NASA Prepares to Say 'Farewell' to InSight Spacecraft

I always wonder why the Martian Landers never have a simple method of reducing the dust load that eventually kills them.

Even a rotating arm could greatly reduce the dust load on panels, or perhaps a fan of some description or perhaps a windscreen wiper or even a small tank of compressed air. They'd only have to be actuated every couple of months or so, whenever the electrical generation begins to fall too low.