Theoretical Models of Kapton Heating in Solar Array Geometries

In an effort to understand pyrolysis of Kapton in solar arrays, a computational heat transfer program was developed. This model allows for the different materials and widely divergent length scales of the problem. The present status of the calculation indicates that thin copper traces surrounded by Kapton and carrying large currents can show large temperature increases, but the other configurations seen on solar arrays have adequate heat sinks to prevent substantial heating of the Kapton. Electron currents from the ambient plasma can also contribute to heating of thin traces. Since Kapton is stable at temperatures as high as 600 Celsius, this indicates that it should be suitable for solar array applications. There are indications that the adhesive sued in solar arrays may be a strong contributor to the pyrolysis problem seen in solar array vacuum chamber tests.