In a future where space travel is common, how would access to space be regulated?
From what I know, currently the International Telecommunication Union (ITU) assigns slots for geostationary satellites (since the range of geostationary is essentially one-dimensional and otherwise interference would commonly occur). Also, there are strict requirements for spacecraft approaching the International Space Station (ISS). Otherwise, even though some spacecraft coordinate their orbits otherwise there is no control and operators are free to choose whatever orbits are convenient.
This works for now since launches are so (relatively) infrequent that there's little chance of two operators choosing the same orbit and not finding out until they both launch. Also, launches are not a huge deal for airplanes since the Federal Aviation Administration (FAA) will declare a temporary flight restriction (TFR) for the area around the launch.
If spaceflight is common to the point where launches occur once or more per day, then both of these situations would have to change. Spacecraft would have to have some way to coordinate with each other and with aircraft: essentially a Space Traffic Control. How would a space traffic control (STC) compare to modern air traffic control (ATC)?
Here are the three scenarios I am considering:
- Reusable rockets: While everyone was busy trying to figure out how to make spaceplanes work, SpaceX surprised everyone by making the traditional two-stage, liquid-fuel, vertical-stack rocket reusable. Everyone adopts their approach: take off like a modern rocket, but each stage flies right back to the launch pad, ready to refuel. The only consumables are fuel and capsule heatshields. Launch costs drop from thousands to hundreds of dollars per pound. Spacecraft spend little time in the atmosphere on both launch and reentry, so there is little interference with aircraft.
- Spaceplanes: Virgin Galactic eventually made it to orbit with SpaceShipFive, their latest air-launched, rocket-propelled spaceplane. Payloads are small, but launch costs are still quite low. Spacecraft now spend much more time in the atmosphere, but act like modern planes while attached to their motherships, and like gliders during reentry. They take off and land from ordinary runways, whether at ordinary airports or specialty spaceports.
- Airbreathing Single-Stage-to-Orbit (SSTO): The holy grail of space travel. With nanotech-age advancements in materials science, we finally made it—-albeit still with razor-thin margins. The extremely complex engines required push the limits of what's physically possible and, while they don't need quite as much maintenance as the Shuttle did, that's not saying much. It's barely cheaper than traditional rockets. They spend a good deal of time in the atmosphere at supersonic speeds, making them a hazard to buildings as well as aircraft. However, they are useful for turning 18-hour flights into one-hour flights.