I snagged a roll of transparent film at the Skunkworks auctions in the eighties, Turned out to be gold film about 2mmm. For a project, I cannot imagine them using it on space or military projects. Since the windows in Quicksilver are fixed, I screwed up the first time I had a professional install it on all the windows and a foot wide margin on the windshield. What impressed me was the gold with throughout the plastic. It cuts solar heating like nothing else I've ever seen. Touching the teak panel overhead the temp seems to be about the same as touching glass. The installer told me "I have never seen anything like this stuff -- can I have the rest of the roll?" HA! FAT CHANCE! The roll weighed around forty-something pounds and the Lockheed auctioneer threw it in with my several hundred pounds of Space Shuttle Wire. I don't want to speculate about the film but it appears to the eye to get darker as the outside gets brighter. Very hard to see inside even when the lights are on, but with polarized sunglasses the film turns opaque black.