Putting a telescope on any object with an atmosphere is a bad idea. Any atmosphere will screw up your pictures with clouds and dust. That's the reason all serious telescopes on Earth are on the highest points possible - to reduce that. You've still got problems though, just with the air being in the way. The best images of anything outside our planet all come from Hubble, which is up there precisely because atmospheric refraction is the limiting factor in getting decent pictures. Even if you're wanting to take pics of something in our solar system, Hubble in space is infinitely better than a telescope on Mars, even if Mars happens to be a bit closer to it (at certain points in its orbit anyway).
That's optical. If you're doing radio astronomy then refraction in air isn't an issue, but if you're looking for serious distance then you're using multiple dishes to give a larger baseline. Planets impose a natural limit to the baseline of your telescope, based on the size of the planet. Satellites OTOH can accurately fly in formation at huge distances, providing ludicrously large baselines which would never be possible any other way.