Jump capacity

[phavoc]

Here's the problem with that - ISW is meant to be a source book for GURPS, covering the period of Terran expansion and wars with the Vilani. GURPS stands for Generic Universal ROLE PLAYING System. On pg 7 of the book it states the the material in the book is meant to run adventures, not wargaming. Wargames are fundamentally different than RPG's, and games like Imperium are meant to be abstracted, not character-based. Imperium also goes on to have a rule that states if both sides happen to enter the same deep-space hex, combat must occur and it's a duel to the death. Again, something that is OK for a wargame, but not as much for an RPG.

As you correctly pointed out upthread, the fundamental concepts of M-drives and how they operate was changed via a different retcon of the rules (there were multiple versions before that do not include this concept). This is nothing new, as pretty much all the editions have done similar things - some with larger impacts and some with minimal. So the idea that there is a need to match such rules together doesn't really make much sense when taken as a whole. That's the point I'm making here.

Ideally as publishers make new editions of the rules, changes are meant to be positive additions to the rules, or clarifications/cleaning up of inconsistencies that help lay a better foundation for the game. In this particular case the retcon didn't really match the wargame rules in their entirety, since the other part of the rules allowed for unlimited number of jumps until encountering a system that had at least one enemy warship in it. So the authors took part of the rule but not the other.

I agree with you the GURPS ISW are not applicable to laying in version of the Imperium that exists from CT onwards. Imperium itself wasn't really meant to be linked up with Traveller the RPG until after both were published in 77. Later editions expanded scope and republishing incorporated things more into the game.

I thank you for input and opinion on this. It's nice to be able to debate.

 

[Vormaerin]

Sure. Traveller has added and deleted things all the time. You certainly aren't going to get any arguments from me about deleting things you don't like from the setting.

I don't have any interest in running in the First Imperium, but I kind of like the idea that the Vilani at that point had decided they had figured out the best way to get to anywhere they wanted to go, so just ran off jump tapes and didn't bother going off the road anymore. But you don't have to like that idea or use it. Similarly, you can assume that they have the same level of computerized navigation capabilities that the Third Imperium has and any suggestion that tech was worse 3000 years ago is stupid.

I disagree that its a retcon, because there was no 'con' about the First Imperium in print to ret. But certainly no one should feel bound by any printed material they don't like.

 

[Sigtrygg]

The M-drive has been described as:
a fusion drive
a reactionless drive
a handwavium drive (MegaTraveller)
HEPlaR
gravitic handwavium
all are canon for their rule iteration.

The jump drive in OTU canon:
early Vilani were large, power hungry and fuel hungry
early Terran were large and fuel hungry with reduced range
had reduced fuel requirements in MegaTraveller and TNE

 

[Condottiere]

It only really becomes important if you end up in an empty hex.

And from my point of view, that's through where the Confederation Navy is sending it's infiltration cruisers to Terra.

 

[BigDogsRunning]

The M-drive has been described as:
a fusion drive
a reactionless drive
a handwavium drive (MegaTraveller)
HEPlaR
gravitic handwavium
all are canon for their rule iteration.

The jump drive in OTU canon:
early Vilani were large, power hungry and fuel hungry
early Terran were large and fuel hungry with reduced range
had reduced fuel requirements in MegaTraveller and TNE

According to the 2004 Joe Fugate interview, the reason they reduced jump-fuel requirements in MegaTraveller and TNE was because they incorporated the Striker rules for fusion powerplant fuel consumption. Now your regular powerplant sucks down enormous amounts of fuel, in addition to your Jump Drive. The ship became little more than a flying fuel tank.

 

[Sigtrygg]

And it never occurred to him to that you could introduce another scale factor for ship scale power plants which would have solved the problem?

 

[phavoc]

Sure. Traveller has added and deleted things all the time. You certainly aren't going to get any arguments from me about deleting things you don't like from the setting.

I don't have any interest in running in the First Imperium, but I kind of like the idea that the Vilani at that point had decided they had figured out the best way to get to anywhere they wanted to go, so just ran off jump tapes and didn't bother going off the road anymore. But you don't have to like that idea or use it. Similarly, you can assume that they have the same level of computerized navigation capabilities that the Third Imperium has and any suggestion that tech was worse 3000 years ago is stupid.

I disagree that its a retcon, because there was no 'con' about the First Imperium in print to ret. But certainly no one should feel bound by any printed material they don't like.

The Vilani empire had stagnated prior to encountering Terra. Rome had done the same thing. One might argue it's a human condition rather than a socio/political one. That's the same reason Vilani had defaulted to using jump tapes rather than making a new plot for each jump - they were tired and had little desire for exploration or continuing to expand their tech/knowledge base. When combined they were ripe for plucking by upstart Terrans (once they were able to bring their economy up to war footing).

I'm going by the timeline of the published materials and what was actually printed. It's contradictory. You may not see that, or agree with it. However it's there in black and white. Imperium (the wargame) states things that Traveller (the RPG) reverses. ISW (the RPG) attempts to bridge the gap by combining some of the wargame rules into the RPG state. The wargame and RPG were never designed to be compatible, just loosely linked.

Clearly we are at loggerheads here. No one should be bound to agree/disagree with phosphors they don't like.

 

[Vormaerin]

Who said you were? You said it was stupid, served no purpose, and was a retcon. I disagree with all that. I certainly don't expect that people actually use it if they don't want to even if they do play at the end of the Vilani Imperium. Which I doubt many people do.

It is a specific rule for a very specific situation with no general applicability. It is trying to square the circle between the RPG and the board game because it is specifically trying to simulate the era of the board game. Which the RPG rules has never, ever tried to do outside this supplement. That's not stupid, it does add something to the game, and it is not retconning anything. Are you required to use it even if you do play in that era? Absolutely not.

But then, no one is required to use any rule. Use stutterwarp in your game instead of jump drives. Have your Aslan be based on the Kzinti if you want. Disallow drop tanks and personal energy shields. Turn the stagnant Vilani into great explorers. Whatever works for you. No one cares what you do in your home campaign. I've certainly never said otherwise, so I have no idea why you think we are at loggerheads over that.

 

[alex_greene]

I have a situation in the MGT2 game I am running. The travellers have effectively missjumped (inflicted by NPC) and are now stranded on a planet 4 parsecs from the next system. They have the Harrier (Pirated of Drinax) with J2 capability. They will have to jump to an empty hex and then wilderness jump to the next inhabited system. They will have to build a droptank/external tank to supply the fuel they will need for the back-to-back jumps they are making adding an additional 40dT to the ships 200dT. This additional mass/volume would require an additional 2dT of jump drives.
HG states that Jump-2 drives are 5% of the ships mass (10dT) plus 5dT. Would you allow the additional volume to be covered by the extra 5dT, allowing the ship to jump-2 parsecs, or rule that you would need 17dT of jump drives and therefore the ship can only make a jump-1 with the current engines (15dT)?

Empty the cargo hold of all but essentials, and partially convert the interior cargo bay into fuel storage.
I just jumped in here a minute ago. This is what I would do.

 

[alex_greene]

I don't think anyone was talking about NAFAL travel. The nerf to Maneuver drives that makes them minimally useful in the outer region of star systems or in deep space is problematic for if you are trying to get to a comet or some deep space anomaly.

That's the first rule I ignored when I looked at HG. Those could be drives built for short range craft. Your ship is designed for interplanetary travel, as well as interstellar.

I've had my characters ride in large ships, Jump into a system in the mainworld's Trojan point, and send in a fleet of smaller boats, launches, and modular cutters for trade. Those boats' M-drives worked perfectly fine between planets. The planetary authorities never saw the mothership, unless it was pulling into some shipyard for maintenance.

 

[PeterDebney]

I am curious to know how the Traveller background explains the incredible accuracy of jump travel. Consider the facts:

• for a 1 parsec jump, any observations of the target system and the planets' locations must be, by definition, over 3 years out of date (1 parsec = 3.26 light years); or nearly 20 years for J6.
• In the World Builder it points out how hard it is for a survey ship to detect a planet in the same parsec hex if there is no sun - the implication being such detection must be mostly optical.
• It would be reasonable to assume that Imperial ships astrogation systems contain databases of all known solar systems and their planets' motions, but what about jumping into a system that is not covered on the charts - wouldn't the chance of arriving next to a planet be infinitesimally small?
• any time variance on the jump must affect the accuracy. The Core rule book gives the jump time as 148 + 6D hours (say +-15) and the Companion allows even larger variations even without a bad jump. In 15 hours the Earth (for example) travels 1,608,270 km (126 diameters - 107,218 km/h) around the Sun, and the solar system as a whole moves 12,420,000 km (975 diameters - 828,000 km/h). That's 1,100 Earth diameters off, which is considerably more than the distance variance given in the Companion.

How does it work?

 

[Arkathan]

Jump at the 100d limit of the star after adjusting for motion and let the gravity well dump you out of jump space. Survey in system form there.
Don't make a J6 jump to survey a system unless you know there is a gas giant in system AND without at least 1J of additional fuel on board (use a drop tank for the first jump).

 

[alex_greene]

Many of the systems in the likes of the Marches have already been visited. The Scout Service will have done all of the charting for you.

If your ship's visiting an outlying sector, there's typically going to be some sort of maps available in a Class A starport, usually obtainable from the TAS, free for all TAS members and Travellers in general. Perhaps TAS members get the latest updates first, but there is bound to be some sharing of map data on public nets, particularly in systems where there is a Scout Base.

And then there's always Traveller bars in Startown, Patrons, other spacers, and fringe sites - plenty of sites in Lanth, for example, discussing the Abyss Rift, with detailed log recordings of ships which have traversed the empty portion of that subsector and lived to tell the tale.

 

[Condottiere]

Within the Imperium, the charts are updated at the local starport through the Ecks Boat network.

 

[Geir]

I am curious to know how the Traveller background explains the incredible accuracy of jump travel. Consider the facts:

• for a 1 parsec jump, any observations of the target system and the planets' locations must be, by definition, over 3 years out of date (1 parsec = 3.26 light years); or nearly 20 years for J6.
• In the World Builder it points out how hard it is for a survey ship to detect a planet in the same parsec hex if there is no sun - the implication being such detection must be mostly optical.
• It would be reasonable to assume that Imperial ships astrogation systems contain databases of all known solar systems and their planets' motions, but what about jumping into a system that is not covered on the charts - wouldn't the chance of arriving next to a planet be infinitesimally small?
• any time variance on the jump must affect the accuracy. The Core rule book gives the jump time as 148 + 6D hours (say +-15) and the Companion allows even larger variations even without a bad jump. In 15 hours the Earth (for example) travels 1,608,270 km (126 diameters - 107,218 km/h) around the Sun, and the solar system as a whole moves 12,420,000 km (975 diameters - 828,000 km/h). That's 1,100 Earth diameters off, which is considerably more than the distance variance given in the Companion.

How does it work?

Surveys would aim for the star's 100D limit (temporally adjusted course, of course), crashing into it to precipitate out, unless they already had a good gas giant or defined planetary orbit to aim at. If if they missed, they would fall out into the system.

The third bullet is.... problematic. At least for any normal space view of what's happening. Okay, watch not-to-closely while I wave my hands widely... so, like, the Astrogation task - more art than science and requiring a sentient mind - is actually tracking the gravity well of the target through 4-space and what you end up hitting is a modified vector exit point at the 100D of the target regardless of elapsed time, because, err... both time and space (not to mention momentum, energy, vector, etc.) are inherently linked variables in the outcome of the jump calculation (?).

(This is why I like the idea of either instantaneous jump or of a 'hyper-drive' or 'warp-drive' effect, but that's not how standard out-of-the-box Traveller works.)

 

[Vormaerin]

Presumably you have to be calculating a relative position to your target, not an absolute position in real space. So mysteriously it doesn't matter where the Earth is relative to the other bodies in the solar system, it only matters where the Earth is to you when you emerge. How that works? I have no idea. But then I don't know how Liquid hydrogen works as a power source for the jump drive or why it is the best fuel for the job given that it has a remarkably low volumetric energy potential. And fuel volume is like the defining problem of starshp design.

 

[ProfGrizzlyJon]

Jump at the 100d limit of the star after adjusting for motion and let the gravity well dump you out of jump space. Survey in system form there.
Don't make a J6 jump to survey a system unless you know there is a gas giant in system AND without at least 1J of additional fuel on board (use a drop tank for the first jump).

Or a high probability of an asteroid with ice, or unless you have exotic matter collectors or ramscoops installed.

I allowed a slightly more advanced (TL12) ramscoop that is able to be fitted on streamlined starships because it is active, not passive (that is, it requires the power to collect instead of maneuvering). It does create quite the signal and eliminates the advantage from most stealth systems (except vislight)

There is always a way.

 

[Condottiere]

 

[PeterDebney]

I am curious to know how the Traveller background explains the incredible accuracy of jump travel. Consider the facts:

• for a 1 parsec jump, any observations of the target system and the planets' locations must be, by definition, over 3 years out of date (1 parsec = 3.26 light years); or nearly 20 years for J6.
• In the World Builder it points out how hard it is for a survey ship to detect a planet in the same parsec hex if there is no sun - the implication being such detection must be mostly optical.
• It would be reasonable to assume that Imperial ships astrogation systems contain databases of all known solar systems and their planets' motions, but what about jumping into a system that is not covered on the charts - wouldn't the chance of arriving next to a planet be infinitesimally small?
• any time variance on the jump must affect the accuracy. The Core rule book gives the jump time as 148 + 6D hours (say +-15) and the Companion allows even larger variations even without a bad jump. In 15 hours the Earth (for example) travels 1,608,270 km (126 diameters - 107,218 km/h) around the Sun, and the solar system as a whole moves 12,420,000 km (975 diameters - 828,000 km/h). That's 1,100 Earth diameters off, which is considerably more than the distance variance given in the Companion.

How does it work?

There is also the question of relative speeds. Any ship leaving a planet must start off with the planet's velocity. A thrust 1 M-drive allows 1g of acceleration (9.81 m/s^2 : 3.53 km/h^2): to match speeds with the Earth (as an example of a planet in a typical orbit, travelling at 107,000 km/h) from standstill you would need to accelerate for 3.5 years!
Jump drive must include major velocity change along with the distance.
Or is this an example of SF in accordance with Arthur C Clarke’s rules: everything must be scientific but you can have one element of fantasy?

 

[Geir]

There is also the question of relative speeds. Any ship leaving a planet must start off with the planet's velocity. A thrust 1 M-drive allows 1g of acceleration (9.81 m/s^2 : 3.53 km/h^2): to match speeds with the Earth (as an example of a planet in a typical orbit, travelling at 107,000 km/h) from standstill you would need to accelerate for 3.5 years!
Jump drive must include major velocity change along with the distance.
Or is this an example of SF in accordance with Arthur C Clarke’s rules: everything must be scientific but you can have one element of fantasy?

I think you dropped some decimals... so Earth, let's call it 30 kilometers per second ( a little high and ignoring that it's an orbit and not a straight line...) then accelerating at, let's just simplify and call it 10 m/s^2, that's 30,000 meters per second, so 3000 seconds to 'match velocity'. About 50 minutes.

The more fun thing is that star are orbiting the galaxy at varying velocity, eccentricity and vector. Most are probably close to another 30 kps in various directions, but some are higher. Groombridge 1830, if I recall correctly, clocks in at about 300 kps relative to Sol. So that's eight hours and change at 1 g. All such factors are generally ignored in Traveller. You could add it to your game, but only if you really enjoy making things extra difficult to play without calculators or spreadsheets. I'm going to stick with my don't-look-behind-the-curtain handwavium answer...