That layer of insulation seems like a double-edged sword. It would keep incoming heat from being wasted on the interior, but without it, the internal heat of th

That layer of insulation seems like a double-edged sword. It would keep incoming heat from being wasted on the interior, but without it, the internal heat of the object can keep the surface from freezing as quickly. So, for example, if an object is moved entirely into the shade for 10 minutes, perhaps in certain cases without the insulation it would not freeze but with the insulation it would. Also, it might be harder to use an internal heating element for the cases (like night time) where the solar approach isn't good enough.