On an asteroid for making telescopes, protect each formed telescope mirror from space junk by a long protective metal cylinder extending out shielding the telescope deep inside. Make this maybe protectively twice as long as from the mirror out to the microgridded image sensor where the reflected images get focused.
To thus protect a new robotically space formed telescope mirror from space junk, on a 50km, 100km, or 200km telescopes making asteroid of density 3g/cc, (Luna is 3.341), then .212%, .424%, or .848% of weights from Earth's surface gravity would easily let a long good shielding metal cylinder be used. (But actually, most space debris is not much bigger than a soft dirt chunk plus frosty dust, with little velocity difference from other things orbiting Sol nearby. On Earth, merely our atmosphere has normally been protective enough.)
Expand computer capacity to also accept and use fresh instructions from Earth, including preparing to collect lots of future images data wanted at low costs for approved astronomers. All this is robotically almost free, in great contrast to some past (not as big) telescopes man-made on Earth and expensively rocketed up into various orbits.
Several good wide telescopes can be formed all around the asteroid. These would be great for viewing anywhere, like viewing planets or their moons, or spotting asteroids, or seeing far out into our galaxy, and beyond. Astronomers should love all this.
Some telescopes may be made with mirrors more curved, to have shorter focusing length, to give less magnified larger area views, such as viewing local planet surfaces nearby. Many mirrors may be less curved, for longer focusing length, giving more magnified (smaller background area) views of a star.
New mirrors and other telescope parts can be tossed out from a telescopes making asteroid using a long cable hung out from the end of a well anchored high inverted L vertical axis motor. Then when weightless slowly orbiting the asteroid, these will easily be assembled into complete telescope etc., to then be ion jetted to wanted orbits around maybe Earth or Sol.
If the telescopes forming asteroid is of density 3g/cc (Luna is 3.341), then total escape velocities to toss loads totally out from a 50km, 100km, or 200km asteroid would be not too awfully fast about 33m/s, 65m/s or 130m/s, (73mph, 145mph, or 290mph), (about like spanning a sports field park in a second).
This is a guest post. Questions? Ask Iwas.A.Member@gmail.com. If interested in much more about advanced future folks living quite well in space, ask for DOS compressed email attached FBW.Z