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Spacecraft design relies upon contamination control plans that specify proper material handling and material choices. Typical manufacturing areas employ control plans that monitor air quality for particulate contamination. All individual materials of construction are controlled for outgassing and purity and are required to comply with ASTM E595 vacuum outgassing requirements. Recently, ASTM E1559 test methods are being used to characterize outgassing of entire systems. However, there is still a significant gap in testing for interactions of multiple materials that may cause a variety of problems, including contamination. Requirements for assemblies such as electronics, circuit cards, and sensors are passed on to subcontractors, often without details beyond meeting ASTM outgassing requirements and particulate standards and neglecting information on design compatibility. Guidance typically is not provided on how to execute assemblies, manage material interactions, or restrict materials that should not be used in manufacturing. Significant contamination can occur during manufacturing from manufacturing tooling aids, fixtures and fixturing designs, accidental or incidental contact, instability of in-use materials (e.g., adhesives), or incompatible material choices in the system design. This contamination may not be detected until failures occur at final assembly or vacuum bake-out because typically limited sampling is specified for cleanliness verification during assembly operations. As innovations to system designs continue, designing and controlling the manufacturing of components and assemblies will require improvements and detailed guidance to minimize material compatibility issues and contamination. Examples of manufacturing tooling aids or material interactions that can lead to contamination will be provided along with recommendations to mitigate the contamination.
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