Imaging Device Thermal Barrier for Satellite Cooling
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Solution Overview
Problem
In satellite applications, the cooling capacity is limited, leading to challenges in maintaining low dark noise and high image quality due to the size and weight constraints of radiators used for cooling imaging devices, particularly in space vehicles where a significant temperature difference between the image sensor and surroundings necessitates efficient heat management.
Innovation Solution
The imaging device employs a thermally insulating barrier with low thermal conductivity materials, such as polymers and glass, to minimize heat transfer from the warm electronics to the cold image sensor, combined with a cooling arrangement that includes a radiator element, heat exchanger, and thermo-electric cooler, allowing for efficient radiative dumping of heat into deep space, and uses optical waveguides for signal transmission to reduce electrical conductor heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large radiator is used to cool the image sensor to maintain low dark noise, then the cooling capacity and image quality are improved, but the size and weight of the satellite increase
Solution Approach 1:
A multi-layer insulation barrier is introduced as an intermediary between the image sensor and the warm electronics/compression unit. This barrier includes reflective layers and vacuum insulation that effectively block heat transfer from the warm side to the cold side, allowing the image sensor to be cooled to lower temperatures without requiring a proportionally larger radiator. The barrier acts as a thermal mediator that decouples the thermal relationship between components.
Solution Approach 2:
The satellite payload is segmented into distinct thermal zones: a cold side containing the image sensor and a warm side containing the electronics and compression unit. The multi-layer insulation barrier physically and thermally separates these zones, allowing independent temperature control. This segmentation enables the image sensor to operate at low temperatures while the electronics can operate at higher temperatures, reducing the overall cooling requirement.
2Measurement precision
If the image sensor is cooled to maintain low dark noise, then the measurement precision is improved, but the heat transfer from warm electronics to the sensor increases
Solution Approach 1:
The multi-layer insulation barrier serves as a thermal intermediary that blocks heat flow from the warm electronics to the cold image sensor. The barrier includes vacuum insulation and reflective layers that minimize conductive, convective, and radiative heat transfer. This allows the system to maintain the necessary temperature difference for low dark noise while minimizing the energy loss through heat transfer.
Solution Approach 2:
The multi-layer insulation barrier utilizes thin film structures including reflective foils and vacuum insulation layers. These thin films create multiple thermal resistance layers that effectively block heat transfer while occupying minimal space. The flexible nature of these layers allows them to conform to the compact satellite structure while providing superior thermal insulation.
3Productivity
If electrical conductors are used to transmit signals from the image sensor, then the data transmission is achieved, but the thermal conduction from warm electronics to the sensor increases
Solution Approach 1:
The patent replaces electrical signal transmission through conductive wires with optical signal transmission through optical fibers. Optical fibers transmit data as light signals rather than electrical signals, eliminating the thermal conduction pathway that electrical wires would provide from the warm electronics to the cold image sensor. This substitution maintains high data transmission rates while minimizing thermal energy loss.
Solution Approach 2:
Optical fibers act as intermediaries for signal transmission between the cold image sensor and the warm electronics. These fibers are thermally insulating compared to electrical conductors and transmit information optically, thereby serving as both a data transmission medium and a thermal barrier. The optical fibers bridge the thermal gap while maintaining communication.
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 effectively reduces the radiator size and weight, maintains a significant temperature difference between the cold and warm sides, and minimizes heat flux to the image sensor, enabling high-quality image acquisition with reduced noise and efficient data transmission.
Implementation Method 1
a thermally insulating barrier with low thermal conductivity materials, such as polymers and glass, to minimize heat transfer from the warm electronics to the cold image sensor
Implementation Method 2
Cooling is achieved by radiatively dumping the heat into deep space
Implementation Method 3
uses optical waveguides for signal transmission to reduce electrical conductor heat transfer
Data Source
Figure 1~2
Figure 3~4
AI summary
Imaging device 10 comprising: a radiation input 12, a radiation-electric converting image sensor 1 the input thereof being operationally connected to said radiation input 12 and having an electrical interface 2 with an output providing electrical output signals representing image data, an electro-optical converter 4 with an electrical input 5 operationally connected to said output of said electrical interface 2 and with an optical output 6, generating from said electrical output signals optical output signals representing said image data, a cooling arrangement 3 thermally coupled to the image sensor 1 and a barrier 13 downstream said optical output 6 and tailored so as to impede heat transfer towards the image sensor 1. The invention is further directed to a space vehicle comprising the imaging device, to a method for reducing cooling energy for an imaging device and a method of producing images.