SEM Perimeter Truss Reflector for Compact High-Gain Deployment
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Solution Overview
Problem
Conventional deployable mesh reflector antennas are costly and optimized for large satellites, making them unsuitable for small satellites that require high-gain antennas with limited launch volume and flexibility for various missions.
Innovation Solution
A perimeter truss reflector system using storable extendible members (SEMs) that expand from a collapsed to an expanded configuration, supporting a collapsible mesh reflector surface to concentrate RF energy, with longerons forming a hoop-like structure and tensioned by a network of cords for efficient deployment and compact stowage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional foldable framework mesh reflectors are used, then large aperture and high gain are achieved, but device complexity and cost increase due to numerous longerons, battens, and joints
Solution Approach 1:
The reflector is segmented into a perimeter truss assembly with battens that can be independently positioned, and a separate mesh surface that can be tensioned independently. This allows the large aperture structure to be divided into manageable segments that deploy and tension separately, reducing the complexity of assembling numerous interconnected longerons and battens.
Solution Approach 2:
The mesh reflector surface is implemented as a flexible thin film that can be tensioned to form the reflective surface. This flexible membrane approach eliminates the need for a rigid framework to support the entire reflector surface, significantly reducing structural complexity while maintaining the large aperture area.
2Area of moving object
If conventional mesh reflectors with numerous components are used, then large parabolic surface is provided, but manufacturing cost increases due to high part count and precision requirements
Solution Approach 1:
The reflector system is divided into a perimeter support structure and a separate mesh surface, allowing each component to be manufactured and tested independently. The mesh surface can be produced as a continuous material rather than assembled from numerous small components, reducing manufacturing cost and complexity.
Solution Approach 2:
The perimeter truss assembly serves multiple functions: it provides structural support, defines the reflector aperture, and enables deployment mechanisms. This multi-functionality reduces the need for separate specialized components, lowering overall manufacturing cost.
3Power
If large aperture antennas are used for high gain, then RF energy concentration is improved, but launch vehicle volume requirements increase
Solution Approach 1:
The perimeter truss assembly and mesh surface are designed to nest within a compact volume during launch, similar to a nested doll structure. The battens and mesh can be folded or compressed into a small package that fits within constrained launch vehicle volume, then deployed to form the large aperture reflector in orbit.
Solution Approach 2:
The reflector structure transitions from a static compact stowed configuration to a dynamic deployed configuration in space. The perimeter truss assembly can expand and the mesh surface can be tensioned after launch, allowing the antenna to achieve its full large aperture size only when needed, minimizing launch volume requirements.
4Area of moving object
If conventional deployable structures with many joints are used, then large reflector surface is achieved, but reliability decreases due to precision requirements and potential failure points
Solution Approach 1:
The mesh reflector surface is implemented as a continuous flexible film rather than a structure with numerous rigid joints and connections. This continuous membrane has fewer potential failure points and requires less precision in assembly, thereby improving structural reliability while maintaining the large reflector surface area.
Data Source
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AI summary
Perimeter truss reflector includes a perimeter truss assembly (PTA) comprised of a plurality of battens, each having an length which traverses a PTA thickness as defined along a direction aligned with a reflector central axis. A collapsible mesh reflector surface is secured to the PTA such that when the PTA is in a collapsed configuration, the reflector surface is collapsed for compact stowage and when the PTA is in the expanded configuration, the reflector surface is expanded to a shape that is configured to concentrate RF energy in a predetermined pattern. Each of the one or more longerons extend around at least a portion of a periphery of the PTA. These longerons each comprise a storable extendible member (SEM) which can be flattened and rolled around a spool, but exhibits beam-like structural characteristics when unspooled.