Hyperspace for dummies

[MrBackman]

Originally posted by Werekoala
I assumed the fuel was consumed pre-jump to charge capacitors that were then discharged to activate the jump drive in one energetic burst, so I come down on the "no fuel in jumpspace" side I guess. It would also (kinda) help explain the Jump Dimming tradition, if you go with the "we need all our energy output at the moment of jump" crowd.

That would mean that jumpdrives are insanely powerful fusion reactors and one wonders why the Navy doesn't use them to power their weaponry for short bursts? A fusion drive consume 1% per week EP (250 MW in the official Traveller universe) per 100 dTon. A jumpdrive consume 10% in less than an hour.

You are probably right about the real world origin of the jump dimming idea.

[Werekoala]

Actually that'd mean that jump capacitors were insanely good at holding a charge from the fusion drives, and then releasing it all at once to kick the ship into jump. I don't think the fusion drives would need to be that powerful, comparatively, although more powerful reactors could charge the capacitors faster. The capacitors would be the powerful bit, and that would make sense with military weapons as well I think (build a charge on the laser capacitor and release it when ready, kinda like a camera flash).

Again, these are all assumptions built over decades, without anything to back them up. If there are places in Traveller canon that contradict my assumptions, that's fine, I must just have missed them.

[rasimus]

Originally Posted by the article

Astrogators presumably do their thing in hyperspace, after jumping, as there would otherwise be no need for astrogator crew on X-boats. As X-boats don’t have maneuver drives one could calculate jump from the outside, set the jumpdrive to jump and pick the ship up at the destination, with no need for crew at all.

Just to double check -- my memory says there was something about sentient life required for jump, which is why the x-boat 'pilots' need to be there. Am I remembering that wrong?

[Apache]

Astrogators' can pre-calculate Jump before the drive is activated.

As long as the parameters don't change (speed, loc, etc), you can plot your Jump while you are on the way to the jump limit.

It's Traveller canon that for whatever reason, automated Jumps (aka, Jump message torpedoes...which are Canon....) with no living crew rarely work properly (ie, they usually Misjump).

Also, there are Jump tapes (see GT:ISW), if you think you don't need a Jump navigator.

You are going to need a real-space navigator regardless, however....

[Hans Rancke-Madsen]

It's jumpspace, not hyperspace.

Originally Posted by Werekoala

I assumed the fuel was consumed pre-jump to charge capacitors that were then discharged to activate the jump drive in one energetic burst, so I come down on the "no fuel in jumpspace" side I guess.

All the fuel is expended prior to jump initiation. You can't have drop tanks if that is not true. Unless Mongoose has retconned drop tanks out of existence, any description that has some of the fuel expended during jump is in direct an unreconcilable contradiction to another part of canon.

A minor additional indication is the canonical instances of jumps that have taken considerably more than the normal maximum of 185 hours. There are examples of ships returning to real space after spending centuries in jumpspace. If you need a steady supply of hydrogen to protect the ship and if a standard supply is exhausted after a week, such extended sojourns in jumpspace would have destroyed the ships.

Also, if a normal supply of hydrogen protects the ship for, say, 185 hours, then the average jump (168 hours) will result in the ship arriving with several tons of hydrogen still left in the tanks, enough to affect the economics of starship travel.

OTOH, the amount of energy you get out of a full load of jump fuel is either insanely high or the fusion process is unbelievably inefficient. Also, if the jump drive is simply a fusion plant, how come it doesn't improve with tech level? (That is to say, a TL15 J1 drive ought to use a lot less fuel than a TL9 J1 drive).

My own suggestion for an explanation, which I've been promulgating for over a decade now, is this:

Jumpspace is dense. How dense? Just dense enough to produce the effect described below. If you just open a hole into jumpspace and shove a starship across the dimensional barrier, you get much the same effect you get if something strikes a water surface at high speed: The water can't get away in time and the object might as well have struck a concrete surface.

So what a jump drive does, is open a small aperture into jumpspace, and then pump in a lot of hydrogen. This process takes 20 minutes and results in the adjacent area of jumpspace temporarily becoming a lot softer, more diluted. The ship is the propelled across the interdimensional barrier, which closes behind it. If the ship doesn't cross the barrrier fast, the hydrogen will disperse and entry once again becomes impractical.

Higher levels of jumpspace are denser and require greater amounts of hydrogen.

It would also (kinda) help explain the Jump Dimming tradition, if you go with the "we need all our energy output at the moment of jump" crowd.

No, it would not. The amount of energy you get out of dimming the lights for two minutes is utterly insignificant, as is the cost of installing enough extra capacity to keep them burning.

Bear in mind that (in my experience), when an airliner preparing to leave the gate switches from the external generators to internal power, the lights in the cabin will dim or go off for a couple of seconds - this might be the real-world origin of the "tradition" in Traveller.

Boxer01 (post #10 of this thread) already gave the correct explanation.


Hans

[Hans Rancke-Madsen]

Originally Posted by rasimus

Just to double check -- my memory says there was something about sentient life required for jump, which is why the x-boat 'pilots' need to be there. Am I remembering that wrong?

It's one of the fanon explanations that has been percolating through the Traveller Community for decades. It's directly contradicted by at least one canonical incident where some rebels sent an empty ship to make a kinetic kill attack against a world ("A Dagger at Efate"). A refined explanation says that a statistically significant number of misjumps (say, 3%) occur if there are no sentients aboard. This explains X-boat pilots and also explains why X-torp networks would be more expensive and less reliable than X-boats, while still keeping jump torpedoes viable for distress calls, 97% being good odds when you're in drakh orbit without a maneuver drive.


Hans

[Werekoala]

Ah, good old Hans, still as charming as ever. :)

re: Dimming and airliners, I was just musing about my own personal explaination as to what a real-world analog might have been, not trying to say that it was THE reason. I never read the adventure where they had to have the lights go out for murder, and I'd never heard that as "the reason" before, so cut me some slack, chief.

[Apache]

Originally Posted by Hans Rancke-Madsen

Unless Mongoose has retconned drop tanks out of existence, any description that has some of the fuel expended during jump is in direct an unreconcilable contradiction to another part of canon.

Nope. Drop tanks are in the new High Guard (Book 2).

They are not very economical, tho.

Originally Posted by Hans Rancke-Madsen

So what a jump drive does, is open a small aperture into jumpspace, and then pump in a lot of hydrogen. This process takes 20 minutes and results in the adjacent area of jumpspace temporarily becoming a lot softer, more diluted. The ship is the propelled across the interdimensional barrier, which closes behind it. If the ship doesn't cross the barrrier fast, the hydrogen will disperse and entry once again becomes impractical..

Almost exactly how MongTrav describes it.

From MongTrav Core Rulebook, page 141......"To Jump, a ship creates a bubble of hyperspace by means of injecting high-energy exotic particles into an artificial singularity. The singularity is driven out of our universe, creating a tiny parallel universe which is then blown up like a balloon by injecting hydrogen into it. The Jump bubble is folded around the ship, carrying it into the little pocket universe. ......while in Jump space, the ship is completely and utterly cut off from the universe.It hangs in a shimmering bubble of boiling hydrogen, a pocket dimension from which nothing can escape."

Also, in MongTrav, actually firing up the Jump Drive normally takes anywhere from 10-60 seconds. And is done once, at the beginning of the Jump.

[allens]

There are a couple of JTAS articles that should be examined on this - one by Marc Miller and another talking about Jump Nets.

[freetrav]

Originally Posted by rasimus

Just to double check -- my memory says there was something about sentient life required for jump, which is why the x-boat 'pilots' need to be there. Am I remembering that wrong?

Nothing canonical, but I did propose that as part of a 'house rule' at The Color of Jumpspace.