While lying awake last night a disturbing thought occurred to me. I am trying to make Aurora as "realistic" as possible, or at the very least internally consistent so I am probably going to have to tackle the following problem in v4.1.
A cryogenic transport module is 10 hull spaces, or about 500 tons, and can carry 10,000 colonists. It occurred to me that an average person weighs perhaps 12 stone (in UK terms), which is 168 lbs or 76 kg. If we round that to 80kg then a 500 ton module is 500,000 kilograms and is equal to only 6250 people even without the cryogenic equipment. Assuming the individual cryogenic modules weigh more than the person they contain, which seems likely even with advanced technology, then the cryogenic transport module is way too small, by a factor of somewhere between 4 and 5. Assuming the individual module+passenger weighs 250 kg then a 500 ton module would hold 2000 people, or the existing module would increase in size to 50 hull spaces and retain the 10,000 person capacity and the same cost. In the former case this effectively reduces the capacity of existing colony ships by eighty percent, which has significant implications for the speed and cost of colonization. In the latter case, colony ships would have the same cost but be almost five times slower, assuming the same engines. It's not quite as bad as it sounds because colony ships are effectively maintenance free so you can just build more without any long-term maintenance issues. I could also increase the chance of civilian colony ships to take up the slack. The upside is that colonization would be more realistic in terms of time and likely ship capacity.
This got me thinking about cargo holds as well. It's pretty unrealistic to think that five 500 ton holds could transport an entire factory complex, even if it is broken down for transport. That 2500 ton requirement should probably be more like 25,000 tons. Assuming I did increase the size of cargo holds by a factor of ten without changing their cost that makes cargo ships ten times as big and almost ten times as slow assuming the same number of engines.
In more general terms that would also mean that cargo ships and colony ships became much larger and slower than warships, which does seems more realistic. It would also mean that commercial traffic would almost certainly need jump gates, because of the individual ship size, and that jump gates would effectively become the sign of 'civilization'. Also, commercial shipping would require substantially larger shipyards, which would mean I would need to create a second shipyard type for commercial designs, which would be much cheaper to build and increase in size but would only be able to build non-warships. Again that seems realistic as in the real world there are many yards capable of building very large freighters but very few capable of building very large warships.
I would appreciate player thoughts on the above musing and the potential implications
I have also been considering ways to change civilian traffic, which partly would offset some of the above implications. At the moment, the reason that commercial traffic exists at all is not clear. The game assumes that colonists pay for their passage, which generates income for the civilian shipping line, and presumably infrastructure is a pre-requisite for colonization so there is a reason to deliver that in order to facilitate further income from colonization. However, that still doesn't explain why they would deliver colonists to some distant frozen wasteland instead of the garden planet next door.
Therefore I am tempted to create a contract system. A player would specify what needed to be transported, the start and destination systems and the wealth payment for delivery. Civilian ships would then fulfil that contract and receive the wealth. If there are multiple contracts available the civilians would decide which represented the best deal in terms of time required vs wealth gained, including the time to reach the start point. A contract might be "transport ten million civilians from Earth to Planet X for a total wealth payment of 1000". As individual ships transported colonists, they would receive a fraction of that amount based on the fraction of colonists transported. The chance of new civilian ships being built would be based on the number and type of outstanding contracts.
If I did this, the existing spaceport/convoy system would also be replaced with a new civilian trade system using a number of "export points" and "import points" building up on each planet. Civilian ships would look for opportunities to move export points to planets with import points. Each export point would be worth a set amount for the player and the civilian shipping line once it arrived. Civilian shipping lines would include these opportunities in their decisions regarding player contracts.
In the above scenario, civilian ships from one Empire could be authorised to fulfil contacts and export point transfers from another Empire. This could be allowed specifically by the player or perhaps as a result of a trade treaty. In this case, export and import points could be interchangeable between the two Empire so it would likely increase wealth generation.
One final option could be tarriffs for passage of ships of one Empire through a jump point controlled by another Empire. The amounts could be set by the player and control of key nexus system might be worth quite a lot in terms of income generated from tariffs. Civilian shipping lines would include tarrif costs in their consideration of which contracts to take. Treaties could waive the tarriff costs for specific Empires. All this would need a lot of work on my part but it would create a much more realistic civilian shipping scenario. It would likely generate a lot more traffic than at the moment and it would be distributed according to economic need. Protecting all that shipping would require naval forces
Steve