Interstellar Shipping Question

[Geir]

Yes, I know about LaGrange points. I don't think those actually serve the purpose that I was interested in.

I wanted to know whether it was possible to put a space station around the 99 to 100 planetary diameters and have it stay on station without needing to have a full on maneuver drive (ie be a regular ship). I don't think the L4 or L5 points are actually close to that distance.

No but Earth-Sun L2 or even L1 would work - L2 better so Earth's jump shadow isn't as big of a factor - at L1 you'd have the sun's shadow going out to .93 AU blocking a whole lot of sky and the Earth's 100D going out to 1,274,000 km blocking the other side of the sky. Earth-Sun L2 is about 1.5 million kilometers beyond Earth, so almost perfect. It is not entirely stable, but a halo orbit around the point with minimal "M-0" space station drives or even a big solar sail could keep it in basically the right place.

 

[Vormaerin]

Thanks @Geir Getting a straight answer about the distance to the LaGrange points without doing the maths myself exceeded my google-fu apparently. That sounds perfect.

 

[phavoc]

Imagine Trade in Traveller between Alpha Centauri and the Sol system. It's Jump 2 distance. You are on the Alpha Centauri world and you have significant volumes of goods for Terra/Luna, Mars, and Titan. And incidental goods for the various other locations in the Sol system. What is the most likely way this trade is managed for the large contract shipping routes? There is obviously going to be tramp trade, but the vast majority of the goods are going to be standard, scheduled routes.

Is it:
1) Three jump ships each loaded with the goods for their specific destination
2) One jump ship that goes to Terra/Luna and lets everyone else's goods get reshipped on non jump vessels based at the starport
3) Jump Tenders that regularly carry non jump freighters between the two systems and they go their separate ways from there?
4) Is the answer different for Mars and Titan, given how far Titan is from Earth compared to Mars?

Secondary questions
1) Does the answers above change depending on how far apart the different planets are at the time of transit? Mars can be anywhere from 50m and 400m km from Earth (farther, really, since you can't fly through the sun).
2) How important is it for a ship to be able to go directly to a Terran downport? Is that even legal or would customs/quarantine be at the highport?

Tertiary Questions
1) How far can you put a starport from a planet without the planet leaving it behind as it zooms around the solar system? Frex: can you put a refueling station at the 100D limit without it needing to be effectively just a tanker ship?
2) Micro jumping is so much more expensive than sublight travel that I don't think it would be used for commercial shipping (except for passenger vessels). Agree/Disagree?
3) Would LASh benefit from making the lighters into drone ships? Does that fit the Charted Space sensibilities?

Primary question:
1) Your question is one of hub-and-spoke vs. direct. There are multiple economic and business questions contained within the question. I think what you will find is the answer is "yes" to both. In SOME cases, hub-and-spoke will be the preferred method from either an economic and/or business question. Large lines may find it most economical to take larger freighters and ship to major hubs and then allow local transport to handle it within each system. In other cases, assuming you have enough cargo, it's cheaper / faster to ship directly to the smaller market/destination than it is to route it through a system hub. While Traveller can answer your question based upon ship operations and charges (to be fair, apply the same Cr1,000 / Dton to each cost model), that's not really going to answer it since we have no idea what an actual cost model would be for an interstellar/intrastellar framework. Using Earth as of today would give you examples of both working very efficiently.

Secondary questions:

1) Technically, absolutely. The cost / time of transit will vary over time as planets move closer/farther apart. One way to dodge that issue is to assume that freighters and liners will already have factored in the average time frame for both the least time / most time trips. Your costs could stay the same for any period, though obviously there will be time-savings depending on the planetary locations. You could try to map it (assign each planet a random location using 12 spaces, like the clock) and then using orbital distances do a rough calculation of how far each one is. For M-drive equipped ships it should be more than good enough.

2) I'd expect it to be relatively common - though you shouldn't expect to see the larger cargo ships doing that. This is a similar comparison between hub-and-spoke vs direct model. Some ships will stop at orbital warehouses at the 100D limit. You'd expect liners to proceed to orbital stations (at a minimum) or else land to disgorge their passengers. People have always been considered the most "perishable" of cargos, so getting them to as close to their final destination is always a goal. For freighters, being able to land cargo's destined for the planet, getting closer to your destination saves time/money. It's also quite probable that you'd have industrial starports/spaceports where freighters would land to unload or take on cargo.

Tertiary questions
1) Yes. Objects will follow the orbital path they are placed. Traveller thrusters for space stations should easily be able to keep a station where it needs to be at the 100D limit.

2) It's reasonable to assume that intrasystem passenger liners would use better M-drives rather than micro-jumping for most transits within a system. There may be a few exceptions, but I'd expect most to stay in N-space for all their travels.

3) Questionable. Drone freighters may not be allowed (legally) due to their requirements to be independent of human control. The costs of drone vs. LASH style containers has been debated elsewhere, but ultimately comes down to whether or not it's economical the majority of the time. You have to pay for installing the engines and control systems and their regular maintenance. That is a fixed cost for a variable use. Without knowing more about usage vs. cost the cost model cannot be calculated.

 

[Nelphine]

Imtu any system with pop 8+ is going to have similar questions. So i like using Sol as an example to get thinking, because i think having scattered colonies all over a system will be the norm, not the exception.

So, we assume a colony of pop 6 at saturn, and the main colony on earth as pop 9 or 10.

Theres 1.2 to 1.6 billion km between the 2.
In other words, 7-9 days at 1G (though i just realized that all the transit times on p163 of 2020 core rulebook appear to use the wrong formula? They forget the times 2?? Am i missing something?)
This drops to 4-5 days at M3.

I think i would definitely use hub and spoke, and have trade ships all go directly to the main world, with non jump ships ferrying it out to the colonies. The volumes going to the outer colonies would simply be too low to justify, unless someone at the outer colony had a reason to custom order it direct.

I would also assume all freighters would be dispersed ships that couldn't land on the planet, so would need a highport. Streamlined ships that could land directly would simply be rare one offs, or small tramp vessels, not megafreighters.

This would also mean that the highport could very easily not be near a world at all, but would instead be as close to the mainworld as jump shadows allow without being in any jump shadow (including of that world) (relevant if the mainworld were equivalent to venus or mercury).

 

[tytalan]

Okay the quick and dirty answer to your question is you would absolutely only us one star ship and you would travel to the system starport and have the items transship from there.

So for question 1 the answer is definitely 2
For your secondary question kind of 2 the Highport and to low port are considered a single unit in fact many systems don’t have a highport
Trinity questions
1) the high port is associated and almost alway orbiting above the low port. This is connected to the fact the both the high port and low port are considered extraterritorial from the planet (they are imperial property essentially in many ways a embassy)
2) The only time micro jumps make any economic sense is a system below TL9 and such a system is not likely to have off world bases/settlement. See below
3) not sure what you mean by LASh

Long answer:

1) from your description I believe your talking the 3rd imperium setting if that’s the case than jumping to any other port than the system one imperial space port and or High port is considered smuggling. Before going anywhere else in the system you have to go thru customs at that one starport only after that can you ship to any of the space ports.

2) this is a big one economics. By TL 10 when you get M-Drive 3 using a jump drive ship to travel in system economically stupid a M 3 ship can travel anywhere in system at a fraction of the cost of a jump ship. A m-3 ship can travel to anywhere in the inner system in less than a day and most of the outer system in less than 5 days. Its tonnage to cargo ratio is insanely lower than a jump drive ship and its fuel requirements is just as low (months of operation for 1 or 2 tons). Even at TL 9 with M1 it’s still more economical to use a none jump ship. For similar reasons the jump carrier concept doesn’t work well. The none jump traders connected to the jump carrier still have to have things like quarters bridge and more crew than a m-drive small craft. And since you have to go to the systems starport anyway that extra crew and quarters are an economic expense that’s not justified.

 

[Anstett]

This made me think, is there a chart anywhere of the transit time to 100D for each system? That might help determine where a secondary Highport for cargo shipments might be (along with Scout tenders) and what Mdrive is needed in a system for best/least transit times.

{edit}
I know it can be computed but wonder if there is a 'simple/master list'

 

[Nelphine]

To take my thought further, i think many systems would have started too small for megafreighters to visit.

But as other systems around them grow, the intervening systems need to be fuel stations. And so the highports of many systems, are actually built out of the need to fuel megafreighters.

So highports (as i described above, which may not actually be near a world) should probably exist far more often than local pop + tech would suggest.

The game rules dont really have a good way of showing this, but imtu, highport existence is determined first by major trade routes between pop 9+ worlds (but would usually max out at class B by function, but would be large enough for 10s of millions of tons of traffic per year). Only if that fails to generate a highport, then you look at the local system to check for the presence of a highport (which would be done using existing rules, but which would generate a highport far less frequently than by trade route. So if a class B highport shows up 10% of the time with local worldbuilding rules, than a class B highport should show up something like 80% of the time by trade route.)


In turn this means most highports would be generated by trade route, and therefore would rarely ever be connected to the main world, as a) they were probably built before the mainworld had any need of a highport in the first place (maybe even before the first person colonized the mainworld) and b) the highport's presence is probably what triggered the development of the mainworld in the first place. So the highport created the mainworld, not the other way around.

 

[Vormaerin]

I think i would definitely use hub and spoke, and have trade ships all go directly to the main world, with non jump ships ferrying it out to the colonies. The volumes going to the outer colonies would simply be too low to justify, unless someone at the outer colony had a reason to custom order it direct.

That is the core problem. We don't know what the volumes are. I mean, a Pop 6 island like O'ahu has a very busy harbor, but nothing that compares to Shanghai or Rotterdam. But would that much trade actually happen on an interplanetary or interstellar level? Who knows? GURPS Far Trader certainly thinks so. But other sources seem to suggest significantly less trade and infrastructure.

I tend to think it is hub and spoke too. I just wonder whether the hub is the starport or a jump tender. But that is another question we can't answer, because we don't know how easy it is to build massive space stations to handle all the cargo transfers.

There's just SO MANY worlds with low to mid grade starports that I wonder if the infrastructure is actually there to support hub and spoke. I think star systems should be pretty developed. Someone earlier commented "because of Earth's unusual circumstances" or some such thing. But lots and lots of worlds have been settled & space faring for centuries or millenia and many of them for longer than Earth. But Traveller wants adventurous backwater type systems so the majority are C or less.

Jump is so much more expensive in terms of fuel (both capacity and cost) that people are going to build their freighters to be jump free as much as possible. I don't think anyone is going to willingly do interplanetary runs in a jump drive capable ship. That's just a lot of deadweight not earning. You need to be charging that interstellar premium even if you aren't spending the fuel because your ship is carrying so much less cargo than its interplanetary competitors. And quite possibly being slower in real space on top of that. If you are jump capable, you are going to be jumping.

If the starports are cheap enough and extensive enough that transshipping is easy peasy, that's the way to go. Specialized jump freighters moving goods from starport to starport for redistribution. But if the ports aren't there to support that, then I tend to think a regular schedule of jump tenders moving the interplanetary freighters might make sense.

 

[Nelphine]

I completely agree, but i just posted at the same time as you, so.. yeah! Game rules and playability get in the way a lot of this kind of conversation.

 

[Alqualonde]

That is the core problem. We don't know what the volumes are. I mean, a Pop 6 island like O'ahu has a very busy harbor, but nothing that compares to Shanghai or Rotterdam. But would that much trade actually happen on an interplanetary or interstellar level? Who knows? GURPS Far Trader certainly thinks so. But other sources seem to suggest significantly less trade and infrastructure.

I tend to think it is hub and spoke too. I just wonder whether the hub is the starport or a jump tender. But that is another question we can't answer, because we don't know how easy it is to build massive space stations to handle all the cargo transfers.

There's just SO MANY worlds with low to mid grade starports that I wonder if the infrastructure is actually there to support hub and spoke. I think star systems should be pretty developed. Someone earlier commented "because of Earth's unusual circumstances" or some such thing. But lots and lots of worlds have been settled & space faring for centuries or millenia and many of them for longer than Earth. But Traveller wants adventurous backwater type systems so the majority are C or less.

Jump is so much more expensive in terms of fuel (both capacity and cost) that people are going to build their freighters to be jump free as much as possible. I don't think anyone is going to willingly do interplanetary runs in a jump drive capable ship. That's just a lot of deadweight not earning. You need to be charging that interstellar premium even if you aren't spending the fuel because your ship is carrying so much less cargo than its interplanetary competitors. And quite possibly being slower in real space on top of that. If you are jump capable, you are going to be jumping.

If the starports are cheap enough and extensive enough that transshipping is easy peasy, that's the way to go. Specialized jump freighters moving goods from starport to starport for redistribution. But if the ports aren't there to support that, then I tend to think a regular schedule of jump tenders moving the interplanetary freighters might make sense.

- Rotterdam is a hub for Europe, so closer to pop 8 area.
- Shanghai is a hub for China (pop 9). And a large part of Earth manufacturing is in or near China.
- O'ahu might be a pop 6 island, but it is one of the refueling stops for transpacific travel.
In those 3 cases, they see more trafic than accounted for just their population or their country's population.

For a crude analogy, in Traveller, O'ahu would be a 'mid-pop' world on a major trade route (a refueling stop with a small local trade). Rotterdam a 'mid-pop' world in a multi-world cluster (either in a binary/tertiary system or an entrypoint for a J1 bubble) and Shanghai a high-pop industrial world.

I have no idea of the amount of trade in Traveller. It is hard to compare with known patterns. Usually non-industrial countries trade ressources for cash and/or high tech goods. But even an industrial world in Traceller will have a lot of ressources floating around that will probably be cheaper to mine locally than of importing.
If you have a tech level high enough, even on a world were you can't grow food you can still build agricultural stations in orbit, under a dome or underground.
The old Pocket Empires book for T4 did account for this part. IIRC each system had it's Ressources code that did limit production if you couldn't import from nearby worlds.

 

[Condottiere]

Geography is destiny.

Usually, it's an intersection of factors that create trade nexus.

 

[MasterGwydion]

Okay the quick and dirty answer to your question is you would absolutely only us one star ship and you would travel to the system starport and have the items transship from there.

So for question 1 the answer is definitely 2
For your secondary question kind of 2 the Highport and to low port are considered a single unit in fact many systems don’t have a highport
Trinity questions
1) the high port is associated and almost alway orbiting above the low port. This is connected to the fact the both the high port and low port are considered extraterritorial from the planet (they are imperial property essentially in many ways a embassy)
2) The only time micro jumps make any economic sense is a system below TL9 and such a system is not likely to have off world bases/settlement. See below
3) not sure what you mean by LASh

Long answer:

1) from your description I believe your talking the 3rd imperium setting if that’s the case than jumping to any other port than the system one imperial space port and or High port is considered smuggling. Before going anywhere else in the system you have to go thru customs at that one starport only after that can you ship to any of the space ports.

2) this is a big one economics. By TL 10 when you get M-Drive 3 using a jump drive ship to travel in system economically stupid a M 3 ship can travel anywhere in system at a fraction of the cost of a jump ship. A m-3 ship can travel to anywhere in the inner system in less than a day and most of the outer system in less than 5 days. Its tonnage to cargo ratio is insanely lower than a jump drive ship and its fuel requirements is just as low (months of operation for 1 or 2 tons). Even at TL 9 with M1 it’s still more economical to use a none jump ship. For similar reasons the jump carrier concept doesn’t work well. The none jump traders connected to the jump carrier still have to have things like quarters bridge and more crew than a m-drive small craft. And since you have to go to the systems starport anyway that extra crew and quarters are an economic expense that’s not justified.

Your long answer for number 2 is invalid in binary or trinary star systems. At those distances it is way more economical to use a J-Drive. A TL12 J-1 Drive optimized for fuel efficiency.

 

[tytalan]

Your long answer for number 2 is invalid in binary or trinary star systems. At those distances it is way more economical to use a J-Drive. A TL12 J-1 Drive optimized for fuel efficiency.

Wrong even optimized for fuel efficiency your still required to use 8.5% of the tonnage of the ship for jump plus the fuel for the power plant. A small craft is using only 1% - 5% of it’s tonnage for fuel to run its power plant and at the tech level needed for a jump 1 to have that much fuel efficiency (TL 12 minimum) you system ship has M-6 which is likely to make its travel time still shorter than a micro jump. Unfortunately it’s almost never more economical in a system with M-Drive capability for a Micro jump to be more economical.

Another crushing economic factor is that by using a high efficiency jump drive you have increased the drives cost and maintenance by 50%. This of course increases them amount of income needed to both pay your payments and the cost of maintenance while the m dive insystem ship still costs less in both than your original free trader.

 

[tytalan]

This made me think, is there a chart anywhere of the transit time to 100D for each system? That might help determine where a secondary Highport for cargo shipments might be (along with Scout tenders) and what Mdrive is needed in a system for best/least transit times.

{edit}
I know it can be computed but wonder if there is a 'simple/master list'

As is stated in both the world builder handbook and the core rule book each system only has 1 low star port and possibly 1 high star port but a system can have multiple space ports(only deal with in system ships) the rules for determining the number if and Space Ports are in the economic section of the world builder hand book.

 

[MasterGwydion]

Wrong even optimized for fuel efficiency your still required to use 8.5% of the tonnage of the ship for jump plus the fuel for the power plant. A small craft is using only 1% - 5% of it’s tonnage for fuel to run its power plant and at the tech level needed for a jump 1 to have that much fuel efficiency (TL 12 minimum) you system ship has M-6 which is likely to make its travel time still shorter than a micro jump. Unfortunately it’s almost never more economical in a system with M-Drive capability for a Micro jump to be more economical.

Another crushing economic factor is that by using a high efficiency jump drive you have increased the drives cost and maintenance by 50%. This of course increases them amount of income needed to both pay your payments and the cost of maintenance while the m dive insystem ship still costs less in both than your original free trader.

0.21 light-years seems to be a bit far to go on an M-Drive and that is the distance from Alpha Centauri AB to Alpha Centauri C, 21 light-years or 13,000 AU. That is 430 times the radius of Neptune's orbit.

 

[ColinD]

IMTU the High Port as where you get Freight and Mail. The Low Port is where Speculative Trade, Smuggling and the most interesting NPCs and Patrons book Passage.

The High Port has more of your Imperial presence while the Low Port has the local materials, produce, goods, services and people that make that planet distinctive.

The High Port is for those who are using the planetary system as a layover or quick market to move their goods through. The Low Port is for those stopping for a while and making the more lucrative deals that require a broker who is tied into the local bureaucracy or where smugglers play their trade away from the more Imperial High Port.

Free Traders are the basis for most trade with Subsidized Traders taking care of the less profitable but much needed staples like

 

[ColinD]

Common Consumables and Common Ore. I do this so as to make Travellers the center of most trade and that they have both competition and the chance for connection with other Traders.

I do like seeing how others have wildly different and interesting ways to portray the economics of the Imperium. Their players must love the amount of work their Referees put in for them.

 

[Peleliu]

The High Port is for those who are using the planetary system as a layover or quick market to move their goods through. The Low Port is for those stopping for a while and making the more lucrative deals that require a broker who is tied into the local bureaucracy or where smugglers play their trade away from the more Imperial High Port.

Matches closely to how I handle it. Most High Ports require inbound traffic, even if transient, to make a stop at the High Port. Most of these ships would not be required to dock, but rather held at a nearby anchorage until they have been inspected, assessed by customs, and cleared to proceed. Even for a Class A port, these traffic control stations can be rather small compared to the Down Port. IMTU, Class A orbital facilities such as shipyards, large cargo handling facilities, and other services are often part of a network of small specialty stations that fall under the control of the primary Port Authority. Massive combined-use High Ports are uncommon. Only Down Ports tends to gather all of these functions into a single large sprawling complex. Class B and C ports are where one might typically find single combined-use stations.

 

[Vormaerin]

Frankly, I prefer the reaction drive system of 2300 or TNE in the abstract. It also makes a lot of these questions easier to answer. I just don't find it something players generally like engaging with in actual play.

 

[Anstett]

As is stated in both the world builder handbook and the core rule book each system only has 1 low star port and possibly 1 high star port but a system can have multiple space ports(only deal with in system ships) the rules for determining the number if and Space Ports are in the economic section of the world builder hand book.

The problem with this is that it excludes all bases (Navy, Scout, etc) which would not be merged with the standard commercial traffic. So there are many systems with multiple 'entry/exit' points that need to be beyond the 100D of various system objects.

I agree with the idea of a large spaceport focused on refining stationed near a gas giant. More efficient, etc. So I can see jumping in or out of the system near that point in space rather than near the primary Starport.