>Using a 700 Isp laser-thermal engine on the lower stage of a 50 ton rocket requires more than 2 GW of laser power to lift off the launch pad. Accounting for inefficiencies, between 5.5 and 18GW of electrical power has to be fed to the launch facility.
Oh that's all?
And you're going to avoid having to spend $600 billion on the equivalent of four Ōi Nuclear Power Plants by wishing a practically impossible flywheel proposed as an exercise in engineering optimism over 30 years ago into existence?
Sweet!
To put less than the payload of a single Falcon Heavy into space?
Why build one when you can have two at twice the price!
edit: forgot the 90s were 30 years ago.....