Composite Shell Segments for Space Tape Measure Deployment

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Solution Overview

Problem

Existing deployable tape measures in space equipment face challenges with compactness, rigidity, and mass optimization, particularly when handling large launch loads, as they require additional stacking that reduces useful surface area and increases on-board mass, and can result in uncontrolled or non-deployment issues.

Innovation Solution

A deployable device featuring a shell made of composite materials with reinforcement and flexible printed circuits, connected to tape measures that can transition from a rolled-up to a deployed configuration, allowing the shell to take up launch loads while maintaining a compact and rigid structure, and ensuring maximum useful surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If additional stacking belts are added to the mandrel to handle large launch loads, then the load-bearing capacity is improved, but the usable surface area is reduced and on-board mass increases

Engineering Contradiction:
Improveload-bearing capacityVSAvoidusable surface area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The shell is divided into multiple segments that can be stacked around the mandrel. Each segment independently contributes to load-bearing capacity while maintaining the overall cylindrical structure. This segmentation allows the shell to distribute launch loads effectively without requiring excessive additional mass or reducing usable surface area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shell segments are constructed using composite materials that provide high strength-to-weight ratio. This allows the shell to bear large launch loads while minimizing the mass added to the system, thereby preserving on-board mass margins and maintaining maximum usable surface area for solar cells.

Inventive Principle:
Principle #40Composite materials

2Strength

If the mandrel diameter is increased to handle larger launch loads, then the load-bearing capacity is improved, but the storage volume constraint is violated

Engineering Contradiction:
Improveload-bearing capacityVSAvoidstorage volume
Core Design Contradiction:
StrengthVSVolume of stationary object

Solution Approach 1:

The shell segments are designed to nest around the mandrel in a compact configuration during launch. Multiple segments stack concentrically, utilizing the vertical space along the mandrel length rather than increasing the radial diameter. This nesting approach allows the structure to bear large loads while maintaining a compact storage volume that fits within launch constraints.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Stability of the object's composition

If the shell is made rigid to ensure structural stability, then the rigidity is improved, but the deployment flexibility is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoiddeployment flexibility
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The shell structure transitions from a compact nested configuration during launch to an expanded cylindrical configuration during deployment. The segments are designed with controlled flexibility that allows them to separate and expand along the mandrel, achieving both rigidity in the deployed state for structural stability and flexibility during the deployment process.

Inventive Principle:
Principle #15Dynamics

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 a robust, compact, and rigid tape measure capable of handling large launch loads while preserving a maximum useful surface area, ensuring controlled deployment and minimizing on-board mass, thus addressing the limitations of existing technologies.

Implementation Method 1

Tape measures are known in the space industry as being flexible ribbons having an arcuate section whose radius of curvature is convex on a first face and concave on a second face, these ribbons being able to pass from the wound state to the deployed state essentially thanks to their own elastic energy

Methodology Applied
Scientific EffectElastic energy: Elasticity

Data Source

PatentEP3795480B1Deployable device
Publication Date: 2024.02.28 THALES SA
  • EP3795480B1 patent drawingFigure 1~2
  • EP3795480B1 patent drawingFigure 3
  • EP3795480B1 patent drawingFigure 4

AI summary

The invention relates to a deployable device (10) comprising a frame (11), a mandrel (12) rotatable relative to the frame (11) about a first axis Z, and a membrane (13) capable of transitioning from a configuration wound around the mandrel about the first axis Z to a configuration deployed along a second axis X substantially perpendicular to the first axis Z. According to the invention, it comprises two fittings (14) integral with the mandrel (12) at their center, arranged on either side of the membrane (13) and comprising first pads (15) on their periphery (16), a shell (17) extending between the two fittings (14), the shell (17) comprising second pads (18) of a shape complementary to the shape of the first pads (15), the shell (17) being capable of transitioning from a wound configuration at least partially enveloping the membrane (13) to a superimposed deployed configuration. at least partially to the membrane (13) in deployed configuration.