Speakers
Description
This paper presents a transient thermal analysis with integrated electrical power assessment of the Spacecraft Orbital Transfer and Return Vehicle (OTRV) using TAITherm, with particular emphasis on Spacecraft thermal control and battery thermal management during orbital operations. Spacecraft incorporates both active and passive thermal control systems, including a fluid-loop heat transport system, thermostatically controlled heaters, multilayer insulation (MLI), and radiator systems including a variable-emissivity radiator. The thermal mathematical model incorporates Spacecraft geometry, material thermo-optical properties, conductive interfaces, internal heat dissipation, and the relevant thermal-control components. The orbital thermal environment accounts for direct solar radiation, Earth infrared emission, albedo, eclipse transitions, Spacecraft attitude, and mission-dependent orbital conditions.
Multiple orbital conditions and operational modes, including safe mode, detumbling, and payload operations, are analysed to determine Spacecraft and subsystem temperature excursions and identify limiting hot and cold cases. Particular attention is given to the battery subsystem, where transient temperatures are assessed against operational limits. Battery heater-control strategies are evaluated in terms of required heater power, duty cycle, and energy consumption. The contribution of the fluid-loop system and radiator configuration to Spacecraft heat transport and heat rejection is considered as part of the overall thermal-management strategy.
The simulations are performed using the finite difference-based solver TAITherm for three-dimensional transient thermal analysis, including multi-bounce ray-tracing view-factor calculations. The thermal analysis is coupled with the Spacecraft's flexible photovoltaic arrays to account for the interaction between solar-array temperature, photovoltaic power generation, Spacecraft power consumption, and battery energy balance. Transient photovoltaic output is evaluated considering solar incidence angle, Spacecraft attitude, self-shadowing, eclipse periods, and temperature-dependent cell efficiency. The generated electrical power is used to supply Spacecraft loads and charge the battery, enabling the thermal and electrical energy behaviour to be evaluated over a common orbital timeline.
The integrated analysis enables the identification of thermally critical orbital and operational conditions, assessment of component and battery thermal margins, and evaluation of the influence of eclipse periods and operational modes on battery temperature and heater demand. The model supports assessment of the combined active and passive thermal-control architecture, including heater operation, fluid-loop heat transport, insulation, and radiator performance, together with battery heater sizing and heater-energy requirements. The resulting methodology provides a Spacecraft-level approach for evaluating the coupled thermal management, battery thermal performance, and electrical energy balance of Spacecraft during orbital operations.