Regarding the color of radiators, people mentioned the KSPI radiators but no one mentioned the nuances of those parts. I think they're really cool (har har) and seem to make a lot of sense. They do the perpendicular-sun-tracking thing, to utilize both sides of each panel. When you see the panels while in an umbra, you also see the glowing heat pipes. I'm guessing the heat pipes are made of oxidized copper or anodized aluminum because of they're good at both radiating and conducting. For the purposes of texturing, the rest of the color of the radiator may not actually matter much, since we're mostly concerned with non-visible radiation. The ISS, though, uses ammonia as coolant throughout the station modules as well as the radiators. You can't really see the ammonia channels, though, maybe the radiator panels are aluminum or something? I'm not sure if the coloring is deliberate or coincidental. https://en.wikipedia.org/wiki/File:STS-134_EVA4_view_to_the_Russian_Orbital_Segment.jpg https://en.wikipedia.org/wiki/File:EATCS.png - - - Updated - - - This discussion also makes me think of the effectiveness of inline, stack-mounted radiators. It would be neat if their effectiveness changed when they're in an umbra, or even when they're tilted closer to perpendicular to the sun. When they're in sunlight, obviously one side wouldn't be able to radiate anything, but since the game is tracking heat on a per-part basis, the end result would be, ok radiation in the sun, better radiation in the shade.