Jump Proceedure

[mike wightman]

My version has the jump drive create a partial wormhole.

Imagine dropping a lead shot onto a thin latex sheet.

The hole the ship falls into is then closed, and the ship is in a bubble of real space suspended in "jumpspace".

Jumpspace then squeezes the bubble of normal space, much like an orange pip squeezed between your thumb and finger.

 

[aramis]

What's Jump Mask?

The extra heat shield plate over your BD Faceplate when doing a drop from orbit, put there so you can't see the ground and chcken out!

 

[Hal]

Originally posted by far-trader:
</font><blockquote>quote:</font><hr />Originally posted by Hal:
...As early as MT, there were rules to the effect that on a 1d6 roll, 16% of the time the ship arrived early, 16% of the time the ship arrived late - the rest of the time it arrived after 7 days in jump space. This +/- 10% bull has been a recent (or so it seems) innovation... grrrrr.

Even earlier, though not fully defined. At least as early as HG1 in '79 (and yes also in HG2) where it says "Any jump, regardless of number, takes approximately one week (150 to 175 hours)..." </font>[/QUOTE]Thanks Far-Trader. I'd forgotten to look in High Guard. Why in the HELL didn't CT or any other game system link Navigation ability (ie skill) to the duration in jump space?

 

[Psion]

As early as MT, there were rules to the effect that on a 1d6 roll, 16% of the time the ship arrived early, 16% of the time the ship arrived late - the rest of the time it arrived after 7 days in jump space.

I thought MT was something like 124 + (2D6*6).

Why in the HELL didn't CT or any other game system link Navigation ability (ie skill) to the duration in jump space?

Right now I am tinkering with some house rules for T20, primarily because it seems to clone CT rules, but I prefer the MT approach of making character skill significant.

For jump duration, I was thinking aobut using 145+5d6 hours for duration. Then, the astrogator can attempt a precision plot, DC 20+(# of dice)^2 to choose the result of the dice instead of rolling. So if you roll 21 on your astrogation roll, you may choose the result of 1 dice and roll the other 4. 24 allows you to choose 2 dice, 29 allows 3, 36 allows 4 and 45 allows all 5 dice to be chosen. But that's pretty tough...

What do you guys think of the concept of sharing jump plots with other ships to come out at a similar time? I don't remember a canonical reference to it, but have seen it in various places such as story hours. Perhaps given my above house rule, I could grant a +10 to the roll if your roll choice is "the same as the other ship." Perhaps a bit more difficult if ship characteristics don't match.

 

[Hal]

Hi Alan,
I wish I could help you and respond to your question. As it stands now, I know practically nothing about T20
Part of the issue here is nailing down what exactly is Navigation? For example...

Marc Miller clearly states that accuracy of jump is +/- 3,000 km per parsec jumped. I can't get my mind around what precisely this means because of the variable of TIME. If Time is variable, then where exactly is the jumpspace +/- error margin supposed to apply to? Planets move. If you aim for a planet and miss it by a day - you miss it by more than a mere 3,000 km! If you miss it by as much as 20 minutes (1 turn in Classic traveller) - you'd miss EARTH by as much as 20,000 miles! Clearly, this is more than the 3,000 km spoken of by Marc.
So where does that leave us? That 3,000 Km has to be based on some specific frame of reference. Is it the star's frame of reference? Is it some absolute frame of reference such as the center of the universe? If you miss by as little as 1 second, the sun will have moved a set number of miles (as suns move at a rate of miles per second!)

For me, and for a play by email game I will run eventually - frame of reference refers to the primary sun. This way, if you miss by an hour, and you hoped to intercept Earth - then you will either be 1 hour ahead of earth or 1 hour behind earth depending how badly off you were in your navigation roll. So, the question you have to ask yourself is this: "Is it good to get out of jump space early?" SURE! If you can make up the distance between you and the world you wanted to end up in - in less than a day's journey. Is it ok to be a day late? Well, not really - because now you have to race to catch up to a fleeing object so to speak. You have to build up momentum, catch up to it, and slow down...

Frankly? The better the navigation roll, the closer you are to your intended temporal (time) exit point. The worse your navigation roll, the worse your timing will be. The question that hits most wargames is simpley this: "If I missed, did I miss short or did I miss long"

 

[Psion]

Originally posted by Hal:
I wish I could help you and respond to your question. As it stands now, I know practically nothing about T20

Well, my question to the crownd was really system-generic: What do you guys think of the concept of sharing jump plots with other ships to come out at a similar time?

Part of the issue here is nailing down what exactly is Navigation? For example...

Marc Miller clearly states that accuracy of jump is +/- 3,000 km per parsec jumped. I can't get my mind around what precisely this means because of the variable of TIME. If Time is variable, then where exactly is the jumpspace +/- error margin supposed to apply to? Planets move. If you aim for a planet and miss it by a day - you miss it by more than a mere 3,000 km! If you miss it by as much as 20 minutes (1 turn in Classic traveller) - you'd miss EARTH by as much as 20,000 miles!

And for that matter, you are being generous. You are generously assuming that the ship and the target system have no relative velocity. With some systems, that can cause a difference much larger than mere orbital velocity.

Here's a technobabble solution I stole from my homebrew game if you want it: when the astrogator makes a plot, he plots for gravitational conditions/curvature of space at the destination. The fine tuning of where the ship arrives is a matter of where it lies in terms of gravitational potential at the destination, i.e., distance to the planet and the star. Jump space might work precisely because it isn't a strict 1-to-1 mapping of real space.

So the result would be that the navigator fine tunes the jump by setting the distance to the sun and planet at arrival.

Of course this has implications that those familiar with celestial dynamics could easily pick apart, so don't think about it too hard...

So where does that leave us? That 3,000 Km has to be based on some specific frame of reference. Is it the star's frame of reference? Is it some absolute frame of reference such as the center of the universe? If you miss by as little as 1 second, the sun will have moved a set number of miles (as suns move at a rate of miles per second!)

Okay, so you weren't being that generous.

 

[Commander Drax]

Sigg Oddra said:

My version has the jump drive create a partial wormhole.

Imagine dropping a lead shot onto a thin latex sheet.

The hole the ship falls into is then closed, and the ship is in a bubble of real space suspended in "jumpspace".

Jumpspace then squeezes the bubble of normal space, much like an orange pip squeezed between your thumb and finger.

Good Idea Sigg, It intuitively makes sense, you could argue that the ship's jump bubble slowly collapses over time due to the pressure of being "Squeezed" in Jump Space and that when it does collapse you exit back out into normal space, as that exact moment of collapse can't be accurately predicted this makes jump travel somewhat variable in terms of both time taken and accuracy of exit point.

 

[Hal]

Jump space theories - ya gotta love them. My favorite is pretty much as SJGames GURPS TRAVELLER has it. You utilize the hydrogen in your jump bubble with the energy utilized to rip open the actual dimensional rift. You enter into the hole in a flash of electromagnetic "noise" because of the conversion of hydrogen to energy as the rift closes. As the rift opens up at the other end, hydrogen of your leading edge of the "jump bubble" is destroyed as the rift is opened up. This "flash" of electromagnetic noise is louder and stronger than the "entry" flash because you're ripping the fabric of 4 dimensional space/time from the wrong side. The hydrogen that still surrounds you as you enter into space then disperses from that region as slightly hotter hydrogen atoms than normal, but very quickly assumes the heat level of space nearest to you (entropy and all that rot).

Multiple entries into jump space from nearly the same point causes a rippling effect not unlike 10 stones dropped into a pond from the same height at the same time - all equidistant from each other. The ripples are worst at the center where all of the ripples collide at the same point. Ships that enter into J-space in a sphere formation (or circle if playing on a 2d map space) have the best chance of arriving together. A ship in the center of the circle also can arrive at the same time because all the same shock waves hit it at the same time more or less. Any other kind of formation however suffers from the uncertainty due to interference from other shockwaves.

In game terms? Navigation requires a normal roll against navigation to enter and exit jump space. The difficulty level of the navigation is made one level worse against ONE navigator's skill - the one who plots all of the ships entering into J-space at the same time. The alternative is that one Navigator must set the plot, and each pilot must plot against their skill levels at one difficulty level higher (as they try to sychronize their plots agianst the main plot. Either way...

 

[Andrew Boulton]

IMTU the entry jumpflash is the biggie (equivalent to a small nuke). The exit is much quieter - you'd probably miss it unless you happened to be looking in the right direction. Big exit flashes would make sneaky arrivals impossible.

 

[fencermatt]

What do you guys think of the concept of sharing jump plots with other ships to come out at a similar time? I don't remember a canonical reference to it, but have seen it in various places such as story hours. Perhaps given my above house rule, I could grant a +10 to the roll if your roll choice is "the same as the other ship." Perhaps a bit more difficult if ship characteristics don't match.

I think I picked this idea up from the Traveller Mailing List, but IMTU I allow one navigator to plot the jump for a fleet of ships. I used it as a plot device more than anything--how else could fleets invade a system, if your tankers arrived three days before your battleships, you'd be sol--but since I've never had characters actually in charge of a fleet of ships, I've never come up with definitive rules.

 

[The Hinterworlds Rambler]

So, like a Chain Jump Field, or a Jump Web?

 

[Ran Targas]

What about jump wash?

If you are in close proximity to a ship activing its jump drive, can you get sucked into J-space, carried along in the wake of the jumping ship? Does it carry you the whole distance? Would the jumping ship realize an increase in fuel consumption?

What if you just happen to be in exact location of a re-entry into N-space? Are you obliterated in a shower of superluminal particles? Does the ship re-entering N-space automatically avoid you, due to your minute gravitic shadow?

Could make trader games a little more fun if it happened just once ... or twice ... at random ... with random results.

 

[Andrew Boulton]

If you're within 100d of a ship that jumps, you won't go with it but you may be damaged, and the other ship may misjump.

Your mass will move the exiting ship 100d away. Scared the crap out of my players when a BatRon on manoeuvres came out of jump all around them...

 

[mike wightman]

Originally posted by Andrew Boulton:
IMTU the entry jumpflash is the biggie (equivalent to a small nuke). The exit is much quieter - you'd probably miss it unless you happened to be looking in the right direction. Big exit flashes would make sneaky arrivals impossible.

I have just been comparing how many EPs a fully charged jump capacitor needs (18xJno.x[hull tonnage/100]).
Now a nuclear missile according to HG gives out 100EP or 200EP at TL13+.
An 800t merc cruiser making a jump3 is going to have to charge up to 18x3x8 = 432 EP.
If this energy is released explosively to open the door to jump space then perhaps small nuke is an understatement, especially for multi-kiloton warships

 

[Andrew Boulton]

Ouch.

 

[mike wightman]

Makes me think that DGP should have called it something like "Nuclear Detonation Containment Chamber", rather than a "High-yield Fusion Power Plant" as listed in the Starship Operator's Manual

 

[Psion]

Originally posted by Ran Targas:
What if you just happen to be in exact location of a re-entry into N-space?

The way one ref of mine ran it, the new ship just gets "superimposed" on the old. During the sixth frontier war (!), one of the naval ships jumped into the same space as an alien ship. The PCs were the crewmembers of the ship that survived; other crewmembers met a grisly fate. My character was leaning down to pick up a pencil or stylus for the captain, and then heard a wrenching sound. As he tried to stand back up, he bumped his head on the deckplate that was now there. He looked over at the captain, whose head was now embedded in the deckplate.

The adventure was to make out out of this mishmash pair of ships alive...

 

[far-trader]

Originally posted by Sigg Oddra:
</font><blockquote>quote:</font><hr />Originally posted by Andrew Boulton:
IMTU the entry jumpflash is the biggie (equivalent to a small nuke). The exit is much quieter - you'd probably miss it unless you happened to be looking in the right direction. Big exit flashes would make sneaky arrivals impossible.

I have just been comparing how many EPs a fully charged jump capacitor needs (18xJno.x[hull tonnage/100]).
Now a nuclear missile according to HG gives out 100EP or 200EP at TL13+.
An 800t merc cruiser making a jump3 is going to have to charge up to 18x3x8 = 432 EP.
If this energy is released explosively to open the door to jump space then perhaps small nuke is an understatement, especially for multi-kiloton warships </font>[/QUOTE]Hmm, so it can't be a simple explosion since we don't roll multiple nuke hits every time we Jump

Maybe it's like a short range energy weapon, the force of which tears open the hole to J-space and the effects go in without any back-blast. Except maybe in the case of a catastrophic mis-Jump incident, then KABLOOIE! You take the whole energy as a hit. That will probably destroy most ships.

I would love to find a good argument to do away with the whole Jump flash tells everybody within a Parsec that you have departed/arrived. A guy could go blind in a busy system. At the very least if would spoil stargazing.

I think you see a flash, or maybe an arcing, when the hole is torn to J-space, not overly bright* but noticeable if you're looking at the right place and close enough.

* I guess intensity would vary with the energy input

Then when you drop out the other side there might be a brief and almost imperceptible glow*, you probably won't spot it even if you are looking for it unless you have excellent sensors at optimal range.

* Probably just a little hull glow, so variable with the size of the ship I guess

Of course there's also the other sensor information to work with that may help. Sudden mass perturbing densitometers, a spike in rf from the electronics and such, not to mention the telltales from the power plant on the neutrino sensors.

 

[far-trader]

Originally posted by Psion:
</font><blockquote>quote:</font><hr />Originally posted by Ran Targas:
What if you just happen to be in exact location of a re-entry into N-space?

The way one ref of mine ran it, the new ship just gets "superimposed" on the old. During the sixth frontier war (!), one of the naval ships jumped into the same space as an alien ship. The PCs were the crewmembers of the ship that survived; other crewmembers met a grisly fate. My character was leaning down to pick up a pencil or stylus for the captain, and then heard a wrenching sound. As he tried to stand back up, he bumped his head on the deckplate that was now there. He looked over at the captain, whose head was now embedded in the deckplate.

The adventure was to make out out of this mishmash pair of ships alive... </font>[/QUOTE]There was a single recorded incident of this type of catastrophe in a TAS news bulletin iirc. So it's rare, once in how many Jumps over the several hundred years. That we know of

 

[mike wightman]

Take a Tigress making jump 3 as the example then
18x3x5000 = 270000 EP.

If the jump transition is 99.9% efficient that's 270 EPs given off as waste EM radiation or exotic particles.
The jumping ship is not affected because it is in the "eye of the huricane" so to speak.
But I wouldn't want to be in a Customs Gig nearby