Ground Radiation Tests and Flight Atomic Oxygen Tests of ITO Protective Coatings for Galileo Spacecraft

Radiation simulation tests (protons and electrons) were performed along with atomic oxygen flight tests aboard the Shuttle to space qualify the surface protective coatings. The results which contributed to the selection of indium-tin-oxide (ITO) coated polyester as the material for the thermal blankets of the Galileo Spacecraft are given. Two candidate materials, polyester and Fluorglas (TFE), were radiation tested to determine changes at simulated Jovian radiation levels. The polyester exhibited a smaller weight loss (2.8%) than the Fluorglas (8.8%). Other changes of polyester are given. During low-earth orbit, prior to transit to Jupiter, the thermal blankets would be exposed to atomic oxygen. Samples of uncoated and ITO-coated polyesters were flown on the shuttle. Qualitative results are given which indicated that the ITO coating protected the underlying polyester.