Fiber Optic Sensing Systems (FOSS) for Expendable Launch Vehicles

High-definition fiber optic sensing (HD-FOS) will enable dramatic reductions in the size, weight, and power of flight instrumentation for expendable launch vehicles (ELVs). Luna’s distributed fiber optic sensing yields thousands of data points per sensor, with spacing between points as small as 0.65 mm. Luna’s optical frequency domain (OFDR) sensing can employ either fiber Bragg gratings (FBG) or Rayleigh backscatter in unaltered telecommunications grade optical fiber, which is orders of magnitude less expensive. During Phase I, Luna identified heterogeneous silicon photonics as the optimal system architecture for deployment of HD-FOS in launch vehicles. Luna also developed a new technique for simultaneous strain, temperature, and liquid level sensing with a single embedded fiber in a composite overwrapped pressure vessel (COPV). A COPV was fabricated with embedded distributed strain and temperature sensors and Luna successfully demonstrated structural health monitoring (SHM) and liquid level sensing. During Phase II, Luna will design and prototype the miniaturized fiber optic interrogation system, further develop the new sensing techniques, and demonstrate SHM and liquid level sensing in a COPV structure that is representative of ELV propulsion systems.