[cripplecreek]

We know that solar works well in well lighted areas of mars but what about areas that don't catch as much sunlight? I'm thinking of canyons and polar regions. Also this will be a much larger lander requiring a lot more power.

[Cincinatus]

Quite true -- if you go to high latitudes or the poles, solar isn't good enough. But the cost and availablity issues are real and difficult (we buy our plutonium from the Russians).

The issue is whether it is better to fly a less capable rover using solar versus the best rover in the world that doesn't fly because you can't afford or get an RTG.