Sunday, November 28, 2021


 To go back to a favorite topic of mine, let's talk about what the implied freight rate says about your setting.  Hopefully by putting something that feels abstract and not particularly meaningful in very concrete terms this post can provide a good framework for thinking about how your setting works.  It definitely informs what is and isn't being shipped. 

Before we begin, a note about assumptions -- a Mothership credit is worth between $1 and $5 depending on a lot of things.  As in my previous posts on starship economics, I've settled on about $4 per credit based on a basket of PSG and APOF items and services that aren't likely to change much in value in a retrofuture setting.  Other baskets may get a lower value.  So there's a bit of an error bar when you connect this stuff to the numbers in the PSG.  Relatedly, I assume (with a very strong basis) that shipping costs roughly reflect energy costs.  The ability to light a fusion torch implies other things about the economy (like how expensive fuel is).  Whatever number you pick has implications elsewhere. 

Also, remember that your freight rates are only a potion of whatever something costs.  The size of that portion is extremely variable and rests on a lot of boring economics but the short answer is that if it's cheaper to pay exorbitant shipping rates than set up a widget factory at the destination the widget will be shipped.  Colonial economies probably have some really bizarre price distortions as a result.  For example, if shipping costs are high and substantially exceed other costs you won't see much difference between luxury foods and regular imported foods (anyone who can afford not to eat locally produced algae glop will be eating lobster, caviar, and fancy steaks).

And now, examples:


$0.01-0.10/kg: This is not Mothership.  This is not even the Culture or Orion's Arm.  If you're shipping things over interstellar distances at the equivalent of one hundredth of the price of US mail, you are dealing with something unlike any society we can conceive of.  In any event, such a society can and will ship anything it wants for really stupid reasons.

$0.10-1.00/kg: This is also a really extreme situation outside of the realm of most fiction.  10x less expensive than utterly preposterous is still preposterous.  There's really no comparing a society like this to real life and again with the amount of energy involved, this society is going to be post-scarcity.  At cents per kg a person will travel for the cost of a short haul airplane flight or a particularly pricey bus ride. 


$1-$10/kg: This captures a lot of campy soft science fiction settings (and is within the range of postage rates).  If ships are small and cheap (closer to IRL trucks or boats in cost), you may see something like Star Wars.  If ships are large and expensive but shipping is cheap, you'll see something like Warhammer 40k.  Regardless, a passenger ticket will cost between $250 (250kg at $1/kg) and $5,000 (500kg at $10/kg).  The higher end of this category is probably the minimum rate that makes sense in Mothership.  You're making a choice not to to extrapolate a lot of complicated consequences but if you own that or find a way around it you're set.  Regardless, at this price, certain things simply won't ship (bulk goods like grain, iron, aluminum, etc.).  Large scale colonization is very viable and large numbers of people can be moved.  Moving a person and ten tons of stuff only costs $100,000.  

$10-100/kg: This is probably your setting! Most people probably fall on the lower end.  I fall on the higher end.  Regardless, bulk goods will not ship at this price.  Colonization will be viable but nontrivial -- but within the range supported by an indenture contract (or if you're a rich eccentric).  Even at the very high end, manufactured goods like guns, drugs, electronics, and complex machinery will definitely be shipped.  On smaller colonies there will be a serious shortage of nonessential heavy machinery (cars, etc.).  A truck will get shipped if it's necessary but the markup will be brutal (people do pay brutal markups for cars though -- just look at Singapore).  Most non-luxury food won't ship (hope you like algae goop!).  This is also the highest price you can plausibly get while having space truckers. Anything higher and you'll see commercial crews that look more like real-life 21st century astronauts.  Why?  Because crew weigh something.  And when payroll expenses are less than cost per kilogram you will prefer elite crews because they're more cost effective.  At most, passenger tickets will cost $25,000 to $50,000 (less if you skimp on weight).  Business travel is feasible at these prices (barely) but most people won't leave the planet they're born on except once as a colonist. Corps may prefer thin employees to save on expenses and the pre-flight scale will be as significant as the one before a boxing match.  I'll expand on this category in a follow-up post.

$100-1000/kg: This is the outer bound of settings in Mothership.  A colonist and the things needed to start up a colony will cost as much as $10,000,000.  If you cut weight aggressively the price goes down to something affordable in exchange for greater risk of colony failure and very perilous setups.  Most goods won't move at all but small colonies will pay obscene markups for essentials (or revert to barbarism).  For what it's worth, it costs about $1,400/kg to launch something on a Falcon Heavy.  You won't see much trade and colonies will probably require heavy subsidies.


$1000-10000/kg: This is comparable to the cost to launch something into orbit.  If you're a human, you'd better be worth spending two to five million dollars on.  Change "Teamster" to "Payload Specialist."  This isn't entirely outside the realm of playability.  With very rich sponsors or very strong pulls, there is stuff that can profitably be traded at this price.  Avatar is the easiest fictional example, but all sorts of exotic drugs (or better yet, just the knowledge of them).  Valuable data will also ship (because a jar of SD cards is very cheap).  Certain very expensive foods ship too!  Saffron costs $10,000/kg and a further 50% markup is not out of the question.  While the ability to engage in large scale space travel probably means that metal prices are a lot lower than real life if they aren't for some highly unlikely reason, gold and other similarly rare metals are worth moving at this price.  

$10000-$100000: Certain very, very unusual cases might support trade.  But this is probably the outer bound for any kind of interstellar exploration.  If somebody has a magical antimatter well, trade makes sense.  Likewise, exotic biologics and scientific data may be profitable (but better to send back the information).   Cynical corporations may prefer to strand people (in the name of science!).  Return shipping probably isn't worth it.



  1. Hey, great post, but why are passenger costs so high if the average cost by mass is 3500? Is the extra the cold sleep pod, and luggage?

  2. Passengers pay for life support, consumables, space, redundant systems because they're alive and want to stay that way, etc.

    I assume this comes out to about 500-1000kg.

  3. (And also there's a premium for passengers)

  4. This kind of analysis is always important, whether in a sci-fi setting or a fantasy one. Shipping costs explain a whole bunch of how society ends up working.

    Battletech's shipping and transport numbers have always been surprisingly thought-through, for another point of comparison that Mothership players and GMs could draw on.

    But what really interested me was how transport to the New World worked. I realized I didn't actually know, so did some brief digging.

    So it turns out this is really variable (unsurprisingly), but apparently your average indenture contract was apparently about double the actual cost of passage, and was about 10 or 11 pounds (with an expected four year term). Some sources say this was double a labourer's yearly income. Appears to be about 8 months for a skilled tradesman. Figure a modern value of maybe 80K.

    Looking at labour rates for the colonies at the time (and for England), an indentured worker, even just a labourer, would seem to work that off in just four or five months (and that's the worst case). Local currency is wildly variable, but even so that's surprisingly quick.

    Perhaps more interesting, it has a modern purchasing power of about 1300 sterling. Assuming a 100kg for a person and their stuff (and that may be optimistic for the era), that suggests shipping to the New World had a value of about $26 a kg.

    I did a lengthy post on Reddit once comparing 19th-century steamship frequency to jumpship frequency in Battletech. Think of a feel for your universe - set shipping costs accordingly - wait for logical results to occur is a surprisingly effective method.