I believe (correct me if I'm wrong) that a microwave receiver is less sensitive to dust than solar panels. Also, if you've got a large solar array in space send

I believe (correct me if I'm wrong) that a microwave receiver is less sensitive to dust than solar panels. Also, if you've got a large solar array in space sending a focused beam of energy to a rover, the receiver can be hit with much more power than a same sized solar panel, which can more than offset any losses from dust on the receiver.