How do Starships stop?

[Albertus]

This is one thing about Trek Tech that has always puzzled me. How do starships stop?

We know from the on-screen commands and actions that a ship at warp speed can translate to a sublight velocity within a few seconds. It is the slowing down from near light speed to a zero velocity that poses the problem.

The impulse engines all point in the wrong direction to be used for a retro-jet action and the Saucer and Battle section thrusters are used for station-keeping and fine maneuvering/attitude control of the ship.

I know that this aspect of Trek ships was considered and the idea of 'reverse thrusters' was mooted but the solution never went further than that throw-away idea and there is nothing in the Tech manual or elsewhere to suggest a method..

So, how does a Trek ship stop?

I have my own solution, but I am interested to hear other peoples ideas.

 

[GodThingFormerly]

The impulse engines all point in the wrong direction to be used for a retro-jet action...

...unless one employs forcefield-based thrust deflectors to channel impulse exhaust along the space vehicle's flight vector.

TGT

 

[Albertus]

...unless one employs forcefield-based thrust deflectors to channel impulse exhaust along the space vehicle's flight vector.TGT

I get the idea, like baffles to reflect the energy backwards? I am not a fan of this idea. This approach would use far more energy than the actual energy needed to slow the ship down.

 

[Manticore]

The impulse engines all point in the wrong direction to be used for a retro-jet action...

...unless one employs forcefield-based thrust deflectors to channel impulse exhaust along the space vehicle's flight vector.

TGT

I personally believe that the impulse engine is primarily a field drive, with only a limited thrust component, so slowing down would be fairly easy.

As for the warp drive, the ship isn't really going so fast. I don't know if it's related to the Alcubierre warp drive concept or not, but slowing down shouldn't be an issue, because the ship isn't really decelerating, just not warping space as much.

 

[GodThingFormerly]

I get the idea, like baffles to reflect the energy backwards? I am not a fan of this idea. This approach would use far more energy than the actual energy needed to slow the ship down.

I may be inclined to take your objection semi-seriously if you can quantify "far more energy".

I personally believe that the impulse engine is primarily a field drive, with only a limited thrust component, so slowing down would be fairly easy.

I prefer to interpret TOS/TAS/TMP-era impulse engines as Newtonian rockets, whether they be thermonuclear fusion energized aboard the original NCC-1701 (see The Doomsday Machine) or anti-matter energized aboard the NCC-1701 Refit (see ST:TMP).

TGT

 

[Gepard]

The impulse engines all point in the wrong direction to be used for a retro-jet action...

...unless one employs forcefield-based thrust deflectors to channel impulse exhaust along the space vehicle's flight vector.

TGT

...wouldn't it be simpler to flip the ship 180º along the flight path?

 

[GodThingFormerly]

...wouldn't it be simpler to flip the ship 180º along the flight path?

Sure, if the thrust reversers fail. But seriously, please feel free to cite an episode or film where we see a standard spacecraft braking maneuver executed via 180º rotation.

TGT

 

[Gepard]

But seriously, please feel free to cite an episode or film where we see a standard spacecraft braking maneuver executed via 180º rotation.

TGT

Unfortunately, I cannot, as film and TV science fiction is filled with stupid.

 

[USS KG5]

...wouldn't it be simpler to flip the ship 180º along the flight path?

Sure, if the thrust reversers fail. But seriously, please feel free to cite an episode or film where we see a standard spacecraft braking maneuver executed via 180º rotation.

TGT

They do it in an episode of TNG actually - though I forget which one.

 

[Christopher]

According to the TNG Tech Manual, impulse engines reduce the inertial mass of a starship to make it easier to accelerate. Since momentum equals mass times velocity, and momentum is conserved, then simply reducing a ship's effective mass would automatically cause it to go faster, and conversely, increasing its effective mass would cause it to slow down. So all a starship has to do in order to decelerate is to dial back the mass-reduction effect of its impulse-drive field. Conversely, though, if the mass is reduced as much as possible, then that makes it easier to accelerate or decelerate with thrusters (assuming that the thrusters' reaction mass is not itself subjected to mass reduction).

And of course no starship ever "stops," it just matches velocity with some other object in space or goes into orbit of some other body. How much deceleration or course change is needed would depend on what the ship's velocity is relative to its destination or to the other vessel it's rendezvousing with.

 

[Forbin]

Perhaps the warp engines are caused to impart a momentary reverse-pulse of the warp field when the captain calls for "all stop." First cutting the ship out of warp, then pulsing to cancel the forward momentum. Once the momentum is below a certain threshold, the thrusters are able to handle the rest

 

[Christopher]

^^That's not how a warp drive works, though. It doesn't impart any actual velocity, it just distorts spacetime so that a pocket of it moves forward FTL with the ship being carried along inside it. So a warp drive would have no effect on a ship's momentum.

 

[Albertus]

According to the TNG Tech Manual, impulse engines reduce the inertial mass of a starship to make it easier to accelerate.......

The impulse engines utilise a small space-time driver coil which accelerates the impulse engine exhaust gasses to near-light velocities, without achieving warp.

Warp drive reduces the ships overall mass, not impulse engines.

And of course no starship ever "stops," it just matches velocity with some other object in space or goes into orbit of some other body.

I meant 'absoute' in terms of reference to the vessels stationary relationship to other 'moving' bodies.

 

[Santaman]

I personally believe that the impulse engine is primarily a field drive, with only a limited thrust component, so slowing down would be fairly easy.

I agree with you on this one, the way starships move around does suggest the impulse drive is indeed a coil drive specialised to work at slower then light speeds, also it would explain the tremendoes acceleration and the little fuel it uses. .

 

[USS KG5]

I personally believe that the impulse engine is primarily a field drive, with only a limited thrust component, so slowing down would be fairly easy.

I agree with you on this one, the way starships move around does suggest the impulse drive is indeed a coil drive specialised to work at slower then light speeds, also it would explain the tremendoes acceleration and the little fuel it uses. .

Add me onto this list as well - the technology needed for the kind of manoevering we see on screen is better explained this way IMHO.

 

[Christopher]

According to the TNG Tech Manual, impulse engines reduce the inertial mass of a starship to make it easier to accelerate.......

The impulse engines utilise a small space-time driver coil which accelerates the impulse engine exhaust gasses to near-light velocities, without achieving warp.

Warp drive reduces the ships overall mass, not impulse engines.

Sorry, I think you're misunderstanding how it works. TNG TM p. 75, para. 2:

The propulsive force available from the highest specific-impulse fusion engines available or projected fell far short of being able to achieve the 10 km/sec^2 acceleration required. This necessitated the inclusion of a compact space-time driver coil, similar to those standard in warp engine nacelles, that would perform a low-level continuum distortion without driving the vehicle across the warp threshold. ...(I)t was determined that a fusion-driven engine could move a larger mass than would normally be possible by reaction thrust alone, even with exhaust products accelerated to near lightspeed.

In other words, reaction thrust alone, even with relativistic exhaust products, is not capable of accelerating a Galaxy-class starship's mass efficiently without the added contribution of the space-time driver coil. Therefore, the driver coil is making it possible to impart greater acceleration (a) with the same amount of force (F) -- which, by Newton's second law, means reducing its inertial mass (m).

 

[Albertus]

...... (a) with the same amount of force (F) -- which, by Newton's second law, means reducing its inertial mass (m).

There is no way that impulse engines can reduce mass for the Saucer section, or indeed, reduce mass for anything other than the exhaust gases produced by the impulse engines. I have the same manual, and I still don't see how you can get to your conclusion.

The driver coils are localised and specific to the fusion reactors that they are connected to. No connection to warp anything. You seem to be confusing the ability to drive gas jets to near warp velocities with driving a ship to warp. Impulse cant do that, no matter if you strung all the driver-coils together.

 

[Tigger]

Since they can cancel inertia inside the ship, maybe they can cancel it outside, as well? Perhaps the inertial damping fields can be extended to affect the entire ship's mass and affect it, accordingly.

So they just have the Impulse Drive stop "pushing" the ship and then cancel the vessel's inertia to the point it "stops" (matches the velocity).

 

[Albertus]

Since they can cancel inertia inside the ship, maybe they can cancel it outside, as well? Perhaps the inertial damping fields can be extended to affect the entire ship's mass and affect it, accordingly.

So they just have the Impulse Drive stop "pushing" the ship and then cancel the vessel's inertia to the point it "stops" (matches the velocity).

Tigger you win the prize, That was my solution as well. It's pointless looking at the drive components of a starship for a way to stop a vessel.

The IDF is a perfect way to slow and stop a ship. Action and reaction, simple physics.

 

[Ronald Held]

Given what we have seen on screen, there has to be a field component to the impulse drive, if for no other reason to reduce the inertial mass of the ship. Changing the shape of the field and intensity should allow it to accelerate and declerate quickly.