Stealth mode is more than just turning the lights off, it also masks EM emissions, especially heat. That's what the aforementioned "switchable insulation layer" is for.
And yes, I know it makes no sense for the EVA helmet to be internally lit, and that the helmet light shouldn't produce a visible beam in a vacuum, but this is a visual medium and if I made this 100% realistic then you'd be looking at a whole lot of black. |