As the SPS program expands, at first thousands, then tens of thousands of people associated with SPS construction begin to live for longer and longer periods in space. However, the workers soon become dissatisfied with their accommodations. Gradually, a part of the output of the manufacturing facilities is diverted to the construction of a large space habitat which creates an Earth-like environment for it's inhabitants. The space habitat is a sphere or cylinder rotating to provide simulated gravity equal to Earth's. Sunlight is brought into the interior with mirrors.
Lunar soil is landscaped and planted to produce a very natural appearance.
Later, much larger habitats are built big enough to have a blue sky with cloud formations and natural weather. As we go farther afield for space resources, the asteroid belt is opened up. The asteroids provide elements the moon lacks like hydrogen, carbon and nitrogen. All dependence on Earth for supply is finally severed. With large human populations now scattered throughout the solar system, no single global catastrophe can wipe out our species.