Movable Flat Panel Sunshade for Space Sensor Solar Exclusion
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Solution Overview
Problem
Existing solar rejection systems for space sensors, particularly those using pointing head mirrors, face limitations in providing effective solar exclusion angles without blocking light or leaving gaps, leading to heating issues and reduced sensor functionality.
Innovation Solution
A two-axis mechanism steers a flat panel sunshade to align between the sun and the sensor aperture, allowing it to 'hug' the sensor line-of-sight and tilt to prevent solar illumination, while also serving as a dust cover and potentially incorporating calibration features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fixed rigid sunshade is used to provide solar protection, then solar exclusion is improved, but the sensor field of view is blocked and the system becomes very large and heavy
Solution Approach 1:
The patent applies dynamics by making the sunshade movable rather than fixed. The sunshade is mounted on a mechanism that allows it to move between a retracted position (allowing full sensor field of view) and an extended position (blocking solar illumination). This dynamic positioning resolves the contradiction between providing solar protection and maintaining sensor visibility.
Solution Approach 2:
The sunshade system is segmented into multiple components: the sunshade panel itself, the mounting mechanism, and the actuation system. This segmentation allows the sunshade to be positioned only when needed, reducing its effective presence in the sensor field of view while maintaining protection capability when required.
2Object-affected harmful factors
If a tubular sunshade/baffle is used to protect the sensor, then solar exclusion is improved, but the baffle heats up due to internal light reflection and heating
Solution Approach 1:
The patent extracts the light-trapping interior surface that causes heating in traditional tubular baffles. The sunshade uses external shading surfaces that block sunlight before it can enter and reflect within an enclosed space. By taking out the enclosed tubular structure with its heat-trapping internal surfaces, the design eliminates the heating problem while maintaining solar exclusion.
3Object-affected harmful factors
If the sunshade is made movable to follow sensor line-of-sight, then solar exclusion angle is improved, but the mechanism complexity increases
Solution Approach 1:
The sunshade mechanism is designed to perform multiple functions: it provides solar exclusion, defines the sensor field of view, and can be actuated by simple mechanical means. This multi-functionality reduces the need for separate components, thereby managing complexity while achieving improved solar exclusion angles that follow the sensor line-of-sight.
4Object-affected harmful factors
If a large fixed sunshade is used to reduce solar exclusion angle limitations, then solar protection is improved, but the sensor field of view is reduced and more material is required
Solution Approach 1:
By making the sunshade movable, the design reduces the amount of material needed compared to a large fixed sunshade. The movable sunshade only needs to be large enough to block the sun when positioned, rather than requiring excessive material to maintain a large fixed structure that would always block part of the field of view.
Data Source
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AI summary
A solar rejection system (10) includes an enclosure (12) for housing a sensor (16), and a movable sunshade (20). The housing has an opening or aperture (18) for admitting light to the sensor, and the sunshade is moved as needed to prevent harmful solar illumination of the sensor. The sunshade may be a flat panel. The sunshade panel is mounted to a hinge (44) that is located on one side of a large diameter bearing (34) that allows the shade to be rotated around the aperture of the sensor to always prevent the sun from illuminating the aperture. The hinge allows the shade to be tilted to either allow the sensor to see further off axis without obscuration or to block the sun when it moves in front of the sensor. Full closure of the sunshade on its hinge allows it to also function as an aperture door, blocking the opening or aperture.