Deployable Stereostructure Spacecraft for Omnidirectional Antennas

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Solution Overview

Problem

Existing deployable space antennas struggle to achieve omnidirectional coverage with high resolution and form accuracy while maintaining lightness, as they often require increased weight and complexity to enhance bending rigidity.

Innovation Solution

A stereostructure spacecraft design using multiple deployable beam members and tension members arranged equidistantly around a virtual polyhedron center, supported by tension members to form omnidirectional apertures, ensuring lightness and form accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the cross-sectional area of the deployment rib is increased to enhance bending rigidity, then the form accuracy of the thin film surface is improved, but the weight of the antenna increases

Engineering Contradiction:

Improveform accuracyVSAvoidweight

Core Design Contradiction:

Manufacturing precisionVSWeight of moving object

Solution Approach 1:

The patent employs a thin film surface with a deployed area of 100 m² or more that maintains high form accuracy without requiring heavy rigid support structures. The thin film is tensioned by cables to achieve the necessary rigidity, eliminating the need for thick deployment ribs while maintaining structural integrity and form accuracy.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent replaces the traditional mechanical support system (thick deployment ribs providing bending rigidity) with a cable tensioning system. The cables create tensile forces that maintain the thin film's shape and accuracy, substituting compressive/bending mechanical support with tensile support, thereby significantly reducing weight.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a planar antenna is formed by extending the cantilevered deployment rib, then the directivity in the direction vertical to the plane is improved, but the omnidirectional directivity in all directions deteriorates

Engineering Contradiction:

ImprovedirectivityVSAvoidomnidirectional directivity

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a two-dimensional planar antenna to a three-dimensional spherical antenna structure. The thin film is deployed on the surface of a sphere with a diameter of 10 meters or more, allowing the antenna to receive radio waves from all directions simultaneously, achieving true omnidirectional directivity while maintaining high measurement precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12620693B2Stereostructure spacecraft

Publication Date: 2026.05.05 HITACHI LTD

AI summary

A stereostructure spacecraft of the present invention comprises multiple deployable beam members, multiple tension members, and a spacecraft for storing the deployable beam members and the tension members. The stereostructure spacecraft is formed by deploying the deployable beam members and the tension members around the spacecraft. The deployable beam members stored in the spacecraft are deployed and arranged equidistantly in directions of multiple rotational symmetry axes, the rotational symmetry axes being rotational symmetry axes of a virtual polyhedron that is formed to have a substantial center of the spacecraft as an origin. The tension members support two end portions of two adjacent deployable beam members with tension. The respective end portions of the deployable beam members are simultaneously supported by three or more of the tension members.