You can harden the payload but as Scott Manley mentioned in the longer video whilst you can chuck something out of this thing (or improved versions) at high speed you still need a rocket stage of some sort to finish the job off and actually inject that payload into a stable orbit.
It be interesting to see you can build a liquid fuel system (such as that hinted at in the diagrams/graphics in the video) that can survive the advertised g's or if it get’s done it gets done with solids.
As you rightly say ORAC linear systems have been proposed for decades..(from WW2 if not before)
Last edited by wiggy; 13th Nov 2021 at 09:14.
Reason: Morning edit