I played a PC game called "Osmos" (http://osmos-game.com/) like back in 2012 or so. It has all this electronic ambient music as the soundtrack. However, the soundtrack is not created for the game. Rather, the soundtrack is a selection of pre-existing tracks already produced by a few electronic music artists. The link above is one of my favorites. Source: almost 2 years ago

You can physically demonstrate orbit with some fabric stretched over a frame, but I really think video games are going to be your best friend here. Osmos (Free demo, $5 full) is a great starting point that uses simplified gravity in two dimensions. Orbit (Free app, $5 on Steam) is another, similar game to introduce orbit. Once you've graduated to three dimensions, Universe Sandbox ($30, $20 on GOG) will really... Source: almost 2 years ago

When you said hopefully to include player campaign notes, I thought of kanka. It's somewhat less feature-rich, I think, but it is potentially-free and collaborative. Source: almost 2 years ago

Our group has been using Kanka (https://kanka.io/en) for the past few years and it’s been super helpful. Source: almost 2 years ago

Some people I know have recommended kanka: https://kanka.io/en. Source: over 2 years ago

I use Kanka, I’ve found it to be excellent. A few key points: - there are loads of different page types you can create, characters, locations, organisations, items, it’s quite varied. Although you can’t make custom ones I’ve never needed to. - you can easily link to other pages within your Kanka campaign by typing and @ followed by the name of the page, so @Barry will pop up a list for you to select from your... Source: over 2 years ago

I've also heard some pretty good things about Kanka (https://kanka.io/en), though I haven't tried it myself yet. Source: over 2 years ago