Composite Spacecraft Radiator Panels for Thermal Pointing Stability

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Solution Overview

Problem

Spacecraft radiator panels face thermal expansion and contraction issues that affect the precision of communication equipment, as they are typically made from materials with similar coefficients of thermal expansion, leading to potential distortions and misalignment of communication devices during temperature changes.

Innovation Solution

A radiator panel design featuring two spaced-apart face-sheets made of fiber-reinforced composite materials with different fiber sets and a honeycomb core, where the fibers differ in diameter and spacing, along with aluminum heat pipes, to manage thermal expansion and maintain precise alignment of communication devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If radiator panels are constructed with materials having similar coefficients of thermal expansion, then thermal distortion is minimized, but the panel cannot effectively manage thermal expansion and contraction to maintain precision under significant temperature changes

Engineering Contradiction:
Improvepointing precisionVSAvoidthermal adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The radiator panel employs a composite structure with aluminum face-sheets and carbon fiber reinforced plastic (CFRP) honeycomb core. The aluminum face-sheets provide thermal conductivity and expansion characteristics matching communication equipment, while the CFRP core provides dimensional stability and structural support. This composite construction allows the panel to maintain precision under thermal cycling by combining materials with complementary thermal and mechanical properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters of the radiator panel by using dissimilar materials (aluminum and CFRP) with different thermal expansion coefficients. The aluminum face-sheets (0.6-1.2 mm thick) have high thermal conductivity and expansion coefficient matching electronics, while the CFRP core (19-25 mm thick) has low thermal expansion and high stiffness. This parameter differentiation allows the panel to adapt to temperature changes while maintaining pointing precision within 0.1 degrees.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If aluminum honeycomb cores with aluminum face-sheets are used, then thermal expansion matching is achieved, but thermal management efficiency and structural stability are compromised

Engineering Contradiction:
Improvestructural stabilityVSAvoidheat dissipation efficiency
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The radiator panel uses a composite construction with aluminum face-sheets for thermal management and CFRP honeycomb core for structural stability. The aluminum face-sheets conduct heat efficiently to the heat pipes, while the CFRP core provides dimensional stability and reduces thermal mass. This composite approach improves heat dissipation efficiency while maintaining structural integrity under thermal loading.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The CFRP honeycomb core acts as an intermediary between the aluminum face-sheets and the heat pipes. It provides a stable structural framework that supports the thermal management components while minimizing thermal interference. The core's low thermal conductivity prevents heat buildup in the panel interior, and its high stiffness maintains the geometric relationship between communication equipment mounts during thermal cycling.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional aluminum panels are used, then ease of manufacture is maintained, but precision under thermal cycling deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpointing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The radiator panel employs a composite construction with aluminum face-sheets and CFRP honeycomb core that can be manufactured using established aerospace composite techniques. The aluminum face-sheets are bonded to the CFRP core using adhesive bonding or mechanical fasteners, allowing integration of thermal management and structural functions. This approach maintains manufacturing feasibility while achieving pointing precision within 0.1 degrees under thermal cycling, compared to conventional aluminum panels that exhibit significant thermal distortion.

Inventive Principle:
Principle #40Composite materials

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 design minimizes thermal-induced movement between communication device mounts by less than 0.1 degrees, even under significant temperature changes and high heat dissipation rates, ensuring precise pointing and functionality of communication equipment.

Implementation Method 1

one or more heat pipes extending through the honeycomb core

Methodology Applied
Scientific EffectHeat pipe: Heat Pipe

Implementation Method 2

aluminum heat pipes extending through the cores

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

Thermal expansion and contraction of a radiator panel may affect the precision of a spacecraft's communication equipment's pointing

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

two spaced-apart face-sheets including an inside face-sheet and an outside face-sheet, wherein the two spaced-apart face-sheets are constructed of a fiber reinforced composite material

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Data Source

PatentEP3620395B1Spacecraft and spacecraft radiator panels with composite face-sheets
Publication Date: 2021.04.14 THE BOEING CO
  • EP3620395B1 patent drawingFigure 1
  • EP3620395B1 patent drawingFigure 2~3
  • EP3620395B1 patent drawingFigure 4

AI summary

Radiator panels include two spaced-apart face-sheets including an inside face-sheet and an outside face-sheet that are constructed of a fiber reinforced composite material, a honeycomb core positioned between the two spaced-apart face-sheets, and one or more heat pipes extending through the honeycomb core. Spacecraft include a body and two radiator panels operatively coupled to the body opposite each other.