Re: Dust
These things always come down to a question of weight. Each and every dust-prevention system means more weight. More weight means a bigger chassis, wheels, motors and more electricity (batteries, panels etc). A heavier robot is harder to land, so a bigger lander is required. And all of that has to be launched out of Earth's atmosphere and gravity well and flung across interplanetary space to Mars, meaning a much bigger rocket...
The point I'm rambling towards is that even a tiny bit of weight on the final payload can multiply up to exponentially more weight on the launch vehicle, and thus more cost. Sometimes, one has to deal with a problem because it's just too damn expensive to fix.
Biting the hand that feeds IT
