You have this backwards, it's much easier to discard waste heat in a car than it is in space. Consider - you have a multi-year mission, surrounded by an insulator that does not allow convective or conductive cooling. In fact, the only practical cooling methods are A.) heating part of your mass and shedding it, and B.) radiating it (as signal or as noise) at some EM frequency.

Not at all... it is the collapse of ignorance that either did or did not kill the cat!

I recently went through a round of attempting to use OpenSolaris on my work laptop (damn I want that ZFS juju)... and there were a couple of things that drove me back to Debian - one of them was the horrible performance of Firefox under OpenSolaris. Under VirtualBox on OpenSolaris host, Firefox was faster on either a Debian or a WinXP guest than it was on the host... the difference between usable and not. The specific application that really showed this was Zimbra (pretty heavily AJAXy). In trying to track this issue down, the general feedback on OpenSolaris forums was "Firefox on OpenSolaris kinda sucks, sorry". My personal experience with Firefox is that under Linux or Windows it's subjectively close enough not to worry about (on a variety of hardware, not just the laptop that I tested OpenSolaris on).