Dyson Mirror

You might be familiar with the concept of a Dyson Ring or Dyson Sphere. One purpose of such a construct is to capture as much of that solar radiation as possible. One of the main problems with such structures is of course the enormous amount of material required to build one.

I'm not sure whether if Dyson has thought about it himself, but after thinking about it, I think it might be possible to help cut down on the construction material problem by using what I call a "Dyson Mirror". The idea is basically something like the following:

Instead of constructing a habitable ring or sphere around a sun-like star to capture its radiated energy, it might be sufficient to construct a giant parabolic mirror like so instead:



The construct would be made of thin aluminum foil (the same as those used in solar sails) instead of the heavier materials required for building worlds. The foils in question need only be 30 to 100 nanometres thick. The energy could be collected by a large space station or satellite in space which would then convert and transmit the energy to Earth via a concentrated microwave beam discussed here (you'll have to scroll to the bottom of that page).

For a mirror at mercury orbit with a diameter, spanning 30% of that orbit (assuming a flat mirror for simplicity purposes, this is just an estimate after all), assuming a foil thickness of 50 nanometres, it would appear that the volume of material required is:

Radius of Mercury orbit = 50 million km

50,000,000km * 2 * pi * 0.3 => 94,200,000km (diameter of mirror)

(94,200,000km / 2)^2 * pi => 6.976 * 1015 km^2

6.976 * 1015 km^2 * 50nm => 34,880,000km^3

…Which translates to a piece giant cube of material that is 700km by 700km by 700km (not too bad in comparison to the volumes needed for a Dyson Ring). This is actually quite a bit smaller than Pluto. Mining out a few large asteriods might suffice (if they were made of the correct material).

Of course one has to consider the effects of light pressure on the mirror, which is a giant solar sail after all...