A method for fabricating a carbon fiber composite part, for example, a sun shield structural assembly on a satellite. The composite part is fabricated on a carbon fiber/bismaleimide (BMI) composite tool, where a moisture barrier is positioned on the tool prior to carbon fiber part ply layers being positioned on the tool to prevent moisture from the tool from entering the part. In one embodiment, the moisture barrier includes cross-wise strips of aluminum foil. A wrinkle barrier is positioned on the moisture barrier before the carbon fiber part ply layers so that anomalies or wrinkles in the moisture barrier are not transferred to the part layers.