Satellites can theoretically all use Sun shade - a shield which is kept oriented to Sun and reflects most light back. This is not ideal for many reasons. More

Satellites can theoretically all use Sun shade - a shield which is kept oriented to Sun and reflects most light back. This is not ideal for many reasons. More weight to carry to orbit, another system to be kept operational. Some satellites need Sun visibility, shield may have some interference with satellite's radios. I'm sure more problems exist. Another approach - also not without problems - would be to aggressively deploy orbit-based telescopes, so they would have access to space above densely inhabited low Earth orbits. It also costs a lot, still leaves problems with ground-based observations, even though space-based tools have some advantages too.