I've been on lots of forums and the structure you have going on here seems a little strange and random to me.
For instance i'd expect "Mappers - Exploring Rocky Worlds" to better reflect the "do science" section of the website with a subforum for each citizen science project.
There's not enough threads going on in "open source projects" to warrant 4 separate forums. Bleak forums never look good. You can always add more later if there's an actual need.
I'd separate news and site administration, Have open source pj as "Admin & Projects" with a subforum for site updates and one for the projects. Stick the lighthouse in here too.
then in General have the first forum as news and events which would naturally include hangouts thus negating the need for a hangouts forum. Make it so general ppl can't create threads.
Then join "Geology & Planetary Surfaces" and a "Cosmology" discussion forum into education
That would make
---News and Events
Listen, Learn, Teach, Engage
---Geology & Planetary Surfaces
Admin and Projects
---Open Source Projects
This seems like an organisation that makes a whole lot more sense to me. I like order. Just my opinion. But I don't know if you could with vBulletin, shuffle round forums and threads, if you wanted to. I'd do it, for you.