In-orbit demonstration of fiber optic sensors based on Bragg gratings

Abstract

FIBOS (FIber Bragg gratings for Optical Sensing) is one payload used to monitor temperature and strain during a nanosatellite mission. Description of the payload and in-orbit results are presented. Fiber Bragg Grating (FBG) sensors offer attractive and robust solutions for temperature and pressure monitoring in a spacecraft. Moreover, they can be embedded in composite structures or attached on their surface for structural health monitoring during the entire life cycle of a satellite, from integration and qualification tests, to final operation. FIBOS contains two FBGs to measure temperature and strain during one space mission called OPTOS. The mission, developed by INTA (Instituto Nacional de Técnica Aeroespacial), was a low-cost nanosatellite based on a triple configuration (3U) of the popular Cubesat standard. OPTOS was launched in November 2013 and was operative during two years. Its main goal was to validate and demonstrate the suitability of novel technologies for space applications inside a miniaturized area with big restrictions in terms of mass and power consumption. This work describes the payload components. FIBOS contains commercial off-the-shelf (COTS) parts like a monolithic tunable laser and a conventional InGaAs pigtailed photodiode. The optical sensor head includes two FBGs mounted onto a steel mechanical structure to monitor temperature and strain. Results of the mission are presented. Measurements performed during the operation in-orbit show good agreement with calibration data performed on earth inside a thermalvacuum chamber (TVC). This paper shows a demonstration of a fiber optic sensor based on FBGs in space environment.