Some stuff lacking details in the OTU

DFW said:
You are reading two different posts and combining them. Hence your confusion.
Hardly. :wink:

You wrote:
They've been defined for decades in original material that defines the Imperium.

And when I asked:
Which original material do you mean ?

... you referred to the Mongoose Traveller Spinward Marches supplement,
which is neither original material nor decades old.

And I would still like to know which original, decades old Traveller material
includes details of the treaties between the Imperium and its member pla-
nets ... 8)
 
rust said:
And when I asked:
Which original material do you mean ?

... you referred to the Mongoose Traveller Spinward Marches supplement,
which is neither original material nor decades old.

No. Notice I didn't quote your question when I mentioned the supplement.

You can look up library data from the time as well as data in Mega rules, JTAS, etc. I don't have them in digital format so you are welcome to peruse your own copies.
 
AndrewW said:
kristof65 said:
IMTU, I've always assumed that every Class A or B and most Class C starports are divided into an orbital Highport, and an on the ground Lowport, with the bulk of the actual facilities being at the Highport, unless there is a compelling reason for them to be on the ground.

Usually not all would have a HighPort:

Traveller Core Rulebook page: 178 said:
Most planets have only a DownPort, a landing zone on the ground accessible only by entering the atmosphere.

Worlds advanced or rich enough may possess a HighPort, an orbiting starport.
Hence the prefix of IMTU. I don't really care what the rules say, because frankly, orbital ports make more sense in a lot of situations:

- large part of port can built out system, and towed into place, making higher TL starport facilities available to even lower TL planets, if desired.
- easier to facilitate ship berthing/docking space for a large number of vessels in the 3d environment of space, rather than the 2d environment of actual landing pads.
- weather on planets with atmospheres
- traffic control reasons
- customs control
- an orbital port can serve as a central station for several ground based ports, etc.
and so on.

Therefore my Traveller Universe 3I has a high frequency of orbital ports.

To bring that back to the traffic control questions vs 3I and COACC, for the most parts the Imperial portion of the Starports would actually be orbital, with traffic between there and the ground port(s) would be under the local COACC jurisdiction.
 
kristof65 said:
Hence the prefix of IMTU. I don't really care what the rules say, because frankly, orbital ports make more sense in a lot of situations:

Which is why I specified usually. Just mentioning it as a reference point. not meaning you wheren't free to use whatever system you like for your own stuff.

kristof65 said:
To bring that back to the traffic control questions vs 3I and COACC, for the most parts the Imperial portion of the Starports would actually be orbital, with traffic between there and the ground port(s) would be under the local COACC jurisdiction.

There is a Space Control Router, Shepherd-Class in Supplement 2: Traders & Gunboats designed for this sort of stuff.
 
kristof65 said:
Therefore my Traveller Universe 3I has a high frequency of orbital ports.
This is standard in the GURPS version of the Third Imperium, too. There
about half of all starports of Class III (= MGT C) and almost all starports
of Class IV and Class V (= MGT B and A) have an orbital element, and
these highports are usually under the same jurisdiction as their planets'
downports, making most of them Imperial starports.

I always preferred this to a universe with fewer highports, because - as
you wrote - it simply makes more sense, especially when the system in
question is on a trade route where goods are in transit, without having to
be shipped down the gravity well and up again.
 
rust said:
without having to be shipped down the gravity well and up again.
I actually refrained from mentioning the gravity well, simply because of Traveller's "magic" grav technology really negates that aspect of a highport's advantage a higher TLs. But the gravity well really does become an argument for lower TL worlds in the 3I - particularly TL 5-8 - importing the materials to have an orbital port, and actually buying/operating grav technology for their own benefit - even if only limited to their starports.

Yes, they could build a chemical rocket to put their own satellites in orbit - or they could buy a used air/raft to do the same thing. I know which path I'd take.
 
kristof65 said:
I actually refrained from mentioning the gravity well, simply because of Traveller's "magic" grav technology really negates that aspect of a highport's advantage a higher TLs.
I am not sure about that.

Even at TL 15 only streamlined and comparatively small freighters can
land on a planet's surface, so many goods in transit would have to be
transported down for storage and then up again.

Whatever technology one uses for this, it would cost a couple of credits
to ship those goods in transit between the orbit and the surface, and in
my view it should be more economical in the long run to store all those
goods up there in orbit, without moving them around at all.

Well, and once there are orbital storage facilities for transit goods, it
would be a small step to add facilities for transit passengers, and so on
- the highport could easily develop from there.
 
rust said:
Even at TL 15 only streamlined and comparatively small freighters can
land on a planet's surface, so many goods in transit would have to be
transported down for storage and then up again.

Which makes no sense when you think about it. A 2G ship can de-orbit on a 1 G world at whatever velocity it wants. It can "hover" down at 40 kph it the pilot wanted. The only ships that couldn't land would be dispersed structures or those unstreamlined that had less thrust than the G level of the planet.
 
DFW said:
rust said:
Even at TL 15 only streamlined and comparatively small freighters can
land on a planet's surface, so many goods in transit would have to be
transported down for storage and then up again.

Which makes no sense when you think about it. A 2G ship can de-orbit on a 1 G world at whatever velocity it wants. It can "hover" down at 40 kph it the pilot wanted. The only ships that couldn't land would be dispersed structures or those unstreamlined that had less thrust than the G level of the planet.

Common misconception. Most larger ships as designed would need a cradle or full body support to avoid breaking their backs; plus, the wear and tear on any ship from a landing and being in a grav field will always be a cost maintainance feature, as will the added risk. Plus, theres lotsa good reasons for planets to not want random ships re-entering/deorbiting if they can avoid it. There was an article about it either in the JTAS or a CT adventure, I think. Possibly in T4 or GURPS starports ? Look it up. Interesting stuff.
 
While advanced gravitics technology could make it possible to land even
a megaton freighter on a planetary surface and keep it in one piece un-
der the conditions there, the economical side of things would probably
make this a bad idea.

To land such a ship and bring it back into orbit needs some time, some
attention from air traffic control, a berth on the ground (where "real es-
tate" is probably more expensive than in orbit), a pilot trained for such
planetary landings, and so on and on - a series of cost factors that could
be avoided or reduced by using an orbital facility.

Besides, a planetary landing would only make any sense if at least most
of the cargo of the ship would have the planet in question as its destina-
tion. Landing a megaton ship just to unload a dozen containers of transit
goods destined for a different planet would seem like a rather ridiculous
idea to me.
 
rust said:
While advanced gravitics technology could make it possible to land even
a megaton freighter on a planetary surface and keep it in one piece un-
der the conditions there, the economical side of things would probably
make this a bad idea.

To land such a ship and bring it back into orbit needs some time, some
attention from air traffic control, a berth on the ground (where "real es-
tate" is probably more expensive than in orbit), a pilot trained for such
planetary landings, and so on and on - a series of cost factors that could
be avoided or reduced by using an orbital facility.

Besides, a planetary landing would only make any sense if at least most
of the cargo of the ship would have the planet in question as its destina-
tion. Landing a megaton ship just to unload a dozen containers of transit
goods destined for a different planet would seem like a rather ridiculous
idea to me.

It's only players that need to park the car nearby and keep the engine running, after all. :wink:
 
Well... a couple of points here. Streamlining is not particularly expensive, and from my reading relates more to control surfaces and the way the vessel flies once it's in an atmosphere. Just because your lift is provided by grav instead of a rotor or wings won't make a 2000 ton brick particularly easy to control to a soft landing.

Also, coming in from orbit requires that a ship Increases its velocity to obtain a lower orbit (I realise this is counter-intuitive, but is a fundemental fact of orbital mechanics). The descent would be able to be controlled by gravitics to an extent not currently possible, but you still have the issue that an object in orbit is travelling at a heck of pace and bringing it down to land is a tricky process that is going to be made more difficult by lack of aerodynamics when an atmosphere is involved.

And once you've interfaced and are flying in, you'd better hope for clear weather. Turbulence and high winds can be brutal.

However, the real reason large cargo boats aren't used is far simpler:

2000 ton standard config non-starship, manuever & power plant K, 20 tons fuel, unarmoured titanium steel hull, one stateroom. Cost is MCr1917.48 (standard design) with a maintenance cost of Cr159,790. Cargo is 1886 tons.

Standard Shuttle is MCr33 and maintenance cost Cr2,750. Cargo is 71 tons.

Crew cost is constant between the two, assuming you can run a 2000 ton shuttle with a flight crew of two and any engineering crew are based on the station or ground base, and that most 95 ton shuttles would also be operated with a crew of two.

The maintenance cost per the big boat is Cr84.72 per ton per month. That for the shuttle is only Cr38.73 per ton per month. If the big shuttle was streamlined or armoured it becomes even more expensive.

It's simply cheaper (and likely safer and more flexible) to run a fleet of shuttles than to operate a large boat. This would also apply for most in-system cargo apart from low priority bulk transfers that don't need to use high levels of thrust (i.e. a big box with a 0.1G reaction drive or solar sail).
 
captainjack23 said:
Common misconception. Most larger ships as designed would need a cradle or full body support to avoid breaking their backs;

No. Common misconception on the subject of physics. If a ship can pull 1 OR 2Gs in space it won't break in two if set gently down on a 1G world. Mass doesn't go away when removed from a gravity well. You are probably thinking that starships are built like ocean going ships. Not at all the case as starships have to maneuver (and take load) on all three axis.
 
DFW said:
If a ship can pull 1 OR 2Gs in space it won't break in two if set gently down on a 1G world.
Traveller starships are designed to take the stress along their axis of
thrust, not perpendicular to that axis - they do not accelerate or dece-
lerate "sideways" with full thrust.

This would be less of a problem for a "tail lander", but this is not the ty-
pical Traveller design, so a long, slender "belly lander" would indeed
suffer from dangerous structural problems on a planetary surface un-
less continually supported by gravitics technology or specifically desig-
ned for this situation.

Besides, since waves and storms are rare in space, a starship is usually
much more fragile than a seagoing ship of the same size would have to
be.
 
rust said:
Besides, since waves and storms are rare in space, a starship is usually
much more fragile than a seagoing ship of the same size would have to
be.

Well, the stresses and turbulence involved in orbit to surface interface transfer put oceanic storms to shame. Even with Gravitic lift.

Plus most space vessels carying people will have hull armour to absorb radiation. At least, that's already a part of normal Traveller canon.
 
rinku said:
rust said:
Besides, since waves and storms are rare in space, a starship is usually
much more fragile than a seagoing ship of the same size would have to
be.

Well, the stresses and turbulence involved in orbit to surface interface transfer put oceanic storms to shame. Even with Gravitic lift.

Plus most space vessels carying people will have hull armour to absorb radiation. At least, that's already a part of normal Traveller canon.



Unless you actually have some references, I really doubt that that is the case: atmospheric entry is mainly thermal and directional stress from deceleration hopefully along one predetermined axis- the actual turbulence is minimized , not resisted (otherwise it comes apart ) and if successful, there is mimimum buffeting for a fairly short period ; big oceanic ships have to survive far stronger impacts and pressures for much longer periods, and a spaceships heat protection is irrelevant. And armor isn't what makes the difference, anyway. Unless it is structurally weight bearing, its just more weight stressing the frame.
 
DFW said:
captainjack23 said:
Common misconception. Most larger ships as designed would need a cradle or full body support to avoid breaking their backs;

No. Common misconception on the subject of physics. If a ship can pull 1 OR 2Gs in space it won't break in two if set gently down on a 1G world. Mass doesn't go away when removed from a gravity well. You are probably thinking that starships are built like ocean going ships. Not at all the case as starships have to maneuver (and take load) on all three axis.

Nice ripost :wink: .

Rust's point is key here. A multi hundred kiloton ship landed on its belly (as with 99%of all traveller ships) is going to need to have much more support than just simple landing gear. It may or may not break, (and I'm not agreeing that it won't), but even if it doesn't "break" what will be happening is the ship will be taking continuous and long term stress (and taking load) in the wrong axis for continual thrust (or in this case G force) and across the entire surface, not just one thrust vector. Different kettle of fish. This will cause problems, and degrade the life of the frame for no profit. Plus, atmospheres are dirty, corrosive and have weather which will at the least mess with the hull coatings, seals and fittings as well as the cool paint job.

Yes, they could be built as tail landers, but they aint. And I'm not sure if tail landers make the most efficient use of internal space, anyway.

In any case, rinku's point is the other issue, and moots whatever physics (and thus engineering) we can argue about. one can land, but there is seldom a good reason to in the common trade (and even passenger) scenarios in traveller. It's unneccessary wear and tear to no profit. And in traveller it is all about profit.
 
captainjack23 said:
Unless you actually have some references, I really doubt that that is the case:

Well, I'll right backatcha on that. There is no real world data on 2000 ton spaceships that use gravity manipulation to maneuver, so it's all speculative. My assertion that reentry stresses would be more acute than an oceanic storm is matched by your assertion that a Traveller spaceship would be more fragile than a seagoing ship of the same size would have to be because there are no oceanic storms in space.
 
rinku said:
My assertion that reentry stresses would be more acute than an oceanic storm is matched by your assertion that a Traveller spaceship would be more fragile than a seagoing ship of the same size would have to be because there are no oceanic storms in space.
First, it was my assumption, not the Captain's. :wink:

A seagoing ship in heavy sea has to withstand being partially lifted out
of the water by a wave, several meters high, and then to be dropped
down again. Not once, but perhaps once per minute, hour after hour.

A ship 50 meters long that is hit sideways by a wave that is 3 meters
high and 3 meters wide and moves at the speed of a lazy pedestrian -
really no monster wave - is hit by about 450 tons of water at 5 kph.

We have only two examples of major vehicles that deorbited, the Space
Shuttle and the Buran, and from what I know none of them could with-
stand such a treatment for more than a few minutes.
 
The 'economics' of making dozens or hundreds of trips in shuttles (or manning fleets of shuttles for speed) versus one trip, on one ship is really not clear cut. Especially since there are additional variables to consider, such as offloading, reloading and personnel time for such, plus relative risks in cargo handling to cargo, craft and personnel. Not to mention the safety issues of big ship in atmo/gravity well versus lots more trips, nor the salary differences between pilots vs. 'shore' crews.

Orbital mass manufacturing is another reason high-ports may be desirable, though gravitics could negate the advantages of such. Again, lots of variables there - like for systems where the bulk of the mineral/metal wealth comes from off-planet due to availability, ease of obtaining, environmental impact or just plain culture and politics.

Irregardless of the 'economics' or any other 'realities', I'll just add, from a sci-fi standpoint, a space station is a whole lot sexier than a tarmac. ;)
 
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