Spaceport types


#21

No prison worlds, but there are places where the O spaceport is owned by the Eichberger Foundation and where the Empire has reasons not to keep stuff on the ground. I’ll change “from the surface” to “to the surface”.


#22

Make that “in high orbit”. If you leave something in LEO for many years, it will come down.


#23

True, but I suppose that a liner will show up at least once every five years to replace Imperial personnel whose postings are over, and that at that point the shuttle will be serviced, fuelled, used, and returned to its proper orbit.

Perhaps “mothballed” is the wrong term.


#24

Hard numbers are depressingly scarce, but the ISS at 420 tons and about 400-410km over Earth gets through 7.5 tonnes of chemical rocket fuel per year. I suspect fuel requirement will scale with about the 5/3 power of mass (mass × frontal area), with good aerodynamics and better engine ISp reducing it.

Put the thing up at 700-800km and you can leave it for years, as long as you don’t need to maintain a specific ground track.


#25

Good point. It also has a strong influence on freight costs, if you aren’t assuming antigravity or reactionless thrusters. And that dictates the transport-cost wedge between different planets’ price ratios.


#26

I suspect that a society with a mature space infrastructure regards the orbital port(s) as the primary ones: once that stuff is working, it’s easier to do maintenance, and store shuttles out of the weather, in zero-G. There’s obvious scope for things like customs posts and bonded warehouses to be safely away from the planet. And so on.

So a ground-facilities-only world, to me, is one that has so little traffic that these advantages aren’t worth the fairly small construction and maintenance costs.


#27

Right. Type N and G spaceports are associated with small economies and low DL. I’m using the ForeSight algorithm, which I will reconsider after I’ve produced an algorithm for trade volumes that is worth basing anything on.