We're trying to be as inclusive as possible, without straying entirely outside of the space theme. Our working definition of "in space" is:

Some sort of intelligent beings in space at some point (before, during, or after canon) in a way that's significant to some aspect of the narrative.

At the moment, we're leaving "significant to the narrative" up to participants and trusting people will keep it in mind. But we do want people (of some sort) in space (at some point), and not just objects. So aliens yes; missiles and satellites, no.

Under that definition, I think War of the Worlds would be eligible. I'm afraid I don't know enough about Sailor Moon to render an opinion on that.