Impulse Drive: What do we know? (Non-canon speculation)

[AriesIV]

Ok I am writing an origin story for "impulse drive."

Some sources (a novel?) indicate that IMpulse means Internally Metered Pulse Drive and that there is a gravetic-wave component to the drive... it's not a rocket at all.

The more official sources indicate that it is a "juiced" rocket that accelerates it's exhaust to extreme velocity via accelerators and that there is some kind of mass-reducing "subspace driver coil" involved in adjusting the apparent mass of the ship.


What else do we know either from written sources or what we saw on screen?

I want to take what has come before and devise a "how it works" then extrapolate backwards to how it may have been developed and test-flighted "back in the day."

 

[C.E. Evans]

I tend to think that a ship can achieve warp speed with impulse power, but it's not as efficient or as powerful as a matter/antimatter reactor and is more ideal for sublight voyages by Federation starships. But Cochrane's Phoenix may have relied on an impulse-type engine on his first warp flight, IMO.

 

[AriesIV]

I think the key to ANY form of star-trek propulsion is "subspace-magic mass reduction."


Without giving too much away I think the "mass reduction/exhaust acceleration" research that lead to the impulse drive lead to the invention of warp-drive 5-10 years later.


But that is speculation. I am looking for "facts" from various sources first.

 

[Crazy Eddie]

^ There aren't any, other than the basic timeline of engine development and I do mean BASIC.

We know that impulse engines were used on NX-01, and we assume that slightly better ones existed on NCC-1701. We know that between the 23rd and 24th century impulse engines haven't changed much, and we know impulse engines leave an ion trail that can be tracked after the ship passes.

Beyond that, we know basically nothing, just speculation from a dozen different sources, most of which contradict. At some point you're better off just making up your own theory and tossing it on the pot.

 

[F. King Daniel]

I wish Enterprise had adopted Diane Carey's "I.M. Pulse" engine idea (from the old novel Final Frontier), especially since ENT's idea of 100-year-older tech was to have the everything exactly the same bit with slightly modified (and often nonsensical - "spacial torpedoes?") names. I would have gone for "space warp" drive, too.

 

[AriesIV]

At some point you're better off just making up your own theory and tossing it on the pot.

Perhaps.

I'll let this thread sit a bit before I start fleshing out the "tech" aspect of the story.


I already know the incident that leads to the "invention" of Impulse Drive. I already know what will take place during the launch and flight phase of the story. I already know how the story ends.

Just need some crunchy bits to add to the story.

 

[Bill Morris]

Research on virtual particles is pretty much in its infancy.

http://en.wikipedia.org/wiki/Virtual_particle

One demonstration is the Casimir effect, where highly polished metal plates once brought together cling so strongly that they can't be pulled apart. In nanotech, this effect interferes with the operation of tiny gears, etc. Harvard University researchers have already made some headway manipulating it but are just scratching the surface.

With iimpulse drive, the driver coils would have to affect virtual particles in a way tantamount to creating a situation as though the ship were falling into a gravity well so that the crew would not feel any g-force despite extreme acceleration.

It's far beyond today's science, but if virtual particles are responsible for the strong and weak forces, magnitism, and gravity, then driver coils that work like that might be possible. The same goes for artificial graviity, force fields, and tractor beams. Nikola Tesla tried to tell people about this, but people had no idea what he was talking about.

And, if virtual particles are also reponsible for limiting speed the speed of light in space, just as water molecules are for limiting the speed of light to a lower velocity through water, for example, then understanding how to deal with virtual particles might even lead to FTL capability. If light didn't travel faster through air than through glass we wouldn't have magnifying glasses or telescopes. In space, something is doing the same thing to light in perhaps a different way, and virtual particles are a likely suspect.

 

[Wingsley]

One of the funny things about TREK is that it depicts a Universe in which starships used by the characters are ever-evolving, with ever-improving warp engines, but the auxiliary propulsion (impulse) seems to barely change. So you have these super-fast starships that apparently keep getting faster as the centuries pass, and all the merry while there must be a growing performance gap between warp and impulse.

The funny thing is, Riker asked Geordi to "increase to warp six" in the teaser to TNG's "Conspiracy", to which Geordi replied "Aye sir, full impulse." This hilarious exchange seemed to open the door at least a crack on the notion that impulse is FTL-capable, indeed, must be a kind of backup warp drive by the time of TNG. (I assumed that Geordi must have been firing up the saucer section's impulse engines for testing purposes and that the saucer's maximum capability would be warp six. This would at least make it logical for a Galaxy-class starship's saucer to have some interstellar capacity.)

And during TMP, Sulu and Decker both seem to measure impulse power in terms of warp factors, i.e., "warp point-eight", not "point-five-one-C", as heard in "The Tholian Web" or "point-six-four-that-of-light" in "The Corbomite Maneuver". This also loosely suggests that impulse may not be limited to sublight.

Just keep one other thing in mind: all through TOS, the humming sound of accelerating and decelerating engines was the same for both warp and impulse. That suggests to me that they may share at least some technology between them.

 

[AriesIV]

The way I see it... Impulse drive finally gave mankind his "infinite acceleration" engine but there were still issues with time dilation.

 

[Ronald Held]

Isn't a static warp field used to lower the ship's inertia, then uses fusion engines to propel the ship?

 

[Santaman]

I always have seen impulse drive as a specialised coil engine like warp drive but then mainly powered by fusion power.

 

[Wingsley]

An important issue for me: when launching the Enterprise from dock in ST2, Saavik orders one-quarter impulse power (IIRC). There have been similar dockyard maneuvering orders in other movies, IIRC. In TMP, Kirk orders maneuvering thrusters engaged to take the ship out of dock.

Given this, the question in my mind becomes: is there a distinction between maneuvering thrusters and "impulse power" and "impulse engine"/"impulse drive"? Are they all the same, all linked or is each term referring to something separate? Consider this:

In TMP, Kirk orders the use of maneuvering thrusters to clear the dock and leave the San Fran dockyard. It is only when he breaks orbit that he orders the use of "impulse power... ahead warp point-five." Note that he doesn't just say "sublight, one-half" as Scotty did in "Friday's Child", or even "half-impulse". So, is there a difference between going "sublight, one-half" and going "warp-point-five"? If you assume that warp factors are simply cubed then multiplied by lightspeed, then it is a no-brainer. But then again, if impulse is used anyway in all sublight thrust-based maneuvers, and if it is nothing but a sublight engine technology, then we would not need to refer to it as "warp-point-five", would we?

Could impulse be a family of fusion-powered propulsion systems commonly used aboard starships, comprised of "maneuvering thrusters" and also "impulse engines", the later designed to propel the ship at high sublight (and maybe lesser FTL) speeds without time dilatation? (Maybe thrusters can boost you up to 0.05 or 0.1 C, then impulse drivers take over for higher speeds.)

I'm guessing from "The Doomsday Machine", with the Enterprise's warp drive disabled (and the Constellation's nacelles apparently severely damaged, with her antimatter "deactivated") that impulse power is capable of propelling both of these ships on fusion power, which is less efficient and less powerful. So maybe the ships can still go fast, but Warp 1.0 (while theoretically possible) would be cost-prohibitive in terms of fuel consumption and stress on the smaller, more-"low gear"-based impulse engines.

 

[Saquist]

Ok I am writing an origin story for "impulse drive."

Some sources (a novel?) indicate that IMpulse means Internally Metered Pulse Drive and that there is a gravetic-wave component to the drive... it's not a rocket at all.

The more official sources indicate that it is a "juiced" rocket that accelerates it's exhaust to extreme velocity via accelerators and that there is some kind of mass-reducing "subspace driver coil" involved in adjusting the apparent mass of the ship.


What else do we know either from written sources or what we saw on screen?

I want to take what has come before and devise a "how it works" then extrapolate backwards to how it may have been developed and test-flighted "back in the day."

Star Trek has been SO devoted to warp drive that Impulse technology has been completely ignored by exception of a few off handed remarks.

-We are not told when it was developed or how old the technology is

-We have to guess at it's capabilities.

-We know just 30 years before the invention of Warp that ION drives were commonly used.

- We know that non canon TM describe Impulse engines under Newtonian physics

- We also know that they have Coils and are capable of reversing the ships direction without directed exhaust

-In TMP they are capable of near light speed.

-In TNG they aren't not capable of near light speed


Trek Tech has been warp specific and everything else has been treated with all the most cursory explanations. Impulse should have been the drive that broke the light speed barrier or some sort of Fusion but First Contact failed to exhibit any logic in this regard and so we're stuck with what we have which is a lumpy expanse of Trek Tivia.

 

[AriesIV]

That will change. Soon.

 

[Saquist]

GOOD luck.

 

[Crazy Eddie]

Actually, for years I've assumed that "impulse engine" isn't any specific type or design for an engine, just a general description for any class of engine that isn't a warp engine. Kinda like how the term "jet engine" can refer to anything from a solid rocket to a turbofan, but in modern terms is GENERALLY used to refer to a more narrow range of aviation engines (turbojets and turbofans, sometimes turboprops).

In this scheme, technically an ordinary chemical rocket would be an impulse engine, albeit an incredibly simple one with limited capabilities (perhaps they choose to differentiate by inventing the term "sub-impulse," like the Bajoran fighters in "The Siege"?). Common usage by the 22nd century, though, would have "impulse engine" referring exclusively to a type of reaction engine that uses a driver coil to accelerate exhaust gases up to relativistic speeds.

Since you cannot use warp drive to control your orbital characteristics (that would be like using a rocket engine to parallel park your car), this would give you an absurdly high specific impulse and bring your delta-v budget up to nearly infinity, allowing for worry-free orbital maintenance over a variety of missions and planetary stops.

The good news is, this can be made consistent with all references of impulse engines being sub-superlight drives. If you're willing to exercise a little handwaving, then impulse engines can accelerate you to any arbitrary speed up to warp nine if you've got enough runway. It all depends on the design of the engine; not all impulse engines will use a physical reaction mass, not all of them will use driver coils, not all of them build acceleration gradually, and a few will almost certainly use some sort of artificial gravity flux. In the end, an impulse engine is anything that produces motion through the application of applied force, as opposed to a warp drive, which produces motion by altering the parameters of your local reference frame.

 

[AriesIV]

I've been saying that for years about warp-drives. Everyone tries to shoehorn the same basic elements (coils warp core antimatter pods fuel tank) into every single design... and they try to retcon those elements into designs that clearly aren't operating on those principles.

I always held the notion that the Constitution Class had a "different" form of warp drive for most of it's career. Yes it had matter-antimatter reactor(s) and it used dilithium... but how it was set up was totally different than the Galaxy Class we saw later. Hell the nacelles should be a dead give-away with the "fins" on the end and the detail piece in the middle.

Later on we see a refit to yet another design standard operating on yet another different principle.

Then we see the Galaxy Class engine... and the Defiant which is similar... then we see Voyager which is closer to Refit Connie design. Later we see two slightly different versions of the Sovereign core.


Impulse I suspect is the same way. Early versions used juiced-thrust accelerated to higher speed in conjunction with mass reduction fields. Later... non-Newtonian gravity wave drives became an option. A quantum leap in technology made the juiced-thrust engines popular again for whatever reason. I suspect there are other more exotic flavors out there.

This is a good starting point though.

 

[C.E. Evans]

An important issue for me: when launching the Enterprise from dock in ST2, Saavik orders one-quarter impulse power (IIRC). There have been similar dockyard maneuvering orders in other movies, IIRC. In TMP, Kirk orders maneuvering thrusters engaged to take the ship out of dock.

Given this, the question in my mind becomes: is there a distinction between maneuvering thrusters and "impulse power" and "impulse engine"/"impulse drive"? Are they all the same, all linked or is each term referring to something separate?

Probably all of the above, depending on how the terms are used at any given time. In Trek, a starship may rely on maneuvering thrusters to stay in orbit or to dock with/depart from an orbital platform for precision maneuvering.

Blasting out of a spacedock at one-quarter impulse may not be something that's recommended, but it may depend on the captain (and the ship having a straight shot out with no danger of colliding into anything).

Consider this:

In TMP, Kirk orders the use of maneuvering thrusters to clear the dock and leave the San Fran dockyard. It is only when he breaks orbit that he orders the use of "impulse power... ahead warp point-five." Note that he doesn't just say "sublight, one-half" as Scotty did in "Friday's Child", or even "half-impulse". So, is there a difference between going "sublight, one-half" and going "warp-point-five"? If you assume that warp factors are simply cubed then multiplied by lightspeed, then it is a no-brainer. But then again, if impulse is used anyway in all sublight thrust-based maneuvers, and if it is nothing but a sublight engine technology, then we would not need to refer to it as "warp-point-five", would we?

They may all be separate terms. "Half-impulse" could be less than 0.5c, while "sublight, one-half" could be 0.05c for all we know.

My take on the use of impulse power in TMP and the one-off "warp point..." measurements that were used, was that it may have been a case that because the Enterprise's new warp engines were kind of wonky at time, they were relying on impulse power for a gradual build-up to warp one, and then kick over to warp power from there (an error in the process might have been the matter/antimatter imbalance that caused the subsequent wormhole during the first attempt to go to warp, IMO).

Perhaps after everything had been ironed out after the Enterprise's proper shakedown cruise, they went back to using warp and impulse engines in a more conventional sense (no more gradual build-up to warp one in fractions)...

 

[blssdwlf]

Or also that calling out "one-quarter impulse power" doesn't necessarily give any indication of requested acceleration or desired speed. There are times when the ship is put at "full power" ("The Paradise Syndrome") but the power isn't going to take the ship to Warp 9. We do get a sense of the acceleration capability in "The Squire of Gothos" when Kirk orders "maximum acceleration" from orbit and also from TMP as they depart Earth (implied as in a hurry to intercept V'ger.)

Since departing spacedock in TWOK/TSFS were at impulse power but fairly slow it could be that "one-quarter power from impulse/for impulse" was available and it was the helmsman's discretion as to how much to use and that impulse drives of TOS/TMP were capable of very fine maneuvering.

 

[C.E. Evans]

Or that it took awhile for the impulse engines to get up to speed back then, which enabled the Enterprise to slide out of dock gracefully before she actually achieved one-quarter impulse. We've become used to ships just jumping to whatever specified speed ordered by the captain since TNG, but they kind of had to work their way to that in TOS...