A superhot 900 deg. Kelvin "death ray", as it's been called, with a 40-kilometer beam spot size would set an entire city on fire almost instantly without any radioactive fallout. And the ash sent into the atmosphere might also trigger a mini-ice age that could last a few years even after the fires are put out. Who would have thought that renewable energy could be so destructive.

What might prevent the weaponization is:

- the delay of eight light-minutes between the Sun and Earth and switch-on/switch-off ability.
- difficulty in the assembly and modularization of a diffraction-limited lens.
- lack of radar for tracking satellites in close orbits around the Sun.
- difficulty in maintenance or servicing.
- no countermeasures.
- funding.