How to maintain operating temperature for outer space electronics ?

[scientist]

Estimate at $10 000 per kilo, but if you can get space and fit in as a ballast mass on a launch ( they actually do add ballast mass to do compensation for uneven satellites or to trim to a specific launch vehicle charactaristics ) along with having something the launch operator thinks is cool, and are prepared to wait and not care much about orbit then it can be a lot cheaper, or even free. A lot of picosats and microsats go up that way as part of another paid for load. Less steel blocks to machine, and so long as you are not a bother and will not interfere with the main payload you are cheap to add. You might have to pay for the added mounting fixtures, testing and release mechanism to free you from the second stage booster before it is deliberately deorbited.

So, would those machined metal panels (http://upload.wikimedia.org/wikipedia/commons/e/ee/Boeing_X-37B_inside_payload_fairing_before_launch.jpg) in most satellite payload fairings be ballast weight? I've always wondered what they're for, other than radar retroreflectors to determine distance to the fairing.