Interstellar Commerce

Hmm. You suggested some interesting directions... In my first post, I was pretty much considering straight trade between semi-established permanent colonies, there are other scenarios even in non-ftl settings.

One of the interesting things I ran across in looking up stuff for that reply was the time experienced *by the traveler*. See, time dilation applies to the mobile part, so, if you could accelerate to 99.99999% light speed quickly (hundreds of Gs), the trip to proxima centauri could be less than a day ship time. So, it *would* be possible to both ship perishables, even fresh foods, and to have a constantly awake crew traveling from world to world. Although the crew would be time-hoppers, because the round trip would still be 10 years planetside.

That assumes that the problems of very near light-speed travel can be solved. Those are not trivial, the interstellar media is sparse, but converting all of it to something equivalent to hard ionizing radiation is a significant issue. That and a dust particle impact being equivalent in energy to an nuclear bomb present some pretty heavy shielding challenges.

There is also a place in some STL scenarios for less than fully capable colonies, mining outposts, exotic waste disposal, hazardous processes, etcetera. Those would need most things shipped in, so there would be the place for shipments of PS-200s.

You're right that there would probably still be a place for slower than light shipment unless the FTL tech is an amazing macguffin. The parallel being: We ship overnight mail by air, fresh fruit by truck, and coal by rail. The cost per kg to ship, versus the value of the item also matters. We generally ship containers of cell-phones by truck even though rail is cheaper, because the shipping cost is insignificant next to the cost of the cargo.

As for the lead-times, a lot of industrial activities involve pretty long lead-times. For example, oil exploration activities are decadal endeavors. It takes 10-20 years between opening a new oil lease and full production, more for offshore. Pipelines take decades at a minimum between construction start and flow initiation. It's a hurdle, but not a barrier. Also on the lead times, if there is a steady trade in any given thing, then the lead times kinda lose significance, if there's a shipload of einsteinium coming in from Betelegeuse every alternate week, and a shipload of aeroponic nutrients heading back out every week (backhauls tend to be 1/2 price), then it really doesn't matter whether the current shipment left Betelegeuse yesterday or 500 years ago. Then it becomes more a throttling issue and less an order filling issue.

There may even be a place for shipment of more basic goods in a simple slower-than-light scenario, for instance, a star that recently underwent a nova or supernova would be unlikely to be able to easily produce food, but it *would* have unusually high proportions of heavy elements, so it might well be worthwhile to send food and get back rare elements.


Slower than light interstellar empires do not figure to go well (plot bait!). Look at the difficulties that even localized empires have in earth history, without constant contact, intermixing, etcetera, the colony and the crown become "othered". The colony becomes very very irritable about paying taxes :P That isn't to say that future-types won't *try*, but they will most likely fail.

Hmm. That brings up the difficulties of slower-than-light interstellar *wars*. Those mean that there is an absolute certainty of the tactical situation changing *dramatically* between the orders and the execution. Send out a fleet to counter a rebellion in Epsilon Eridani and it's 10 years dead minimum before it gets there. That'd mean that in order to maintain anything but a completely voluntary coalition, the home system would have to keep a standing fleet big enough to defeat their largest vassal system and anything their vassal could conceivably build in the entire transit time. That would get pricey!