This is the full sized helmet form the STAR TREK The Motion Picture. Screen captures are from the movie. The orange firefighting helmet was made in production but I'm not certain that helmet ever making it to screen.
The model is high poly and was constructed with 2mm holes for inserting pins for accurate part alignment. I recommend joining the pieces with 10mm 1/16" brass rod, but you can use what you have on hand. The onscreen helmets had a tinted clear plastic shield that you have to obtain. If you want you can pick up some window tint from the auto parts store or perhaps a DIY home store. To make it accurate as possible, you can find some rubber edge guard to put on the bottom of the helmet and around the visor.
See the attached pictures for painting ideas.
Part 1 250x143x123mmPart 2 250x142x123mmPart 3 253x189x191mmPart 4 243x165x126mm