Impulse Engines: Newtonian Physics or Non-Newtonian?

[Albertese]

So, here's the deal:

Trek impulse engines have been debatably "rockets" or "mini-warp drives" for some time. This topic evidently came near to derailing Cary L. Brown's super cool TOS Enterprise interiors project. Which can be found here:

http://www.trekbbs.com/showthread.php?t=89810

Here is where this technical debate began:

http://www.trekbbs.com/showthread.php?t=89810&page=8 (scroll down to post #145)

If you havn't been following this, I highly recommend it. It's an art project to be sure, but it's the techy sorta art we love.

Anyway, CLB argues that the very term "impulse engine" is so rooted in actual science that having it be anything but a physical drive system is patently ridiculous. He argues that to call a non-Newtonian field drive device (related to a warp engine) an impulse engine is akin to calling a sink's faucet a light-switch. While this is an interesting hyperbole, I don't think it's fair.

To my mind, there is a wider usage to the word "impulse" than the strictest science text definition. I point out that one common usage in our times is that of nerve impulses to the brain, which consist of very brief, relatively low voltage pulses. I posit that impulse engines are a field device, not unlike a warp engine in theory, but instead of being fed a very high voltage continuous stream of power, they are powered by an intermittent power feed of dramatically lower voltage.

Is that totally unreasonable? Now, this discussion started with Matt Jefferies' ship in mind, but citing examples from the later shows would be admissible.

Discuss!

--Alex

 

[JNG]

I think they were intended to be primarily physical drive systems, but even in TOS we see evidence of warp and impulse drive acting together in certain ways, which along with the terminology suggests that there is a bit more to it. As with "warp engines," the term incorporates both the fusion reactor power systems and the sublight propulsion mechanism of the ship. Ultimately, I think the term "impulse" refers to a hybrid system wherein fusion reactors drive an accelerated exhaust product system to provide thrust, but also interact with subspace fields that reduce the relative mass and possibly have some impact on relativistic effects; I also suspect there is a gravitic field-effect component that may aid in accelerations counter to the primary flight direction. The term would stand for a lot, but I think this may be just why they use it and not something more specific.

 

[TIN_MAN]

Anybody familiar with Tesla technology, or T.T. Brown's "Gravitors"? These men both refered to "impulse" technology that utilised the unified field relationship of electricity to gravity, which resulted in a "longitudinal" shock wave in the fabric of space-time itself whenever a sudden, high voltage discharge is created?

 

[Myasishchev]

I once did some math that showed that the impulse speeds often stated (maybe not onscreen but I'm unsure), powered by fusion, and presuming a magical 100% efficiency, would require a fuel density roughly that of a neutron star.

The short of it is, I do still think it's a Newtonian device, but the velocities attained are much more modest than we think. More like several tens or hundreds of kilometers per second, as opposed to 300,000.

If it isn't a fancy rocket engine, there just doesn't seem to be a need for it--if you're using warp drive to go places even at impulse, why not just, you know, use the warp drive?

 

[Praetor]

I personally think the original engines were meant to be Newtonian. ("Impulse rockets" and all.) However, I don't have a problem with this grandfathering the term in for later, more advanced and even fundamentally different sublight engines.

I draw the line at hyper-impulse though. That just sounds stupid.

 

[Cary L. Brown]

Well, I'd like to thank Albertese for bringing that discussion here.

His description of my take on this system isn't 100% accurate, but that's largely because I really didn't go fully into my own perspective on what this is, in that forum.

Some of you have seen this before, so feel free to skip ahead. For those who haven't, though... here's how I see "impulse" in Trekkian terms. Some of this is directly supported with on-screen evidence (from various series), and some is purely conjectural.

Here are a few "iffy" factoids from Trek:

1) The first ship with Warp Drive was the Bonaventure. However, it's pretty obvious that this ship couldn't have been the first FTL space vessel... considering that the Bonaventure made it as far out from Earth as the "Delta Triangle," and without SOME form of FTL drive, you can't even practically navigate in-system.

2) The Romulans fought the Earth-Romulan war with ships "powered by simple impulse."

3) We've been told that TOS shuttlecraft are impulse-only, yet they can navigate interstellar distances (say, to research a quasar, or to carry a Federation commissioner, or to pursue the Enterprise away from a starbase).

A few other bits that are very interesting...

1) We're told by Jose Tyler that "you won't believe how fast you can get back (from Talos)... " which clearly infers that there was SOME sort of propulsion breakthrough between the time of "The Cage" and the time that Vina's spacecraft crashed.

2) The Enterprise, with inoperable warp drive, is able to fly from the Galactic Barrier to an already-settled star system (Delta Vega... the TOS version, not the nonsensical '09 "able to see Vulcan from here" version) before the crew dies of old age.

But, of course, it's also well-established that impulse engines are thrust-based... not only by virtue of the literal meaning of the words, but also by virtue of how it's established in the TNG Tech Manual.

SO... how do you reconcile all of that? For me... the way to do that is to make it a hybrid system.

Up until, say, 50 years prior to TOS, there was no such thing as "warp drive." But there was still FTL travel.

The way this worked was to create a "subspace bubble" around the ship. We've seen that, in Trek, a "subspace field" both increases the local speed of light (relative to the "real universe") and decreases the observed mass (relative to the "real universe" again) of anything in it. We see the "reduced mass" used in TNG and in DS9 (and maybe in VOY too, though I never really watched that show). And we know that the optical computers on the 1701-D were faster than light, due to the use of a local subspace field inside the computer.

So, I'm saying that Zephram Cochran invented the space warp... aka the "static subspace bubble." This allows the vessel to use regular, Newtonian propulsion systems, and yet accelerate FAR faster than it could without that "field assist." It's still using thrust, however, to do this.

Suppose, for instance, that "inside the bubble" the observable mass of the ship is 1/1000 of it's "real" mass. That means that for a given thrust, you can accelerate 1000 times faster. And with that "decreased observable mass" you also get decreased inertial effects inside the bubble, too... meaning that you don't smear the crew against the bulkheads during acceleration.

And since the "local speed of light" inside that bubble is faster, you're still limited by relativistic effect but those effects don't really start kicking in until well past "real C"... my (semi-arbitrarily-determined) value was 75C, or approximately WF4.2 on the old scale.

At some point... very likely due to a malfunction (that's how these things often happen!) someone had their "static subspace bubble"... or "space warp"... go out of form. The result was that the fabric of space/time "pushed on it" in a way... attempting to correct the imbalance... and the result was a purely non-Newtonian "surfing on subspace" effect, where you've effectively created your own "pocket universe" within which you're not moving at all... but your "pocket universe" is moving relative to the "real" universe. This was originally called the "time warp drive" and later just "warp drive" as it became better-understood.

The Bonaventure was the first ship to get this, launched around the time that Vina was crashing. By the time of "The Cage," this had become pretty common, but was still not universally-used.

When the Enterprise was crippled by the barrier, they lost their ability to create a "warp effect" but not to create a "static subspace bubble." So, they used this "legacy" propulsion system... which IS Newtonian, but is "subspace-assisted thrust," remember... to get to Delta Vega.

Kirk and the illusory Mendez pursued Enterprise at about WF4.2 in their impulse-only shuttlecraft.

The Romulans fought the war at a max speed of WF4.2, too... as did Earth.

You'd be able to generate enough power to energize a "static subspace bubble" using fusion reactors... but you need a lot more power to create the "warped subspace bubble" that gives you warp drive.

By the time of TNG, you'd had another major breakthrough (no more "bubble," but rather an open "flow" of subspace ripples... and hence a different scale, but also massive space/time damage). By the TNG-era flicks... I'm guessing something else has changed as well, and the TNG-era concept has largely been scrapped (I'd love to see them go back to the classic WF scale!)

SO... to sum up... "impulse" is Newtonian in nature. But by adding in that static subspace field, you can use it to travel FTL as well.

With the TOS Enterprise, the saucer would not have its own integral SSF generator, and would be dependent on the nacelles. But the 1701-D has integral SSF generators right there with the impulse engines, which allows it to travel at up to WF4.2 (old scale... dunno where 75C falls on the "new scale") on its own, or to "maintain" a handed-off warp-inertial effect as well.

That pretty much sums up my perspective. Impulse is thrust... but it needs a boost to really be useful in "Trekkian" terms.

 

[Praetor]

FWIW, I like that scheme, Cary. It helps solve a lot of the "we're at impulse but still inexplicably going FTL" shenanigans and the argument about the nature of "impulse power," and generally a lot of perpetually annoying inconsistencies.

 

[Myasishchev]

I could buy that, say, the E-D saucer section has some warp coils powered by fusion reactors. We know that fusion can propel FTL from Balance of Terror and (by almost sure inference) First Contact. And deflector shields, surely installed in the saucer, appear, more or less, to be based on the same spacetime warp principles of its propulsive counterpart. This of course applies equally to impulse-powered (but not lightspeed-limited) shuttles...

I've never liked the reduced-mass concept of warp, however. Too many questions are raised: 1)where does the mass go, 2)why is this a side effect of a space-distorting field, and 3) does this not screw with stuff like electrons and the strong force, since reducing the mass of a physical system is also reducing its energy? Also, a prospective question 4 is avoided by Cary's explanation, but I'd point out that even massless particles have a speed a limit.

When it's directly referenced in the series I prefer to think of it as a metaphor. "We can (effectively) reduce the station's mass with the deflector shields."

 

[Timo]

The first ship with Warp Drive was the Bonaventure.

To be more exact, she was the first "to have warp drive installed", which may be a crucial distinction.

OTOH, we could just as well speculate that the name Bonaventure is a historically significant one in the Trek universe, and that there is a long line of ships by that name. And it just happens that the ship that was spotted in the Delta Triangle otherspace was the first Bonaventure with a warp drive installed. Not the first ship with warp, only the first Bonaventure.

Remember Scotty's full wording:

Scotty: "Captain, there's the old Bonaventure. She was the first ship to have warp drive installed. She vanished without a trace on her third voyage."

A possible interpretation: "Captain, that's the old Bonadventure, not the current one which is also pretty famous. You know, the first Bonaventure to have warp drive installed. The one that vanished."...

The Romulans fought the Earth-Romulan war with ships "powered by simple impulse."

Not really. They fought NCC-1701 with a ship "powered by simple impulse". Nothing was stated about how they fought the old war, beyond the weaponry used ("atomic", whatever that means - today, it would refer to chemical weapons).

We've been told that TOS shuttlecraft are impulse-only.

Uh, never. There's no episode, even animated, that would make this claim.

We're told by Jose Tyler that "you won't believe how fast you can get back (from Talos)... " which clearly infers that there was SOME sort of propulsion breakthrough between the time of "The Cage" and the time that Vina's spacecraft crashed.

As long as I'm nitpicking, I might also postulate that the ability to get to Earth from Talos IV faster was not due to faster ships - but to better protected ships, ships that could utilize a dangerous shortcut. That is, they could break through the feared Tyme Barrier instead of taking the long route around it.

The Enterprise, with inoperable warp drive, is able to fly from the Galactic Barrier to an already-settled star system (Delta Vega... the TOS version, not the nonsensical '09 "able to see Vulcan from here" version) before the crew dies of old age.

More specifically, the distance spanned is explicated in the episode: "a few light days". And extreme relativistic speeds probably aren't involved, because the backstories of the characters suggest that they aged at roughly the same rate as loved ones left behind.

Timo Saloniemi

 

[JNG]

The mass reduction is outlined as a sort of side effect in the TNG Technical Manual, but it is not the principle on which warp operates. There was a cadre of fans for a long time on rec.arts.startrek.tech pushing the idea that the fields reduced the mass of the ship to zero so it could go any speed, but there are a number of reasons this would not work and it is not supported by the shows very well anyway.

 

[Santaman]

There is no way that the impulse engines are newtonian, first of all there is almost no ship with the exhausts in the right place, some haven't even got an exhaust like the Nebula and the D'Deridex class Warbird, also the way the ships move at impulse speed is way beyond whats possible with a newtonian device, last but not least, inpulse vectoring and all is neat but not if you have things like saucer sections and nacelles in the way and don't even get me started on Ent-B and E who have the exhausts aimed t nacelles and/or their pylons, one quick acceleration and they will be blown off, remember that Scotty stated that impulse engines had about the power of 1000 atom bombs (TMP novel), you so don 't want to aim that on parts of your ship. however, sending all that neat raw power into specialised coils would make sense, well at least to me.

My 2 Euro cents adjested for 1979 inflation.

 

[Cary L. Brown]

The mass reduction is outlined as a sort of side effect in the TNG Technical Manual, but it is not the principle on which warp operates. There was a cadre of fans for a long time on rec.arts.startrek.tech pushing the idea that the fields reduced the mass of the ship to zero so it could go any speed, but there are a number of reasons this would not work and it is not supported by the shows very well anyway.

It's not the principle upon which "warp" is based, in my proposition, either.

And it's not that the "mass" is actually changed... but rather the "projected mass." Think of it this way... the subspace bubble (or "space warp") is, essentially, another "pocket" universe, but not independent from "real" space/time. Anything in its own little "pocket universe" of subspace still projects a mass-shadow into real space-time... but not a full shadow, just a partial one.

INSIDE the bubble, you still have all your original mass... it's not that you're losing it. It's just that, relative to the rest of the real universe, you appear smaller.

And this isn't how "warp drive" is supposed to work according to my supposition, anyway... it's just how "FTL impulse" would work (or half of it, anyway).

(And you can never go to "zero projected mass" unless you totally disappear from the real universe, so you don't have a mass-shadow at all. This, to me, would mean that you've probably transitioned yourself entirely out of this universe and would be lost forever.)

There is no way that the impulse engines are newtonian, first of all there is almost no ship with the exhausts in the right place,

Not true. The TOS 1701's exhausts, for example... why would you say that they're in "the wrong place?" We only know that they have to be able to fire in a vector passing through the center-of-mass of the ship.

Well, first off... we don't really KNOW how the TOS Enterprise's mass is distributed. If you recognize that the two nacelles, together, take up a bit more volume than the secondary hull does... and that they're probably quite a bit more dense... there's nothing to infer that the impulse exhausts aren't actually passing directly through the center-of-mass when the ship is flying straight ahead.

And even if you disregard that... well... look at the TOS opening credits. The ship, in those scenes, is flying a bit "nose down." Maybe its doing that to compensate, so that the thrust-vector is through the center-of-mass? It's easy to handle.

The 1701-D, on the other hand, is nearly PERFECTLY designed in this regard. The impulse port on the secondary hull operates through where Probert assumed that the center-of-mass of that hull would be... the two on the primary hull do likewise for that hull... and by altering the total output of all three, when combined, you can easily have a vector passing through the combined ship's center-of-mass.

DS9's Defiant? Regardless of which location you accept ("red circles" or "hidden on the trailing edge") it works just fine.

Excelsior? We don't really know enough about the internal configuration of that ship for any of that to make sense... maybe there's a tertiary engine in the little alcove on the underside secondary hull, so that the 2000 has three inpulse systems, not just the two we know of?

Reliant? Well... it works if you don't mind flying "nose up" slightly.

Voyager? Dubious... but most everything about that design is dubious to me.

Most ships in actual filmed Trek can work. The real problems crop up with fan works.

some haven't even got an exhaust like the Nebula and the D'Deridex class Warbird,

Are you sure that the nebula doesn't? I'd have sworn that they kept the "saucer engines" and seem to recall a third engine on the trailing edge of the "central tower" piece between the pod and the underslung hull. And as for the D'Deridex, there are plenty of details on that ship which might be where the impulse engines are. Maybe on the aft ends of the nacelles? (impulse-on-nacelle is something which was used by Vulcans... see TMP... so why not Romulans?). All we know is that we never saw "glowy red squares" on that ship. But I HATE "glowy red squares" as some sort of visual cue for "impulse engines... I see that as "kindergarten thinking."

also the way the ships move at impulse speed is way beyond whats possible with a newtonian device,

In what way? Other than "accelerating faster than seems practical" (which I've already addressed, above)... everything else is entirely patterned on "flying" concepts... including tons of on-screen evidence.

last but not least, inpulse vectoring and all is neat but not if you have things like saucer sections and nacelles in the way

At what point did a "saucer section" get in the way of impulse engines?

and don't even get me started on Ent-B and E who have the exhausts aimed t nacelles and/or their pylons, one quick acceleration and they will be blown off,

I DO have problems with the "refit Excelsior" and, to a smaller extent, the Sovereign, on the nacelle issue... but the original designer of the Sovereign wanted those to be landing bays, and the impulse engine to be in the middle... Berman dictated that it be changed, because it would "look cooler" or some such nonsense. And to this day, I refuse to accept that the big "warehouse engines" on the Excelsior refit are engines... I think they're just hangar bays with red lights shining on the doors.

remember that Scotty stated that impulse engines had about the power of 1000 atom bombs (TMP novel), you so don 't want to aim that on parts of your ship. however, sending all that neat raw power into specialised coils would make sense, well at least to me.

My 2 Euro cents adjested for 1979 inflation.

But... if you have that much power being driven into "coils" you're still dealing with every bit as much power, and in that case, it's being exerted inside the hull...

I think we all get that some people like "magic" solutions better than "real" ones. Because "magic" can do anything we want, without actually having to make sense. The "coils" sounds really cool... except that we're talking about "magic," nothing more. Saying it's a "coil" is no more or less practical and logical than, say, saying it's a big vat filled with boiling "eye of newt and tongue of frog." Not unless you're talking about electromagnetism, or something very analogous to electromagnetism, and not unless you know what the nature (and interaction with nature) of the resultant field really is.

I have no fundamental problem with there being Trek-universe cultures which use field-drive sublight propulsion systems. But those systems would not be "impulse."

The real problem is that Trek fans have created a false connection between words. "Impulse" means "secondary drive" or "sublight drive" all the time, and "warp" means "faster-than-light" drive, all the time. But this isn't reasonable or true.

Rather...accept that (unassisted) impulse is one possible form of sublight drive, and that warp is another possible form of FTL drive, but that there can be many forms of FTL or sublight propulsion which are NOT "warp" or "impulse."

Hell, we've seen many "non-warp" FTL drive systems throughout the runs of all of the TNG-era series... not just "warp drive." Haven't we?

Maybe we should just use those terms... "sublight drive" and "faster-than-light drive" in the future?

 

[Ronald Held]

It cannot be Newtonian at the rates they accelerate/decelerate. Maybe a small part is Newtonian for the fusion exhaust, but the vast majority has to be a field drive

 

[Santaman]

If you want to reduce speed with the impulse engines then about the whole saucer section is in the way and partially the neck as well.

Probert actually admitted that he forgot to create impulse engines for the D'Deridex.

Nebula's have no impulse engines, they don't have the saucer engines Ent D's saucer has.

http://www.ex-astris-scientia.org/scans/nebula1.htm

Now something that bothers me about the mass reduction thingy, well yes, you can do that but you will reduce the mass of your exhaust product as well so it will still do nothing.

As for the rest, the impulse deflection crystal on TMP era ships, those vessels are stated to be capable of using warp drive plasma, and thats not something you want to vent into space since you kinda need it to transfer energy from the warp core to the nacelles.

Another thing that bothers me is that some people assume that nacelles are incredibly heavy, we've had quite a few discussions about that IMO the reason to say that the TOS Enterprise has massive nacelles is because of their size relative to the rest of the ship and not that they're made of something ultra dense.

And then there's Roddenberry, he didn't want anything rocket-ish on the show and indeed we never saw any starship have an exhaust trail, not even the Ent D when it used its main impulse engine in "Booby trap" (the ep with the Promellian battlecruiser) it just glowed (just like the warp engines when they do something.)

So I still believe that the exhaust port thats fitted on the back of the saucer of the TOS E is for getting rid of the heat and waste fusion product from the fusion reactors.

But again, just my own opinion.

 

[Herkimer Jitty]

 

[JNG]

^

Yes, those are the impulse engines of the Nebula. Clearly, the size of the "exhausts" is not directly proportional to, well, anything in particular. The Nebula was originally intended to be smaller in scale than the Galaxy, making for some lil' impulse engines.

Re: the D'deridex not having large, obvious impulse engines, I find that this kinda makes sense for a ship on such an enormous scale that is intended to operate under cloak much of the time. To aid in concealment, exhaust products are probably temporarily stored and released through some secondary system, as they supposedly are on the Defiant.

As for "assuming" that nacelles are massive, I read it in the Technical Manuals and the Voyager Writer's Technical Guide, and would have been likely to assume the warp coils were made of some dense material anyway; I don't recall an episode where they directly commented on this characteristic of the warp coils, though.

 

[Praetor]

I queried Mr. Probert on where the D'Deridex impulse engines might be, and he suggested they are vertically in the tail. Works for me. The original BoP didn't even have visible traditional impulse engines either. Must be a Romulan thing, presumably, as JNG suggests, to do with emissions conflicting with the cloak.

 

[Myasishchev]

^Something those silly Klingons forgot in Star Trek VI.

 

[Praetor]

Which is why they blew up.

 

[Crazy Eddie]

Now something that bothers me about the mass reduction thingy, well yes, you can do that but you will reduce the mass of your exhaust product as well so it will still do nothing.

As described, for conservation of matter/energy requirements, the field would have to balance the reduced mass of the ship by increasing the mass of the exhaust products. Call this "subspace polarity," where the negative (mass reducing) charge is distributed throughout the ship and the positive (mass increasing) charge is concentrated in the impulse engine's exhaust nozzle. furthermore, since this is an otherwise symmetric warp field, it remains the case that the driver coils themselves provide no propulsive energy and require from the action-reaction thrust from the exhaust plume as it leaves the ship.

This is hardly a non-newtonian drive system. Actually it's a kind of magneto-plasmadynamic thruster, except the field it generates is subspace as opposed to electromagnetic.

As for the rest, the impulse deflection crystal on TMP era ships, those vessels are stated to be capable of using warp drive plasma, and thats not something you want to vent into space since you kinda need it to transfer energy from the warp core to the nacelles.

At the time, the drive plasma was a product of the reactor; the warp engines vented it too whenever they were active.

Another thing that bothers me is that some people assume that nacelles are incredibly heavy

It's not exactly unjustified. A device that has to bend the very fabric of space in order to function normally is probably designed to handle alot of artificially produced gravitons; that the warp engines are extremely heavy may well be a consequence of their function.

And then there's Roddenberry, he didn't want anything rocket-ish on the show

Heh... I'm sure someone else will/has covered this in a minute, but just to be a jerk I'll say

"Engineering, switch to rockets we're blasting out!"

and indeed we never saw any starship have an exhaust trail

Real space craft in a vacuum don't have exhaust trails.