alt Hacker NewsYou would need like 1,000,000,000,000 SQFT of solar panels to even begin to approximate a space based directed energy weapon that has a fraction of the effect of a nuclear weapon. Tens of thousands of times more than all that have ever been produced on earth. And then you have to move them to space.
nuclear was the only available solution at the time and an overkill. The lasers in SDI are MW scale. Even at 10% (and modern solid state lasers have better than 10% efficiency) we're talking low tens of MW per laser. A 10MW is 40K m2 of solar panels - 200m x 200m, may be like 100-150 tons, one Starship payload.