There’s scintillation of the Interstellar medium, that is radio waves are affected by the interstellar medium on different paths. For my second year degree pro

There’s scintillation of the Interstellar medium, that is radio waves are affected by the interstellar medium on different paths. For my second year degree project we did a project on space based VLBI, being just theory we were looking at a bird cage orbit, as you go out further one needs to fill out the “UV plane” (I’m just recalling bits on my 6 week study on interferometry). ISM is a thing for continental VLBI, as pointed out by the head of Jodrell Bank when I went to a public out-reach talk in London. Whilst not interferometry it would (might) be good to have a Gaia type galaxy mapping mission further out, although it if there were a few satellites they could account for the larger orbits. I’m not sure if a birdcage orbit would improve things much the cost of having a high inclination orbit out of the solar plane would be huge.