CubeSat Thermal Louvers Using Bimetallic Springs
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Solution Overview
Problem
Existing thermal control louver designs for full-sized spacecraft are too large for CubeSats and small spacecraft, and previous adaptations like Micromachined Louver Arrays face issues with dust accumulation and active control requirements.
Innovation Solution
A thermal control louver assembly for CubeSats featuring a back panel with bimetallic springs and a front panel that secures flaps, using a modular design with interlocking panels and passive actuation to manage heat transfer efficiently, allowing for adaptability and redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If full-sized spacecraft thermal louver designs are used, then thermal control function is achieved, but the size is too large for CubeSats and small spacecraft
Solution Approach 1:
The louver assembly is divided into multiple discrete flaps (e.g., five rows and two columns) that can independently pivot and adjust. This segmentation allows the system to achieve effective thermal control with a much smaller overall footprint compared to traditional full-sized louver designs, as each flap contributes to the thermal regulation function collectively
Solution Approach 2:
The patent transitions from the two-dimensional planar structure of traditional louvers to a three-dimensional configuration where flaps pivot on shafts perpendicular to the back panel. This dimensional change enables more efficient heat rejection with reduced surface area, fitting the compact CubeSat form factor while maintaining thermal control effectiveness
2Volume of moving object
If Micromachined Louver Arrays are used, then size is reduced for small spacecraft, but active control is required and dust accumulation inhibits movement
Solution Approach 1:
The louver assembly employs passive bimetallic spring actuators that automatically respond to temperature changes without requiring external power or control systems. The bimetallic springs expand and contract based on thermal conditions, causing flaps to pivot open or closed autonomously, eliminating the need for active control mechanisms and reducing susceptibility to dust accumulation
Solution Approach 2:
The patent replaces the electrically actuated micromachined systems with a purely mechanical passive actuation mechanism using bimetallic springs. This substitution eliminates complex electrical controls, sensors, and power requirements while providing reliable thermal response through inherent material properties of the bimetallic springs
3Use of energy by moving object
If passive actuation is used to conserve power, then power consumption is reduced, but thermal control precision may be compromised
Solution Approach 1:
The patent utilizes parameter changes in the bimetallic spring materials to achieve precise thermal control. By selecting materials with specific thermal expansion coefficients and designing spring geometries with particular pitch and diameter ratios, the system achieves accurate flap positioning responses to temperature variations without requiring active control, thus maintaining precision while consuming no power
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
The solution provides effective thermal control with passive actuation, built-in redundancy, and adaptability while conserving power, suitable for various CubeSat missions by efficiently transferring heat and maintaining a standard form factor.
Implementation Method 1
the bimetallic springs uncurl causing the flaps to open and change the emissivity of the spacecraft
Implementation Method 2
When the components inside the spacecraft reach a high temperature, the bimetallic springs uncurl
Implementation Method 3
the flaps to open and change the emissivity of the spacecraft
Implementation Method 4
The front panel may cover the spring to protect the spring from heat from outside of the apparatus
Data Source
AI summary
Thermal control louvers for CubeSats or small spacecraft may include a plurality of springs attached to a back panel of the thermal control louvers. The thermal control louvers may also include a front panel, which includes at least two end panels interlocked with one or more middle panels. The front panel may secure the springs, shafts, and flaps to the back panel.