RE: NASA is back on track to colonize the moon, by destroying some grains of moon material brought back by Apollo 17.

How did solar power kill the Mars Rover? Did it have no backup power in case there was no sun or was there some kind of surge, as in too much power all of sudden, like EMP or something that fried the power? Was there no like buffer or surge protection or what about solar power that would kill the rover on Mars? I'm asking because I love solar power and I hate to see it cause problems at all. If it was just a lack of sun, I'd understand.