Further brainstorming over a solar array / weapons defense system did produce one interesting possibility: a low-cost space-based mirror array for CSP (concentrated solar power). The idea seems silly at first glance because it seems far easier to place the optics on earth close to the energy converting apparatus – however some out-of-the-box thinking (as shown below) reveals that space-based optics could be far easier, cheaper, maintenance free, and effective than an earth-based solution (note that optics can be the biggest cost and maintenance for CSP):
1) Orbiting the earth are giant concave mirrors (parabolic in shape), each 7 square miles in area made from ultrathin reflective fabric (like mylar) stretched between 3 structural points (2 miles between each point in this example). Each mirror keeps its parabolic shape by solar wind. Secondary optics are also located at the focal point of the mirror and continually adjust to redirect the beam of concentrated light back to a receiving solar plant on the earth where the suns rays would be converted to usable energy.
Above: a small section of a giant array of parabolic reflective fabric mirrors.
2) Innumerable additional 7 sq.mile mirrors can be simply added, each requiring only one additional structural point, 7 more square miles of reflective fabric, and optics at the focal point of each mirror to send the concentrated solar power to a receiving solar plant on earth.
3) The incoming solar power would be distributed among receiving solar plants strategically placed on earth, so each plant would receive the maximum amount of suns possible without damaging the energy conversion facilities. Maintenance could be performed on these earth-based solar plants at night.
The solar reflectors, being in the vacuum of space, would never require any kind of maintenance. Periodic adjustments can be made to keep them approximately facing the sun via temporarily collapsing one mirror to let solar wind push the array back into orientation. The focal point optics necessary to send each mirrors rays to the right location on earth would be powered by solar power of course.
Oh yeah, another thing … this can indeed also be used as an anti-missile defense system if multiple arrays are used, providing round-the-clock protection, while being tons cheaper than any other Star-Wars type technology. It overcomes all the problems of the Solar Missile Defense scenario posed below and has countless advantages.
Also, nighttime surveillance in other parts of the would could be as easy as turning on a light bulb, and can you imagine the psychological effect it could have on the enemy?