Re: Why solar
'concerned about the dangers of a failed launch dumping a live nuclear reactor back on earth'
Yes, that is the principal concern in selecting the power source.
Opportunity was at the limit of the power to weight ratio where solar was feasible. The last rover, having more mass and greater scientific capability was only feasible using a nuclear power source.
By the way, an RTG is not a nuclear reactor in the sense I believe you are infering.
Biting the hand that feeds IT
