Why is there artificial gravity in Jeffries Tubes?

[Cary L. Brown]

The only problem I see with the pylons of the 1701 existing in zero-G is that it would seem that they would then exist outside the field of inertial dampening, at least as I would tend to interpret things. I always assumed that the gravity and inertial dampening were part of the same field. So, if gravity ever switches off, then so does inertial dampening, which could be really bad news.

To go a step further, I also always assumed that structural integrity and inertial dampening were also interrelated. This isn't really necessarily a TOS concept, but the presence of structural integrity fields wouldn't contradict anything in TOS either, that I'm aware of. If structural integrity fields exist in TOS, then they should apply to the pylons, and in my opinion so would inertial dampeners necessarily, and consequently artificial gravity.

There is, in this view, therefore no reason why artificial gravity couldn't extend throughout the entire ship, pylons and nacelles included, at all times, simply as a by-product of the inertial dampeners (and possibly also structural integrity).

---

Now I think that in the 1701, turbo elevators should be able to go from the engineering hull up the pylons and into the nacelles, at least as far as just after the top of each pylon.

That is, assuming there's room in the pylons for a turbo elevator shaft. Is there?

If so, then this also has a bearing on the issue of gravity in TOS Jefferies tubes. For in my opinion, structural integrity and inertial dampening would apply to the whole turbo shaft, and therefore gravity too. With a Jefferies tube running right beside, at least when an elevator is active a pylon, gravity (at least of some kind) would be present in the tube just as a byproduct of accommodating the elevator, the structural integrity of the pylon itself notwithstanding.

There is not space for a conventional turbolift to go up the pylon. And by the way, my pylons aren't 100% accurate right now... since creating my model, I discovered, to my great surprise, the the nacelle leading and trailing edges are not rectangular at all, but are in fact "full rounds" (though the DIMENSIONS I have are correct).

No, there's insufficient space for a standard turbolift car. However, that's not an indication that there is not room for a "specialized lift" in those. I actually worked it out, and the "chair lift" concept works the best. It's a three-man "bench seat" which slides up or down the incline. It's not an enclosed car, either... because it's used for service access at various points along the length of the pylon as well as access to the two termini.
___________

IF we proceed from your assumptions, you'd be entirely correct. However, I don't proceed from those assumptions. I believe that artificial gravity, anti-acceleration systems, and the SIF are totally independent systems.

There is NOTHING to make us believe that SIF is related to anything else. SIF is basically a "force field" of additional mechanical structure, as defined in TNG-era shows.

But you could argue that both AG and Intertial comps are both "acceleration-related" and thus are a common system. I disagree, but that's not something that's really provable either way.

We have only one significant example of loss of gravity on a starship... that being on "Enterprise" (during Captain Archer's shower).

I, personally, treat these as entirely separate systems, though perhaps based upon similar technology. (You could think of them as "nested" systems, I suppose, or "layered" might be a better term?)

Artificial gravity is always-on, and is designed to be very stable. I like the TNG-TM explanation of AG, where they describe it as generated by an ultra-high-speed rotor... the thing takes days to "spin up" to full speed, and even if power is cut, takes almost as long to spin down again (which explains why you can lose power and not float off the deck in Trek!). There are multiple grav generators, and a series of "Gravity waveguides" which distribute this uniformly through areas which require gravity (explaining how you can shut off gravity or alter it in various locations while still being consistent with the above).

But the inertial-compensation system isn't a steady-state system, but is rather an "impulse-based negative feedback" system, with a very, very fast response time.

Of course... both would be based upon the same "magic science," most likely.. . since in real life we have no conception whatsoever of what gravity REALLY IS, this is, of course, pure "magic."

You might claim, for example, that the IC subsystem actually taps into the same "gravity generator turbines" as the AG system does, but redirects it in different ways. Again, I like dedicated systems... redundancy... all those things that make for a higher safety factor. But there's no "real science" reason not to do it as you envision, is there?

Of course, there is one other thing I treat as a "constant" (albeit this is my own conceit, and lots of folks dont buy into this).

I have adopted the idea (supported by DS9's pilot, at least two episodes of TNG, and the like) that a "subspace field" can reduce the "apparent mass" of an object and allow it to be accelerated to "ludicrous speed" through the use of conventional thrust based propulsion.

So... if the Enterprise has a nearly perpetual subspace field in place... the need for "anti-acceleration" systems during thrust is dramatically reduced as well. Yes, the ship may be accelerating very quickly in relationship to "real space," it is accelerating, from its own frame of reference, much more slowly.

In other words, the same concept that I've adopted from those episodes, and various TOS episodes, to permit "Faster than light impulse" also serves, in a sense, the very purpose you were suggesting.

 

[Timo]

The overlapping existence of AG, IDF and SIF does undermine one argument for zero-gee Jeffries tubes - namely, that zero-gee would save power. Since every part of the ship has to be zealously guarded against inertial and other forces anyway, the savings would probably be minimal.

I actually worked it out, and the "chair lift" concept works the best.

Is a physical lift really needed? It would tend to get in the way if one needs to move bulky equipment... The space available would probably be better utilized if the tube were simply provided with a gentle gravitic pull up, and a parallel tube with a similarly gentle pull down, plus "boundary layer" effects to prevent bumps. One could send personnel, warp coil segments and individual spanners up and down with great ease that way.

OTOH, if the run includes "stops of interest", say, pieces of important machinery every ten meters along the pylon, then it might be useful to send a "work platform" up the shaft to provide a single, always optimally placed stable foothold.

Timo Saloniemi

 

[Ghrakh]

^Saucer separation only had to be filmed once and then recycled again and again (even then it was very rarely used). Try doing that with live people in "0g".

they wouldn't have to have jefferies-tube sequences often

Except for the fact that in over 20 seasons of the show they did have a relatively high number of scenes in Jefferies tubes. So no, from a filming standpoint; not financially practical.

Yeah, if jefferies-tube 0g sequences were too expensive then there would have been less them.

Well, the ISS doesn't seem to have this problem.

It does; it gets away with it because it's so small and well stocked in ventilation systems.

A big difference is that a large portion of the jefferies-tube network, at least from what I've seen on screen and inferred, is surrounded on all sides by conditioned spaces. So there's no heat gain or loss from the exterior imposed on it. Also I would assume a starship, being built in orbit, is not as concerned with economy of mass, and its shell would be a whole lot more substantial and insulated that the comparatively flimsy ISS.

 

[CorporalCaptain]

There is not space for a conventional turbolift to go up the pylon. And by the way, my pylons aren't 100% accurate right now... since creating my model, I discovered, to my great surprise, the the nacelle leading and trailing edges are not rectangular at all, but are in fact "full rounds" (though the DIMENSIONS I have are correct).

No, there's insufficient space for a standard turbolift car. However, that's not an indication that there is not room for a "specialized lift" in those. I actually worked it out, and the "chair lift" concept works the best. It's a three-man "bench seat" which slides up or down the incline. It's not an enclosed car, either... because it's used for service access at various points along the length of the pylon as well as access to the two termini.
___________

IF we proceed from your assumptions, you'd be entirely correct. However, I don't proceed from those assumptions. I believe that artificial gravity, anti-acceleration systems, and the SIF are totally independent systems.

There is NOTHING to make us believe that SIF is related to anything else. SIF is basically a "force field" of additional mechanical structure, as defined in TNG-era shows.

But you could argue that both AG and Intertial comps are both "acceleration-related" and thus are a common system. I disagree, but that's not something that's really provable either way.

We have only one significant example of loss of gravity on a starship... that being on "Enterprise" (during Captain Archer's shower).

I, personally, treat these as entirely separate systems, though perhaps based upon similar technology. (You could think of them as "nested" systems, I suppose, or "layered" might be a better term?)

Artificial gravity is always-on, and is designed to be very stable. I like the TNG-TM explanation of AG, where they describe it as generated by an ultra-high-speed rotor... the thing takes days to "spin up" to full speed, and even if power is cut, takes almost as long to spin down again (which explains why you can lose power and not float off the deck in Trek!). There are multiple grav generators, and a series of "Gravity waveguides" which distribute this uniformly through areas which require gravity (explaining how you can shut off gravity or alter it in various locations while still being consistent with the above).

But the inertial-compensation system isn't a steady-state system, but is rather an "impulse-based negative feedback" system, with a very, very fast response time.

Of course... both would be based upon the same "magic science," most likely.. . since in real life we have no conception whatsoever of what gravity REALLY IS, this is, of course, pure "magic."

You might claim, for example, that the IC subsystem actually taps into the same "gravity generator turbines" as the AG system does, but redirects it in different ways. Again, I like dedicated systems... redundancy... all those things that make for a higher safety factor. But there's no "real science" reason not to do it as you envision, is there?

Of course, there is one other thing I treat as a "constant" (albeit this is my own conceit, and lots of folks dont buy into this).

I have adopted the idea (supported by DS9's pilot, at least two episodes of TNG, and the like) that a "subspace field" can reduce the "apparent mass" of an object and allow it to be accelerated to "ludicrous speed" through the use of conventional thrust based propulsion.

So... if the Enterprise has a nearly perpetual subspace field in place... the need for "anti-acceleration" systems during thrust is dramatically reduced as well. Yes, the ship may be accelerating very quickly in relationship to "real space," it is accelerating, from its own frame of reference, much more slowly.

In other words, the same concept that I've adopted from those episodes, and various TOS episodes, to permit "Faster than light impulse" also serves, in a sense, the very purpose you were suggesting.

All good points, thanks for the detailed treatment.

 

[sojourner]

Except for the fact that in over 20 seasons of the show they did have a relatively high number of scenes in Jefferies tubes. So no, from a filming standpoint; not financially practical.

Yeah, if jefferies-tube 0g sequences were too expensive then there would have been less them.

You can't get less than 0. Or did I miss something? All of the Jefferies tube scenes I recall were filmed as if in 1g (because they were).

 

[Ghrakh]

^^ Look, even though this thread was specifically posted in the "trek tech" forum (you know, where people are given an opportunity to speculate about the science and mechanics of ST) and I did mention in the OP that I was interested in an "in-universe" discussion, you seem to want to ignore that. So OK, you win.

 

[sojourner]

For this aspect of trek you do have to take in filming constraints to a certain point because there is no satisfactory reason "in universe". Me personally, I would have both. make them 0g while moving through them, but turn on gravity at the section where you need to work as needed. If we are going to portray the artificial gravity as having as fine a control as it does, we might as well do cool things like that.

 

[Cary L. Brown]

Well, since we're talking about what's on-screen as "representative" rather than "gospel," this might bring into the conversation an interesting point.

You've all likely noticed, in TOS, that the Jefferies tube had stair-steps for the first several feet, but then become flat-bottomed (not every time, but most of the time).

In-studio, I presume that this is because they started laying the tube down to be able to shoot down it's length.. or at least they made it this way to permit Doohan to not get a series of painful lateral welts on his back from laying against the steps?

But "in universe," perhaps this "really" means that, at that point in the tube, you no longer have gravity?

 

[tighr]

RE: nacelles/pylons, in TNG's Eye of the Beholder, we see a crewman commit suicide by jumping into the plasma stream of one of the Enterprise-D's nacelles. Troi nearly did as well. Wouldn't be possible if the area was in zero-G.

 

[Cary L. Brown]

RE: nacelles/pylons, in TNG's Eye of the Beholder, we see a crewman commit suicide by jumping into the plasma stream of one of the Enterprise-D's nacelles. Troi nearly did as well. Wouldn't be possible if the area was in zero-G.

Of course, nobody in this conversation has said that there cannot be gravity in either location, have they?

Clearly, at that point, that part of the nacelle had gravity.

But is that room manned at all times?

Is there gravity anywhere in the nacelle except in that monitor room?

The answer, of course, is "we don't know."

But if there's still a reason for the nacelles to be remote in TNG times, and if that reason continues to be "safety," then it's safe to assume that when the ship is traveling at warp, the nacelle would not be manned. And that if it's not manned, there would be no reason to maintain gravity, or other environmental controls at that point. You'd only turn these services on when you need them, and leave them off when you didn't, in other words.

Is there any indication that the nacelle monitoring room is a fully-time, permanently-manned facility? For that matter, is there any indication that there is any way to access the nacelles except through the little docking port at the aft underside? How do we know that the folks in the nacelle at that point didn't have to be shuttled there by the 24th-century equivalent of a TMP "Travel pod?"

 

[Mr. Laser Beam]

The sets used for filming Jeffries tubes are so small that there'd be barely any special filming requirements for simulating 0G. Wouldn't be much more than in 2001 with the 'grip shoes'. There'd be barely any room for the characters to float to, so very little floating would be shown.

 

[sojourner]

Sigh, and yet, with over 20 seasons of episodes in the can, they never did portray it as 0g.

 

[Ghrakh]

The sets used for filming Jeffries tubes are so small that there'd be barely any special filming requirements for simulating 0G. Wouldn't be much more than in 2001 with the 'grip shoes'. There'd be barely any room for the characters to float to, so very little floating would be shown.

Yes agreed. It wouldn't need to be elaborate, just use some basic editing tricks, maybe a few instances of wire work, but mostly use camera angles and have the cast simulate a 0g environment through animated movement. In the original Star Wars when Luke and Han went to the Falcon's gun turrets, there's this neat trick where the gravity appears to change orientation. They didn't float or anything, it was a simple edit and use of camera angles. I thought it was a cool touch that put a bit of "realism" in, and visually it did the job.

Something like EVA scenes weren't shown in TOS and TNG (as I recall), not sure about DS9 or VOY but they did do at least one in ENT. Even then it was mostly the actors animated movements that carried it. EVA sequences would need a more expansive set for one thing so the writers simply didn't put them into the scripts often, but that doesn't mean EVAs never (or very rarely) happened.

 

[CorporalCaptain]

I can see it now.

If they had tried to make the tubes 0g, and shown a few floating tools every now and then, then the tech fans would be arguing back and forth about which in-universe explanations were the right ones for why a certain object stuck to the side of the tube in a certain episode, when the real explanation was that the production got sloppy, or simply overlooked something, or just let it slide when crunched for time.

"One can infer that the back of this doo-whicky is magnetic."
"But why did it float around in Episode 13?"
"OK one can infer that the magnet can be switched on and off."

Yes, I can see it now.

 

[Ghrakh]

^so, same as what fans do now?

And do let me know of any advantages of 1g cramped tubes on a starship that has to create that gravity in the first place. Anytime I go into my attic or under the floor boards to do something with the plumbing or wiring, crawling through with tools and supplies, working awkwardly on something overhead or in a tight corner, I always wish I could turn the gravity off. Sadly, my wish goes unfulfilled.

 

[tighr]

Something like EVA scenes weren't shown in TOS and TNG (as I recall), not sure about DS9 or VOY but they did do at least one in ENT. Even then it was mostly the actors animated movements that carried it. EVA sequences would need a more expansive set for one thing so the writers simply didn't put them into the scripts often, but that doesn't mean EVAs never (or very rarely) happened.

We see variable gravity in the Enterprise pilot (the "sweet spot" on the ship, where gravity plating doesn't reach). The Voyager episode, Day of Honor, featured Tom and B'Elanna stuck in EV suits for nearly half the episode, floating in space after their shuttlecraft exploded. If I recall, the producers said it was quite expensive and time consuming to film, because the two had to be suspended from wires on a bluescreen for all their scenes.

That doesn't mean it wouldn't be easy to come up with a way to simulate 0g in Jeffries tubes, however. It could probably be done with camera tricks quite easily.

The best way (though not the cheapest, probably) would be to build a dedicated Jeffries tube set vertically. Actors would be filmed dropping down through the set suspended by a wire harness, similar to what was done in the film Inception. The camera would then be oriented so it appeared as if the set was horizontal, not vertical. If the set was dedicated, then every time they used it they would get back some of their investment.

Of course, if we lose the 1g tubes that we see so frequently, then things like chases through the tubes and climbing the ladders would lose a lot of their dramatic flair. It would also take away a little bit of the drama from being stuck in turbolifts (turbolift malfunction? open the ceiling hatch and float away safely!)

 

[CorporalCaptain]

^so, same as what fans do now?

And do let me know of any advantages of 1g cramped tubes on a starship that has to create that gravity in the first place. Anytime I go into my attic or under the floor boards to do something with the plumbing or wiring, crawling through with tools and supplies, working awkwardly on something overhead or in a tight corner, I always wish I could turn the gravity off. Sadly, my wish goes unfulfilled.

Yes, same as what fans do now.

It's really hard to comment on what might be advantageous if one doesn't know the in-universe principles behind why something would be the way it is. Some authors would say that gravity can be controlled arbitrarily; others would say that edge effects are important and arbitrary control of the ship's gravity just isn't possible. I think CLB's explanation makes pretty good sense because he doesn't assume arbitrary control of gravity; the tubes just protrude out of the influence of the ship's main field further and further. Me, I would have the drop off of influence be gradual, because from engineering in real life I know that edge effects are real problems. But it's also good that he acknowledges that what I proposed about the interrelationship between inertial dampening and artificial gravity could also be plausible. Perhaps it's just simpler from an engineering perspective to give the whole ship a uniform down under artificial gravity. We just don't know enough/can't know enough really to say.

By the way, it seems that Orci et al. are really leaning towards the uniform artificial gravity over the entire ship in the JJverse, given the reputed rationale for why the ships are constructed on the surface of the Earth.

 

[Timo]

Of course, if we lose the 1g tubes that we see so frequently, then things like chases through the tubes and climbing the ladders would lose a lot of their dramatic flair.

To the contrary, I'd think zero-gee chases would be the scifi equivalent of car chases if not for the expenses of filming such!

They might lose one sort of flair or flavor, but would certainly possess another. It's a bit strange this hasn't been done already to a greater extent...

Timo Saloniemi

 

[Deks]

in Voyager, When the ship was docked with the Varro vessel, one of the Varro boarded the ship and hid inside the Jeffries tube.
Tuvok said that life support was routed to a specific tube (where the escapee Varro was).
This implies that at the very least, some Jeffries tubes don't have life-support on, but I'd venture a guess that artificial gravity is not part of that system.
To that end, running the gravity is probably very low on the power curve compared to air/heating (which would probably constitute 'life support' and was touted to usually be energy demanding).

 

[Cary L. Brown]

You'd probably have issues with air and heat flow inside a gravity free area. RE: Apollo 13

Well, the ISS doesn't seem to have this problem. Neither did Apollo 11 or 12 for that matter, so that's already not an issue.

Yeah... setting up this sort of system is actually easier when not dealing with gravity. But the solution is different for either situation, and the solutions are not necessarily compatible.

Why not? Well, think of natural convection... of the fact that warm air is less dense than cool air... and thus that "hot air rises." Remove gravity, and this is no longer an issue.

This means that you don't need to defeat this (like you do, today, in two-story houses, for example) but that you need to provide more hardware to ensure airflow (since this natural convection isn't working for you at all)

The obvious answer? It was cheaper to film than simulating 0g.

Saucer separation wasn't a cheap effect to film either. And it doesn't have to look like a NASA 0G video feed, but simply implied.

You mean sort of like how they did it in "2010," where everyone was clearly in full gravity all the time, but they inferred zero-G with a "floating pen" shot at one point?