Inhabiting geocentric orbit in permanent, comfortable structures will mark life's toehold into space. Once Asgard has reached maturity, humanity will finally have escaped it's gravitational confinement. Free of planetary constraints, we will rapidly develop into a space-based civilization. Initially using prefabricated modular parts sent up by the mass launcher, incrementally larger and more complex structures will be built. Once orbital fabrication facilities are constructed and asteroid and lunar mining is established, the rapid construction of adaptable Gravity EvoHabs will be possible, extending humanity's capability to exist in micro-gravity environments.
Zero Gravity Mining
The composition of the moon is 40% oxygen by weight, and the balance is made up of heavier elements such as silicon, sodium, potassium, calcium, and metals such as aluminum, magnesium, and titanium. The moon can provide us with 90% of the required materials to prosper in space. The missing 10% are the light elements such as hydrogen, nitrogen, and carbon. These can be found in asteroids. As it turns out, the Apollo and Amor families of asteroids are in our immediate vicinity, the former crossing Earth's orbit, and the later merely grazing it.
In space, energy is a much greater concern than distance. The amount of energy it takes to transport material from Earth to geocentric orbit is magnitudes greater than the energy required from the moon to geocentric orbit. Due to an absence of gravity, asteroid mining is the most efficient despite the extra distance. Using mass launchers powered by solar bubbles, mining outposts will be able to supply the inhabitants of Asgard all the material they require.
We will find that material decay and an expanding population will create difficulties in static habitats. Therefore the habitats that glide over the Earth's atmosphere will need to be modular in design. Using a protective outer shielding and a separate inner pressure shield, worn out parts can be replaced with ease, and sections of the habitat can be expanded and modified without compromising the integrity of the rest of the structure.
The rigid nature of the habitats will allow for artificial gravity to be created via rotation - a necessity for human space colonization in its early stages. Eventually the inefficiencies and engineering difficulties of creating a habitat capable of withstanding the stresses of centrifugal rotation will be eliminated as we progress our technology and our understanding of the human body.
The single largest problem for humanity's expansion into space is the deterioration of bone and muscle tissue in microgravity environments--informally known as space waste. Even consistent, vigorous exercise has difficulty overcoming this problem. Hypothetical solutions that have been proposed include biotechnology, nanotechnology, and tissue-friendly electric impulses, but at the moment a clinical solution for this problem does not exist. Until this pressing health issue is solved, a human's stay in an orbital habitat will be limited. Artificial gravity will slow space waste, but not stop it. This is a technical problem, and therefore eventually will be solved.