Would a far/free trader ever use missiles?

[Sigtrygg]

An empty hex is large. A parsec takes years for light speed sensors to detect things if it is far enough away. What do they gain in that kind of patrol?

They find the Zhodani invasion fleet using collector equipped tenders to move from empty hex to empty hex...

 

[Sigtrygg]

I think the "empty hexes are not empty" concept is a great one...for a different setting. It breaks how Charted Space works. IMHO.

But even still, I don't think anyone is patrolling empty hexes, but scouts would be mapping them and turning them into not empty hexes.

I would assume the IISS would survey the "empty hex" for useful !flotsam!, fuel from brown dwarfs, rogue planets, minerals to feed makers to make spare parts.

They would also leave "listening posts" near those...

but

even a hex with a populated planet in it is very big with lots of empty space to hide shenanigans within.

Look too closely and the entire setting falls apart, or a lot more automated sensor stations are needed.

I wonder if the Imperium has considered seeding empty hexes with self replicating robots that are tasked with building more of themselves and lots of sensor stations?

What could possibly go wrong...

 

[Sigtrygg]

I am using things from many systems where MGT2 is silent. I just don't like contradicting the rules system I am currently using as it creates knock on effects.

I concur with Very Long since beyond that you cannot detect EM regardless of the quality of your sensors (Core Rulebook P160).

Whilst electro magnetic emissions do have infinite range, the power reaching an antenna drops rapidly with distance. In theory you could have an infinitely high gain antenna, but the higher the gain the more directional it becomes, the harder to target the antenna and the more interference can impact the reception. At some point the ship itself will become the biggest source of interference and that imposes a practical limit to the amount of gain.

High guard clarifies that Distant is out to 300,000 km and adds some extra range bands where sensor checks become even harder (and these would be limited to Thermal and Active Radar and Lidar).

Jump events are sufficiently dramatic that there appears to be no range at which they cannot be detected, so presumably by some thermal signature. Which I would say would allow you to determine the tonnage of the jumping or arriving vessel but nothing else at that range.

Over 5 Million Km active RADAR/LIDAR would allow you to target and detected object and determine whether it is a ship or some sort of astronomical object.

One word

Voyager.

 

[Sigtrygg]

What are these other fleets and how many ships are we talking.

The IN has many regular fleets in a sector, It has one sector fleet , and then one fleet for every subsector.
Those are regular, TL15, state of the art IN fleets, whose job it is
1. to protect the space lanes and keep trade flowing
2. defend against foreign threats

If the IN is not capable of doing 1. then worlds should stop paying their taxes and build their own ships.

So the IN has to patrol the space lanes of every member world,

 

[Arkathan]

I thought we’d already clarified this but apparently we must do so over and over.

Yeah. I was letting you know where the confusion started and that had people thinking you said something you didn't.

 

[Arkathan]

Yes, I did say uninhabited hexes. A hex with a gas giant but no inhabited planet counts. It might be patrolled simply by virtue of it being a refuelling point. A hex with no star can still provide that facility as I would expect the IN to put at least fuel dumps there "just in case", they just don't advertise the fact so it doesn't appear on the maps.

On the borders these empty hexes might be mined or contain automated sleeper stations that monitor the system and would need to have that data collected periodically. That would also constitute a patrol cruise.

I'm talking about occupied hexes that have unoccupied binary or trinary systems in the same hex. It multiplies the hiding places

 

[PeterDebney]

I think the "empty hexes are not empty" concept is a great one...for a different setting. It breaks how Charted Space works. IMHO.

IMHO empty is relative. Our own asteroid belt is far from empty, but it looks nothing like the Star Wars version. If we pass through the asteroid we would be lucky to see even a single asteroid. Out in the Oort Cloud it is even sparser.
In interstellar space there are rogue planets (ejected from solar systems), brown dwarfs, and potentially even difficult to spot things like cold neutron stars or even black holes. True there will not be many of those latter ones.
In game terms, a non-empty hex is one with a solar system suitable for exploitation. Elsewhere there is all sorts of space junk, but well spread out. The chance of encountering any of it is slim.

 

[Terry Mixon]

They find the Zhodani invasion fleet using collector equipped tenders to move from empty hex to empty hex...

You mean they get the lightspeed indications of something months or years after the Zhodoni already passed. An empty hex is too large to cover in a timely manner.

 

[Sigtrygg]

The gravitational wave signature of the jump transit leaves an imprint on space time that can be detected if you tune your grav sensors and grav comms just so... If you know where they were you can then go looking for where they have gone to.

But the same can be said about the populated systems. Stop and think and none of it makes sense. I could jump an invasion fleet into the Oort cloud, fully refuel from an icy body and then jump out, you may find out in a few months what I did.
Or, the IN has to maintain listening posts monitoring the entire Oort cloud of every system...

I'd stick to them just patrolling the 100D limits.

 

[Vormaerin]

I accept how all the above could be possible (and maybe even desirable for a specific referee) but it would have avoided a whole lot of previous posts had you made it clear that this was your opinion of how it should work, rather than your understanding of the rules that stated how it did work. I have less interest in someone's opinion versus their reasons for holding that opinion. I also note that you agree that your hypothesis only applies to class C+ ports and not every system in the empire. As I indicated some posts ago I am simply trying to align the encounter tables with your perception of the way the universe should operate. The vast majority of encounters are not authority vessels.

You say that you can choose where to arrive on the 100D limit. I don't think that is the case. You cannot even guarantee you will arrive at a specific distance from the planet.

You are choosing to assume an equivalence to terrestrial equivalents and whilst that has validity for many aspects of travel it needs to be remembered that terrestrial travel lanes are within a fixed geography. The port of Dover is always at the same latitude and longitude regardless of the the time of year and has been for centuries. Some planets rotate so your arrival points would need to be at the poles for your routes to be geostationary. Once you get to the 10D limit I can see the need for some control and as thus is a far more compact volume. It is also far more credibly within the scope of a planetary based sensor net to monitor and can therefore be geostationary. Whether a world that only has the resources for a landing beacon has the resources for a planetary sensor net is for the referee's judgement.

The planet also rotates around the star and jumping in earlier or later than you plotted will mean the site you selected at the time you jumped will not be far away from where you intended. I presume this is covered within of jump variance. The traveller companion expands on this and makes it clear that that 100D is the limit and a target but the vast majority of astrogators will routinely be double digit percentages off it. In addition to avoid the effects of precipitation captains tend to add a 10% safety margin.

Once you add all that in perfectly legitimate ships will be emerging well over 100D possibly as much as 160D before it is even classed as a bad jump. Hopefully that will coincide with the engineer managing to emerge early so you can make up the time in normal space. but that is not guaranteed. This massively increases the required catch net of the patrols if you are going to check everyone at emergence and means you cannot be sure that someone arriving somewhat out of place is "a wrong un". It doesn't stop you creating a patrol network at 100D (since you need to establish the boundary somewhere) but you probably are not going to send a ship out to 160D to investigate what turns out to be cadet astrogator having a bad day as the ship you send is itself going to vulnerable if it turns out that ship is in fact a pirate. Also this is technically Imperial Space and the job of the IN to investigate should they deem necessary. I have still seen nothing to suggest the IN has enough ships to do this effectively.

This actually allows more of that intersystem travel at risk that you were bemoaning the lack of.

The accuracy of Jump drive arrival is one of those things that varies every time someone writes about it. Just in the Mongoose 2e version of Traveller there is 3 or 4 different versions. It is extremely swingy in the Companion rules, though very unlikely to be outside of the bounds I mentioned. This is by far the least accurate version of Jump I'm familiar with from any edition of Traveller. It is noticeably more accurate in the Mongoose JTAS #3 article on "Jump Drive Operations". It is a little less accurate than the JTAS article, but still very much more accurate than in the Companion in the rules on jumping in the World Builder's Handbook (where it is talking about jumping to objects in Empty Hexes).

As far as explicitly stating this is my opinion. First, I did that pages ago. Two, you would be best off assuming that is the case for every statement made by anyone on any topic that isn't an explicit game mechanics quote. And, even then, a lot of them are subject to contradictory interpretations and sometimes even contradictory rules. Such as, for example, the jump space accuracy issue just discussed.

Charted Space does not have any significant discussion of how things are actually done "in universe". On basically any topic. And the few topics where there is some discussion (usually in an adventure) it is generally specific to a given world.

For instance, on the other topic going on about patrolling. In sourcebooks, it says the Imperium patrols. It says nothing about what that actually looks like, beyond that it is mostly the smaller ships because everyone runs as soon as cruiser or the like shows up. There are a few adventures where local ships are intercepting craft for inspections. Others where you find an Imperial ship running silent spying on everyone. And naval adventures where you are out actively searching for pirates in extra Imperial space. Sometimes in the aforementioned Cruiser. So, basically, it works however the GM thinks makes sense.

Btw, 160D is only a couple hours further out than 100D even at the slowest speeds (1G), so I don't actually consider that a significant difference.

 

[PeterDebney]

You are choosing to assume an equivalence to terrestrial equivalents and whilst that has validity for many aspects of travel it needs to be remembered that terrestrial travel lanes are within a fixed geography.

This is all totally correct.
To add to it:
Air travel is constrained by shortest paths and avoidance of war zones, constantly guided by air traffic control, because our skies are reasonably crowded.
While shipping lanes are restricted by islands and shoals, in the open ocean they just take the shortest paths with no outside control.
In both cases, shipping lanes / flight paths are crucial only near (air)ports and narrow areas like the straits of Dover.
In both cases the islands and ports stay still. A space port on the Earth’s equator, on the other hand, is moving round at 1,700 km/h. A high port will move at, at least, an order of magnitude faster.
The Earth itself is moving at about 107,000 km/h.
With everything moving, the arrival/departure points may match the relative direction of the adjacent systems, but they will be essentially random compared to the space port locations. Traffic lanes will only be needed / enforced once the ships are within an appropriate distance.
What that distance is might depend on the port or its quality. I’ve seen 10d mentioned, which is IMHO perhaps a large value, but could work. Remember that our geostationary orbit height is at about 3d and the Moon at 30d.

 

[Vormaerin]

IMHO empty is relative. Our own asteroid belt is far from empty, but it looks nothing like the Star Wars version. If we pass through the asteroid we would be lucky to see even a single asteroid. Out in the Oort Cloud it is even sparser.
In interstellar space there are rogue planets (ejected from solar systems), brown dwarfs, and potentially even difficult to spot things like cold neutron stars or even black holes. True there will not be many of those latter ones.
In game terms, a non-empty hex is one with a solar system suitable for exploitation. Elsewhere there is all sorts of space junk, but well spread out. The chance of encountering any of it is slim.

Yes, I am aware of that. But just like Charted Space ignores 80% of the stars we know about, it also has "impassible" terrain in the form of empty hexes. If you start including all of that material in the Charted Space setting, you radically change its history and operating parameters. The Great Rift is considered a nearly impassable barrier with only a few specific crossings. But that's nonsense if the Scouts have have a thousand years to chart out the "empty" hexes for rogue bodies and map pathways.

I love the idea of exploring like that. I think it makes a great campaign idea for players interested in such. But it is a radical change to this particular setting.

 

[Vormaerin]

This is all totally correct.
To add to it:
Air travel is constrained by shortest paths and avoidance of war zones, constantly guided by air traffic control, because our skies are reasonably crowded.
While shipping lanes are restricted by islands and shoals, in the open ocean they just take the shortest paths with no outside control.
In both cases, shipping lanes / flight paths are crucial only near (air)ports and narrow areas like the straits of Dover.
In both cases the islands and ports stay still. A space port on the Earth’s equator, on the other hand, is moving round at 1,700 km/h. A high port will move at, at least, an order of magnitude faster.
The Earth itself is moving at about 107,000 km/h.
With everything moving, the arrival/departure points may match the relative direction of the adjacent systems, but they will be essentially random compared to the space port locations. Traffic lanes will only be needed / enforced once the ships are within an appropriate distance.
What that distance is might depend on the port or its quality. I’ve seen 10d mentioned, which is IMHO perhaps a large value, but could work. Remember that our geostationary orbit height is at about 3d and the Moon at 30d.

Yup. Jump drives make no sense whatsoever. You could interpret them as taking you to a specific spot in space. You could interpret them as taking you to a specific spot in relation to another stellar body (some write ups do that). The Starship Operator's Manual adopts the obstruction model, where jumpspace travel is a literal straight line between where you leave and where you arrive and if you clip any large mass in real space, you drop out of jump space. T5 has whole passages on getting knocked out in empty space short of your destination because you forgot about a rogue planet.

Apparently jump drives correct for galactic vectors but not for individual vectors on your ship? Since we generally don't account for the motion of galactic objects for simplicity of calculations. But you can have a ship vector going in that remains when you come out.

 

[Sigtrygg]

The whole jump line description makes no sense.

jump from point A in real space to point B in real space, this takes one week.

jump from point A as above, but you risk misjump if you are within 100D of a planet, later moon, later star, later any object larger than your own ship.
You arrive at point B, unless point B is within 100D of all that junk, in which case you leave jump space at the 100D limit. This takes a week.

Now it used to be that it didn't matter what was in your way, which makes a lot of sense, but now you have to know where are you in jump space relative to A and B after a day, three days, almost a week? So now jump space maps 1 to 1 to real space only the distances are much smaller?

Also everything is moving, so stuff not on your real space jump line may cross your jump line during those 7 days and drag you out of jump space.

So now you need to know the relative motion of A, the relative motion of B... and the relative motion of everything that could be on a straight line path between the two points at any time during the week in jump.

Does that add anything to the game?

 

[PeterDebney]

Also everything is moving, so stuff not on your real space jump line may cross your jump line during those 7 days and drag you out of jump space.

So now you need to know the relative motion of A, the relative motion of B... and the relative motion of everything that could be on a straight line path between the two points at any time during the week in jump.

Does that add anything to the game?

Not only that but, if you are detecting anything from 1 parsec away, that information is 3.5 years old.
At least space is mostly empty, so even a large star’s 100d sphere will be difficult to hit unless you are jumping into that system and not just passing though.
Ultimately it is just a game. The players should experience peril from their own decisions or those of the referee, and not from random stellar mechanics.

 

[Vormaerin]

Does that add anything to the game?

Not even remotely. It's even worse in that regard than the 1000D limit on M-Drives, which are pretty un-useful for gameplay too. Too much trying to apply physics to space magic. And, worse, different people applying physics to space magic in different ways.

This one is particularly annoying to me because you can't have it work like that when your time in transit is an uncontrolled variable.

 

[swordtart]

One word

Voyager.

One word

And?

 

[swordtart]

The IN has many regular fleets in a sector, It has one sector fleet , and then one fleet for every subsector.
Those are regular, TL15, state of the art IN fleets, whose job it is
1. to protect the space lanes and keep trade flowing
2. defend against foreign threats

If the IN is not capable of doing 1. then worlds should stop paying their taxes and build their own ships.

So the IN has to patrol the space lanes of every member world,

Yep. And sending a single ship down those lanes every other week is patrolling those lanes.
Has it fulfilled its obligation? Absolutely.
Has it significantly reduce the chance of the Zhodani setting up a base on the third moon? Absolutely.
Has it verified that the system government hasn't introduced unfair tariffs? Absolutely.
Has it liaised with the provincial fleet and conducted joint training. Absolutely.
Has it collated all the reports on pirate activity from the provincial government and forwarded them to the flag ship? Absolutely.

Has it investigated every ship that has entered the system? No.
Has it been present at every part of the lane at all times? No.

According to the IN Handbook, at least in the So-Shire subsector the member worlds do build their own ships and even have to loan them to the IN.

 

[swordtart]

The whole jump line description makes no sense.

jump from point A in real space to point B in real space, this takes one week.

jump from point A as above, but you risk misjump if you are within 100D of a planet, later moon, later star, later any object larger than your own ship.
You arrive at point B, unless point B is within 100D of all that junk, in which case you leave jump space at the 100D limit. This takes a week.

Now it used to be that it didn't matter what was in your way, which makes a lot of sense, but now you have to know where are you in jump space relative to A and B after a day, three days, almost a week? So now jump space maps 1 to 1 to real space only the distances are much smaller?

Also everything is moving, so stuff not on your real space jump line may cross your jump line during those 7 days and drag you out of jump space.

So now you need to know the relative motion of A, the relative motion of B... and the relative motion of everything that could be on a straight line path between the two points at any time during the week in jump.

Does that add anything to the game?

No, so it is abstracted to an Astrogation roll and an Engineering roll.

Just because we use a simplified system to play it out in game sessions doesn't mean however that we should infer that it is simplified when designing our setting or we start introducing lazy handwavium that starts getting in the way. Player never need know about the complexity under the bonnet, but they will appreciate on the day they decide for play reasons they really need to know a fact and it turns out the referee has it all laid out. You don't even have to use it every time as long as every time you quote an effect as long as it is within the scope of probability.

We use the "simple" accelerate-turn-decelerate maths when moving between planets in normal space, but we don't do that for space combat, as a result you make assumptions on how effective ships are that doesn't hold up under even simple analysis.. We are also told that ships cannot exceed the speed of light, so if your journey length and acceleration are such that you reach light speed before the mid point some stage of your journey will only be at light speed and your journey will take longer than the simple calculation indicates.

Even that is not as digital as it first seems. You cannot accelerate at 10G until 1mph below the speed of light and suddenly acceleration stops when you speed up that last 1mph. According to the last text book I read you gain mass as you approach the speed of light and at the speed of light you acquire infinite mass. Before that point the thrust that gave you 10G at zero will give you less the closer you approach light speed*.

Is this too hard for game play. Not really it is a simple formula that you could set up in excel (or a programmable calculator or a trivial Python** script). You only need to conduct the calculation when you want to know how long it takes to get there. Once you have that number you go on with your day. Unless your session consists on multiple hundreds of transits through normal space that you actually need to know the duration of then it is not even a minor inconvenience. Heck you could even go old school and prepare a table in advance (exactly like the Core rulebook did).

But if you say that the Navy inspects every ship that enters a system then you need to be sure that this is a credible statement, beacuse one day a player decision is going to be based on that "fact" and when it turns out to be bogus they are going to feel cheated.

**Other programming languages are available

EDIT:
* Ok just did that and even at 10G travelling for a week you only add 2.1% of the mass which isn't significant enough to bother with. If you are forced to transit for a month however you start to suffer integer percentiles of acceleration inhibition due to relativistic mass effects. After roughly two months at 2G your ship will have acquired approaching 50% of it's mass so thrust will have diminished. At 3G you would have hit light speed even ignoring relative mass, but at the 1 month point you ship would be 20% heavier and your thrust would have dropped below 3G. In addition once you suffer relativistic mass effects you also get similar time dilation effects so time passes slower in your frame of reference so it might not seem as long. Not only you be late... you will be later than you think.

Lots of crunch here if you like that sort of thing, so don't transit a parsec thought normal space, it takes even longer than you would think using the simple constant acceleration model, longer than it would if you could actually achieve light speed. It might be easier to just say it takes a loooooong time.

 

[Vormaerin]

The Mongoose 1e sourcebook "Sector Fleet" is the predecessor of The Imperial Navy sourcebook. Rather than the Solomani Rim, it details the fleet of the Spinward Marches.

In the Aramis Subsector:
The Spinward Marches Fleet maintains three patrol groups totalling 20 light (ie not fleet combat worthy) escort vessels.
The 214th Imperial Fleet (the Aramis Subsector Fleet) has two flotillas totally 19 more light escort/patrol vessels.
The Aramis Colonial Fleet Assets that aren't SDBs or Monitors (ie can be used for multiple system patrols) include 34 more such ships.

So you have 73 1000dton or less jump capable patrol craft available, aside from whatever SDBs and Monitors any given system has (though most probably don't have many, since the worlds here are mostly pretty poor). That is to cover 26 worlds. That does not include the ships assigned to the fighting formations stationed at Natoko, Aramis,and L'oeul d'Dieu, which are all light cruisers, destroyers, and escorts.

A Zhodani border subsector like Jewell has more heavy ships in its colonial fleet, because those planets are more concerned about heavy warships than light raiders/piratees. The overall patrol numbers are not that much lower.