[hattmall]

You 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.

[trhway]

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.