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Economics of Spaceflight – part 1b – Starliners

Last week we looked a bit at the logistics of running a passenger transport system between the various worlds and saw that if you wanted daily flights between all the worlds, you’d need over 600 ships.  And that would only give you 250 people moving between each world each day.

Now you can change that a bit by making the ships a bit larger or increase the passenger density. But it gave us a feel of what assumptions or changes you need to make to your setting if you want a certain level of interaction between the worlds.  Or if you limit the number of ships and passengers, some ideas of what impacts that has on the culture and setting.

In this article, I am going to look at the financial side of the passenger transport business.  We’ll start by actually designing our starliner to get an idea of costs and expenses, look at ticket prices, and decided if it is even worth it.  Then we can talk a bit about other changes that we need to make, if any, to make this all make sense.  Let’s get started. You might want to settle in. This one is a bit long.

Our Ship

If we’re going to look at economics, we’re going to need details on the ship.  In the last article, I based everything on a HS 10 starliner. We’ll detail that ship out and look at its cost. 

Hull and Engines

As a HS 10 ship, it will have three engines, which from the discussion last week, are atomic.  I realize now that as a passenger liner, maybe we don’t need the power of the atomic engines and can get by with ion engines. Surprisingly, in the discussion that the previous post generated, no one mentioned that.  It would also save on the overhaul time as ion engines don’t need that so the ship could be turned around in port more quickly.  But for now, we’ll stick with the atomic engines.

Cabins

The next major question is how many of the various passenger berths we have of each class.  We have a total of 250 berths.  Journey class are the standard.  Interestingly, the only safety requirement listed in the rules is that a spacesuit has to be provided.  You don’t actually have to have lifeboats for everyone. First class berths are more expensive and require more cabin space, cargo space, and facilities for the passengers. And do need access to a lifeboat.  Storage class cabins are cheaper for the passenger and have minimal storage space, but are more expensive to install in the ship, costing as much as a First Class cabin. With the standard starship construction rules, these tradeoffs really don’t affect the design of the ship other than the final cost as the system doesn’t really account for the space and facilities needed.  So for this analysis, I’m going to roughly base these ships on our modern airlines, with most of the cabins of the base Journey Class category with a few First Class and some Storage Class.  The breakdown will be 40 First class, 180 Journey Class, and 30 Storage Class.

Crew

The other major decision is the size of the crew.  We will need to purchase cabins and life support for them as well.  The rules give no guidance on this.  Looking at cruise ships, it is about a 1-to-5 ratio, crew to passengers.  Some of that, such as janitorial and maintenance work, will get automated away to robots on our star liner, but then we’ll need people to look after the robots as well.  We’ll design the ship around a crew of 50.  We’ll talk about the breakdown later when we have to figure out what they are paid.

Ship Vehicles

While we only need lifeboats for the First Class passengers, we’re going to have lifeboats for all of the passengers (except Storage Class, that’s just one of the hazards of the cheap fare, you are frozen and can’t get to a lifeboat) and the crew.  And we will toss in 10 escape pods so not everyone has to make it to a lifeboat.  As the final vehicles, we’ll add in 5 large (10 being) launches for shuttling people around between the station and ship, 2 small (4 being) launches for the crew’s use, and 2 workpods for ship maintenance.

Spacesuits

We are required to have spacesuits for all of our non-Storage Class passengers.  Plus we’ll have them for the crew as well.  Technically, each species has its own style of spacesuits adapted to their physiology.  The rules, however, only distinguish between vrusk and non-vrusk as they are only really concerned with cost and the standard spacesuit is 1000 cr. while the vrusk suit is 1,500 as they require more material.  If we assume that vrusk make up one quarter of the crew and passengers, and we build in a bit of buffer in the numbers to account for varying numbers of the different species, we’ll get 80 vrusk spacesuits and 220 non-vrusk ones.  This is 300 total, which is exactly our crew and passenger count but remember that the 30 Storage Class passengers won’t be using one so we actually have 30 extra.

Robots

There will be a number of robots on board to handle things like cleaning, maintenance, some food production, etc.  We’ll design the ship to have 50 robots, basically doubling the crew size.  These will be a mix of level 3 and 4 service and maintenance robots, will possibly a small number of security robots.  Overall the average cost of each robot will be 4,000 cr.

Other items

There are a number of other items that go into building the starship such as radios, intercoms, computers, portholes, Velcro boots for crew and passengers, toolkits, etc.  We’ll add those in as appropriate and list the details in the final stats when presented in the next section:

PGCSS Prenglar Glory

Here are the full KH stats for the ship along with its price tag, fully fueled.

HS: 10
HP: 50
ADF: 3
MR: 3
DCR: 50
Engines: 3 Class B Atomic, 6 fuel pellets each

Communications Equipment:  Videocom radio w/ 4 extra panels, Intercom system: 5 master panels, 400 standard panels, Subspace Radio
Sensors: 400 Portholes, radar, camera system, starship astrogation suite
Weapons: None
Defenses: Reflective Hull
Life support capacity: 500 beings, 200 days with full backup
Passenger Accommodations: 40 First Class cabins, 180 Journey Class Cabins, 30 Storage Class cabins
Crew Accommodations: 50 Journey class cabins
Vehicles: 10 escape pods, 14 lifeboats, 2 workpods, 5 large launches, 2 small launches
Computer Level: 4 (175 FP)
Computer Program: Drive 5 (64), Life Support 1 (4), Alarm 3 (4), Computer Lockout 4 (8), Damage Control 3 (8), Astrogation 4 (24), Cameras 1 (1), Robot Management 4 (16), Information Storage 3 (8), Communications 2 (6), Installation Security 3 (12), Computer Security 4 (16), Maintenance 2 (4)
Backup life support computer: Level 1 (4), Programs: Life support 1 (4)
Robots: 50 level 3-4 maintenance, security, and service robots
Other equipment: 220 non-vrusk spacesuits, 80 vrusk spacesuits, 300 velcro boots sets, 5 Engineer’s toolboxes, 10 sets of Magnetic shoes
Cost: 5,658,000 Cr.

The Ship’s Crew

Now that we know the design of the ship, we need to decide on crew makeup.  This will determine the wages owed as we operate the ship in the space lanes.  This is going to be an approximate mix.  The exact details may vary ship to ship but will give us a starting point to figuring out the operating costs when we get to that stage.  The crew makeup I settled on, allowing for round-the-clock operations is:

  • 2 Pilots – level 5 – necessary to operate a HS 10 vessel
  • 2 Astrogators – level 3 – It’s an established route so these could be even lower level
  • 2 Engineers – level 4 – as discussed last week for effecting the engine overhauls
  • 4 Technicians – level 4 – assistants to the engineers and helping with on-board maintenance
  • 4 Roboticists – level 4 – maintain the ship’s robots
  • 2 Computer technicians – level 2 – basic computer operations and maintenance
  • 10 Safety and Security staff – level 3 (beam) – assisting passengers and keeping everyone in line
  • 3 Doctors – level 4 – for maintaining the health of crew and passengers
  • 10 Food Services staff – level 3 – cooking, maintaining hydroponics, servers, etc
  • 11 other staff – level 2 – any other duties, entertainment, etc.

Now some of those, such as security, food services, and other could slosh around a bit depending on exactly want you want on the ship and what roles all those robots play, but this mix give us a starting point.

The Economics

Okay, with the ship squared away, let’s look at the income and expenses of running this ship. 

For this analysis, we will be looking at a single jump.  This means that we’ll be covering the 14 days from departure from one station until the ship is ready to depart the other one.  The Knight Hawks rules are based around yearly or 40-day “months”.  So we’ll often be scaling the values from the rules to cover just the 14 day period.

Let’s dive in.

Income

There is really only one source of income on a starliner, paying passengers.  The KH Campaign Book, page 44, covers the operations of a starliner.  We’ll start with the Spaceliner Bookings Table.

This table tells you how many of your berths a ship will fill traveling between different population worlds.  Now to be honest, I believe that this table really represents the situation if there were lots and lots of travel available.  If there is only a single ship flying between the two worlds each day, it will probably fill every berth every trip.  And depending on the route, it might be higher than that given by the table.  For example, traveling from Prenglar (high population) to Dixon’s Star (outpost) gives only a low fill percentage but in truth, most of those people are actually going to Truane’s Star (medium population) and so the ship would be fuller.  But I’m going to leave those details as an exercise for you to do for your version of the Frontier. I’m going to take the table at face value here.

This ship is flying between Gran Quivera (Prenglar) and Triad (Cassidine), which are both high population worlds.  According to the table the ship will fill 80+2d10 percent of its berths on any give trip.  We’ll just deal with the average which is 91%.  That means on an average trip we will fill 36 of our 40 First Class cabins, 164 of our 180 Journey Class cabins, and 27 of the 30 Storage Class berths.  Sometimes it will be more, sometimes it will be less but that’s the number we’re going to use.

The jump from Prenglar to Cassidine is 7 light years.  That means that a First Class ticket costs 1400 cr.  A Journey Class ticket costs 700 cr. And a Storage Class ticket costs 210 cr.  Given the number of berths being filled, that means that our income for any single jump is 170,870 cr.

That’s our gross ticket sales.  We need to fit all of our expenses for a trip into that number.  So let’s look at our expenses.

Expenses

First up is fuel.  We have three atomic engines and each jump uses a fuel pellet in each engine.  Since each fuel pellet costs 10,000 cr., each jump costs us 30,000 cr. in fuel.

The next obvious cost is the crew salaries.  Daily wages for characters with spacecraft skills are given on page 54 of the KH Campaign book.  Daily wages for characters with AD skills are given on page 60 of the AD Expanded Rules book. For the “other crew” line I just uses 10 cr. x level as their pay rate and for the food services crew I use 10 cr. x level+1.  I’ve also ignored the fact that characters may have multiple skills and the pay rate is just based on their primary skill level.  With the crew as detailed earlier, the daily cost for the entire crew is 3,690 credits.  Which means for the 14 days of our trip, the crew wages come to 51,660 cr.

After those two, the next largest cost is maintenance.  The ship has to spend 15-16 days in maintenance each 400-day year at the cost of 1,000 cr. per day.  In 400 days, a ship can make 400/14= 28 trips 8 days left over.  That means that we can make 27 trips a year.  So each trip needs to save away 16000/27 = 593 credits to cover that expense at the end of the year.  To be safe, and cover other unexpected maintenance costs, we’ll stash away 1500 cr. each trip.

We’ll also need to pay the crew during those 16 days as well so we need to save away a total of 59040 credits to cover wages.  That means each trip needs to save 59040/27 = 2187 credits which we’ll round up to 2200.

Each trip consumes life support.  According to the rules, refilling the life support system on the ship costs 15000 credits every 200 days or 75 credits a day.  Thus our 14 days of operation use up 1050 credits worth of life support.

Another expense is an office at each end of the line where passengers can come to buy tickets.  The rules state that this costs 500 credits per 40 days at each station or 12.5 credits a day.  With two end points that’s 25 credits a day or 350 credits of expenses for the 14-day period.  We need to squirrel way a bit of funds to cover the 16 days in maintenance but it’s not that much and we can assume it’s covered by the extra maintenance money we saved.

Finally, there are docking fees.  Here we are going to use the number given on page 32 of the module SFKH1: The Dramune Run, where it says that the standard rate for docking fees is 2000 credits a month.  Assuming that is the 40 day “month” we’ve been using, that works out to 50 credits a day or 250 credits for the 5 days in port during each run.

Tallying that all up, we get that the operating expenses for the ship total 86,810 credits for each leg of our run between Gran Quivera and Triad.

That seems pretty good.  We’ve got just over 170,000 credits in income and just under 87,000 in expenses.  Which is all well and good if there aren’t any taxes, and if the ship is paid for.

Now the rules don’t explicitly give rates for taxes, tariffs, and other fees associated with interstellar travel although they do talk about varying the rates for wages, docking fees, ticket prices, etc. that can affect the income or expenses for our ship.  And in the AD rules, when talking about PC and NPC character wages, it says to assume half of all their income goes towards living expenses and talks about raising/lowering taxes to adjust the amount of money the PCs have.  And local governments and the UPF need to get income from somewhere.  I’m going to leave the taxes issue up to you for your campaign.  But a corporate tax of say 5-10 percent of gross sales might not be unreasonable. 

Paying for the ship

But now we come to the biggest expense, at least during the early years of operating the spaceliner. How did we pay for that ship in the first place?  Maybe this is a mega-corp and they had a huge budget and could just pay for it outright.  They still need to recoup the cost of the ship but at least don’t need to take out a loan.  If it’s a smaller organization, they may have to get a loan for the cost of the ship, either in part or in full.  Let’s look at those two scenarios.  And we’re going to ignore taxes.  Subtracting our expenses from our income, that leaves us with 84060 credits after each trip. 

First, the mega-corp, paid in full option.  Assuming every one of those net credits earned goes into paying back the cost of the ship (which from above is 5,658,000 credits), it would take 68 trips to pay off the value of the ship.  At 27 trips a year, that’s two and a half years to recoup the cost of the ship.  If there are unexpected costs, it will take longer.

Let’s look at a smaller organization that has to take a loan.  Pager 42 of the KH Campaign book gives the monthly payment on a 10,000 credit loan amortized over a number of years from 1 to 20.  Now, the game was written in late 70’s to early 80’s and the interest rates back then were high, on the order of 10-15% for low risk ventures.  So the interest rates for starship loans, which are considered high risk, are set at 4% every 40 days or, over the 400 day year, an APR of 48%!  That may seem a bit high, even by late 70’s standards and especially today, but we’ll go with it as that is what is in the rules.  If you want to do the math and come up with a different interest rate for your setting, go for it.

We’ll start by looking at a 10-year loan.  Using the table on page 42 and the cost of the ship from above, and assuming we finance the whole thing.  The cost of the loan is 230,903 credits every 40 days or 80,816 credits every trip.  We had 84060 credits left so that’s good, the net difference is still in the black at 3,244 credits.  But we have to account for that 16-day maintenance period where we still have to pay the loan but aren’t making any income.   The loan cost for that 16 days is 92,362 credits.  Spread over the 27 trips in the year that comes to 3421 credits that need to be saved.  Which puts us in the red by 177 credits.  Considering we had a bit of buffer in our maintenance budget, to the tune of about 850 credits, we can cover that small deficit from that.

So that means, if we have a 10-year loan for the entire value of the ship, we can just break even if the ship operates continuously and don’t have any problems for a decade.  It can be done, but it will be tight.  But if we run into unexpected problems, we’re going to be in trouble.  We could look at a longer loan, but beyond 10 years, it doesn’t really help.  Even a 20-year loan only puts us at 1454 credits in the black each year but takes twice as long to pay off and we end up paying twice as much for the ship.

That’s just to break even, there are no profits beyond the wages for the crew so hopefully the owner is part of the crew or they get no money for the first decade.  And that is the economics for a run between two high population worlds were we basically fill the entire ship each trip.  On a run with fewer berths sold, there would issues on the scenario where the ship was financed. Also, if there are any taxes, we would really be in trouble.  It looks like any fraction of the ship that can be paid for up front will make the operation be more financially stable.

Some Variations

This article gives you a baseline for operating your starliner.  I will leave most of the variations up to you but look at one.  Some of those variations include, but are not limited to, changing ticket prices, changing the mix of berths, shortening the time in port so you make an extra run or three each year, selling more (or less) of the berths, different crew expenses, and using ion engines instead of atomic engines.  I’m just going to briefly look at the variation where we fill the ship completely every trip.  Which may very well be the case if there is only a single flight each day between worlds.

In this case, the only real change is that have 13 more paying customers across all three berth classes.  That means that our income goes up to 188,300 credits an increase of 17,430 credits.  Since our expenses don’t actually depend on the number of passengers (the life support costs probably would, but we ignored that), that is all extra profit.  In this case, we are now 17,253 credits in the black after each trip, assuming we keep the 10-year loan.

And that means we either have some profit for the owners and can save a bit for other unexpected expenses, or we can shorten the loan term a little bit.  We were right at the bleeding edge as far as the loan went and were already in the point of diminishing returns with respect to lengthening the loan.  With a full ship every trip, we could shorten the loan period from 10 years to 5 years and still have a 5,400 credit surplus.  And reduce that actual amount we pay for the ship (principal and interest) by 57%, a savings of 9,921,303 credits, which is enough to buy almost 2 more ships!  The total cost of the 10-year loan was just over 23 million credits, four times the cost of the ship.  That interest rate is very expensive.

Conclusions

So, running a passenger liner between two high population worlds is doable.  It might be tight for a few years (up to a decade) if you can’t pay for at least part of the ship up front and have to finance it, but it can be done.  Runs between smaller worlds might not be possible using the table from the rules to determine the number of berths filled.

This also gives you as a setting designer some ideas of knobs to turn to tune things in your setting or describe what PCs see as passengers on one of these ships. 

What did I miss?  What other variations might we look at?  Have you ever had PCs try to run a passenger liner?  What happened?  Share your thoughts in the comments below.

Economics of Spaceflight – part 1a – Starliners

My Starship Construction in the Frontier post generated a lot of discussion in the Star Frontiers group on Facebook. In some of the discussion, the commenters seemed to be making the assumption that I wanted to increase the number of ships flying around and that my post was advocating for ways to do that. I actually don’t have a strong feeling one way or another. In fact, I’m much more in the camp of small numbers of ships.

What I’m really looking at, and am interested in figuring out, are the implications those small numbers have and whether or not it makes sense to increase the numbers. Or if you don’t, what that implies for the realities of life in the Frontier and how that impacts the player characters.

I’m interested in questions like, if you only have a small number of ships across the Frontier, what does that mean for interstellar commerce? What impacts does that have on interstellar travel? Who owns the ships? What do they cost? And questions like that.

Since that starship construction article came out, and the ensuing discussion, I’ve been thinking more and more about this and have decided to do a series of articles on the topic. They will all have the Economics of Spaceflight title and a similar tag. In this first article, I’m going to look at interstellar passenger travel.

From the Rules

Let’s start by looking at what the rules say about these ships, which it calls starliners, and interstellar travel. We’ll begin with the description given on page 6 of the Knight Hawks Campaign Book:

Spaceliners. HULL SIZE = 6-15. Spaceliners (passenger transports) are built in a wide variety of sizes. Modern spaceliners are fast, quiet ships, capable of providing the wealthy passenger with any conceivable luxury. Many of the older liners are smaller, somewhat decrepit vessels that promise only the fundamental requirements of life support. The number of passengers carried by a spaceliner is about 25 times the ship’s hull size. For example, a spaceliner with a hull size of 10 can carry 250 passengers. Engine durability varies as much as size on spaceliners. Some will require an overhaul after three jumps, while others will be able to make 8 or 10 interstellar trips without maintenance.

KH Campaign Book, p. 6

This gives us a bit of information right off the bat. First, we have the range of hull sizes for these types of ships and the number of passengers per hull size. I’ll have more to say on that latter concept later. It also seems to imply that there are a bunch of these flying around as it describes various generations of ships. Other bits, such as the comments on engine overhauls, tell us that they typically sport atomic engines (as ion drives don’t need overhauls) and indicate some of the properties of the Class B and C atomic engines which the rules haven’t covered yet if you’re just reading through the book.

In the original Alpha Dawn Expanded Rules book, pages 49 and 50 talk about they modes and costs of interstellar travel. It lists three “classes” of travel accommodations and their costs:

  • First Class – luxurious accommodations with the best rooms, food, and and best access to survival gear in the case of an emergency. 200 Credits per light year traveled.
  • Journey Class – This is the standard accommodations. 100 Credits per light year traveled.
  • Storage Class – In this class, you travel as frozen cargo. 30 Credits per light year traveled.

More details on the accommodation types are given on page 21 of the Knight Hawks Campaign Book.

Travel time is one of the areas where the Alpha Dawn (AD) and Knight Hawks (KH) rule sets conflict with one another. The AD rules say that interstellar travel occurs at the rate of one day per light year, while the KH rules, require 10 hours (one day’s work) per light year to plot out the jump, but actually making the jump takes 8.7 days regardless of the distance. Reconciling and clearing that up is a whole article in and of itself. We’ll save that for a future date. For this article, we’re going to assume that it takes 9 days to make a jump, regardless of the distance.

Of course that probably means the cost of a ticket should be fixed as the same number of resources go into making a jump regardless of the distance but for now we’ll go with the AD rules ticket costs.

If the PCs come into possession of a starliner, either via salvage, original constructions, or some other means, the KH Campaign Book (p. 44) provides guidance on what it costs to operate such a ship, how much of the ship is full on any given trip, and the risks involved. We’ll come back to those numbers later as well.

How Many Passengers – revisited

For this article, we’re going to be looking at a HS 10 passenger liner which falls in the middle of the range specified in the KH rules. According to the rules, this ship can carry 250 passengers. The question is, does this make sense?

A modern cruise ship, roughly the size of a HS 10 starliner.

Let’s look at some sources. A HS 10 ship is roughly the size of a modern, large cruise ship here on Earth. These ships typically hold up to 2800 passengers and 1200 crew, for a total of 4000 people, or 400 per hull size. But that’s the maximum capacity and typically means 4 people to a cabin. If you’ve ever been on a cruise ship, you know those cabins are small, typically 15-22 square meters. Now this is roughly the size of a Journey Class cabin on our starliner (16-24 square meters), the difference being that that size on our starliner is for a single being, not a group of four. That immediately means we need to cut our passenger estimate down by a factor of four putting us at about 700 passengers.

The other thing our starliner has to deal with, that a cruise ship doesn’t, it life support. On a cruise ship, air is free. And while there is probably some recycling of water, it’s not a closed loop with full filtering needed. And cruise ships tend to stop and replenish supplies every couple of days unless it’s a long trans-oceanic cruise. So they don’t carry a lot of food on board. In the Frontier, ships are typically designed to carry half a year of food and the systems to process the air, water, and waste onboard which eats up more space on the ship.

Then you have all the lifeboats, spacesuits, and other ship’s vehicles that our starliner has to have. Cruise ships have lifeboats but the passenger density on them is going to be higher than the ones on our starliner and the some of the lifeboats on cruise ships are inflatable. That’s not going to happen on a starship. Those eat up space as well.

Finally, a cruise ship has a lot of the upper decks exposed to air. That doesn’t count against it’s volume but provides a lot of communal space for the passengers. That space needs to exist on starliners as well but has to be enclosed within the hull.

Between the extra life support machinery, the communal space, and the ship’s vehicles, that could easily reduce the capacity of the ship by 30 to 70 percent depending on how you figure it. 250 passengers is just 36% of the 700 passenger number we had left above. It’s possibly at the low end, but reasonable.

Another point of comparison is the volume based rules I created for starship generation. In that system, which accounts for passageway, cabin space, and storage space, I designed a ship the same size as a HS 10 ship in the KH rules. It had a total of 100 First Class cabins, 1250 Journey class cabins, and 200 Storage class cabins. And that includes the cabins for the crew, the size of which the rules don’t address. For this I’ll assumed 50 of the Journey class cabins are for the (lots of robots on Frontier ships). So the total capacity is 1500 passengers, which is a little large. However, this system doesn’t currently account for communal space which could easily be as much or more than the space taken up by the cabins. So if we cut that number in half we’re back to 750 passengers, similar to our initial estimate from the cruise ship.

The bottom line is that while 250 is probably a bit low, it’s not unreasonable and the actual number might be only a factor of 2 or 3 higher. So we’ll go with 250 passengers for our analysis.

A Typical Journey

The Starliner

Okay, we have our ship, it carries 250 passengers. What does a typical journey look like? For this example, we’re going say this ship makes the run between Gran Quivera in the Prenglar system and Triad in the Cassidine system, a jump of 7 light years. We’ll look at the finances later, right now we are going to just look at logistics.

We’ll start the journey at the point when the ship is all loaded and ready to depart Gran Quivera for Triad. The first step is the jump to the Cassidine system. It takes just under 4.5 days to get to jump speed and the same amount of time to slow down. We’ll assume the total travel time is 9 days. In truth it could be up to 11 days depending on the orbital dynamics of the two systems and how accurate the jump is but we’ll go with 9 days.

After docking at the station around Triad, the ship has to do a number of housekeeping activities. First, the passengers have to disembark, then the interior of the ship needs to be cleaned. And new provisions need to be taken aboard. Then the passengers and the luggage for the next trip need to board.

Since this is a HS 10 ship, it has three Class B atomic engines. These engines require an overhaul after every three jumps. Since there are three engines, it makes sense to stagger the overhauls so that you do one after each jump. You’re always doing an overhaul each time in port, but you are only doing one and that make it reasonable. We’ll also top off the fuel pellets in the engine we’re doing the overhaul on. We’ll assume that the ship has two level 4 engineers on board that work alternating shifts so that maintenance and overhaul work can proceed around the clock to be as efficient as possible.

Let’s look at time scales. If a cruise ship can load or unload it’s 2800 passengers in a single day, I think it’s safe to assume that our 250 passengers can be loaded and unloaded in a single day as well. So that requires two days in port for those two operations. Refueling one engine takes on average 7 hours. The engine overhaul takes on average 38 hours. That’s a total of 45 hours of work. Assuming it is split between the two engineers, either working together on 10 hour shifts or around the clock on alternating shifts, that takes two and a quarter days. We’ll call it three to account for any variations and potential issues that come up. The provisioning and cleaning can occur while the engine work is happening. So our ship spends 5 days in port and then is ready for the return journey to Gran Quivera. So far we’re up to 14 days.

The trip back is exactly the same. It takes 9 days to make the jump, and another 5 days in port before it’s ready to leave. That is a total round trip time of 28 days.

The Shuttle

That’s the main part of the journey. You also need some way to get the passengers from the surface of the planet up to the station to board the starliner. That means you’re going to need a shuttle. For comparison, a Boeing 737 is about the size of a HS 2 ship. And it carries 175 people and their luggage. A Boeing 747 is about the size of a HS 3 ship and it carries 416 people plus luggage.

Now the trip up to the ship isn’t that long. As the Dutch astronaut Wubbo Ockels commented about his 1985 trip on the Space Shuttle Challenger:

Space is so close: It took only eight minutes to get there and twenty to get back.

That was at 3g and we probably want to be a little gentler on our passenger but it shouldn’t take more than a half hour to get into orbit and an hour back. They will need acceleration couches regardless and those take up a bit more room than a typical airline seat but not by much. It’s completely reasonable that a HS 3 shuttle can carry the 250 passengers for our space liner.

That means that we’ll need one shuttle at each system. If we let our spaceliner carry more than the 250 passengers, we’ll need more shuttles as well.

How Many Ships Do We Need?

With one ship, every 28 days we can move 250 beings from Gran Quivera to Triad and another 250 beings in the reverse direction. If this is the only ship running the route, there will only be a single trip once a month between the worlds. If you miss your flight, you’ll have to wait 28 days for the ship to be back. And if you want a round trip then you will spend at least 5 days in the destination system assuming you fly back out immediately when the ship leaves, otherwise it will be 33 days (or longer) after you arrive before you can catch a ship back.

Of course we can increase the frequency by adding more ships on the route. Let’s say we want a flight leaving every day. That’s easy enough. It’s a 28 day round trip for a single ship, you just need 28 ships and means you have a departure and arrival every day. And that allows you to move 250×28 or 7000 beings each way between the two systems in that same 28 day time period.

Regardless of how often you have interstellar departures (as long as it’s not more than once a day), your one shuttle can supply all of those ships. So even though you have 28 starliners, you only need a single shuttle at each system to handle the passenger traffic.

But that’s not the whole story. Each of those ships needs to have annual maintenance performed and that will take on average 15-16 days per ship. Which means once a year, each ships needs to be pulled out of rotation for one cycle to have it’s maintenance done. That means we need a spare ship to fill in while it’s out of commission. If you’re running a ship every day, you’ll actually need two spare ships to cover the gaps as the repair time on 28 ships is longer than a year and there will be some times when two ships are in maintenance. The shuttle needs annual maintenance as well, but that only takes on average 8-9 days as it is a smaller ship. If you only have 1-3 flights in that 28 day period, you can get away with a single shuttle and squeeze in its maintenance between runs, otherwise, you’ll need two of them to cover the maintenance periods.

My rendition of the AD star system map. Click for full size version.

That’s the numbers for a single system. There are 17 inhabited star systems on the AD map (not counting the Zebulon system) for a total of 19 jump routes. If there is a single flight along each route, once a month, you need a starliner for each leg plus a spare. And a shuttle in each system. That’s 55 ships. Of course that ignores the fact that some of the systems have two inhabited worlds (23 in all) and you’ll need more shuttles at those worlds and some ships to move passengers between the two planets in the system.

Now 55 ships (or 67 to account for the two world systems), isn’t too bad, but that is only a single trip every 28 days. If you want a daily trip between systems, you need 30×19 starliners (570 ships) plus 2×17 shuttles for a total of 604 ships. Again, accounting for the two planet systems, that’s another 6-12 shuttles and anywhere from 6 to 168 interplanetary starliners depending on how frequent you make the trips (6 shuttles and 6 ships for once every 28 days and 12 shuttles and 168 ships for daily trips).

With the starship construction centers only capable of supporting about 1500-2300 ships, we’re now looking at about one quarter to one half of the total ship capacity of the Frontier just to connect the worlds for a few hundred people moving between each system each day.

If you want more people moving between the worlds, you have several choices. First, you can make the passenger density higher and make each ship carry more. But that’s only realisticaly a factor of 2 or 3. As another option, you can make the starliners bigger. But remember, if the average ship size increases, the total number of ships the Frontier can support goes down. The final option is to increase the number of ships that the Frontier can support.

Implications

What this all means is that you have to make a decision about interstellar travel. If you have few ships, then trips are few and far between and not a lot of people will be traveling between worlds. Your characters should expect to spend months or years on a single world with all their adventures there, as getting tickets to move between worlds could be relatively rare depending exactly on how you structure it. It also probably means they won’t have their own ship as they are too rare.

Additionally, unless there are daily (or every other day) flights between each world, then it will take a long time to travel across the Frontier with layovers of several days to weeks in each system depending on the frequency and scheduling. If they are traveling between worlds, then there will be even longer spans of time (above the already long base travel times) between adventures and your plots need to account for those long time scales.

This article was focused simply on the logistics of travel and the number of ships it would take to support that. I didn’t even address the costs and economics of each individual flight. That will be part 1b at a future date.

What are your thoughts on the number and size of passenger liners? How do you handle it in your game? What other implications have you thought of that I didn’t cover? Let me know in the comments below.