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Old 11-18-2017, 07:13 AM   #1
AlexanderHowl
 
Join Date: Feb 2016
Default Does Interstellar Trade Make Sense For Realistic Science Fiction?

I was just curious if anyone else thought that the majority of the assumptions about interstellar trade did not make sense? Shipping essential materials lacking in a system? Yes, that makes sense. Shipping supplies for an outpost or a new colony? Yes, that makes sense. Shipping any raw goods between to established worlds? There is where I have a problem because of the markup for transportation costs.

In reality, the cost to operate a spaceship should probably be around 2.5% of its cost per month. A TL11^ Free Trader costs $94.3M, so it should cost $2.36M per month to operate. Since it has a cargo capacity of 300 tons, it should probably cost $10k per month to ship anything, since the owners will want to make a profit.

If we assume that it takes one day to leave the hyperspace exclusion zone, one day to travel through one parsec of hyperspace to a new system, and one day to travel from the hyperspace exclusion zone to the destination, the minimum travel time for short journeys is 3 days, around 10/month. That would suggest a minimum cost for interstellar transportation of $1,000 per ton, but the suggested rate in Spaceships 2 is $10 per parsec, which would bankrupt any owner within a year. The passenger rate would be 10x the cargo rate.

So, how do you deal with it in your games? Do you use the figures given by GURPS or do you use a more realistic approach? If you use a more realistic approach, what do people trade in your games?
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Old 11-18-2017, 07:51 AM   #2
Ulzgoroth
 
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

For realistic science fiction, interstellar goods transport would cost an absurd amount and take a long time, and basically makes no sense. But you're not talking that kind of realistic, with your 'hyperspace exclusion zone'.

So it looks like you mean economically realistic, given highly unrealistic technological premises that lift it to the point of being at least technically plausible. There's a lot of interesting things to be said, I think, about the extent to which a solar system would have reason to import or export goods rather than running an almost entirely autarkic economy. Though that isn't where you seem to be going either...


If the focus is on the profit/loss figures for individual shippers, first of all you probably shouldn't simply drop '2.5% per month' expenses as a fact on the ground without explanation. Where's that coming from? It's certainly not immediately obvious from Spaceships 2, which is where you seem to be deriving your other numbers.

Other than that, your accounting of the price of transport is simply incorrect. This is right in the book on page 41: "For voyages that involve a combination of deep space, interface, or stardrive travel, calculate the rate based on each leg of the journey.

In particular, many stardrives – especially jump and probability drives – function only in specific environments (far from a gravity well, at a particular jump point, etc.). For example, a starship may need to travel to a point at least 0.1 AU from a sizable planet before it can activate its hyperdrive. If this is the case, shipping rates are based on the sum of the deep-space and stardrive rates."

In short, you're not expected to eat three days of travel time for one day of payment. You get paid for the STL flight too.


Finally, the Dark Horse class free trader is not a design that's intended to be worth operating on milk runs. For that, you want the Anthem-class light star freighter, just above, with 50% more cargo capacity for less than a third the price. This is right in the descriptive text! The Dark Horse class is for adventurous operations that pull in a major hazard premium one way or another.
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Old 11-18-2017, 08:14 AM   #3
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

Quote:
Originally Posted by AlexanderHowl View Post
That would suggest a minimum cost for interstellar transportation of $1,000 per ton, but the suggested rate in Spaceships 2 is $10 per parsec, which would bankrupt any owner within a year. The passenger rate would be 10x the cargo rate.
Beyond Ulzgoroth's comments (which I support), if you want to use your own value for O&M costs then don't try to use the suggested freight rates -- use the value that makes sense in your setting. A rate of $1,000 per ton isn't bad, actually. It just makes your interstellar trade more like air freight than surface shipping: fewer containers full of t-shirts, more medical supplies and fresh fish.

At root, the question you have to answer for your setting is, "What is cheaper to ship than to manufacture in-system?" After all, a setting that can reach the next star system in a self-contained, reusable vessel probably won't have many problems mining asteroids and comets for basic commodities. If your freight rates work out low enough, comparative advantage may make shipping everything (except perhaps bulk construction materials) feasible. Colonies will often be established with an eye to what products they will produce for export. If your freight rates are high, the only things that will ship are luxury goods, unique biologicals, and information. Colonies will usually be established for social or political rather than economic reasons, with the intent of being entirely self-sufficient fairly quickly.
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Old 11-18-2017, 08:47 AM   #4
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

Quote:
Originally Posted by AlexanderHowl View Post
I was just curious if anyone else thought that the majority of the assumptions about interstellar trade did not make sense? Shipping essential materials lacking in a system? Yes, that makes sense. Shipping supplies for an outpost or a new colony? Yes, that makes sense. Shipping any raw goods between to established worlds? There is where I have a problem because of the markup for transportation costs.

In reality, the cost to operate a spaceship should probably be around 2.5% of its cost per month. A TL11^ Free Trader costs $94.3M, so it should cost $2.36M per month to operate. Since it has a cargo capacity of 300 tons, it should probably cost $10k per month to ship anything, since the owners will want to make a profit.

If we assume that it takes one day to leave the hyperspace exclusion zone, one day to travel through one parsec of hyperspace to a new system, and one day to travel from the hyperspace exclusion zone to the destination, the minimum travel time for short journeys is 3 days, around 10/month. That would suggest a minimum cost for interstellar transportation of $1,000 per ton, but the suggested rate in Spaceships 2 is $10 per parsec, which would bankrupt any owner within a year. The passenger rate would be 10x the cargo rate.

So, how do you deal with it in your games? Do you use the figures given by GURPS or do you use a more realistic approach? If you use a more realistic approach, what do people trade in your games?
It makes sense in my setting, because I don't use hyperspace. Or spaceships. Trade between worlds happens via trains, going through planet-based wormholes.
http://panoptesv.com/RPGs/Settings/V.../VergeTech.php
Trade between planets is every bit as viable as trade between, say, Lewiston, ID and Seattle, WA using train tracks and train cars.

Luke
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Old 11-18-2017, 08:49 AM   #5
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

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Originally Posted by thrash View Post
At root, the question you have to answer for your setting is, "What is cheaper to ship than to manufacture in-system?"
It's also worth keeping in mind the principle of comparative advantage. Even if some good is cheaper to produce locally, it's still worth trading for when you have even more of an advantage producing some other product. It's the relative differences in efficiency in each system that matter more than the absolute efficiency when it comes to driving trade.
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Old 11-18-2017, 09:11 AM   #6
Ulzgoroth
 
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

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Originally Posted by Anaraxes View Post
It's also worth keeping in mind the principle of comparative advantage. Even if some good is cheaper to produce locally, it's still worth trading for when you have even more of an advantage producing some other product. It's the relative differences in efficiency in each system that matter more than the absolute efficiency when it comes to driving trade.
That said, at least introductory models tend to treat transportation costs as zero.

In a super-elementary analysis, comparative advantage works when (letting A and B be costs locally and a and b be costs remotely, with transport cost T per unit):
B > b/a*(A+T) + T
or
B/A > b/a + (b/a + 1) * T/A

If your transport cost is high relative to the cost of your export, that's liable to get unattractive.
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Old 11-18-2017, 09:13 AM   #7
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

The GURPS Traveller: Far Trader supplement talks about this a lot, especially about differentials between rich high-TL worlds and lower-TL worlds, and how trade under comparative advantage can benefit both. I mean, otherwise why would anyone ship farm equipment, really? Granted, it's not the same system as used in Spaceships, but the economics is still there. You mind find it useful.

That being said, you're correct that it seems unlikely that bulk commodity trade will be profitable in almost any FTL scheme, short of making space travel as cheap as marine shipping on Earth. The rub is getting it to orbit in the first place, the cost of which nothing short of antigravity can fix. And reactionless thrusters help, too. Which is essentially the Traveller model. But if you want non-superscience (except for FTL), then it's hard.

Using any remotely non-superscience reaction drive, damned near everything on the Cargo Table on page 37 of Spaceships 2 is uneconomical to ship. Which is probably realistic. In such a scheme there are only a few things that might be worth shipping, such as colonists. Or information, if no FTL radio exists.

Last edited by acrosome; 11-18-2017 at 09:24 AM.
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Old 11-18-2017, 09:59 AM   #8
David Johnston2
 
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

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Originally Posted by AlexanderHowl View Post
I was just curious if anyone else thought that the majority of the assumptions about interstellar trade did not make sense? Shipping essential materials lacking in a system? Yes, that makes sense. Shipping supplies for an outpost or a new colony? Yes, that makes sense.
Actually interstellar travel doesn't make sense. "Realistic" universes would make interstellar travel so expensive and slow that nobody would do it. A realistic science fiction setting is one in which space travel is almost entirely automated and restricted to the solar system.

Last edited by David Johnston2; 11-18-2017 at 11:26 AM.
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Old 11-18-2017, 10:12 AM   #9
Ulzgoroth
 
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

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Originally Posted by acrosome View Post
Using any remotely non-superscience reaction drive, damned near everything on the Cargo Table on page 37 of Spaceships 2 is uneconomical to ship. Which is probably realistic. In such a scheme there are only a few things that might be worth shipping, such as colonists. Or information, if no FTL radio exists.
If you've got a TL10+ space elevator and don't need to cover too many AU under rockets, most of the cargo table is within the realm of possibility.

If you're lifting the stuff with rockets at the listed rates you lose most of it, though 10 of 36 entries remain with high enough price/ton to be possible.
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Old 11-18-2017, 11:16 AM   #10
jason taylor
 
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Default Re: Does Interstellar Trade Make Sense For Realistic Science Fiction?

Quote:
Originally Posted by AlexanderHowl View Post
I was just curious if anyone else thought that the majority of the assumptions about interstellar trade did not make sense? Shipping essential materials lacking in a system? Yes, that makes sense. Shipping supplies for an outpost or a new colony? Yes, that makes sense. Shipping any raw goods between to established worlds? There is where I have a problem because of the markup for transportation costs.

In reality, the cost to operate a spaceship should probably be around 2.5% of its cost per month. A TL11^ Free Trader costs $94.3M, so it should cost $2.36M per month to operate. Since it has a cargo capacity of 300 tons, it should probably cost $10k per month to ship anything, since the owners will want to make a profit.

If we assume that it takes one day to leave the hyperspace exclusion zone, one day to travel through one parsec of hyperspace to a new system, and one day to travel from the hyperspace exclusion zone to the destination, the minimum travel time for short journeys is 3 days, around 10/month. That would suggest a minimum cost for interstellar transportation of $1,000 per ton, but the suggested rate in Spaceships 2 is $10 per parsec, which would bankrupt any owner within a year. The passenger rate would be 10x the cargo rate.

So, how do you deal with it in your games? Do you use the figures given by GURPS or do you use a more realistic approach? If you use a more realistic approach, what do people trade in your games?
You are assuming that most trade is based on rational needs or wants. The most expensive products come from aesthetic instinct or desire to keep up with the Joneses. There is no obvious reason why any particular person needs beaver hats so much as to get into a multi-continent war to possess them.
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