Spacecraft Capture Mechanism for Rapid Grasp and Rigidization
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Solution Overview
Problem
Current capture mechanisms for spacecraft are inadequate in quickly grasping tumbling, free-flying spacecraft with non-prepared features, as they struggle to achieve a rapid and secure grasp over a large range of relative motion, leading to increased complexity and propellant usage in spacecraft design.
Innovation Solution
A two-stage capture mechanism featuring a quick grasp mechanism with pivotally mounted clamp jaw assemblies that can close rapidly to soft capture a feature, followed by a rigidizing contact to secure the capture feature within the mechanism, allowing for adjustable jaw alignment and compliance to accommodate various spacecraft protrusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single-stage capture mechanism is used, then the structure is simpler, but the capture speed and ability to handle large relative motion are insufficient
Solution Approach 1:
The capture mechanism is divided into two distinct stages: a quick grasp mechanism with pivotally mounted clamp jaw assemblies for rapid engagement, and a rigidizing contact mechanism for securing the capture feature. This segmentation allows each stage to be optimized independently - the quick grasp stage provides speed while the rigidizing stage ensures stability, resolving the contradiction between capture speed and mechanism complexity.
Solution Approach 2:
The clamp jaw assemblies are pre-positioned and biased to automatically close when the capture feature enters the grasp zone. The pivotal mounting and spring bias create a preliminary action that initiates closure before full engagement is required, enabling rapid capture response while maintaining manageable structural complexity through automated actuation.
2Measurement precision
If precise spacecraft positioning is used, then the capture accuracy is improved, but the propellant usage and design complexity increase
Solution Approach 1:
The capture mechanism transitions from requiring precise static positioning to accommodating dynamic relative motion. The pivotally mounted clamp jaws can adapt to variations in the capture feature's position and orientation, while the rigidizing contact maintains stability during capture. This dynamic approach reduces the need for high-precision positioning maneuvers, thereby decreasing propellant consumption while maintaining capture reliability.
3Adaptability or versatility
If the clamp jaw assemblies are rigidly fixed, then the structural stability is improved, but the ability to accommodate various spacecraft protrusions is reduced
Solution Approach 1:
The clamp jaw assemblies utilize pivotal mounting that allows dynamic adjustment of jaw alignment during the capture process. This pivotal connection provides compliance to accommodate variations in protrusion geometry while maintaining stable closure through the rigidizing contact stage. The system transitions from compliant initial contact to rigid final engagement, resolving the contradiction between adaptability and stability.
Solution Approach 2:
The mechanism changes the compliance parameter of the jaw assembly through the pivotal connection, allowing the jaw angle to vary within certain limits to accommodate different protrusion shapes. The spring bias and pivotal geometry enable parameter changes in jaw orientation while maintaining capture force, achieving both versatility for various protrusions and stability during the capture operation.
Data Source
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AI summary
The present invention provides a capture mechanism for capturing and locking onto the Marman flange located on the exterior surfaces of spacecraft/satellites. The capture mechanism achieves its goal of quickly capturing a client spacecraft by splitting the two basic actions involved into two separate mechanisms. One mechanism performs the quick grasp of the target while the other mechanism rigidises that grasp to ensure that the target is held as firmly as desired.