White Molecular Adsorber Coating for Spacecraft Contamination Control
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Solution Overview
Problem
Conventional zeolite-based molecular adsorber systems used in spacecraft and instruments are hindered by weight, size, and mounting requirements, limiting their effectiveness in controlling on-orbit molecular contamination and requiring lengthy bake-out durations.
Innovation Solution
A sprayable white molecular adsorber coating system comprising zeolite, binder, and water, with an epoxy-based or colloidal-based primer, applied to a substrate, either prepped or abraded, to enhance adhesion and molecular contaminant trapping capabilities, offering improved flexibility and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional zeolite-based molecular adsorber systems are used, then molecular contaminant trapping is achieved, but weight, size, and mounting requirements increase
Solution Approach 1:
The patent applies this principle by converting the traditional bulk puck-type adsorber into a thin-film coating system. The zeolite-based molecular adsorber coating is applied as a thin layer on substrate surfaces, eliminating the need for thick, heavy puck structures while maintaining contaminant trapping functionality. This thin-film approach dramatically reduces weight and space requirements.
Solution Approach 2:
The patent utilizes porous materials by employing zeolite as the active adsorbing component. Zeolite's inherent porous structure provides high surface area and adsorption capacity within a minimal volume. The coating leverages this porosity to trap molecular contaminants effectively while maintaining a thin, lightweight profile that avoids the weight penalties of conventional solid puck adsorbers.
2Reliability
If conventional zeolite-based molecular adsorber systems are used, then molecular contaminant trapping is achieved, but device complexity and mounting requirements increase
Solution Approach 1:
The patent applies merging by integrating the adsorber function directly into the substrate surface through coating. Instead of separate puck-type adsorbers that require mounting hardware and installation, the zeolite coating becomes an integral part of the substrate, eliminating mounting complexity and simplifying the overall system architecture.
Solution Approach 2:
The patent replaces the mechanical mounting system of conventional adsorbers with a chemical bonding approach. The coating adheres to the substrate through chemical adhesion mechanisms, eliminating the need for mechanical fasteners, brackets, and mounting hardware. This substitution of mechanical mounting with chemical bonding dramatically reduces device complexity.
3Reliability
If conventional adsorber systems are used, then molecular contaminant trapping is achieved, but bake-out durations increase
Solution Approach 1:
The thin-film configuration of the zeolite coating provides significantly shorter diffusion paths for contaminants to reach the adsorbing zeolite sites. Compared to thick puck-type adsorbers, the thin coating allows rapid contaminant transport and adsorption, enabling shorter bake-out durations while achieving the same level of contaminant trapping effectiveness.
Solution Approach 2:
The patent changes the physical parameter of adsorber geometry from bulk three-dimensional pucks to thin two-dimensional films. This parameter change fundamentally alters the mass transport characteristics, reducing the distance contaminants must diffuse to reach active sites. The thin-film geometry enables faster adsorption kinetics and shorter processing times while maintaining trapping capacity.
4Ease of operation
If sprayable coating system is used, then ease of application and flexibility are improved, but coating uniformity and adhesion may worsen
Solution Approach 1:
The patent introduces a binder as an intermediary material that mediates between the zeolite particles and the substrate. The binder forms a matrix that holds the zeolite particles together and provides adhesive bonding to the substrate, ensuring uniform coating formation and consistent adhesion. This intermediary binder system enables the sprayable coating to achieve manufacturing precision comparable to conventional methods.
Solution Approach 2:
The patent creates a composite coating material combining zeolite particles with binder and optional primer layers. This composite formulation integrates the adsorbing zeolite with materials that provide coating integrity, adhesion, and uniformity. The composite structure enables sprayable application while maintaining manufacturing precision through the synergistic properties of the combined materials.
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 coating system provides superior contaminant trapping properties, reduces material restrictions, and extends the life of instruments and spacecraft by eliminating the need for extensive bake-outs, while maintaining stability across a wide temperature range and vacuum conditions.
Implementation Method 1
The primer is configured to adhere the coating to the surface of the substrate
Implementation Method 2
zeolite based molecular adsorbers have been used in spacecraft and instruments to collect and retain outgassed molecular effluent
Data Source
AI summary
A method of coating a substrate with a white molecular coating. A colloidal based primer is prepared having on a mass basis between 30-40% suspensions of fine-sized spherical particles of nonporous silica dispersed in liquid phase. The primer is applied to the substrate and allowed to dry. A molecular adsorber coating is prepared by treating a zeolite with a colloidal silica binder thereby providing a treated pigment having a mass ratio of the colloidal silica to the zeolite is in a range of 2.0 to 2.6, then processing the treated pigment into a powder thereby facilitating sprayability and then mixing said treated zeolite with a colloidal solution containing silica. The coating is then sprayed onto the primer and allowed to dry. The resultant coating provides adequate bond stability and strength necessary for flight applications within an environment for vacuum of space applications.