After spending some time looking through various rules sections in various incarnation of Traveller, I tried to find something, anything that would say whether or not the TL of a world impacts on what a starport can build or can not build, I came across the following:
MgT: Starports can be built to either the TL of the world outright, or it can build Starports capable of a higher technology value than the home world. The problem is - the rules specify that the starport is now of a higher tech, but the specifics are not well fleshed out. To wit:
If you have a TL 10 world, and you build a TL 12 Starport, the cost of the modules that make up the TL 12 Starport at the TL 10 world now cost multiples of 100% above the current world TL. Problem is - if you build a TL 12 starship at a TL 10 World using an upgraded TL 12 Starport, does the cost of the ship itself now have the same cost multiplier as the starport itself? Since the increased cost involved is related to having to import everything from elsewhere, the inference (not necessary the implication!) is yes. But I can easily see where one could argue "No" - that which is not explicitely stated in the rules might not mean one or the other interpretation.
MT: I came across two things of note. The following is almost a DIRECT quote from CT material, which means that it was not intended for a generic system, but for the MT game universe, to wit, the Third Imperium in a civil war. Its direct quote taken from page 61 of the Referee's Manual says this:
Tech Level: The Tech Level of the building shipyard determines the Tech Level of the ship being constructed (a class A starport on a Tech Level 14 world constructs a Tech Level 14 ship). Equipment and components of a starship may always be equal to or less than the ship’s Tech Level The Imperial Navy may procure ships of up to Tech Level 15, although it also procures vessels at Tech Levels 10 through 14. A subsector navy may procure ships at any shipyards within its borders. A planetary navy may procure ships at any shipyard within the borders of its subsector; alternatively, a planetary navy may construct ships on its planet, using local resources. A shipyard navy may construct ships on its planet using local resources, even if a shipyard is not present.
I always had a problem with the "produced on a planetary surface even if a shipyard is not present" aspect, largely because it implies that a ship can be produced at a world with an X starport, which is lesser than any Starport type between E and A. But, that's a discussion for another day perhaps.
The second item I spotted was this quote in the same book, page 51:
Once a prototype craft has been created, additional craft of the same design may be produced with a quantity discount of 80 percent of the full price.
The research and development craft design is an exception; it may have components in a single section that are one tech level beyond its current tech level limit. Such a crafl is typically
one-of-a-kind, and it may not benefit from a quantity discount.
If I understand the wording properly, one COULD for example, have a ship that is being researched/produced at a TL 14 world. It's primary components would ALL be at TL 14, but ONE component (in this case, it could be a Jump Drive) could be produced. However, this "ability" could be abused by players in a campaign world by building a TL 14 prototype ship that has TL 15 power plant components. Then, they build another ship with TL 14 components, but a Jump Drive. Eventually, they build a prototype ship that when the prototype devices are removed, can be used to build a pure TL 15 ship. Maybe that was the intent, maybe not.
I went through T4's rules, looking for an explicit point blank "TL limits what can be built" kind of thing, but the direct linkage between TL of a world and its starport regards to ship building was absent. When designing a ship, the only thing mentioned was the TL design limit - NOT what determines the limit. Consequently T4 users could state that the rules do not couple the world's TL with the starship production limit.
GT: GURPS did not specifically limit the TL of the ship production to that of the world. It took the approach that most shipyards are at TL 10 (GURPS TL 10 that is) or TL 12 with the reasoning that the starports themselves are built by the Imperium via Starport Authority, and are thus independent of the World's overall TL. Oddly enough? GURPS TL 10 translates into Traveller TL 11 and 12.
T5: Took some creative search parameters, but I finally came across this:
Ship Design Tech Levels
The Building World’s base Tech Level constrains the capabilities of the shipyard constructing the ship. Unless otherwise specified, all mechanisms on the ship will be at the base tech level.
Imported Components. Some components and mechanisms can be imported from neighboring shipyards with the appropriate tech level. Standard mechanisms at TL +1 are available and can be imported at their standard cost plus 10%.
Early, Prototype, and Experimental mechanisms are available locally.
Now, the implications of that statement seem to line up with the concept that the TL of the world in question limits what ships can be built. The limits are a little bit looser than the original wording from either of CT's High Guard or MT's wording, but it is relatively close. To wit: A TL 10 world with a Class A starport, could built a TL 11 starship, providing there was a neighboring TL 11 world also capable of producing what the TL 10 wishes to build.
As a GM, if a player said to me "Hey, there is a neighboring TL 11 world with a Class B starport, this world should be able to manufacture a TL 11 starship" - my answer would be "Since the neighboring world can't produce starships, it can't ship starship parts to the TL 10 world". THAT however, is not written in the text...
So, here's my take on the whole issue regards to TL and whether or not a Starport can service ships above its TL. This is a judgement call, and not supported by any given rule set...
Worlds have a baseline Tech Level - for which a Starport either shares the Baseline Tech level (Ie was built at the world's technological base) or was built to produce a higher baseline ship providing it has access to a neighboring world that can produce those parts. Since cost of components are based upon the base tech of the world that produced them, shipping those parts from one location to another, incurs a higher production cost for starports building ships independent of the main world's tech base.
T5 says +1 tech level, GURPS seems to imply that the shipyards are independent of the World's TL, as does MgT.
My thoughts are this: TL is an abstraction. With the exception of WORLDBUILDER'S HANDBOOK for TNE, there was little work done to detail the productivity of worlds, their industries, and surpluses or deficits of production. POCKET EMPIRES goes so far as to determine if a world is a net importer or a net exporter type world, but that is not sufficient detail to determine how many worlds a TL 15 industry can support in addition to itself. Most GMs are not even going to CARE (and I can't blame them!). So, when dealing with abstracts, the GM will have to use an abstraction himself. Probably the best way to handle which worlds gain the best benefits of trade, will be the ones with the best "interaction". GURPS treats this is Bi-World Trade Numbers, and each world gets its own World Trade Number (based largely on the population and starport type). Distance between worlds require more attention to logistics, and thus lessen the BTN that is generally a sum of WTN between two worlds.
So, can a Starport handle TL 15 maintenance? I'd say yes - with one proviso... That maintenance costs are increased in the same manner as imports cost. If the nearest TL 15 starport is 20 parsecs distant, then the cost of TL 15 materials should also go up by the same amount that buying a TL 15 import goes up.
That's my take on it at least. Much of the work done on the Third Imperium took place in the 1980's (Heck, I even took the time to catalog publishing dates for various of the CT products so I could see the relationship between when one book was written and another dependent book was written). By the time MT hit the shelves, the issue of "Canon" became something of a problem. By the time T5 came into being, it was supposed to be the definitive final say in a lot of things, but not necessarily meant to invalidate existing licenses (such as MgT for example).
