Madowanai Hoshi 

The world is in devastation! Humanity is forced to live in domes to survive, with the elite living in the inner dome working in the animation industry, and the general masses forced to live in the outer dome, doing various jobs. The dome is masqueraded as an anime funland. The MC is a jaded man who works in the outer dome. The dome then receives a message from "Earth", and are then visited by aliens who look like cute girls. They introduce themselves as the "planets", with each girl having their own orbiting moon(s) (think of the microbes from Moyashimon). They state that they're here to help fix Earth's pollution, but they seem to prefer slacking off.