Man, I just went to a good seminar today on finding habitable exoplanets that emphasized that we currently need ground based telescopes, because it is still impractical to make 30+ meter telescopes in space and would be very expensive, even if could be done. But progress is just launching a bunch of bullshit into orbit to avoid real investment in infrastructure like fiber and other telecommunication lines.
They can’t make them non-reflective enough to not interrupt really deep observing. Also, that just shifts the problem around. If they are absorbing in the visible, they will likely have huge amounts of blackbody radiation in IR, sub/millimeter, and radio. You would need to make a satellite out of dark matter to not interrupt astronomy.