You arrive at the 400KM Earth orbital transit station late as usual. Your approach was delayed because the gate was tied up. After checking through Space Federation customs you can now proceed by a different vehicle to get to your ultimate destination. No one actually lives in the transit stations, they are almost totally automated, most of Space is automated. To be exact, Humans are restricted to very specific areas in Space due to radiation. It has often been said that Space was made for silicon life forms, computers, and that Humans are just baggage.
Flight through Space is much different than the flight up from Earth. To get anywhere you take a short hop to the 800KM Brick Moon. An orbital transfer shuttle is just a collection of tanks, engines, passenger modules, etc., which travels back and forth in near earth space. The OTS engines are almost always nuclear thermal units with an ISP of about 3000. The Brick Moon is the remains of the four near earth asteroids pushed into Earth orbit by Texas Space Industries starting in 2010. After the minerals were mined and either sent down to Earth or used for solar power stations, the remaining slag was vitrified into massive blocks and used to create the Brick Moon. The moon's secondary function is an orbital mass to create a resonant gap in the debris ring that formed around Earth in 2030. The orbital gap created is a safe zone occupied by the 400KM orbital transit stations and other low earth orbit satellites. The moon's primary function is the base for the ElectroMagnetic mass drivers used to throw passenger and cargo modules to the Near Earth Colonies, or to the Lunar L1 Station. The BM supports a rather large community of residents, about 20,000. The flow of commerce through the BM has created it's own port city. The BM is pierced by the hollow tubes of the mass drivers and a warren of other tunnels holding various small colony hulls and modules. The great mass of the BM serves as an excellent radiation shield for the humans who live there.
The colonies located in geostationary orbit, at the Lagrange points, L4 & L5, comprise the Earth Space Union. Their construction differs somewhat from the Brick Moon. They are primarily residential and light industry colonies with large cylindrical hulls and detached shield cylinders.
Next issue, how to build a space colony.