It would be really cool to have an array of space-based telescopes spaced out evenly in the Earth's orbit around the sun, and use each as relay for the others t

It would be really cool to have an array of space-based telescopes spaced out evenly in the Earth's orbit around the sun, and use each as relay for the others that cannot directly communicate with Earth, because the path is blocked by the Sun. Then you could do observations outside the solar system's orbital plane with a 2 AU synthetic aperture. And maybe even do double duty as a gravitational wave observatory. (And yes, this is currently more science fiction than science, but it's at least plausible that we can build such a thing one day).