Modeling the release, transport and deposition of contaminant molecules for spacecraft in vacuum

What is it about?

As space exploration missions grow more advanced and ambitious, their scientific instruments grow more sensitive to contamination. Spacecraft that operate in vacuum experience outgassing as their materials naturally release molecules over time. These outgassed molecules can travel from source materials to sensitive surfaces, like optical elements, and deposit - causing performance degradation. Understanding contaminant release, transport, and deposition is therefore a key role of aerospace contamination control engineers. In this paper, we describe the physics and mathematics of modeling foundational outgassing processes in the context of free-molecular transport (i.e., transport in vacuum or near-vacuum conditions).

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Photo by NASA on Unsplash

Photo by NASA on Unsplash

Why is it important?

Space exploration vehicles must be carefully designed and built to keep their most sensitive instruments clean, and therefore to protect mission science and engineering objectives. In this paper, we lay out key methodologies for the mathematical modeling of contamination sources and transport processes by aerospace contamination control engineers. These models have been used to support many past and upcoming NASA missions and, as future missions grow more advanced and contamination-sensitive, they are under active development.