I suspect it wouldn't be easy to incrementally build up a single large aperture because the secondary optics needed would be different at each size. If we buil

I suspect it wouldn't be easy to incrementally build up a single large aperture because the secondary optics needed would be different at each size. If we build telescopes for optical vlbi we could build a fleet to have the resolution of a telescope kilometers across... I believe VLBI has been accomplished experimentally at MWIR wavelengths.