Design, Fabrication, Testing and Validation of a Ruggedized Fiber Optic Sensing System (FOSS) for Launch Application

Fiber-optic sensors based on fiber Bragg grating (FBG) is desirable for structural health monitoring and is used for various aerospace applications such as measuring strain and temperature, where a single optical fiber can multiplex hundreds of FBG sensors. The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center (AFRC) (Edwards, California) has been developing an optical fiber-based sensing suite called Fiber Optics Sensing System (FOSS) over the past two decades. Successful strain monitoring flight demonstrations such as the NASA Ikhana (General Atomics, San Diego, California) remotely piloted aircraft and the X-56A Multi-Utility Technology Testbed (Lockheed Martin Corporation, Bethesda, Maryland) remotely piloted subscale aircraft have been performed. Interest in adapting fiber-optic sensors for aerospace applications has led to commissioning the development of a ruggedized FOSS system for spaceflight through the NASA Launch
Services Program (LSP) at the NASA Kennedy Space Center (KSC) (Merritt Island, Florida).

In this paper, a ruggedized FOSS suitable for a launch environment is discussed in detail. Thermal analysis and enclosure design will be discussed as well as environmental testing such as shock, random vibration, thermal vacuum, and electromagnetic
interference/electromagnetic compatibility (EMI/EMC). With all relevant environmental testing completed, a ruggedized FOSS unit has successfully passed all testing and is now deemed space-launch ready.