For as long as I've been playing the settings menu is basically inaccessible while you are already in game because the game needs to rerender everything. Can this be changed?
i think it maybe harder to do that than it may appear. some of the settings only take effect when the planet is being generated, in example the texturing system generates the textures at the time of planet generation so when a setting is changed it needs to regenerate the entire system to regenerate the textures and map the lower/higher qualtiy textures to the sphere's I do understand your point that if you just go in there then back out it shouldn't need to refresh the game, but i think it's done as a precautionary step incase any settings are changed.
the planets don't actually un-render as per say. When you exit the setting page it forces a refresh to make sure any changes are forcibly applied to the game.
That's true. But an F5 refresh takes less than a second. Whereas this actually completely regenerates the planet. I understand what you're saying. But there are also lots of settings that appear client side only (e.g keybinds, some of the camera options and so on). And I don't understand why it needs to force the game to generate the system again.. Graphical settings taking a long time to recover from are a given. But changing the binding for your commander or reminding yourself of a couple of useful keybinds?
It's a bug. Opening up settings does not cause the planets to get "lost", rather leaving the settings menu is erroneously telling the game to rebuild everything. That said, it does make sense to make the settings a transparent overlay at some point.