This effort involves development of the fiber-optic cablefeedthrough and sealing for sensor and multiplexed fiber- optic data busconcepts in cryogenic liquid propulsion system environments. Thisdevelopment includes assessment of current sealing material andtechniques for adequacy in meeting cryogenic liquid propulsion systemrequirements; a new method to construct the hermetic seal fiber-opticfeedthrough; and a method to develop the fiber-optic backshellsurvivability against propulsion system environments.These results would be useful to manufacturers of both civilian ormilitary equipment to improve their reliability, accuracy ofmeasurement, and data transmission.fiber-optic, sealing, temperature, vibration, feedthrough, cable,pressure, backshell