re: Why don't NASA's $800 million Mars Rovers have solar panel cleaners?
They could test different systems of cleaning solar panels...but then it would cost more money and it seems you don't think they should be spending what they are...
Suggest a system that wouldn't be a waste of time.
A brush might jam over the solar panels and block light! Besides you would need several of them and motors and controllers for each. If they can raises and lower the panels they might try that. But, again what happens if a panels stalls in the upright position That blocks light and stops that one from being any use.
Are you trying to suggest ways to kill the mission, increase cost or increase productivity? RTGs would not have the issues solar panels do...
--Chris Vancil