Thermal Propellant Gauging,SpaceBus 2000 (Turksat 1C) Implementation

摘要

Knowledge of propellant remaining is one of the most paramount tasks whichshould be addressed in order to complete the mission of GEO satellite successfully. The paper discusses a development and implementation of the thermal propellant gauging system for Turksat IC (SpaceBus 2000 satellite). Several techniques are typically used to measure the amount of remaining propellant. The bookkeeping, PVT (Pressure, Volume, Temperature) and thermal Propellant Gauging System (PGS) are the most popular methods. Only the thermal PGS method accuracy of propellant estimation increases as propellant load decreases due to increase of temperature rise sensitivity when the tank load decreases. The method can be used for mono or by-propellant propulsion system with one or multiple tank configuration. Implementation of the developed PGS method for Turksat IC ( SpaceBus 2000) satellite is discussed by the current paper. The method consists of several steps, namely, building Tank and Satellite Thermal Models, calibration of the model using current flight data, running the integrated model for several propellant loads for each tank under identical boundary conditions, fitting flight data to simulation results and finding propellant load of the tank. Simulation includes tank temperature change (by heater and/or from sun). Along with propellant estimation, uncertainty analysis is also required in order to determine an error of propellant estimation. The current paper shows that the developed method provides a high accuracy of propellant estimation at EOL. An accurate propellant estimation at EOL is important form business point of view. Knowledge of propellant remaining allows making correct business decisions, like, timely supersinking of a satellite, optimizing profit, avoiding gap in services, etc. The current paper discusses business implications of the PGS method.