MIL-DTL-38999 Hermetic Connectors: Glass-to-Metal Seals
MIL-DTL-38999 hermetic circular connectors use glass-to-metal seals rather than elastomeric seals to provide pressure-tight sealing for flight-critical applications .
Why Hermetic Matters:
Standard 38999 connectors seal against environmental exposure (moisture, humidity). Hermetic 38999 connectors seal against pressure differential, with specified helium leak rates.
When Hermetic Connectors Are Required:
Avionics bays pressurized for high-altitude flight
Cryogenic systems that must hold vacuum (satellites, instrumentation)
Hazardous-location equipment that must contain ignition
Fuel-system or hydraulic bulkheads crossing pressure boundaries
Test cells, vacuum chambers, and altitude simulators
Longevity Advantage:
Glass-to-metal seals do not age. Elastomers do. For 30-year program life, hermetic terminations are the only seal architecture that survives unattended.
