[TXnMA]

" Not enough Falcon 9 Heavy or Delta 4 Heavy rockets available for that!"

~~~~~~~~~~~~~~~

As we in engineering & science say, "That's about the size of it!" ;-)

The basic unit of measure for any beam weapon is Power Density on target. (i.e. watts/sq. cm.)

To overcome the inverse square law, that infers hellacious power (and power supply) -- and/or -- unheard-of collimation and focusing.

For simple ground attack, it's more "throw-weight-economical" to deploy kinetic weapons (e.g "Rods from God") than to deploy space-based DEWs.

TXnMA    
  

[Drago]

OK, you are getting past my level of knowledge in physics...(I didn’t stay at a Holiday Inn Express last night!)....but kinetic weapons from orbit look like a more viable (cheaper/actually deployable) option than “energy beams”.

https://www.nextbigfuture.com/2018/11/orbital-kinetic-bombardment-gets-close-to-nuclear-on-damage-and-cost.html