Liner operations with the Eichberger Drive

spaceships
faster-than-light
transport-economics

#21

Ugh. I forgot to modify for thrust.

These vehicles are going to have to be warped into their docks.


#22

That’s presumably OK for the big ones: like sea ships, they don’t go to places where there is no dock for them.


#23

I haven’t finished the fare & freight estimator — it doesn’t calculate the mass and luminosity of the stars given the stars’ spectral classes and the planets’ relative positions in the Goldilocks zones yet. And fares don’t include the services of stewards and corporals yet either. And everything needs checking: I’m a bit puzzled that fares are so high compared to freight*. But it’s late here, so I’ll finish that tomorrow.

But preliminary results are available.

For a trip from a typical planet orbiting a typical G1 start to its very similar nearest neighbour at average nearest-neighbour distance, the freight rate is $361/ton in the large carrier and $403/ton in the feeder, not including the ground-to-orbit legs, not including loading and unloading, not including docking charges, and not including insurance.

For the same trip the basic fare (i.e rent of a compartment, no personal service, no amenities) is $3,294 in the feeder and $3,290 in the large carrier.

In longer trips the large ship pulls ahead. At 148 light-years (migration from the Core to the Fringe, perhaps) it’s $845 per ton and $9,709 in the large carrier, but $1,058/ton and $10,493 in the feeder.


* A passenger compartment is eight tons. That seems high.


#24

7½ or 8⅓ depending on which rounding you use…

But that’s one or two berths, plus immediate locker space, plus a slice of air- and water-recycling, plus a slice of climate control, plus a slice of those “sanitary, galley and dining facilities” – plus structural support to make it all into a working spaceframe. I haven’t broken down individual components, but that seems to be about the right order of magnitude.


#25

I’m going to be less enthusiastic about providing facilities, and less skeptical about shared staterooms. Also, I’m going to push more strongly for hibersleep compartments to pack more people in.


#26

If your hibernation works reliably, by which I mean “if you die on a space voyage it isn’t because of the hibernation”, then there’s no reason not to encourage everyone to use it. In a more conventional SF game this would remove the possibility of shipboard shenanigans, but I think that’s not what Flat Black is intended for.


#27

So: high-automating a workspace costs G$1.111 million and saves G$67,000 per annum in wages, a return of 6.05% p.a… I’m assuming 8% p.a. interest, depreciation, and insurance. Automation is only financially viable because you also save habitat and food for the technicians as well. Each compartment is G$167,000, bringing the net cost of automating down to G$0.944 million and the return up to 7.12% p.a.

Then I notice that at SM+10 and larger habitat systems have workspaces, which makes them just more expensive than in smaller ships.

Dunno. I think I’m pushing a system that rounds things off to the nearest half-order-of-magnitude, and that is based on tech and cost assumptions that weren’t made carefully for economic modelling, a bit further than it will go. I’m getting a ballpark figure, and that will do.

Notice in last night’s results that the making the trip ten times as long only increased the freight and fare by about 2.5 times? That’s because of the cost of propellant for the reaction drives at the beginning and end of the trip.

If I use inexpensive water as the propellant instead of hydrogen the large ship benefits more than the small one because tankage eats into its proportionally larger payload proportionally less. The freight rate comes down to G$58/ton and the fare to G$762 per compartment for the 14.8 light-year trip. For the 148 light-year trip the freight rate is G$543/ton and the fare is $7,227 per compartment.

Comparing a zero-lightyear trip with a 100-lightyear trip I get:

Freight rate, per ton:

  • G$ 4.39 + G$ 3.64 per light-year in a large carrier
  • G$ 5.14 + G$ 4.92 per light-year in a SM+9 feeder

Fare, per compartment, no service

  • G$ 43.43 + G$ 48.53 per light-year in a large carrier
  • G$ 45.00 + G$ 54.05 per light-year in a SM+9 feeder

By a quirk of the rounding, adding a 10% margin for safety to the fuel load doesn’t affect the large carrier, but it reduces the payload on the feeder, increasing the freight rate to (G$ 5.66 + G$ 5.35 per lightyear) per ton, and the base fare to (G$ 48.15 + G$ 57.38 per lightyear) per compartment.

I’m not sure that this is worth chasing a lot further. I think any further refinement will be small compared to the rounding errors, GURPS Spaceship v. Flat Black differences of assumptions, and the generous margin of profit that the Foundation cuts itself to fund the Empire. I know what to write about the technology used and I’m confident in saying that interstellar travel is kind of slow and not terribly expensive.


#28

I have done some shipboard shenanigans and onsen episodes. The trick is to assume that the hibersleep drugs leave you feeling awful for three days (-1 to all activity, EN roll at the end of each 24 hours to recover) and that you lose physical condition while you are in hibersleep as though you had spent the time in idleness. The Navy won’t put marines in hibersleep in case it needs them without about a week of warning, Survey specialists will refuse, and on a liner only the cash-strapped dregs (migrants) will travel that way.


#29

Or they stop in orbit with no need of precision manœuvring and small, nimble shuttles with high thrust dock with them.