These are two major areas in Space where both Space Exploration and Astronomy might claim significant overlap, and I think it's worth exploring in more detail. What do we do with Planetary Sciences?
Planetary Sciences is the science of other planets, comets, asteroids, moons, etc. What is Jupiter made out of? Is there life on Mars? Are there valuable minerals in Asteroids?
These questions fall outside of the traditional realm of Astronomy, but are more sciency than most of the proposed questions on Space Exploration. I think these types of questions belong on one of the two proposals, and if we can figure out now how to distinguish them, both sites will be better off during the private betas.