I was curiuous about the materials that would be used to make a giant sun-orbiting reflector, and approximately how close they could be to the sun's center without being destroyed by heat/flares. Why? Just wanted to know the feasability of using wasted solar energy (meaning energy that normally just shoots into space in no particular direction) to heat up a suitable planet, like mars. What kind of devices would be used, and how big would they be? I calculated a reflective sheet orbiting at the distance of mercury's orbit would require a functional radius of around 9*10^5m, which is quite a bit of material, to double the radiation reaching mars. This obviously isn't within the scope of todays technology to launch and deploy. Is there something out there that would achieve the same effect with much less material, like maybe a closely orbiting lens? What kind of climate change would doubling the radiation reaching mars achieve? Yeah I know its a complex question.