Downport Docking

[Vormaerin]

What's the largest size spaceship that you have landing at downports? I know that WBH suggests that 1000dt is pretty standard and 2-5k is possible.

Personally, I don't have ships larger than 600 dtons actually landing on planets as a normal thing. But then I like the aesthetic of close and dispersed structure ships. And also think that more use of those inexpensive hulls would dominate in commercial shipping. A streamlined hull for a 1000dton ship is MCr60 compared to MCr40 for a close structure or only MCr25 for a dispersed hull.

I'm also fond of the earlier Traveller edition definition of 'partial' that meant the ship could skim fuel, but not land on planets with real atmospheres. Obviously the current rules, partial is just a penalty to pilot checks. Probably the better rule for game play purposes, because folks will want to know what happens if they are forced to enter an atmosphere with a partially streamlined ship. But I doubt it would be considered an approved behavior for a commercial vessel to take that additional risk. YMMV.

Anyway, curious about how others actually play. Or if they even think about it, since PCs rarely have ships that size

 

[Condottiere]

 

[Sigtrygg]

I do it as 1,000 at all ports, A and B starports can take up to 5,000 but spaces are limited

 

[Galadrion]

For me, it's very situational, but some generalizations can be made.

For civilian ports, it's going to depend on readily available tech level, and on perceived need. Tech level is, for the most part, a minor consideration - by the time a world can build skyscrapers, they have the materials and the civil engineering techniques necessary to build a landing pad to arbitrarily large scale; it becomes a matter of whether the project would be economically feasible, not technically so. For the perceived economic need, starport class is probably the best guide.

A class D port isn't going to have much need for a landing pad much larger than 200 dtons - large enough for the tramp freighters which will be the most common visitors. They might put in one or two 400 dton pads, mainly to accommodate the one or two decommissioned CEs that have been bought to act as SDBs, and those pads could be used for the occasional larger visiting ship, but honestly, no one's expecting that sort of visitor at most class D's.

A class C port will have several 200 dton or smaller pads, maybe ten to twenty pads that can handle 400 or 600 dton ships, and maybe one or two 1000 dton pads - probably only if they have reason to expect ships that size on a semiregular basis. If they don't expect to need a pad that size more than once in a great while, they'll probably just have a couple of largish shuttlecraft outfitted for ship-to-ship docking and transfers.

Class A and B ports are really only limited by what they expect to need - technically, there's no reason they couldn't build a pad that could handle a mega-dton ship, assuming you could find a crew crazy enough to try landing it. But how often is the port likely to need a pad that's probably going to cost as much or more to build as most entire class C ports? Unless there's a specialized need, you're rarely going to see a landing pad big enough to handle a 10,000 dton ship.

Now, I've said that this was highly situational. Some - well, not exactly common, but less rare - exceptions are ships such as large-scale troop transports/assault landers, or very large freighters which are expected to come by on a regular basis. But those types are more likely to be accommodated by, respectively, a port attached to military base, or a private port owned by the same company which owns the large freighter. In both cases, the landing pads will be constructed to order by the military or private port's owning authority, and will be no concern of the civilian port except as an emergency diversion destination, assuming some agreement can be reached.

TL/DR - if a ship can be piloted in atmosphere, it can be landed on a planet... if you can find a big enough parking space. But you may have to build your own, if you're flying something bigger than the locals are expecting.

 

[Vormaerin]

Well, the economics is part of why I asked. Ships designed for atmosphere are substantially more expensive. So you need the ship builders to pay more and the downport to pay more. Vs leaving those ships up in orbit and using shuttles or whatever to bring the cargo down.

But also was interested in the aesthetic choices made. Do you imagine your large ships primarily as sleek lifting bodies or cones? Or more boxy and industrial looking?

A lot of the published mid to large ships are partial streamlined (standard/close/sphere) hulls. Which used to mean emergency atmospheric operations only, but it doesn't feel like Mongoose intends it that way? Like you can land no problem, just don't try dogfighting in atmosphere. So just interested in how others were doing that these days.

 

[Condottiere]

There probably is an optimum tonnage to directly land on a planet, if you have a good reason to do so, and the landing area is suitable.

If it's a secured area, you could land a battleship.

If it's unsecured, Adventure class.

 

[Jame Rowe]

For me, it's very situational, but some generalizations can be made.

For civilian ports, it's going to depend on readily available tech level, and on perceived need. Tech level is, for the most part, a minor consideration - by the time a world can build skyscrapers, they have the materials and the civil engineering techniques necessary to build a landing pad to arbitrarily large scale; it becomes a matter of whether the project would be economically feasible, not technically so. For the perceived economic need, starport class is probably the best guide.

A class D port isn't going to have much need for a landing pad much larger than 200 dtons - large enough for the tramp freighters which will be the most common visitors. They might put in one or two 400 dton pads, mainly to accommodate the one or two decommissioned CEs that have been bought to act as SDBs, and those pads could be used for the occasional larger visiting ship, but honestly, no one's expecting that sort of visitor at most class D's.

A class C port will have several 200 dton or smaller pads, maybe ten to twenty pads that can handle 400 or 600 dton ships, and maybe one or two 1000 dton pads - probably only if they have reason to expect ships that size on a semiregular basis. If they don't expect to need a pad that size more than once in a great while, they'll probably just have a couple of largish shuttlecraft outfitted for ship-to-ship docking and transfers.

Class A and B ports are really only limited by what they expect to need - technically, there's no reason they couldn't build a pad that could handle a mega-dton ship, assuming you could find a crew crazy enough to try landing it. But how often is the port likely to need a pad that's probably going to cost as much or more to build as most entire class C ports? Unless there's a specialized need, you're rarely going to see a landing pad big enough to handle a 10,000 dton ship.

Now, I've said that this was highly situational. Some - well, not exactly common, but less rare - exceptions are ships such as large-scale troop transports/assault landers, or very large freighters which are expected to come by on a regular basis. But those types are more likely to be accommodated by, respectively, a port attached to military base, or a private port owned by the same company which owns the large freighter. In both cases, the landing pads will be constructed to order by the military or private port's owning authority, and will be no concern of the civilian port except as an emergency diversion destination, assuming some agreement can be reached.

TL/DR - if a ship can be piloted in atmosphere, it can be landed on a planet... if you can find a big enough parking space. But you may have to build your own, if you're flying something bigger than the locals are expecting.

That's a pretty good take on it. I'd modify it by the world's population and what planets are nearby, plus their population, TL and port quality.
E.G., a class C port with 100 million people will need more port space than a class A port with 10,000, especially if the class C is next to a class B with 1 billion. There'd be a greater volume of traffic between the C and the B because of market size.

 

[Vormaerin]

I know that Traveller's default assumption is that the highport is optional. Even a high pop, high tech A port has a slight chance of not having a high port if you do the random generation. But I tend to assume that larger ships aren't visiting worlds that don't need a highport. Also that highports are more common than the base rules assume within the Imperium.

 

[Galadrion]

To expand on my whole "it's situational" argument, I will add this: I tend to use far more custom-designed ships than appears to be the average. In brief, if a standard ship is ideal (or even just "mostly good enough") it's likely to be used, but if there are local factors which point to a likely modification, it's almost as likely that the locals will go with a custom ship as a modified standard one.

For example, a local group of worlds has a high demand for inter-system trade, enough to justify a large subsidized freighter, but none of the local starports currently has a landing pad large enough to handle such a ship. Rather than build pads at each starport, I'd be more likely to have a consortium commission a large freighter (say, 10,000 dtons or so) with a 400 dtons shuttle carried aboard... or more likely a couple of 200 dton shuttles, trading a little engine redundancy for a little more flexibility.

Such non-standard situations get used more frequently in my games than most, but they're pretty much all within the normal rules. Just not used as frequently by most referees, as far as I can tell.

 

[Vormaerin]

IMC, the "standard" hull is the default for military vessels, while close is the most common for commercial jump ships. Interplanetary vessels tend to be unstreamlined "dispersed" hulls.

 

[Condottiere]

If you look at it from an economic point of view, starships and spaceships that aren't streamlined, are unlikely to try an atmospheric reentry, even with a manoeuvre drive.

If a planet deliberately doesn't maintain even a space station that could cater to some spacecraft traffic, that's a removal of the welcome mat.

This might be countered with a metered shuttle service, and a large downport in a really remote, desert(ed), area.

 

[Nelphine]

In mtu, both the docking space, and the existence of a high port, is based on trade volume (which means I have to calculate out the other systems nearby, as trade between 2 billion pop planets completely dominates trade volume, particularly if you are on the route between them).

Class of star port would only come up as a factor if the trade volume suggested a large range was possible, and needed some kind of tiebreaker.

Determining class of star port and existence of high port also both get determined by trade volume first, and I only use random generation if trade volume doesn't already predefine something at the top end.

Basically for everything starport related:
1) determine trade volume
- determine what this tells about the starport
2) Determine random generation
- only use the random generation results if they are bigger than what was determined by trade volume (if random generation is not used, you might have to modify population (and therefore govt and law) based on trade volume but I haven't really worked these rules out yet)
- If random generation wasn't used, roll a 'disaster check' (basically a 1% roll that says there was a recent disaster that caused huge problems, which is why I use the result from random generation rather than from trade volume)