> Are we reaching the point of diminishing returns of what a reasonably sized (for our current rockets) space telescope can see?
In terms of sensitivity, yes. Collecting more light needs more light-collecting material, which ultimately means more mirror, or detector, surface area. Little more gain to be had there. We're not going to see much more that's really, really faint.
But we're just getting started with resolution. Apertures can be synthesized in software. Theoretically, a handful of space telescopes, orbiting the Sun, linked together, could have an angular resolution equivalent to that of a physical telescope with a mirror the same diameter of the orbit. Not the light sensitivity (since the "mirror" is mostly empty space), but it would have the ability to distinguish between two points like such a giant telescope would.
This has been done with radio astronomy already; things have just recently gotten fast enough for aperture synthesis at infrared wavelengths; optical is probably not too far behind.
I think optical is pretty far behind. EHT was already dealing with 100s of TB of data per telescope. Going to visual turns that into ~10s of PB. I think the more likely advance is some way of doing space based radio wave interferometry.
In terms of sensitivity, yes. Collecting more light needs more light-collecting material, which ultimately means more mirror, or detector, surface area. Little more gain to be had there. We're not going to see much more that's really, really faint.
But we're just getting started with resolution. Apertures can be synthesized in software. Theoretically, a handful of space telescopes, orbiting the Sun, linked together, could have an angular resolution equivalent to that of a physical telescope with a mirror the same diameter of the orbit. Not the light sensitivity (since the "mirror" is mostly empty space), but it would have the ability to distinguish between two points like such a giant telescope would.
This has been done with radio astronomy already; things have just recently gotten fast enough for aperture synthesis at infrared wavelengths; optical is probably not too far behind.