A study on degradation of germanium coating on Kapton used for spacecraft sunshield application

摘要

Sunshield membranes made of germanium-coated black polyimide (GBP) or Kapton are often used on the reflector/transmitter antenna of satellites for thermal control applications. However, the germanium top layer is prone to degrade during ground storage and implementation. Hence, vacuum/inert gas-sealed packaging is required for storing the membranes, followed by a staggered fabrication schedule as the shelf-life of the GBP is identified as only similar to 6 months. In the present study, microstructural, thermo-optical, and electrical properties along with X-ray photoelectron spectroscopy (XPS) studies for evaluating oxidation states of the as-received and degraded GBP films have been investigated thoroughly. The radio frequency (RF) loss behavior of both the films has also been studied for S band (2.5-3.5 GHz), Ku band (10.5-14.5 GHz), and Ka band (30-35 GHz). Copyright (C) 2015 John Wiley & Sons, Ltd.