Belts and safe jumping
- Thread starter nDervish
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You know, I'm sorry, maybe I shouldn't have gotten into this one. I deal with regulations by profession, and in my line of work words have specific meanings and interpretations, or else the poor sap we're regulating finds himself in a very bad way. Maybe that puts me in a poor position to understand your viewpoints.
There's no question of that. Traveller ships are quite marvellous things. Even a 1-g free trader can manage a million miles or two in no more than a few hours, no big shakes after a week-long journey; NASA engineers would sell both kidneys for that kind of technology. And, Hans' point is well made - even if we assume a big error, the size of that 100-diameter "target" renders the issue mostly moot - and as you point out, even when it's not moot, it's not a big deal.
However, when the man who made the game tells me 3000 klicks, I don't jump to the conclusion that he's made a mistake, nor that he's using some reference point that the average player will misunderstand. If people are wedded to the idea of jump time being a mystery up until drive-activation, I am in no position to naysay them - but I grow quite confused at the effort to cast the view as official canon.
As I said, I deal in regulation by trade. Words have specific meaning - to the point where the regulations I deal with will carefully define them before launching into the actual regulatory language. "Established" is not quite "fixed". "Established" connotes that it is set at that point and not before. "Fixed" connotes that it is unchangeable at or after that point. "Established" implies it can not be known with certainty prior to that point; "fixed" has no such implication - you can calculate the variables beforehand and arrive at the knowledge of what will happen when you do X, but once you do X you are irrevocably committed, no way to shorten the ride or back out.
I am very sorry to be rocking boats. There is clearly a strong sentiment for the unknown-jump-time paradigm. Some interesting possibilities there, including a little betting pool for passengers, trying to guess when exit will be. There are even some interesting arguments in its favor. However, I don't find anything in canon that specifically says jump time is or is not knowable prior to jump - other than the statement that misjump durations are utterly unknowable.
And then I have Marc saying, "One of the benefits of the jump drive is its controllability: jump is predictable. When known levels of energy are expended, and when certain other parameters are known with precision, jump drive is accurate to less than one part per ten billion," and (with due respect to the Old Timer), "The exact time of emergence is usually predicted by the ship's computer and the bridge is well-manned for the event." And then there are those neat little navigation cartridges that very clearly make the case for calculating a jump well in advance - but somehow that is not considered to translate to an ability to know the jump duration beforehand.
The argument for jump duration being unknowable before jump is clearly based on inference and preference, not on anything definitive in the game material. Those self-erasing cassettes of Book-2 stand squarely in its way, evidence that a computer can pre-calculate the parameters well in advance of jump. It is possible to rationalize them away without too much difficulty - but it is also necessary to rationalize them away, whereas the counterargument doesn't really need any rationalizing to defend it: if jump is precise, and the duration is knowable, and a computer can calculate the jump beforehand, then duration is knowable beforehand.
However, that last statement is a series of logical deductions, not a statement of canon. Neither argument is specifically enumerated in canon, and that is probably the only wholly true statement we can make on the subject.
There's no question of that. Traveller ships are quite marvellous things. Even a 1-g free trader can manage a million miles or two in no more than a few hours, no big shakes after a week-long journey; NASA engineers would sell both kidneys for that kind of technology. And, Hans' point is well made - even if we assume a big error, the size of that 100-diameter "target" renders the issue mostly moot - and as you point out, even when it's not moot, it's not a big deal.
However, when the man who made the game tells me 3000 klicks, I don't jump to the conclusion that he's made a mistake, nor that he's using some reference point that the average player will misunderstand. If people are wedded to the idea of jump time being a mystery up until drive-activation, I am in no position to naysay them - but I grow quite confused at the effort to cast the view as official canon.
As I said, I deal in regulation by trade. Words have specific meaning - to the point where the regulations I deal with will carefully define them before launching into the actual regulatory language. "Established" is not quite "fixed". "Established" connotes that it is set at that point and not before. "Fixed" connotes that it is unchangeable at or after that point. "Established" implies it can not be known with certainty prior to that point; "fixed" has no such implication - you can calculate the variables beforehand and arrive at the knowledge of what will happen when you do X, but once you do X you are irrevocably committed, no way to shorten the ride or back out.
I am very sorry to be rocking boats. There is clearly a strong sentiment for the unknown-jump-time paradigm. Some interesting possibilities there, including a little betting pool for passengers, trying to guess when exit will be. There are even some interesting arguments in its favor. However, I don't find anything in canon that specifically says jump time is or is not knowable prior to jump - other than the statement that misjump durations are utterly unknowable.
And then I have Marc saying, "One of the benefits of the jump drive is its controllability: jump is predictable. When known levels of energy are expended, and when certain other parameters are known with precision, jump drive is accurate to less than one part per ten billion," and (with due respect to the Old Timer), "The exact time of emergence is usually predicted by the ship's computer and the bridge is well-manned for the event." And then there are those neat little navigation cartridges that very clearly make the case for calculating a jump well in advance - but somehow that is not considered to translate to an ability to know the jump duration beforehand.
The argument for jump duration being unknowable before jump is clearly based on inference and preference, not on anything definitive in the game material. Those self-erasing cassettes of Book-2 stand squarely in its way, evidence that a computer can pre-calculate the parameters well in advance of jump. It is possible to rationalize them away without too much difficulty - but it is also necessary to rationalize them away, whereas the counterargument doesn't really need any rationalizing to defend it: if jump is precise, and the duration is knowable, and a computer can calculate the jump beforehand, then duration is knowable beforehand.
However, that last statement is a series of logical deductions, not a statement of canon. Neither argument is specifically enumerated in canon, and that is probably the only wholly true statement we can make on the subject.
Carlo:
The issue with jump duration predictability is that the ONLY place it's mentioned as canon is a little known, seldom used article from the last issue of a magazine that was suffering dropping sales prior. To be honest, it never entered my radar until I got the JTAS CD... But then, I never considered magazine articles part of the canon, either.
Anyway - space measurement is ALL relative. You have to specify a reference frame to make sense of it. There are three that make sense for jumps -
1 - source system
2 - destination system
3 - galaxy
No matter which of the three it is, Marc failed to account for relative motion in the rules - either out of ignorance or desire to simplify the rules - and his 3000km accuracy is irrelevant unless the only reference frame used is #2.
In any of the cases, the ship should be spending 2-12 hours per jump matching the planet's orbital vector... and being "on time on target" isn't going to help reduce that... provided you pick your target point well, it won't hurt it, tho.
The aim point is both a time and a place. The time accuracy is MUCH less than the space accuracy. Resulting in HUGE probability of miss for small worlds, and almost no probability of missing the 100D limit if you aim for it.
But you're often better NOT aiming for it, but instead to be able to accelerate to orbit from well beyond it.
The issue with jump duration predictability is that the ONLY place it's mentioned as canon is a little known, seldom used article from the last issue of a magazine that was suffering dropping sales prior. To be honest, it never entered my radar until I got the JTAS CD... But then, I never considered magazine articles part of the canon, either.
Anyway - space measurement is ALL relative. You have to specify a reference frame to make sense of it. There are three that make sense for jumps -
1 - source system
2 - destination system
3 - galaxy
No matter which of the three it is, Marc failed to account for relative motion in the rules - either out of ignorance or desire to simplify the rules - and his 3000km accuracy is irrelevant unless the only reference frame used is #2.
In any of the cases, the ship should be spending 2-12 hours per jump matching the planet's orbital vector... and being "on time on target" isn't going to help reduce that... provided you pick your target point well, it won't hurt it, tho.
The aim point is both a time and a place. The time accuracy is MUCH less than the space accuracy. Resulting in HUGE probability of miss for small worlds, and almost no probability of missing the 100D limit if you aim for it.
But you're often better NOT aiming for it, but instead to be able to accelerate to orbit from well beyond it.
Fritz_Brown
Super Moderator
I do understand the gearhead/gronard/engineer/scientist need among Traveller players to nail every last bit down. But, it is science fiction, and it is a game. The only thing you're guilty of Carlobrand is trying too hard. 
(Holding my LBBs to my heart, breaks out in a chorus of "If loving you is wrong, I don't want to be right".........)
Make it work in YTU, so your players have fun. And, make it work to your advantage for plot purposes.
Having said that, jumping to a point out of the elliptic really does solve most of the problems with this, no matter how you fill-in the details.
(Holding my LBBs to my heart, breaks out in a chorus of "If loving you is wrong, I don't want to be right".........)
Make it work in YTU, so your players have fun. And, make it work to your advantage for plot purposes.
Having said that, jumping to a point out of the elliptic really does solve most of the problems with this, no matter how you fill-in the details.
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We're not dealing with regulations and it's already been explained to you that you're looking at the problem backwards. You're using the wrong frame of reference.
Consider a jump from Regina to Ruie. You're mistakenly assuming that a navigator plots an exit point which is a certain distance from Ruie when he actually plots an exit point which is a certain distance from Regina. The navigator doesn't say "Give or take 3000km, we'll end up this distance from Ruie in the Ruie system", he says "Give or take 3000km, we'll end up this distance from Regina where the Ruie system happens to be"
That 3000km variation per parsec jumped is what MWM means when he wrote about jump being accurate to "one part per ten billion".
Over 30 years of canon supports this. Over 30 years of adventures supports this. The materials written MWM, LKW, and the other GDW staffers supports this. The third party materials vetted by GDW support this.
You're using the wrong frame of reference, you're looking at the problem backwards, and you're interpreting the rules to support that mistake.
mike wightman
SOC-14 10K
Lol - frame of reference - classic.
As Aramis has pointed out there are 3 frames of reference and the last one is the big one.
If jump time means you are an hour away from your arrival point do you know how far the galaxy has travelled from that point - or are you now claiming that jump drives move ships relative to galactic motion?
The answer is close to 2 million km by the way - that's per hour.
It's not canon that supports a jump time variable - it's 30 years of a mistaken interpretation being largely ignored.
As Aramis has pointed out there are 3 frames of reference and the last one is the big one.
If jump time means you are an hour away from your arrival point do you know how far the galaxy has travelled from that point - or are you now claiming that jump drives move ships relative to galactic motion?
The answer is close to 2 million km by the way - that's per hour.
It's not canon that supports a jump time variable - it's 30 years of a mistaken interpretation being largely ignored.
mike wightman
SOC-14 10K
You still end up 3000km from your plotted arrival point though don't you.
Actually, it doesn't.
It all repeats a mistake or doesn't discuss it at all.
Nope, Carlo is quite correct. And if the internet had been around when this stuff was originally written it could have been clarified and cleared up at the time.
mike wightman
SOC-14 10K
Another question - where is it actually mentioned that the jump time variable is a standard distribution?
That +/-10% doesn't have to be a bell curve or does it?
That +/-10% doesn't have to be a bell curve or does it?
Yes you do, you just don't know when you'll arrive there.
And because all those bodies in the Ruie system are moving in relation to that point measured from the Regina system, you don't know what distances they'll be from that point. Your exit point is measured from where you initiated your jump because that is where you plotted your jump.
Wil listed three frames of reference for making a jump: the Origin system, the Destination system, and the Universe as a whole. Jump having a know physical accuracy and a variable temporal accuracy works with two out of the three frames of reference. You and Carlo are arguing from a mistaken point of view.
Give us one cite that doesn't support the general consensus explained here and don't use the JTAS 24 essay which you've deliberately misinterpreted.
Carlo has it ass-backwards and you're simply being a contrarian.
The internet has been around for nearly 20 years now, nearly two thirds of the games life, and Traveller discussions held on fora ranging from BBSes to mailing lists to php style boards have hashed out this issue for just as long. GDW settled this issue before they closed up shop and Mr. Miller has settled this issue for the various post-GDW versions of the game up through T5.
You're wrong and you need to admit it to yourself. What you do IYTU is your own business but in the OTU you do not know jump duration until after jump is initiated.[/i] Period. Full Stop. End Of Discussion.
It puts you into a position to provide a different angle in the discussion, which is not a bad thing, as long as we can understand each other's arguments.
One thing you might want to consider is that the regulations you deal with by profession was (presumably) written by people who also deal with regulations by profession. Most of Traveller was written by wargamers and roleplaying gamers.
Wil already dealt with this, but I'll add that I have a very practical reason for preferring that jump duration is not established until the jump is initiated. It's by far the simplest way to explain why people don't cherrypick a jump solution that routinely lets them perform the jump in less than the average time. I'm not saying thare aren't ways to explain it otherwise, but they all have drawbacks, chief among them being to eliminate the fascinating plot potential of having pursuers jump 12 hours after the pursued and arriving 12 hours before them.
Don't worry about that. Challenging accepted notions is a good way to test them. If those of us who have a strong sentiment for the unknown-jump-time paradigm can't defend it, why shouldn't it be changed?
Hans
No, but the rule in MT does. A very crude bell curve admittedly
. Seriously, the bell curve distribution was an assumption for a long time. But it's a very reasonable assumption. When T20 introduced a roll of 147+6D hours for jump duration, I had been using 140+8D for a decade or more (I still like that better as being easier to add 140 than 147; 143½-7D would come even closer to +/- 10%, but that would be a lot more awkward
). IIRC MgT also has a die roll for jump duration, but I could be misremembering.
Hans
T20 copied it straight from the Canon-for-MT/no-quote-canon of Starship Operator's Manual (DGP), not introduced. Otherwise, yeah.No, but the rule in MT does. A very crude bell curve admittedly
Seriously, the bell curve distribution was an assumption for a long time. But it's a very reasonable assumption. When T20 introduced a roll of 147+6D hours for jump duration, I had been using 140+8D for a decade or more (I still like that better as being easier to add 140 than 147; 143½-7D would come even closer to +/- 10%, but that would be a lot more awkward
IIRC MgT also has a die roll for jump duration, but I could be misremembering.
Hans
If you have them 144+2d8+4d6 is a better fit still...
mike wightman
SOC-14 10K
So it is a DGPism - it could be a linear distribution, bimodal, anything.
The folks at DGP made it up.
I suppose that if you are using a d6 game it make sense to try to use d6s which naturally produces a standard distribution.
So is the +/- 10% the 68% confidence limit or the 95% or the 99.7%?
The folks at DGP made it up.
I suppose that if you are using a d6 game it make sense to try to use d6s which naturally produces a standard distribution.
So is the +/- 10% the 68% confidence limit or the 95% or the 99.7%?
Two things immediately come to mind:
1) If you know the duration of your jump plot prior to initiating jump, then why doesn't everyone just re-plot their jumps continuously for their entire week in port and then choose the plot that will get them to the destination fastest, making (effectively) all jumps take 151 hours rather than averaging 168 hours? Those jump tapes you keep bringing up would also all be for 151-hour jumps, of course.
2) At risk of opening another controversial can of worms... I like to have piracy IMTU. If the circumstances surrounding jump plots ensure that you can always arrive at exactly 100d from your destination world, then that makes life a lot rougher on pirates (or anyone else trying to avoid detection). If ships can arrive within 100d of anywhere the planet has been or will be within a 34-hour window, that substantially increases the amount of space the authorities need to monitor and ships arriving farther from the destination also means nearby hostiles will have more time to intercept them, offsetting the larger hunting ground. (Although I can see how the larger hunting ground could also swing this one the other direction, since the pirates will also have a harder time finding prey.)
I can't speak for anyone else but, as the one who started this discussion, I'm not trying to cast either interpretation as official canon. My interpretation of your posts is that you've been saying that jump duration is known prior to initiating jump and that the 3000km accuracy is relative to the destination world, so I have been arguing that both of Marc's statements are ambiguous, allowing you to have prior knowledge of jump durations, while I have jump durations that aren't knowable until the ship enters jumpspace, without requiring either of us to contradict canon.
Yep, exactly!
I still don't see how that's relevant to the discussion. It would be true even if the exact time is only predicted 30 minutes prior to precipitation, after the vast majority of the jump time has passed - it would still be predicted and that would still allow time for the crew to take their stations. It does not imply anything at all about whether the jump duration is or is not known prior to the initiation of jump.
Yes, it is. And so is the argument for it being knowable in advance.
Mongoose gives jump duration as 148+6d6 hours.
You say that as though it automatically invalidated it.
It was fanon long before that. Other than that, sure DGP made it up. That's what happens when people produce additional material for a game. They make stuff up. If it contradicts previously published information, there may be a problem. But if it doesn't contradict anything, it becomes part of the setting. Especially if explicitly confirmed by subsequent versions, such as T20 and MgT.
Hans
Why? My thought was the random roll reflected the variables of planetary alignments - including potential intervening masses - among other things. Ergo, the roll for that jump window was the roll for that jump window - period. Wait a bit, or try a different departure course, you might get a slight change but not a reroll. If you wanted something utterly different, you'd need to wait about a day, which eliminates the benefit.
I've been thinking that the jump masking bit makes life a little easier for pirates, though it complicates things quite a bit gamewise. Players can't just jump from 100D to 100D, safely within reach of the patrol boats. They have to accept jumping into a system at some considerable distance from the desired planet when that system's sun happens to be between them and the target, or spend some time moving within the origin system if THAT sun happens to be between them and their target system. Leaves the local constabulary having to cover much more ground and having to fly much farther to come to the rescue.
I'm saying the available evidence leans in that direction - but it is very much not definitive, certainly not enough to bet the house on. One thought I belatedly had is that the mechanics of jump with respect to normal space are exceedingly precise, sufficient that a jump can be calculated well in advance and place you within 3000 klicks of your intended exit point, but that there is some specific feature of jump space itself that makes precision possible in normal space but makes an estimate of duration impossible until the jump is activated and measures of the accessed jump realm can be obtained by the jumping ship.
Perhaps the vagaries of time flow in jump space are such that your experience of time within the jump realm, while you and your ship are essentially an isolated pocket of normal space within jump space, cut off from the rest of normal space, could vary from the rest of normal space by 10%. Of course, that opens up the nasty possibility of time mismatches in misjumps. I may have to try that as an IMTU thing. Imagine a misjump in which you spent what felt like a week in jump space only to arrive in normal space 36 weeks later, hundreds of millions of miles from your intended exit and posted as missing and presumed lost. :devil:
And now we agree. I am content to consider either alternative as equally valid. As Aramis points out, Marc's statement occurs not in a rule book but in a support magazine not accessed by all players. While it carries weight to me, it does not carry anything like the weight that something in a rulebook or adventure might - and the incompletely understood nature of jump space is such that the level of accuracy he describes still does not rule out the possibility for unusual effects.
I'll note that the DGP sources confirm the 3000km/parsec location accuracy, while firmly establishing a bell curve distribution within the temporal accuracy. A bell curve that fits with the wording of Marc's article, and that was approved by Marc for later editions as canonical. Marc's own manuscript doesn't use 6d6, but does specify 150-175 hours (T4, p89, LC). 6d6 is a 31 hour window - exactly what Marc used. (144+6d6)
Which eliminates the fascinating plot potential of having pursuers jump ahead of the pursued (or having the lead opened).
That's not possible for any single universe. Since the OTU is, essentially, a single universe (the common frame of reference for Traveller authors), it has to be one or the other for the OTU.
(And for any of our personal universes, the discussion is moot. In your TU it's the way you prefer and in my TU it's the way I prefer. What's to discuss?)
As for magazine articles not being canon, that is, AFAIK, only for JTAS Online articles and articles clearly marked as variants. Even if I'm wrong about that and magazine articles in general are iffy, I think articles and adventures by Marc Miller himself might be given a little more weight than the average article. A Traveller writer might be able to persuade an editor to let him contradict an article more easily than to let him contradict something in a book (I wouldn't know; I've never tried the first), but I think that unless there is a compelling reason to do so, one shouldn't contradict canon-compatible articles, if for no other reason than that its a sad waste of material to invalidate anything needlessly.
Hans
True, but which one seems to be in some dispute, as indicated by the discussion here. Unlike, say, setting the per-ton charge for shipping cargo at Cr1000 irrespective of jump distance - which is clearly established in CT canon but unpopular in some quarters (like mine) - this one isn't set in stone. It's hinted at by one element of canon (the flight-plan cassettes of CT Book-2) and implied by Marc's remarks in an article appearing late in CT evolution, but not clearly stated. And, Whipsnade implies other canon sources that contradict that view.
Folk on both sides have become accustomed to a specific interpretation, have evolved their gaming around that interpretation, and are clearly reluctant to abandon long precedent and fondly-remembered history in favor of an alternate interpretation that isn't specifically and unambiguously stated.
Marc says there's jump-masking too, and it's become woven into later canon, but there are any number of people who don't include that feature in their otherwise-OTU games. That strikes me as having much broader impact.
You're absolutely right.
I'm actually liking the possibilities implicit in that time relativity bit. Distinctly non-canon, but I'm thinking I'm going to adopt it.
As I see it, if Marc says it then it's the way the game works. However, the average player looks to the rulebook for rules. Plowing through adventures and supplements - some of which they may not own - for additional interpretation is already more than enough work. Asking them to also adjust their view of canon based on a JTAS article that they might not have access to, that was never (to my knowledge) formally embodied in official game material, and that - if Whipsnade is correct - is later contradicted by other official game material, might be asking a wee bit much.
HEY!
Stop talking about my ass!:rofl:
--->
would be pleased to see citations. Always willing to change mind in response to citations.<---Goodness! Who died and made you moderator?
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