Jump Occlusion

[Bloo]

Here's a link of sorts http://forum.rpg.net/archive/index.php/t-313683.html

I always rationalised it that you kind of launched yourself into Jumpspace and then sort of fell back out in to real space. Just like the way a shell from a gun follows a parabola, with gravity pulling it back to earth, a ship in jumpspace launches itself in a 5 dimensional course and 'falls back to realspace'. This means that J2 takes just as long as J1 because even though it's twice as far, you have to launch off with twice (or some other function) as much energy to get there. Accordingly, you can't do a J1 twice as fast as a J2 jump because if you launch with J2 energy you'll just go deeper into jumpspace than you need to, and will in fact take longer.

Wow. I almost convinced myself

Also, I rationalised that each increased in jump distance gave diminishing returns. By the time you get to J6 you're up against some absolute limit, beyond which you'd rapidly approach infinite launch energy to go further.

This is in a direction I like, but it reminds me of an issue that irks me a little bit: jump ranges and technology levels. If you only need more energy to get longer jumps, then these aren't really different technology - it's just power and efficiencies.

It would be easier for me to buy that jump levels were logarithmic or exponential than simply additive: +3.26 light years/max per TL.

But if powering up shorter Jump distances was faster than longer jumps, I think that would lead to short fast jumps out of danger, and then longer ones to where you really want to go. And presumably, a jump to the edge of a solar system would be the fastest 'bugout' option, and you're not too far out for a rescue if you're low on fuel, etc.

100 AU jump to other side of solar system = 13 light hours, Jump 0.0005.

 

[Cryton]

Here are my thoughts on the matter:

1) While it is possible to "step on the tail" of a smaller ship and pull it back from Jump space, you do have to sit there for a week to do it. So accidents are unlikely.

2) I guess your Scout/Courier or Far Trader can't run from the Pirate/Corsair anymore...LOL.

Cryton

 

[Hal]

From what I recall of the Beta rules, I did note that the ship with its diameter didn't have to be ON the entry point to work - it merely had to interpose its "100 diameter" aspect at ANY point on the jump line before the ship would enter normal space at the termination of its jump duration.

So, a body of a certain size could cross the path at zero+1 pico second after jump ship enters jump, or it could cross the path of the jump line at 1 picosecond before the ship were to exit into normal space. If ANY mass cross the jump line, the ship precipitates out that THAT point.

Now, wanna have some fun? What happens when you have three or more bodies that intersect that jump line at various points of the jump line before the ship exits jump space? Does it exit at the one closest to the point of entry into jump space? Does it exit at the point closest to its destination? Does it exit at the point closest to the greatest (aka largest) item that crossed its path?

<sigh>

 

[cuTTer]

Now, wanna have some fun? What happens when you have three or more bodies that intersect that jump line at various points of the jump line before the ship exits jump space? Does it exit at the one closest to the point of entry into jump space? Does it exit at the point closest to its destination? Does it exit at the point closest to the greatest (aka largest) item that crossed its path?

Yes.

 

[Hal]

Yes.

While I'm sure you didn't mean to spark THIS thought...

Maybe ships that attempt to jump with pursuit too close, end up being destroyed in jump. Multiple ships or objects on the same jump line could result in three separate (but equal) portions of the hull showing up at all three points. The tip of the hull, half the bridge, and the ladie's head aft the engineering room could show up at point A, the sectional ribbing of the hull (ie its structurals) plus the left manuever drive could show up at point B, and all the rest show up at Point C.

 

[aramis]

Hal, my interpretation is that in the case of multiples, it's the one with the least distance from origin point that triggers the dropout. The wording of the process in the release implies this, as well.

 

[BTolputt]

And thus the true dread secret of jump travel is revealed...

Every time you precipitate into real space it's the next reality along, not yours.

A always suspected as much.

There was a science fiction series that explained their jump drives like that. Every jump took the ship from their current universe and moved it into another one almost exactly the same. As such, no physical laws are violated because nothing actually travels faster than light in the universe, it simply leaves one and turns up in another at a different location. They hand-waved away the fact the universes were exactly the same (for all measurable purposes) through "the principle of least surprise".

Can't remember the name of the series, but they copied the minds of old people into green cloned soldiers. Perhaps that'll jog the mind of someone else who can recall the books or author.

 

[mike wightman]

here's what Dave Nilsen, designer of TNE, had to say on the nature of jump space:

Jumpspace similarly allowed travel faster than the speed of light (i.e., arrival at a point
in the future, at least by the vantage point of light), by allowing entry into it for ~168
hours to allow you to move 1 parsec (J1 space) to 6 parsecs (J6 space). We also know that
N space impinged into J space via gravity fields (the 100-diameter G-field causing
J precipitation and preventing J insertion. It is therefore possible to imagine the
different J# spaces to be similarly related to each other, so that penetration into
J space could be thought of as a parabola on a graph. A J1 journey could be thought
of as a shallow parabola that did not peak above above the "J1" value on the Y axis.
A J6 journey could be thought of as a parabola with a much steeper entry into Jspace
which peaked at the "J6" level. The inside of Jspace is a hostile environment for
Nspace objects, which require the maintenance of a jump field around them in order
to survive Jspace and come out intact after the ~168 hour "immersion."

In CT - TNE jump space is an alternate dimension/universe where our normal laws of physics don't apply.

J1 drives allow access to the jump 1 jump space, J2 the jump 2 jump space etc.

I'm not sure that T5 is moving away from this model...

 

[Reban]

I agree Mike. T5 says the following:

JUMP DRIVES
The key to the stars is the jump drive: an almost magical technology that shifts a ship through a tear in the fabric of spacetime into an alternate universe where the generally accepted laws of physics don’t apply.

I'm going to implement the occlusion rule with the simple proviso that the object creating the blockage must be intersecting the jumpline when the jump is initiated. In other words a ship cannot come wandering along to the jump point a week after a ship has jumped and intersect the jump line causing a ship in jump to perciptate out at the same point that it started at.

By the way I don't think I've seen any discussion of the Jump Damper from the ACS weapons selection or for that matter the Jump Inducer.

 

[David Johansen]

I think the decision to include jump occlusion goes back to the old arguments about the viability of piracy. Though I'm not sure what the intended effect was.

To my thinking this mainly makes your manuver drive more important because you want to get a week out before jumping if you're off the space traffic control grid and running for it. You just pick your destination and head out that way for long enough that they'll need a really fast ship to occlude you.

Pirates would work low population systems with decent traffic and lurk around gas giants waiting for cheap merchant men. It would make picking off a big corporate ship much rarer.

Because let's remember. Space is very big and it's not that hard to be a week away. Sadly with many warships having M4+ you'll want to be four weeks out if you've got an out of the box free trader.

Of course the biggest problem is that Han couldn't have possibly escaped the Imperial Star Destroyer in A New Hope. It would have occluded his jump line and waited a week.

 

[BytePro]

Is the effect an absolute, or just a chance...

In CT LBB2, the 100 diameter distance simply decreased the odds of a misjump so that past 100 dia a misjump did not occur with the proper fuel/maintenance. The -2 DM for a Scout ship ensured that a properly fueled/maintained scout ship not only had pretty good odds for not misjumping within 100 dia, but would not be destroyed. Even within 10 dia the penalty DM allowed a small chance of not misjumping.

To me, any precipitation out of jump space for masses on a planned route, at least, should have odds. And unplanned, probably as well.

 

[HG_B]

Is the effect an absolute, or just a chance...

Absolute

 

[aramis]

Is the effect an absolute, or just a chance...

Absolute

Concur.

In CT LBB2, the 100 diameter distance simply decreased the odds of a misjump so that past 100 dia a misjump did not occur with the proper fuel/maintenance. The -2 DM for a Scout ship ensured that a properly fueled/maintained scout ship not only had pretty good odds for not misjumping within 100 dia, but would not be destroyed. Even within 10 dia the penalty DM allowed a small chance of not misjumping.

To me, any precipitation out of jump space for masses on a planned route, at least, should have odds. And unplanned, probably as well.

T5 doesn't allow jumping at all within 100 diameters. CT through MGT did/do, at risk of misjump.

In some ways the T5 jump rules are doing the same thing, by having a chance of occlusion occuring, as CT did by having a random chance of misjump.

 

[Magnus von Thornwood]

Not so fast there...

Concur.



T5 doesn't allow jumping at all within 100 diameters. CT through MGT did/do, at risk of misjump.

In some ways the T5 jump rules are doing the same thing, by having a chance of occlusion occuring, as CT did by having a random chance of misjump.

Actually, if I am remember in How Jump Works says you can depending on the Stage of the Drive. Sorry, no book at work, so no page number.

 

[Vladika]

Sorry to have been away from this thread since my last post but serious health issues prevented participation. I've read the threads and have one thing to interject.

Except that I believe it was described as a quantum event; a ship doesn't actually "travel" in jump, it just disappears from point A and reappears at point B (if all goes well). The transition takes approx. one week, but there is no "movement" during that week in jumpspace; the ship is a quantum particle of indeterminate location.

T5 claims a ship CAN change vectors while IN jump space, hence "movement". That pretty much tosses out everything that has gone before.

I don't like. The ramifications are far reaching.

 

[mike wightman]

In every prior version of Traveller a ship travels through the jump space dimension.

In T4 there is even an adventure where a collision occurs in jump space.

 

[Vladika]

In every prior version of Traveller a ship travels through the jump space dimension.

In T4 there is even an adventure where a collision occurs in jump space.

Interesting point. While a ship can't be detected it could certainly hit something in that "other universe". Let's just hope T6 (or whatever Marc will call it) doesn't fill it with solar sized masses.

Since a ship destroyed in jump space is never heard from, or seen again, who knows?

 

[aramis]

T5 claims a ship CAN change vectors while IN jump space, hence "movement".

No, it doesn't. The vector change in jump has no effect on the jump, only the direction one is going upon jump exit. It doesn't affect the jumpline, doesn't move you through J-Space, and doesn't change when or where you precipitate.

It's the solution to the question, "Systems have several G-days difference in velocity, how do we account for this without breaking the setting?"

The answer is "By accumulating N-space inertial vector while in jump."

 

[mike wightman]

So are you using your maneuver drive in jump space to change your real space vector?

Or are you using your jump drive to change your real space vector while in jump space?

Either way you are still travelling through jump space for a week according to every version of Traveller, and I can't see anything in T5 that explicitely changes this.

 

[Vladika]

So are you using your maneuver drive in jump space to change your real space vector?

This appears to be what T5 means. It also states that Drives dependent on gravity don't work...