To get this resolution without the magnifying power of the Sun, we calculate that you would need a telescope with a diameter of about 75,000 kilometers, or about six times the diameter of the Earth. This is, to put it mildly, impractical.
...
No it wouldn’t.
https://en.wikipedia.org/wiki/Astronomical_optical_interferometry
Using the sun for gravitational lensing would be far more impractical.
For instance, why not build an interferometer the size of the solar system? Imagine what we could see with that baby!
But I've been told there are problems that will need to be overcome. Cost is a big problem, but one article I read said flying such a large formation of telescopes in rock solid unison down to a fraction of a wavelength is a big problem.
Not sure why, myself. I mean, if you look at a parabolic mirror, it doesn't matter which precise bits are present, only that they are present and span a great distance, and any variance could, it seems to me in principle, be fixed with signal processing and correction. Does that sound feasible to you?
Anyway, I'm on board with space-based optical interferometry!