OFS-embedded smart composites: OFDR distributed sensing for structural condition and operation monitoring in spacecraft propellant tank

Spacecraft and launcher development has recently focused on new design concepts employing intelligent propulsion systems, enabled by advanced AI-based paradigms for operations and condition monitoring (OCM) and structural health monitoring (SHM). The main challenge, however, remains providing abundant sensing data points to ensure reliable OCM and SHM processes for effective onboard systems control. This paper presents a case study on a smart spacecraft propellant tank prototype manufactured through carbon fiber filament winding and additive manufacturing of carbon fiber-reinforced polymer, using a Distributed Optical Fiber Sensor (DOFS) system. The optical fiber sensors (OFS) embedding technique is discussed, highlighting methods to optimize temperature isolation from strain variation effects. Composite structure post-processing considerations are also addressed for compatibility with acrylate-coated fibers. Thermal test results, using a high-backscattering OFS interrogated by a Luna ODiSI-6000 OFDR system, are presented.