Tuesday, January 17, 2012

Space Infrastructure: How Much Stuff is Moving?

Just pretend they're friendly.
Space Infrastructure:  How Much Stuff is Moving?
 
         Greetings, RocketFans!  I wasn't sure if I would get the CASSTOR published on time, seeing as we had some nasty weather and use satellite Internet.  Fortunately, a reboot of, well, everything, fixed our issues and the CASSTOR is available for you right now!

         This week, I'm going to be talking about something I worked on this weekend:  Infrastructure.  I multi-planet trading network isn't something that can just be thrown together, after all, I takes all sorts of supplies and logistics to launch even one spacecraft.  How much then, does one need to launch a dozen, or a hundred?  How many cargo craft, tankers, and space stations are necessary to support an interplanetary vehicle, or a fleet of them?  The Black Desert is a setting that features over two hundred years of permanent presence in orbit and colonies on Luna, Mars, and scattered across dozens of asteroids in between.  This begs the question: just how much stuff is moving up there?

         In this pursuit, I was once again aided by the meticulous work of author and blogger Rick Robinson.  His essay on Interstellar Trade, which is easily convertible to interplanetary trade, provided both inspiration and a springboard for me to calculate all of the information you'll see posted this week.  So, without further ado, let's get to it!

The most important factor:  Money

         The first thing that must be considered is just how much money is changing hands.  Every other factor, from the number of tons of goods that move between planets to the number of flights an average space station sees a day is dictated by money.  The money spent on trade, in turn, is dictated by population.  Below is a table that shows the population of most of the major settlements and their Gross Planetary Product (GPP), as well as the amount of trade that translates into.  Let's take a look, shall we?

Table 1: Population, GPP and Trade
Planet
Population
Gross Planetary Product
Trade
Total import Tonnage
IPV Transpot Tonnage
% of IPV Transport
Terra/Luna
5 billion
1 quadrillion
3.75 trillion
116 million
1 million
(97%)
Hektor Node
2,000
200 million
100 million
3,000
1,000
(0.1%)
Paris Node
1,250
125 million
71 million
2,200
2,200
(0.21%)
Mars
120,000
60 billion
30 billion
923,000
9,000
(0.88%)
Agamemnon Node
1,750
175 million
76 million
2,300
2,300
(0.21%)
Achilles Node
1,125
112 million
56 million
1,700
1,700
(0.17%)
Aldrin Node
6,000
600 million
300 million
2,200
920
(0.09%)
Odysseus Node
?
?
?
?
?
?
Totals
5,000,132,125
15,013,420,000,000
3,780,603,000,000

116,941,400
1,022,520
(100%)


        There are quite a few assumptions built into this model which need some explanation before we move on.  You'll notice that the different planets must have different average wages per person for me to arrive at the numbers I've chosen for the GPP of the different settlements on the list.  Terra/Luna (from an interplanetary perspective, the two are a matched set.) with a fantastic GPP of one quadrillion, has the lowest annual earnings per person, at 20,000.  Despite this, with a population 3 billion lower than we have currently, the GPP is at least five times higher than 2012 estimates.  Then when you factor in the fact that 99% of the GPP has historically been held by only about 1%....sad, ain't it?
        Anyway, it would also seem that Mars has a GPP of a half-million per person, which seem far fetched until you realize that a 120,000 people living in an area half the size of all the land-masses on Earth means really large pieces of pie for everyone.  According to Bob Zubrin (and he should know, right?), there will be a chronic labor shortage on Mars that drives up the wages and will continue well into the late twenty-third century at the very least.

How much to import?
          This is another place where there is significant inequity between the numbers.  Terra imports less than 4% of its GPP in goods from space (It's only that high because of Luna's need for stuff that's cheaper to ship from Mars) while some of the asteroid node import over half their GPP in goods.  These colonies, especially the ones that support Nav Lasers, are not self-sufficiant and will starve without high imports.  Even Mars has a 50% import rate, due to the difficulty of making quantum computers and QOOR processors, which is the AI equivalent of biomass, from a certain point of view.

Why are the IPV numbers so low?
      The amount of tonnage IPVs carry is so a lot less than the total amount of tonnage.  The tonnage itself is calculated by factoring in the cost to boost to orbit ($20.00/kg)  and the cost of intra-orbital transport and other back-of-the-envelope factors.  The amount that IPVs actually ship is so low because most of the tonnage and all of the bulk cargo is carried via the asteroid cyclers of the Aldrin node.  IPVs only came into service at the start of the Great War, and while they are the fastest way to travel between worlds, they are also expensive compared to the cyclers.  The only exception to this is personnel transport; the difference between the consumables for a ten-week trip compared to a six-month cycler journey makes IPVs cheaper for passengers.

Table 2: Consumables and how they factor in
       In space, imports are not just a luxury, they are literally the stuff of life.  It takes air, water and food to just survive, and in many places most of these supplies must be imported.  Below is a table that explains how much of the import tonnage is just food and the like:

Table 2: Consumables Trade Percentage by Planet
Planet
Population
Consumable imports (%)
Annual Tonnage (Cost)
Terra/Luna
5 billion
-
-
Hektor Node
2,000
33%
1679 (53,720,000)
Paris Node
1,250
33%
1058 (33,856,000)
Mars
120,000
1%
3066 (98,112,000)
Agamemnon Node
1,750
33%
1450 (46,400,000)
Achilles Node
1,125
33%
949 (30,368,000)
Aldrin Node
6,000
10%
1533 (49,056,000)

      You'll notice that even for the Nav Laser installations, the consumables imports account for only a third of the total consumables needed.  This is based on the assumption that most if not all of the air and water is recycled.  This is a practical consideration, not a meta- one; IPV transport, the only kind that can reach the Navigation Nodes, is too costly to import water and air in addition to groceries.  The only reason these stations import even this much is that you don't want the hard SF analog of a Death Star to be self-sufficient.  It breeds insubordination.

What next?
         Now that we have some idea of the tonnage and costs of importing to the different locals in The Black Desert, we can start to figure how many ships we need to move the stuff and how big they have to be.  We'll pick up tomorrow with the cargo and propellant requirements to ship to the different planets, which will give us an idea of how much traffic they see on a routine basis.

         See you then, RocketFans!
  

2 comments:

  1. I do like the point about Death Star like stations being tied to a supply chain. Funny most people don't think about the other meaning of that phrase I bet.

    ReplyDelete
  2. Its a pretty hydrolic economy, as far as those stations are concerned, that's for sure. I would speculate that any attempts to introduce a permanent food supply to the Trojan Nodes would have to be dealt with harshly...

    ReplyDelete

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