Bit more of a wish than a plan I guess...
Super-reflectors will need some tweaking. I don't think 0.95 reflective layers are too much to ask, but it'll need cooling to avoid melt-down at a photospheric perihelion. Perhaps the energy needed to ablate the shield can be increased by mixing things in the ice, thus slowing the ablative mass-loss and reducing the total mass. Multi-layers of reflector in the ablative?