Jump Theory 101

[far-trader]

Greetings Sophonts, rather than a formal study and lecture format this session will be a casual group discussion. All questions are welcome and will be answered as best as possible by the professors given the limited knowledge of even the most educated on the actual physics involved. Feel free to also put forward any idea you may have heard or imagined for discussion.

Scott Martin, I believe you had a few points to start us off with...

Originally posted by Scott Martin:

IIRC HG required that power be put in to make a jump, and could be allocated *over 2 turns* which suggested that minimum PP rating could be 1/2 J-Drive rating.

You are correct in your recollection, but not the application I believe. The required level of power must be allocated over 2 turns. Not half one turn and half the next. If there is sufficient power, that is twice or more the required power, then it may be done in 1 turn instead. What is clearly know is that a jump drive must be powered completely within 2 turns or the jump will fail. So a slow charge for the jump drive, say over 12 turns to pick a number from the hat, will not work. This of course is with the current jump drive technology of the Imperium and know alien versions.

I'll address your other questions shortly, unless someone else would like to jump in.

 

[mike wightman]

And, not only do you need this energy from the power plant or black globe capacitors, but you also need the full required jump fuel.

Which suggests that the jump fuel is either not part of the energy requirement for jump, or that the initial charge is just a warm up before a much more massive energy release.

 

[RainOfSteel]

My apologies. I was going to post the reference to Graeme Batho's famous "[TML] How Jump Works 201 (very long multi-part)", in seven total parts, but the TML Archives are experiencing a problem.

 

[Klaus]

Originally posted by Sigg Oddra:

Which suggests that the jump fuel is either not part of the energy requirement for jump, or that the initial charge is just a warm up before a much more massive energy release.

And why not helium?
Possibly jump engines use hydrogen because it's a source of clean protons, perhaps for the jump grid?

Funnily enough, 1 dton of water contains as much hydrogen as 1 dton of H2, as does 1 dton of methane, well, more or less. Basically refined or unrefined fuel takes up the same space, despite unfefined carrying all those other atoms of oxygen or carbon. It will obviously mass more, but the ship design formula works on volume and not mass, indicating that volume is significant to jump in some way.

 

[robject]

Originally posted by Klaus:
</font><blockquote>quote:</font><hr />Originally posted by Sigg Oddra:

Which suggests that the jump fuel is either not part of the energy requirement for jump, or that the initial charge is just a warm up before a much more massive energy release.

And why not helium?
Possibly jump engines use hydrogen because it's a source of clean protons, perhaps for the jump grid?

</font>[/QUOTE]"Helium is much more expensive than hydrogen, harder to come by, and about 10 times more difficult to liquefy."

- Graeme sez

 

[far-trader]

Thanks for that RoS and robject, I knew it was out there somewhere but couldn't recall where and my bookmark to it was lost long ago.

 

[Scott Martin]

I'll take a look at the article later (when I have more time) but (in reference to an earlier rant of mine) should we consider this source "Authoritative" or "Somewhere to get good ideas from"?

If it is the first, then most of this thread will be hashing out an interpretation of this article, if the latter, then I'll have some input on the use of non-hydrogen jump fuel.

IMTU Hydrogen was used because it is the most plentiful element in the universe. If you're going to "consume" something (leave it in an alternate universe / jumpspace) then use something expendable.


Scott Martin

 

[Whipsnade]

Scott,

It was well recieved on the TML, but I think "Somewhere to get good ideas from" would be a better way to view it than "Authoritative". There are a few canonical problems with it but, after 25+ years and so many versions, there's going to be canonical problems with any model.

That brings up my next suggestion: We limit the discussion here to the bog standard OTU Third Imperium jump drive. Canon mentions other ways to jump and including them here will just confuse the issue.

For example:

- The Annic Nova drive which may or may not use fuel
- The early Terran Confederation 'fuel hog' jump1 drive
- The early Hiver 'melt down' jump1 drive
- The early Vargr jump drives that used barium instead of lanthanum

There's even mentions of interstellar teleportation, although what link it may have to jump space and jump drive is unclear.

So let's stick to the standard drive and leave all the others out.


Have fun,
Bill

 

[RainOfSteel]

Originally posted by robject:
</font><blockquote>quote:</font><hr />Originally posted by RainOfSteel:
My apologies. I was going to post the reference to Graeme Batho's famous "[TML] How Jump Works 201 (very long multi-part)", in seven total parts, but the TML Archives are experiencing a problem.

I've cloned it. Here it is:

http://eaglestone.pocketempires.com/rules/jumpdrive.html </font>[/QUOTE]Yes! robject is knighted in the Order of Sylea for his heroic efforts in saving one of the most invaluable user contributions to the body of Traveller fan-generated material.

 

[robject]

Originally posted by Bill Cameron:
Scott,

It was well recieved on the TML, but I think "Somewhere to get good ideas from" would be a better way to view it than "Authoritative".

What he said...

 

[Scott Martin]

A question before starting: Why do we care what the actual mechanism of jump is? Are we planning on proposing a few that look good and fit most of the published Traveller stuff, and asking MM to pick one? I'm asking because I'm mostly trying to focus on getting a reasonable set of "layers" for technical architecture (FF&S / FF&S "lite" / HG / LBB-2) and I'm trying not to get too distracted (ooh look! shiny!)

Folks should also be warned that I have ulterior motives for favoring a "big energy pulse" with little or no energy maintenance requirement. One of the things that I always liked about Traveller were the wierd juxtpositions of technology, and some of my favorites were extreme mixes: Cannon armed stone ships with steam engines powering imported CG lifters, or the previously mentioned "battery powered" jump ship.

I suspect that Ptah is a bit better for deconstructing the previous article than I am. Physichal Chem was not my strongest subject (I passed because the majority of my classmates were more lost than I was)

That said, there are a few issues about lasing that are important to note which raise some problems with the proposed mechanism:

1) Energy in > energy out
2) They require a meta-stable (higher) energy state
3) Your "first" energy transition will give you the most energy (mostly due to #2)

The first kyboshes getting extra power from this (unless using more handwavuim / unobtanium) I don't know about the apresence of a meta-stable excited state in vaccum hydrogen, but the hydrogen "dumped" around a ship would not be a very good vaccum. I honestly can't recall whether H2 is a poor lasing candidate, or if most labs don't use hydrogen lasers because H2 + Oxygen atmosphere + high voltage sparks are a generally poor combination. The third means that the mechanism for jumping "farther" would actually take *less* energy for each step. Perhaps the quantization is based on a set number of hydrogen molecules reaching the excited state (1%=Jump-1, 6%=Jump-6) but this kills the nice "I can make a progression that sums to 36" bit, although I note that he did mention that Hydrogen doesn't actually have 8 excited states

There are also a few inconsistencies: the lanthanum jump grid needs to be protected from interaction so that it doesn't get cooked on re-entry, but it needs to be exposed so that the Hydrogen can interact with it... It might make for an interesting Traveller universe if jump-capable ships *couldn't* enter atmosphere, but that's nowhere near what people expect from Traveller.

So on to the more more constructive part of the post.

The "Jump Glow" could be (and IMO probably is) cherenkov radiation, at the interface between "our" universe (held in the jump bubble) and the velocity of light in the "Jump" universe . The other mechanism for this glow would be due to high energy particles interacting with the "atmosphere" that is enclosing the ship with a similar mechanism to the northern lights

My cut at how jump worked was that it was based on gravitic technology, a controlled grav "implosion" that punched the jump "tunnel". One of those "obvious once you think of it" things like the discovery of fire, chemistry or nuclear fission. World-changing, and historians will constantly be trying to figure out why the Romans / Greeks / Hungarians / "JH'as-*#$h tribe" didn't think of it (and "proving" that they did, just as the nation fell to the barbarians) in antiquity. It also means that if you haven't figured out the theoretical basis for gravitics, you can't develop a jump drive.

Here we are at Tech/9, and we haven't figured out gravitics yet: why should we expect to know about Jump Drives? (and where's my flying car dangit!)

Scott Martin

<EDIT> Anyone reading the first part of this post might think that I am trashing the referenced article: please go and read it! I thought that it was a well-written article with a few logical holes which would only be obvious to someone who had taken way too many physical chemistry courses, and some stretches to plaster over inconsistencies in a SF universe. We of course know that the Traveller universe is *always* consistent between versions </EDIT>

 

[robject]

Originally posted by Scott Martin:
A question before starting: Why do we care what the actual mechanism of jump is? Are we planning on proposing a few that look good and fit most of the published Traveller stuff, and asking MM to pick one? I'm asking because I'm mostly trying to focus on getting a reasonable set of "layers" for technical architecture (FF&S / FF&S "lite" / HG / LBB-2) and I'm trying not to get too distracted (ooh look! shiny!)

[...]

My cut at how jump worked was that it was based on gravitic technology [...]

My opinions.

(1) Traveller doesn't really care about how jump works.
(2) Marc isn't going to pick one.
(3) The gravitic explanation sounds cool.

To me, a good mix of technical architecture layers is:
(1) FFS
(2) HG, with accessories ported from MT and tables extrapolated for LBB2-like friendliness.

 

[mike wightman]

Originally posted by Scott Martin:
My cut at how jump worked was that it was based on gravitic technology, a controlled grav "implosion" that punched the jump "tunnel". One of those "obvious once you think of it" things like the discovery of fire, chemistry or nuclear fission.

That's pretty much how I've explained it over the years too.

The link between acceleration compensation, null grav lifters, grav plates, and the jump drive all being part of one technology progression allows Traveller to break less rules of physics - good sci-fi is supposed to be only allowed to break one at a time according to some sources

 

[Ptah]

Originally posted by Scott Martin:

I suspect that Ptah is a bit better for deconstructing the previous article than I am. Physichal Chem was not my strongest subject (I passed because the majority of my classmates were more lost than I was)

...

I honestly can't recall whether H2 is a poor lasing candidate, or if most labs don't use hydrogen lasers because H2 + Oxygen atmosphere + high voltage sparks are a generally poor combination.

...

My cut at how jump worked was that it was based on gravitic technology, a controlled grav "implosion" that punched the jump "tunnel". One of those "obvious once you think of it" things like the discovery of fire, chemistry or nuclear fission. World-changing, and historians will constantly be trying to figure out why the Romans / Greeks / Hungarians / "JH'as-*#$h tribe" didn't think of it (and "proving" that they did, just as the nation fell to the barbarians) in antiquity. It also means that if you haven't figured out the theoretical basis for gravitics, you can't develop a jump drive.

Here we are at Tech/9, and we haven't figured out gravitics yet: why should we expect to know about Jump Drives? (and where's my flying car dangit!)

Scott Martin

</EDIT>

Hi Scott,

Thanks for the compliments, I think. I'll have to read that article more closely, it seems a pretty elaborate explaination. I personally like a gravatic technology based explaination/ newly discovered physics; as in once you have the theory it's really quite simple given enough energy.

On H2 and H lasers, they exist and laze in the vacuum ultraviolet. I think I may have used one at one point. But for scientific and technical applications excimer lasers are more cost effective and can also laze in the UV. Although an H2 laser is probably a lot safer than the HF used in excimers. As potentailly explosive compounds go, H2 is very weak producing more of a wumpf than a crack/boom. (This based on personal experiments setting off acteylene vs. H2 filled baloons ). If traveller ships are using liquid hydrogen I'd be very afraid of accidentially producing liquid oxygen, which is very reactive and explosive. Things burn really, really well with liquid oxygen nearby (even things that normally wouldn't burn will burn). Current work on H and H2 lasers I beleive is driven by the semiconductor industry.

Lanthanum, I always wondered why this metal. It's not very rare, (it's found in monazite and is more common than mercury) although it is sometines called a "rare earth" metal. I saw a part about H uptake, Lanthanum Hydrides are very reactive (pyrophoric) with air and water, make sure your jump grid is de-gassed beofe landing.

I'd have to read it more closely to figure out what the game reason for this is. There are other metals that are much better at H uptake and release. Maybe lanthanum was chosen because a lot of work was done with Lanthanum Hydrides in the 1970s (for reasons of chemistry more than practical applications, e.g., the core ion La+3 has the electronic structure of Xe, so it would be the most stable of the series.)

If I was going to pick a rare metal for sci-fi purpose, I'd choose the undiscovered element 126, nuclear shell theory predicts a stable element at 126. I should say not conclusively discovered last I looked; but I have it on personal information from Darleane Hoffmann that it certainly could exist and was worth looking for. Since Darleane was Glen Seaborg's protegee, and is prememinant in the field, I take it as pretty much discoverd for sci-fi purposes.

 

[Scott Martin]

(Physical Sciences Warning)
Ah the joys of "Magic Number" theory...

I played with Nitrogen lasers, which are in the "soft" UV range, with no danger at all of a chemical "bang", and some fairly easy ways to "step down" the wavelength by using the beam to kick other lasing compounds into the excited state (shifting your "effective" wavelength into the visible range)

IIRC the 1970's was before ion-exclusion chromatography was an effective industrial technique, so "Lanthanum" may just have been shorthand for "Lanthanides". That said, I'd prefer to avoid both berellium hydrides and actinide hydrides: they're things that I would really rather leave for other folks to play with.

An explanation of "Magic Number Theory" for the non-chemist readers:

Some elements are more stable (from a nuclear chemistry point of view) than others, and it appears to be based on the configuration of their nucleus. Lead and Iron are extremely stable, Uranuim and Plutonuim are not (IIRC Plutonuim only exists as a manmade material, generated by neutron bombarding uranium) Extrapolating out from our current understanding of trends in the periodic table, there should be "islands" of stability somewhere in the trans-uranics, way past element 100. (Element 126-128 is the range that I have heard for the beginning of stability my eyes glaze over when people discuss the right "mix" of protons and neutrons) Unfortunately the only way that we have come up with to "create" these elements is to smash nucleii togehter with a particle accellerator, so it's an open question as to the actual stability of elements that are created this way. Do they decompose (fragment) because they are unstable, or because the residual energies of the collision break them up?

Scott (too geeky by half) Martin

 

[Whipsnade]

Gents,

Okay, I'll make a "How Jump Works IMTU" post too.

Background - I began developing MTU's answers to the 'how does it work" question back in the very early 80s. I was running sessions as a navy nuc for navy nucs in training, so my early explanations had to keep those sorts happy. One thing to keep in mind, most of MTU's answers were formed well before any later CT information, all of the MT materials especially DGP's SOM, and naturally before all of TNE, T4, GT, and T20.

When the information in later products meshed well with MTU's answers, it was incorporated. When the information in later products was IMO better, it replaced MTU's answers. When the information in later products was IMO worse, it was ignored. The Batho article is a good example of this.

I liked Graeme's work and felt it had some good ideas. However, because it was predicated on one item MTU's jump drives do not have, I use very little of the Batho article IMTU. You'll see what I mean below.

Oh, as I posted earlier, all of this is refers to the standard Imperial jump drive and not any of the other varieties.

With all that laid out, away we go...


Jump Dimensions - Jump may be measured in parsecs but it's not the parsec we use in 2006. That term was appropriated when it was realized that the maximum displacement possible by a jump1 drive was sort of close to the old parsec distance. Self important nitwits in the various government agencies involved came up with their usual dippy acronyms for the distance(1), but when regular folks began jumping the term 'parsec' came into wide use.

As in canon, there seem to be 36 dimensions but only 6 can reached safely and with certainty. The Jump1 dimension should really be called the Jump0-1 dimension. You enter it to make jumps ranging for any distance up to 1 parsec. Jump2 is thus really 1-2, 3 is 2-3, and so on.

Jump Fuel - Fuel is used for both energy production and jump bubble creation. I never fixed the proportions between the two; how much for the energy and how much for the bubble, but the amounts increase with each jump dimension. It's harder to break into 'higher' dimensions and its harder to protect the ship in 'higher' dimensions, so more fuel is required for each task. The actual percentages of each I never determined, not did I want or need to.

Jump Grids - Not used IMTU. This is why the Batho article is of little use to me. Why aren't they used? Look at the HG2 damage tables.

You've got this lanthanum grid running all over the hull emitting hydrogen right? How come a surface explosion hit doesn't effect your jump rating then? The only way a surface hit can effect a ship's jump drive is to cause an interior explosion or a critical hit. I can ping the ships' suface long enough to empty every fuel tank, scrub off every turret, destroy every weapon, and knock out the maneuver drive, but the only way I can effect the jump drive (or power plant) is through an internal explosion. You still want to tell me about lanthanum hull grids? Sorry, not IMTU.

There are other reasons too. In MT, which introduced the hull grid in DGP's SOM, you can't damage a jump drive via surface hits either - unless your surface hit causes an interior explosion. Look at battleriders and tenders. Mostly configuration 7, dispersed structures. Our only canonical picture of a tender and her riders shows that. Where's the grid there? Do the riders have a grid that plugs into the tender's grid? If so, why don't you have to pay for it when you build a rider? Ask those same questions regarding TNE's modules and sockets.

Hull grids? Not IMTU.

Lanthanum - MTU uses it in CT fashion as 'lanthanum coils'. The coils are an intregal part of the jump drive. Remember those six large 'machines' on each of the eleven AHL jump drive decks? Lanthanum coils are in those along with other equipment.

Zucchai crystals - MTU does not use them in the MT/DGP heat sink manner. They're still important, but they're used for something else. They're in those 66 'machines' on the AHL jump drive decks too.

Jump Initiation - This isn't an attempt at a blueprint or at detailed operations. You notice the descritpive words I'll use will be in quotes. This somewhat vague description satisfied my players; who were running reactors at the time, and myself. It met our needs. Whether it satisfies you depends on your needs. Okay?

A portion of the jump fuel is used to create an energy pulse within the jump drive(s) itself. The pulse is contained and directed within the machinery and the machinery also shields surrounding equipment and personnel from the effects of the pulse. The pulse allows a zucchai crystal 'needle' or 'injector' to be 'inserted' into the proper jump space dimension. The crystal does not physically 'move' relative to our dimension but it is nonetheless 'inserted' into the jump dimension.

The rest of the jump fuel now enters the picture. It has been 'modified' by an application of energy within the lanthanum coils. In this 'modified' state - which I never detailed or explained - the fuel passes along the zucchai crystal 'needles' or 'injectors' into the jump dimension being accessed. As the jump fuel is 'injected' or 'pumped' into that dimension, it creates a 'normal space' bubble.

So, IMTU, a vessel does not 'rip' or 'tear' an opening between jump space and normal space. Instead it creates a 'blister' in jump space which first 'ruptures' into normal space around the vessel, engulfs that vessel, and then 'seals' or 'heals' itself. The vessel is now within a normal space bubble within a jump space dimension.

Please note, the 'bubble' is created by an inflation of normal space within jump space and not by tearing into jump space from without. Also, real space vectors are of no consequence. The injectors are accessing a part of a jump space dimension, their vector in normal space is of no consequence.

What happens after a vessel IMTU enters jump space will be in my next post.


Have fun,
Bill

1 - Like 'MAHD' for maximum achievable hyperspace displacement or 'SDM' standard distance measurement or some other such other acronym-happy crap.

 

[Scott Martin]

Far Trader:

your comments on the "charge over 2 turns / 60 minutes" hasn't been addressed yet, so I'll offer my interpretation.

The capacitors / HPG / whatever for the jump drive are not perfectly efficient: if you can't pump enough power in over a 1 hour period, then you will be "bleeding" significant amounts of power from your initial input. While you could argue that putting in 1.2x the power over three turns would work, who wants to deal with those mechanics?

The "Battery Powered" jump drive simply exchanges one power source (a nuclear plant) for another (a bank of batteries) If the only requirement is electrical power, then it doesn't matter where it comes from. This results in the batteries providing a huge pile of power as electrical energy over the *same* hour as the powerplant would have. The *effect* is as if you charged your jump drive over a longer interval, but the *application* is different. This is possible because batteries have less of a power bleed issue than HPG's, and commonly store power for weeks or months. Note that this still only works if the power input is to generate a power "spike", and doesn't need to maintain high power levels over the week in jump.

The "battery" idea was a result of thinking about implications of the "Gravitic Tear" Jump drive mechanism, not the other way around, since a logical assumption is that once you have "punched the hole" for jump, you don't need to do anything other than "fall" through it to your destination.

There are some other interesting implications from linking gravitics to jump. It explains why the 100D limit "precipitates" ships from jump. It also means that a jump interdiction device would be nothing more than a large grav projector (or a black hole. I believe that Niven used this as a plot device in a "known Space" short story) This *doesn't* mess with my understanding of the Traveller universe, since (at imperial TL's) the size and cost of building such a projector (for system-wide coverage) would make it impractical and require an artificial G-Field equal to that generated by a star larger than the system primary. Similarly the chances of intercepting a jump with a "smaller" projector given the amount of space available at the system level is pretty mind-bogglingly tiny.

IMTU I have a few ancient artifacts stashed that actively interfere with Jump by generating a low-level modulated gravitic field across a massive volume (past the Oort belt) powered (and propogated) by a "pocket universe" (a la S.o.T.A.) This gets around the requirement for a single massive grav source, as well as sneaking around the inverse square law. This also assumes that very small gravitic disturbances will interfere with Jump. These interdiction devices can be easily counteracted (in the system) by building a generator to create a "flat" or "null" gravitic area of space to jump *out* of, but the problem is getting back *into* the system.

Grandfather dealt with the problem by using KKM's fired at several parsecs distance (since he had lots of time, lots of materials and lots of energy)

The effects of this interdiction may be similar in application to the "Null Space" phenomenon I keep running into in some T5 literature.

Scott Martin

 

[Whipsnade]

Originally posted by Scott Martin:
There are some other interesting implications from linking gravitics to jump. It explains why the 100D limit "precipitates" ships from jump.

Scott,

The 100D limit does not precipitate ships from jump. It merely stops them from going any further in space but not in time.

If it precipitated them, you could plot jumps lasting less than 168 hours by deliberately intersecting a 100D limit. We know that is not the case.

Also, 100D limits are not required for jump precipitation. You can precipitate anywhere outside a 100D limit with an accuracy of 3000km per parsec jumped. That's straight out of Marc Miller's 'Jumpspace' article in JTAS #24.


Have fun,
Bill

 

[Scott Martin]

Bill

My terminology may suck, since I'm not familiar with the word use in the TML / Board context. If a ship leaves jump space when it hits a 100D limit, that's close enough for my usage of "precipitate". While you can precipitate outside the 100D limit, I was under the impression that the 100D limit *forced* jump precipitation. This is not something that I have looked into in depth, since MTU has much more stringent limits on where you can and can't jump that the OTU, so you'll have to let me know if that is a correct assumption.

The time factor might have something to do with how you "pop" between universes. Especially if a set amount of time is required to enter and leave the "bubble" universe, regardless of the intervening space (Which looks suspiciously like the Traveller jump paradigm)

I'll need some time to think about your jump mechanism (and steal pieces I like) You have already given me an idea which might allow "harmonization" of the jump fuel volumes used in the various traveller versions, but I'll think on that a bit more before making an utter ass of myself

The time offest makes small area "interdictors" even more of a PITA to use, since ships could be dropping out of jump up to a week after you activated one...

I did miss one of the "important" side effects of "gravitic" jump: if you jump you will (at least for a period of time) actively interfere with jumping vessels in your vicinity due to the large gravitic disturbance created.


Scott Martin

 

[Whipsnade]

Originally posted by Scott Martin:
While you can precipitate outside the 100D limit, I was under the impression that the 100D limit *forced* jump precipitation.

Scott,

I guess it all hinges on just what the wrod 'precipitation' means to the reader.

However, I wanted to quickly remind everyone that the idea of requiring a 100D limit for jump precipitation is incorrect for the OTU. That particular 'interpretation' has caused a great deal of trouble(1) and, although always refuted, it sadly arises again and again.

...since MTU has much more stringent limits on where you can and can't jump that the OTU...

You wouldn't beleive how stringent MTU's requirements are!

I did miss one of the "important" side effects of "gravitic" jump: if you jump you will (at least for a period of time) actively interfere with jumping vessels in your vicinity due to the large gravitic disturbance created.

I much prefer 'tidal' or 'gravity based' jump limits too. Sadly, the OTU insists on the strictly dimensional 100D limit and that's what we're here to dicuss.

If you can use anything from my jump drive blather to enhance YTU good for you. It suited the needs of me and mine a long time ago. It certainly won't suit everyone's needs.

Have fun,
Bill

1 - Just think of all the 'deep space' jumps in canon that 100D limit precipitation requirement would negate. Yikes!