A question about Star Trek's impulse drive

[GW150914]

We all know that starships in Star Trek have artificial gravity. They also have inertial damper. Therefore, we can conclude that they have the ability to counteract gravity.
However, as those technical manuals of Star Trek tell us, starships are using impulse drives for slower-than-light travels, and those impulse drives are traditional fusion drives which use reacting forces to create thrust.
Now here's my question: since we have the ability to create anti-gravity field, why not use anti-gravity thrusters instead of those fusion drives? Anti-gravity thrusters are much more agile than normal thrusters, obviously.

 

[Drakkith]

Now here's my question: since we have the ability to create anti-gravity field, why not use anti-gravity thrusters instead of those fusion drives? Anti-gravity thrusters are much more agile than normal thrusters, obviously.

I'm not aware of any rules or laws regarding the operational principles of anti-gravity thrusters, so I can't say anything on that subject. Perhaps it causes problems in the metric of space-time, or time-travel paradoxes between the thruster manifolds and the food replicators. Perhaps an anti-gravity thruster would actually still be attracted towards a regular source of gravity, which is the complete opposite of what one might expect. Maybe an anti-gravity thruster only works when near a very large mass like a planet or a star (which may or may not be effective for interplanetary travel). Who knows?

The real answer, of course, is that the creators of Star Trek simply decided that their thrusters are fusion drives that obey known laws (when the plot allows) instead of anti-gravity thrusters. Maybe they wanted to keep some semblance of real science in their technical manuals.

 

[GW150914]

I'm not aware of any rules or laws regarding the operational principles of anti-gravity thrusters, so I can't say anything on that subject. Perhaps it causes problems in the metric of space-time, or time-travel paradoxes between the thruster manifolds and the food replicators. Perhaps an anti-gravity thruster would actually still be attracted towards a regular source of gravity, which is the complete opposite of what one might expect. Maybe an anti-gravity thruster only works when near a very large mass like a planet or a star (which may or may not be effective for interplanetary travel). Who knows?

The real answer, of course, is that the creators of Star Trek simply decided that their thrusters are fusion drives that obey known laws (when the plot allows) instead of anti-gravity thrusters. Maybe they wanted to keep some semblance of real science in their technical manuals.

What is strange, however, is that in Star Trek Voyager, there're some episodes in which Captain Janeway mentioned anti-gravity thrusters, especially when Voyager was trying to land on a planet's surface.
Besides, a few modification on inertial damper can create a nice anti-gravity drive, and inertial dampers aren't affecting food replicators, as I can tell!

 

[Drakkith]

What is strange, however, is that in Star Trek Voyager, there're some episodes in which Captain Janeway mentioned anti-gravity thrusters, especially when Voyager was trying to land on a planet's surface.

I'm not sure what to tell you. Are you trying to find an in-universe reason they don't use anti-gravity thrusters?

 

[newjerseyrunner]

I have a hypothesis. The effects of a nuclear engine would radiate away from the ship at the speed of light, so if you're using an impulse engine at Alpha Centauri, it'd take 4 years for anyone in Earth orbit to detect it. Maybe those anti-gravity forces are in subspace. Subspace has a causal velocity way faster than light. No matter what you do, you are broadcasting your position. If the Borg are listening for particle emissions from a nuclear engine, by the time they hear you, years will have past. If you're screwing with subspace fields and they're listening, resistance would be futile.