I also have a scifi-setting homebrew After Earth/Under the Red Skies. They are two distinct settings within the same universe.
After Earth is about humanity surviving on the outskirts of galactic community. Earth was destroyed twenty years earlier, getting caught in the crossfire of two ancient races (think Shadows vs Vorlons from Babylon 5)... All that remains of Earth is desolate world surrounded by a red cloud. The cloud blocks all scans and every ship that has gone in haven't come back up...
And you might guess what Under the Red Skies is about... Post Apoc Earth with nasty red clouds surrounding the planet....