jumping times

Condottiere

Emperor Mongoose
I got the impression that in previous editions you needed to keep the lanthanum grid powered (on), otherwise, you eject prematurely from jumpspace.

Tee Five introduced a tiered gravitational based Newtonian (or is it Einsteinian? Newsteinian, as opposed to Oldsteinian?) universe (Einverse? Zweiverse would be jumpspace?).

I have no particular view on this, as long as it makes, sense.
 

Sigtrygg

Emperor Mongoose
There is no lanthanum grid apart from in MegaTraveller

T5 introduces different types of magical gravitic drives. Off the top of my head lifters, grav drive, maneuver drive and NAFAL drive. As to the universe model it can't be Newtonian or Einsteinian.

It should make sense and be consistent for your own game. How it works in the OTU is defined, how individual referees choose to do things is up to them.
 

phavoc

Cosmic Mongoose
Powering the jump grid was not necessary in CT - once you activated your drive and popped into jump space you popped out at your destination or earlier if your path was intersected with a sufficiently powerful gravity well.

Lanthanum for jump drives was introduced in CT (as were Zuchai drive crystals). In one of the earliest adventures, Kininur, in the Library Data section it states " Lanthanum: A rare earth element, the first of the inner transition metals. Vital to the construction of the inner coils of interstellar jump drive units." I'm not certain if other versions go into much detail, if any, on these items. I think for the most part they were ignored in the future versions. Doesn't mean they go away, just means it's not repeated.

I'm very much in favor of the it should make sense idea and be consistent with the setting. What's being discussed here is the fact that some things don't and that that what is being defined is not internally consistent within the OTU. Personally I'm not a fan of the "IMTU" as a default for when problems or inconsistencies are pointed out in the game rules/settings. When players point out the inconsistencies of the OTU rules/settings, publishers should actually FIX these things through errata or future editions. Traveller has a long history of not doing that - case in point is the Gazelle. It violated the design rules since it's debut in JTAS, yet multiple future editions continued to publish it even though it was inconsistent with the rules.
 

Sigtrygg

Emperor Mongoose
HG80 and CT81 changed things to a power plant being required equal to the jump number or better, and MWM's jump space article - which is MgT canon also - mentions that the cabling in the hull maintains a field of normal space while in jump.

The same article also states that gravity only affects the jump when the ship enters jump space 9within 100D things get interesting) and when the ship is exiting jump space, it does not say that something big in normal space can pull something out of jumpspace anywhere - that was a bit of fanon that became canon after a while.
 

Condottiere

Emperor Mongoose
That was retconned in that power plants for starships were overclocked, to provide a sudden large spike of power, I think, over two turns, which was why fission and diesel power plants aren't compatible.

What does Tee Five say about keeping the power running during transition?
 

phavoc

Cosmic Mongoose
No, it wasn't retconned. Rather it is edition specific.
Millers JTAS 24 article went into more detail about it - basically to power the jump drive you had to power the capacitors quickly because they couldn't hold the charge long. So his logic was that you (in car terms) ramped up on the accelerator and redlined the engine, but it was very wasteful in fuel, hence you consumed far more fuel in a very, very short period, to power the jump.

And yeah, I agree that each edition changed/tweaked the explanations and mechanics. Very confusing at times, and the changes really never seemed to justify the changes in my opinion. Since nothing was materially changed, why did that edition decide to change it?

Jumping in a gravity well was generally considered a "bad" thing to do. But once you were in jump gravity wells could also be used to pull you out of jump. The one thing I can't remember seeing anywhere was the idea of distance travelled. In theory you could do an in-system micro-jump, intentionally intersecting your path with a planet or gas giant, and you would be forced out of hyperspace. The question would be how long would you be in jump space travelling only a few AU?
 

Condottiere

Emperor Mongoose
I suspect the jump governor regulated both actual distance calculated and fuel consumption, though in the latter case, still in ten percent batches.
 

Geir

Cosmic Mongoose
The question would be how long would you be in jump space travelling only a few AU?
One week (168 hours - or 160 from the Companion) plus or minus. The time for a jump is independent of the distance travelled - half an AU or 6 parsecs. You pop into the jump-space universe, hang out for a week, and pop out. The 100D limit is pretty clearly articulated for precipitating out of jump, but you can jump at less than 100D with increasing risks of misjump. And as currently written the mechanic for entering jump is a little strained - it's a task chain, without indication that a 'failed' Astrogation check carries forward, since a failure 'must' be attempted again - so it never passes a negative DM to the Engineering roll. Therefore the misjump is always the engineer's fault... Would have worked better with the MegaTraveller uncertain task mechanics.

Core book, any jump within 100D is a DM-4. Companion makes it DM-8 within 10D and nothing in the rulebook(s) says you can't also take that DM-8 (or Core's DM-4) jumping from the ground. A referee might disagree.

But I do like the Companion's 'bad jump' rules, though they can get rather involved, especially on a ship with a lot of crew and passengers.
 

Condottiere

Emperor Mongoose
Early jumping can be an expensive hobby.

One diameter is basically about ground level, so you may want to adjust that to plus short range, twelve hundred fifty klix.

Speaking of which ...
 

phavoc

Cosmic Mongoose
One week (168 hours - or 160 from the Companion) plus or minus. The time for a jump is independent of the distance travelled - half an AU or 6 parsecs. You pop into the jump-space universe, hang out for a week, and pop out. The 100D limit is pretty clearly articulated for precipitating out of jump, but you can jump at less than 100D with increasing risks of misjump. And as currently written the mechanic for entering jump is a little strained - it's a task chain, without indication that a 'failed' Astrogation check carries forward, since a failure 'must' be attempted again - so it never passes a negative DM to the Engineering roll. Therefore the misjump is always the engineer's fault... Would have worked better with the MegaTraveller uncertain task mechanics.

Core book, any jump within 100D is a DM-4. Companion makes it DM-8 within 10D and nothing in the rulebook(s) says you can't also take that DM-8 (or Core's DM-4) jumping from the ground. A referee might disagree.

But I do like the Companion's 'bad jump' rules, though they can get rather involved, especially on a ship with a lot of crew and passengers.
Yeah, that is what precipitated the question. We know that during jump you can be pulled out of jump prematurely if your path intersects a large gravity well. The 100D limit is the DEPARTURE limitation. What I was talking about was being beyond the 100D limit to ENTER jump.

We know that there is a time period to jumping, and it's the same for a jump of 1 or 6 parsecs. However, the books have always stated that being pulled out prematurely by a large gravity well also happens regardless of your original planned jump distance. So it is possible to plan a 24 parsec distance jump but only travel 3 and leave jump space because a star, gas giant or planet happened to be along the path of your planned jump (obviously your navigator needs to check their charts!)

From the mechanics explanation of jump we know that distance isn't a factor. Though we also know leaving jump prematurely is also not a distance factor. The explanation for jump, as written, seems to have a logical flaw in that it's trying to explain two diametrically opposed issues with the same explanation. MGT changes the equation further by restating the process and creating a jump bubble that degrades over time, and that is what sets your time period in jump. It, too, retains the gravity well thing that can pull you out of jump space.

Under the current rules you could be at 101 diameters and jump towards the planet, be in jump 1 week, and then emerge at the 100D limit 1 week later, having moved only 10,000km. That just seems very odd to me. What I think is that nobody tried to connect the dots and they just went with it without bothering to actually fix the explanation so that it remained constant. It's N-dimensional space and sure, the laws of physics may be different, that's a given. But when you inject 3-D physics into it that can also affect the N-dimensional, then it falls apart.
 

Sigtrygg

Emperor Mongoose
Being pulled out of jump wasn't a thing until GT. The authors got MWM to agree to their interpretation of part of one sentence in MWM's Jump space article. Two other sentences refute the idea.

In CT and MegaTraveller once a ship is in jump it is outside of our universe, and it doesn't matter what is in a 'line of sight' (which in itself is pretty difficult to define thanks to the real movement of systems being very different to the flat plane of jump travel in our universe) the ship precipitates out of jump space at the end of a week. As it is leaving jump space if it is within 100D it precipitates at the 100D limit rather than inside it.
 

phavoc

Cosmic Mongoose
Being pulled out of jump wasn't a thing until GT. The authors got MWM to agree to their interpretation of part of one sentence in MWM's Jump space article. Two other sentences refute the idea.

In CT and MegaTraveller once a ship is in jump it is outside of our universe, and it doesn't matter what is in a 'line of sight' (which in itself is pretty difficult to define thanks to the real movement of systems being very different to the flat plane of jump travel in our universe) the ship precipitates out of jump space at the end of a week. As it is leaving jump space if it is within 100D it precipitates at the 100D limit rather than inside it.
I didn't find any specific mention of gravity well in the CT books, or in MT. The earliest (or maybe clearest) explanation is in JTAS 24. SOM has a very off-hand reference in a single sentence (referencing gravitational perturbations as a reason for leaving jumpspace outside of your planned reentry point).

I found the references to jump masking in GT and Starships (Starships has a more complete explanation). Some of the descriptions in JTAS 24 are carried over into SOM and GURPS. I'm not sure which section you are referring to that would refute it - the passages I saw seemed to agree with each other. I'd be interested to look them up and compare to the other portions.

The "line of sight" issue really only makes sense if you are looking at 3D maps. I agree with you that in a 2D world its much easier to ignore it. GT jump point masking (in both departure and arrival systems) does make sense when taken as a complete model, though it's mostly working towards the star and destination planet. It's much easier to take this up a level and stay out of the weeds for trying to plot the orbital mechanics of all the planets in both systems - let alone on the chance your path takes you through another start system.

100D precipitation, depending on the rules, is either just dropping out of jump at the 100D, or else you 'bounce' and can be deposited quite far from your originally planned arrival point.

Still, taking into account the expanded-upon explanations, I don't think the scenario as I stated has a good explanation within the rules. With jump space being outside of our normal universe, I think it's a safe handwavium to deal with as is. However I do have to wonder if that sort of idea was ever thought about. GURPS seems to have made the most effort in all the versions to really explain and model the system - and even that one doesn't cover it.

I appreciate the conversation on this though!
 

Condottiere

Emperor Mongoose
I came to the conclusion that understanding and manipulating gravity was the foundation of most of the technology in Traveller, plus the hundred diameter limit, seems within the bounds of whatever universal rules Traveller operates with.

It also removes most of the chance that you rematerialize in the middle of a star.
 

phavoc

Cosmic Mongoose
I came to the conclusion that understanding and manipulating gravity was the foundation of most of the technology in Traveller, plus the hundred diameter limit, seems within the bounds of whatever universal rules Traveller operates with.

It also removes most of the chance that you rematerialize in the middle of a star.
Gravity manipulation has nothing to do with jump drives. Jump space is outside our normal space - but only partially since gravity wells can affect your ship while in jump space. But only to the extent of returning you to normal space.
 

NOLATrav

Banded Mongoose
I've pushed jump drives back to TL 10. Still gets you jump 6 at TL15 and avoids the weird progression. Also a little more time for STL ships and the like.
 
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