Inflatable Cassegrain SAR Antenna for Low-Mass Microsatellites
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Solution Overview
Problem
Current satellite-based Synthetic Aperture Radar (SAR) systems are unable to achieve global revisit within 1 month, have a high cost exceeding US$ 10 million, and exceed 100 kg in weight, lacking an optimal cost-benefit ratio.
Innovation Solution
A micro-satellite equipped with a Cassegrain type antenna, utilizing inflatable balloons and a two-dimensional active antenna array, enabling electronic beam steering and reduced power consumption, allowing for global revisits with a cost under US$ 10 million and a mass under 100 kg.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional satellite-based SAR systems are used, then imaging capability is achieved, but cost exceeds US$ 10 million and weight exceeds 100 kg
Solution Approach 1:
The antenna system is segmented into multiple inflatable panels that can be deployed separately and assembled to form the complete Cassegrain antenna structure. This allows the large antenna to be launched in compact segments and deployed in orbit, reducing launch weight requirements while achieving the necessary aperture size for high-resolution imaging
Solution Approach 2:
The patent employs inflatable membrane structures to form the Cassegrain antenna reflectors and sub-reflector. These thin-film inflatable structures provide the necessary large aperture area for high-resolution SAR imaging while maintaining extremely low mass, directly addressing the weight-cost contradiction by replacing heavy rigid structures with lightweight flexible membranes
2Measurement precision
If conventional satellite-based SAR systems are used, then imaging capability is achieved, but cost exceeds US$ 10 million
Solution Approach 1:
The inflatable Cassegrain antenna uses thin-film membrane structures that are significantly cheaper to manufacture than rigid metallic antenna structures. The inflatable design allows for simpler materials and construction methods, directly reducing the manufacturing cost while maintaining the large aperture necessary for high-resolution imaging
Solution Approach 2:
The antenna system incorporates deployable inflatable structures that transform from compact launch configuration to full operational aperture in orbit. This dynamic deployment capability allows the system to achieve high-resolution imaging performance with a much smaller and cheaper launch vehicle, thereby reducing overall system cost
3Measurement precision
If large antenna dimensions are used to improve spatial resolution, then resolution increases, but satellite weight and cost increase
Solution Approach 1:
The patent uses inflatable membrane structures to create large-aperture Cassegrain antenna reflectors with masses fractions of traditional rigid antennas. The thin-film inflatable design provides the necessary large surface area for high spatial resolution while keeping the mass extremely low, directly resolving the contradiction between resolution and weight
Solution Approach 2:
The large antenna aperture is divided into multiple inflatable panel segments that can be deployed and assembled in orbit. This segmentation allows the large area necessary for high resolution to be achieved through distributed lightweight panels rather than a single heavy structure, reducing overall antenna mass while maintaining resolution
4Productivity
If global revisit within 1 month is achieved, then monitoring capability improves, but traditional systems exceed 100 kg in weight
Solution Approach 1:
The inflatable Cassegrain antenna provides large aperture area with extremely low mass, enabling high-resolution imaging that maintains effectiveness at higher orbits. This allows the satellite to achieve global revisit within one month while staying under 100 kg by using lightweight inflatable structures rather than heavy rigid antennas
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 high-resolution imaging capabilities with a global revisit time of 1 month or less, achieving resolutions comparable to existing systems while significantly reducing cost and weight, and enabling continuous monitoring applications such as deforestation and subsidence tracking.
Implementation Method 1
The satellite (50) includes a Cassegrain type antenna with physical aperture size in a range between 15 to 30 meters, built of one or more inflatable balloons
Implementation Method 2
The Cassegrain type antenna comprises a two-dimensional active antenna array enabling electronic beam steering
Implementation Method 3
the synthesis is carried out by using a computer to coherently combine the backscattered echoes received and recorded along the flight path
Implementation Method 4
an antenna emits a microwave (ultra-high frequency radio transmission) pulse. When the emitted microwaves strike an object, some of the microwaves are reflected back to the emitting antenna
Data Source
Figure 1
Figure 1A
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AI summary
The example non-limiting technology herein provides a Synthetic Aperture Radar (SAR) solution on board a micro-satellite that provides global revisit within 1 month; a cost below US$ 10 million; and satellite mass lower than 100 kg. One solution uses an inflatable Cassegrain type antenna with a phased beam steering array in the 1.2 GHz band.