And yes, lunar landers have successfully been put on the moon
Hmmm..., so where does he ever say *he* is going to personally finance a lunar lander? Where did you get that idea in your head??? And yes, lunar landers have successfully been put on the moon, so if you have the $$$, it can be done.
What I want is to be able to build a cheap robot with a camera that could go to the Moon or Mars and wander around taking pictures
Well, I'd like to... What would it take to space harden an AVR? Or do space hardened AVRs exist already?
The cooling would be simple enough, just attach every single thing to a heatsink (probably including passive devices like resistors and capacitors).
What I want is to be able to build a cheap robot with a camera that could go to the Moon or Mars and wander around taking pictures, the Moon would be preferable.
My conclusion so far has been that the reason space-based robots tend to be extremely expensive (in the range of billions of dollars) has less to do with what they make them out of than how much it costs to get there. In other words if it costs on the order of trillions to get there then it doesn't really matter if you're spending $1000 on your robot or $10 billion, it's such a tiny part of the overall cost anyway, might as well make it worth it.
For those of you who just think space is cold, anything stationed on the moon will have to be able to operate in complete darkness at around -200°C to sustained sunlight at a bit more than 100°C. Anything traveling through space will probably have to rotate, as someone stated, so that there isn't a single side facing the Sun. If it wasn't rotated the side facing the Sun would get very, very hot while the other side would get very, very cold.