AI becomes the tricky part, as has been discussed many times before regarding land units carrying other units.
1. BUT the AI can transport units over water, correct? So what would happen if we'd define Orbit (near earth), Space (between earth and moon) and far Space (between the earth moon system and mars / astroid belt) as "water"? This work similar like coast and oceans:
Ships can enter coast terrain. With Navigation, they can enter Coast and Ocean. With Advanced Rocketry, they can enter Orbit. With Astronautics, they can enter Space and another tech that unlocks far space.
The main problems I see here are:
- Units can enter Oceans before Navigation if these tiles are within cultural boarders.
-> Make orbit and space terrains in a way that they will never be in cultural boarders of anyone.
- When Rafts are able to enter Oceans after Navigation, they would be able to enter space after Astronautics... Which is theoretical possible (when someone decides to launch a rocket with it), but I can't see any scientific use with that experiment.
-> Caravels can enter Oceans before Navigation. Sooo... You could make Orbit etc be "enterable" with a very very late game tech: String Analysis. Or even better a pseudo tech that can't be researched. Then you can create units that are able to enter orbit etc. at the appropiated techs. I hope this is clear, but I'll give an example:
Caravel can enter Ocean when you can build them. Rafts can enter Ocean after the research of Navigation.
Rockets can enter Orbit etc when you can build them. Rafts and other Ships can enter Orbit etc after the research of "Tech that's non researchable.
Would this solve the Transport AI problem?
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Something completely different:
I'm about to make a three planets map (as discussed with Hydro). Unfurtunatly, the Southpole of the Moon (which IIRC is a very interesting area of the moon) won't be on the map. Also, I had a new idea about resources on other plantes:
Helium 3 and other ET (extra terrestrial) resources should not be visible after a certain tech. Instead you should have to send probes to the moon and mars and discover them. I was thinking of a modified great farmer code:
You can send a probe to a specific area of the moon. Then, there is a chance that they will find a ET resource reservoir. In game terms, they won't find any, but places one on the map. Later satellites and advanced technologies allow probes to prospect a greater area, like 3x3 plots where a resource can be found. It would be best if the chance of "finding" a resource is depending on a) the type of Probe, b) the type of resource and c) the terrain type. Like you can find Helium 3 more often in crates for example.
Of course, there has to be a cap on how many resources could be found this way on a given map.