Igniter, Pneumatic and Valve Tests - May 14th–22nd, 2023
This campaign combined five igniter trials, a revised igniter geometry, pneumatic leak checks and pressure tests of Spender's valves.
Igniter tests
Tests 1 and 5 fired as intended. Tests 2 and 3 stopped at E-match failures. Test 4 ejected its thermocouple, and only test 1 produced valid traces from both thermocouples. The igniter head or end cap also lifted during several firings.
The tested outlet pattern had doubled the number of holes while reducing their diameter from 4 mm to 2 mm. That change halved the total outlet area and increased internal pressure. The grain was also too close to the flame separator, which restricted redirection of the flame and contributed to cracking.
Revised igniter
A follow-up prototype used eight 4 mm holes in two rows and fired successfully. The next revision specified a larger grain, thinner walls, an air gap at the flame separator, better thermocouple retention and dual E-matches.
Pneumatics and valves
The upper and lower pneumatic assemblies passed their leak checks. A later impact and vibration test, performed while the system was pressurized, measured approximately 0.7 psi per minute of pressure loss. All valves then passed pressure testing, including the valve involved in the January scrub. That result confirmed that the January event came from the missing packing hardware, not a damaged valve.
