Jump Precisions

The board game Imperium originally had nothing to do with Traveller.

As GDW looked to invent a universe for Traveller the Imperium backstory was fleshed out and adapted as one of the historical eras of the Traveler Imperium.

Trouble was the movement rules in the boardgame and the jump rules in the rpg are different.

When SJG began the playtest for GT:ISW one of the more... interesting discussion were how to reconcile the two.

Some argued that empty space jumps were a maths issue - which was adopted, while others said it was a only a problem for a coordinated fleet jump, the flaw in that argument is the turn length, and there were other ideas but I would have to go and see if I can find the emails.

One of the issues was that the Imperium rules were then used for another era - the Solomani Aslan wars - set long after the ISW era.

Note that there is no evidence that the Vargr or the Zhodani were ever restricted in the way the Vilani, Solomani, and Aslan were (the Aslan copied their jump drive from a Terran ship that misjumped). The Solomani/Aslan answer to empty hex jumps was learned sometime during the Dark Nebula board game era. How it was communicated to the Sylean Federation is a bit of a mystery, or perhaps they learned to do it via the Vargr.
 
No worries. Phavoc suggested there was such a rule. Sygtrygg was going to look for it. I commented that I didn't think it was a rule, just that it was a harder jump.

Being a harder jump plot is definitely a way to bridge the gap between early era jumps not being into empty space and later learning how to do it

Still have the core problem that difficulties in MgT2e increase in units of 2, while character skills increase in units of 1. But, that's also a different topic.
 
No one really knows.

However, the fact that almost all technology seems to hang on our understanding and application of gravity, and gravity influences jumps, it seems plausible.
 
No. they work the opposite of M-drives.
J-Drives are perfectly happy in flat space. They get finnicky on steep slopes and so those slopes are a convenient spot for astrogators to use as a backup for ensuring you get spit out where you want to be.
M-Drives need a slope to operate on when they coast off the slope, they go on strike and start yelling Foxtrot-Uniform.
 
It seems to be gravitational based, and there's no obvious large gravity well in an empty hex.
This is the section from the World Builder Manual about jumping into “empty” hexes:

——-
JUMPING TO ‘EMPTY’ HEXES
Jumping to hexes not marked as containing star systems is risky. Even if a large gravitational anchor such as a white or brown dwarf is present, a jump is more hazardous than normal. Some jump-space theorists believe this is an effect from the paucity of neutrino emissions from ‘stars’ not fusing hydrogen but regardless of cause, such jumps are inherently riskier.

Jumps to smaller mass targets such as gas giants or terrestrial planets become increasingly risky and less precise as mass decreases. Jumps to the smallest targets add another factor of risk: far from a gravitational anchor, manoeuvre drive thrusters do not have a local gravity well to interact with and will operate at less than 1% efficiency, relying only on their interaction with the galaxy’s overall gravity gradient. Ships designed to operate far from normal stars are either equipped with fuel-hungry reaction drives or a power-hungry deep space manoeuvre system (DSMS – see Deepnight Revelation Campaign Guide (Book 2), page 33) capable of creating a local field to ‘bootstrap’ a standard manoeuvre drive.
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This Astrogation check can also benefit from any task chain DM from the initial Astrogation check. A prepared jump template solution to a known deep space location such as a jump bridge, fuel depot or other station may be available for purchase (usually 1D × Cr100) at a Class A or B starport in an adjacent hex. Such solutions ‘degrade’ every full week after generation by DM-1. A ship can generate its own template – only if it knows the precise current coordinates of the target – by running its Jump/x program with 10 extra Bandwidth for 2D hours. The precision required to run this program requires input of astrogation data from a ship that has visited the target within the last month.
——-
So it seems that a ship can easily jump to planet about a star, but not easily to one that is rogue.
Also, the survey classes table states that only stars and large gas giants from an adjacent hex, suggesting that planet locations for jumps about stars must also be pre-known, though the star makes it easier (I suspect by reducing the location unknowns, apart from providing the gravitational anchor).
Does the Deepnight Revelation book say anything about jumping into new systems?
 
The above implies it's risky in general, to jump into an empty hex, which risks just sort of compound each other.

It's probable that a well prepared crew, could mitigate most of them, if jumping into a comprehensively explored empty hex.
 
I'm sorry to say that the entire passage is what is wrong with Mongoose Traveller.

"Some jump-space theorists believe this is an effect from the paucity of neutrino emissions from ‘stars’ not fusing hydrogen but regardless of cause, such jumps are inherently riskier." lol

"far from a gravitational anchor" - yes I know I have taken it out of context, but I will put money on people now thinking this is relevant to the jump drive rather than the maneuver drive

"capable of creating a local field to ‘bootstrap’ a standard manoeuvre drive." isn't this the equivalent of lifting yourself into the air by pulling on the back of your own pants?

The section fails to answer the question of just jumping into empty space.

"This Astrogation check can also benefit from any task chain DM from the initial Astrogation check" task chains are the worst rule in MgT and should have been changed a long time ago.

Every additional time you roll the dice to achieve something you increase your chance of failure, not success.

If you don't like statistics just give it a try.

The following task chain has a target number of 6 at each step because each is a routine roll. To succeed you have to roll 5 times successfully.

A better way to do it is to total the effect numbers for each roll until a threshold number is achieved, in my opinion of course.
 
Looking for the passage about empty hex jumping in Deepnight Revelation, but ran across this in Book 4 that I thought seems to contradict other jump space operations (or, arguably, this rule ADDS to jump space ops):

Starship Operations

Nebulae and interstellar dust clouds can interfere with jump drive operations but are not dense enough to prevent interstellar travel entirely. Ships jumping into or out of a nebula (or from point-to-point within one) are more prone to misjumps, with DM-4 imposed on Engineer (j-drive) checks made to jump into or out of a nebula and DM-2 applied to jumps passing through one. The denser gas of a protostar is not quite sufficient to prevent a jump through it but imposes DM-4 on attempts to jump through and DM-8 on attempts to jump into or out of the cloud.

This dovetails into the Jump Space shoals blurb:
JUMPSPACE SHOALS A shoal is a region where jump drives do not function to their full capacity. Shoals are designated by the minimum jump number required to enter jumpspace within the shoal; thus, a jump-2 shoal requires a jump-2 or better drive to enter and requires sufficient fuel for a normal two-parsec jump to cross a single parsec. A jump-3 shoal requires a jump-3 drive and enough fuel for a normal 3-parsec jump per parsec travelled. Jumping ‘over’ a shoal is not possible unless the vessel possesses sufficient range to completely clear the shoal in a single jump, expending fuel at the increased rate.

Not sure how a gas cloud is supposed to interfere with a ship that is not in N-space. Gravity wells of significant size (planets, stars, etc) have been there since LBB days, but never interstellar gas.

I found this passage in The Great Rift book.

When operating within a rift, however, the risks do increase. Some Travellers are adamant that the jump drive is subject to greater variance when operating in empty space or that jump plots can be less precise; there is little room for error when jumping to a star system deep within a rift and none when attempting to make a rendezvous with a tanker or deep-space refuelling cache. Hitting such a precise point in empty space requires a particularly good jump plot, made more difficult by the need to define the target location in a very sparse frame of reference. If the coordinates of the target are not known, a jump cannot be calculated although the ship could jump into the target hex and hope for the best.
Calculating a deep space jump: Difficult (10+) Astrogation check (3Dx10 minutes, EDU) with negative DM equal to the distance in parsecs.


Thus far I have not found a reference stating one needed a gravitational point to jump to in a deep space hex. I could have been wrong on the reference, I'll have to keep looking.
 
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I have nothing against navigational hazards, but they have to be canonically fixed in empty hexes.

I'm pretty sure most players will welcome a Bermuda Triangle.
 
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