I've heard in some of the press conferences questions from the press about
concerns for potential dust devils in the vicinity of Spirit. The response
to the questions was something like: the MER is heavy and could not be
tipped over by the dust devil. I think this misses the point. I'd be
concerned that the dust devil would churn up so much dust that the solar
panels would be seriously degraded. I suppose dust devils come up so
quickly that it's an unavoidable, but remote, possible hazard. I did
wonder, though, what the prospect is of an "emergency folding" of the solar
panels...

How much extra could a couple of "windshield wipers" have cost in weight?
:-)

Jon