Spacecraft Thermal Control with Variable Radiator Area
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Solution Overview
Problem
Conventional thermal control systems for satellites are limited by the need for large, bulky radiators to manage heat dissipation, which restricts the design and efficiency of spacecraft due to the fixed temperature range of radiators, leading to increased size and mass, especially for high-energy missions.
Innovation Solution
A refrigeration-based thermal control system that decouples equipment temperature from radiators, allowing radiators to operate at higher temperatures without impacting equipment functionality, using a refrigerant circulation system with evaporation, compression, condensation, and pressure reduction zones to increase thermal efficiency and reduce radiating surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional radiators are used to dissipate heat from spacecraft equipment, then heat can be removed from the equipment, but the required radiating surface area becomes very large and the system becomes bulky and heavy
Solution Approach 1:
The invention changes the temperature parameter of the radiator from conventional low temperatures (linked to equipment operating temperatures) to very high temperatures (up to several thousand degrees Kelvin). This parameter change fundamentally alters the radiation efficiency, allowing the same heat dissipation capability with a much smaller radiating surface area, since radiated power is proportional to T^4 according to the Stefan-Boltzmann law
Solution Approach 2:
The invention introduces an intermediary system (a thermal control device acting as a heat pump or refrigeration cycle) between the equipment and the radiator. This intermediary transfers heat from the equipment at moderate temperatures to the radiator where it is dissipated at very high temperatures, decoupling the equipment operating temperature from the radiator temperature and enabling compact radiator design
2Temperature
If the working temperature of radiators is limited to be lower than the maximum acceptable temperature for equipment, then equipment temperature can be controlled, but the dimensions of radiators increase significantly
Solution Approach 1:
The thermal control device acts as an intermediary that decouples the equipment from the radiator, allowing independent temperature control. The device extracts heat from the equipment at its operating temperature and rejects it to the radiator at a much higher temperature, enabling small radiator dimensions while maintaining proper equipment temperature control
Solution Approach 2:
The invention changes the operating temperature parameter of the radiator from equipment-linked temperatures to independently controllable high temperatures. This parameter change allows the radiator to operate at temperatures optimized for compact size while the thermal control device maintains equipment at their required temperature ranges
3Loss of energy
If deployable radiator structures are used to increase radiating area, then thermal control capacity can be improved, but the system becomes bulky and heavy
Solution Approach 1:
The invention changes the fundamental operating parameter of the radiator from low temperature (requiring large area) to very high temperature (enabling small area). This parameter change eliminates the need for deployable structures to increase radiating area, as the high-temperature radiator achieves the required thermal discharge capacity in a compact, fixed form with reduced mass
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution significantly enhances thermal efficiency, allowing for a radical reduction in radiating surface area, enabling more energetic missions without increasing satellite size or mass, and providing robust thermal control across various environmental conditions.
Implementation Method 1
means for circulating a refrigerant; an evaporation zone comprising means for circulating the refrigerant
Implementation Method 2
a compression zone; then to compress the resultant vapour (thus ensuring circulation of the refrigerant) and thus raising the temperature of the refrigerant
Implementation Method 3
At the compression zone outlet of the device the refrigerant in the gas state will condense in the dedicated radiating panels (condensation zone of the device), which discharge, by radiation at high temperature, the total energy into cold space
Implementation Method 4
which discharge, by radiation at high temperature, the total energy into cold space
Implementation Method 5
a pressure reduction zone comprising means for circulating the refrigerant
Data Source
AI summary
The invention relates to a thermal control device intended to dissipate the heat generated by a payload on a spacecraft, comprising a number of surfaces and including means for circulating a refrigerant. An evaporation zone (Z1) comprises means for circulating the refrigerant, a compression zone (Z2), a condensation zone (Z3) comprising at least one radiating panel, linked to a part of the means for circulating the refrigerant, including several branches and comprising means to allow or inhibit the circulation of the refrigerant within these branches so as to vary the area of the heat exchange surface in the condensation zone, a pressure reduction zone (Z4) comprising means for circulating the refrigerant. Such a device is particularly well adapted to thermal problems encountered in telecommunications satellites.