 from occurring.
Failure Investigation
Black Powder Sizing Investigation
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We then tried to determine the maximum force felt by the bulkhead:
Step 1: Determine pressure in the piston prior to rod extension
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FEA Investigation
Analysis Summary
To perform this analysis, we performed a static load analysis on the Avionics Bulkhead modeled in CAD as of November 16, 2017. Some notable limitations of this analysis are:
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