Defense
Shields

Vehicles
Artificial Gravity
Hyperdrives
Life Support
Sublight Engines
Transport Tubes
Walkers

Space
SAG
Time Travel

Weapons
Blasters

Time travel is used every day by trillions in the form of interstellar communication. To accomplish communication to another star system instantaneously, relay stations at the edges of systems simply calculate distance to the communiqué's destination and deploy the transmission to the appropriate point in time to arrive, to the recipient, instantaneously.

However, time travel is currently believed utterly impossible by all but those of highest status in the most secret societies. Founded by Dominion Master Jonathan in the year 1 I.C., at which time he intercepted a radio message from the future containing the plans for a time machine, built the machine following the plans, and subsequently tested the device by sending a radio message containing the plans back in time.

There's no way this could possibly work, ever, but it does.

This is because the entire timeline, forever, is what it is. Nothing can be changed, and there can never be a timeline in which a given instance of time travel does not occur. Time travel from the future will definitively exist in the past, regardless of if that existence in the past causes the time travel.

In a nutshell, time travel can cause itself. This is known as a paradox, but this causes no ill effects, because it was going to happen anyway.

Consider that a mortally wounded man travels back in time to deliver a warning to himself, giving specific instructions how not to be killed. Following those instructions, in effect (though not quite) causes the man to become mortally wounded and to travel back in time to deliver a warning to himself. It's already been established in the fabric of history that he is going to be killed and that he is going to go back in time to tell himself that he's going to be killed. Then he just gets to count down the days, or hours, minutes, or seconds, however the case may be, because now he just has the knowledge of his death and it can't be changed.

Bottom line: You can't save yourself or anyone else through time travel, because if it happens, it already happened and nothing can be done about it.

That doesn't mean time travel is futile, unless you subscribe to the belief (with your newly gained knowledge that fate is even more exacting than you thought) that life itself is futile. Time travel is a part of history, and if you meet yourself from the future, and decide not to go back in time to cause that to not happen... well, you can't. Some way or another, you still will. And you will meet yourself, decide not to go back in time, and still go.

This doesn't mean that you will see a divine force strong-arm you into that result against your will, you just won't catch that you just happen to be guiding yourself toward the exact same outcome because, in the end, that time you saw yourself in the past was because of this time you're taking yourself to the past. It always was going to happen this way.

The few secret people in secret societies have therefore determined to never reveal time travel to the public, because such an act could be considered a crime against humanity. People in general just can't handle this sort of thing.

Therefore, time travel is only used for "instant" data transmission rather than moving people through the stream of time, except in the extremely rare case that some poor sap breaks the rules.