I know for a fact it is gossamer thin. It does need structure, but there’s a fundamental limit to how small your spot size is anyway due to Conservation of Etendue, so small deformations aren’t a huge problem.
> Conservation of Etendue,
Sounds like you think I have in mind something like an Archimedes' heat ray. I do not see anything close to that for the presented satellites.
I would aver that the presented design is so far from being useful that making it useful requires solving enough engineering challenges to also enable an Archimedes' heat ray; but again: what is actually shown is not that.
The numbers I see from Reflect Orbital suggest they have an expectation of the apparent brightness fluttering by 5x from internal motion of the reflector. At the scale involved, may be easier to consider the imperfections/ripple as behaving the same as if some of the specular reflection becomes diffuse reflection.