One would assume that you would want it in front of the ship. As is the case with the "USS. Enterprise NX-01" Also why is there only a front facing deflector, when the ship can travel along several different axis.

The dreadnought USS Federation "also" has a rear-facing deflector dish(!) 'In the diagram the notation on the "main sensor dish F/A" the notation (F/A)=(Fore, & Aft); on the Star Trek USS. Enterprise Original Blueprints it reads "main sensor and navigational deflector" I have always wondered about that; is there an actual explanation for this? uss-federation-class-dreadnought-sheet-1.jpg

For example; in the TOS episode "Balance of Terror" the Enterprise goes to "full reverse", or in the Wrath of Khan when the Enterprise goes straight up and then back down again. What protects the ship during these maneuvers?

Because the shield are not always on??? right? or am I confusing deflectors, & shields?

Funny thing well for everyone but me. I have the technical manual, I do not remember seeing that in there.


3 Answers 3


The ship's deflector dish needs a clear line of sight along which it can project a deflection beam, hence why it needs to be at the front of the ship. Its exact placement is largely irrelevant. The deflector in the Galaxy-Class is below the saucer whereas it's right at the front of the Defiant-Class.

enter image description here
Star Trek: The Next Generation Technical Manual

Since the navigational deflector only operates when the ship is at warp (and since the ship can only warp forward, not backward), by necessity it needs to be at the front, rather than the rear.

When the ship is at sub-light speeds, the deflector tends to be turned off and the ship's shields take care of low-speed impacts.

For the record, the USS Federation (which appears briefly as a background image in Star Trek II) also has a deflector at the front. What you've mistaken for a rear-facing deflector is in fact a secondary sensor array.

enter image description here
Star Trek Star Fleet Technical Manual

  • Are you sure ships can only warp forward - no reason that limitation should be present given the way it's supposed to work? I have faint recollections of reverse wrap being used to hold position or similar... (although admittedly most to swing around to the direction they're heading) Commented Apr 6, 2017 at 12:20
  • @JonClements - How fast can the Galaxy class Starships go in reverse?. Not warp speed.
    – Valorum
    Commented Apr 6, 2017 at 13:30
  • @Valorum - I added some more to the question; but thanks to the diagram from the technical manual (mine is still boxed from my last move) I had forgotten about the deflector screens / shields. However it raises the question about something moving at a right angle to the ship, and depending on the size of the object(s) how it is deflected, or destroyed? I feel like I am leaving something out though... Commented Apr 6, 2017 at 20:46
  • @WilliamThompson - The deflector can wiggle around a few degrees.
    – Valorum
    Commented Apr 6, 2017 at 20:50

Because the saucer can detach

As per this answer, many earth-built Star Fleet ships had the ability to separate the saucer section.

This is featured most prominently in the TNG series, but dialogue in TOS indicates that the original enterprise could do it as well.

NX-01 was all one piece, as was the Defiant. Voyager was built for navigating turbulent places, so was all one piece.

In each case where separation was possible, the saucer section did not have warp drive, so did not need a big deflector dish. It can be assumed they did have some deflection ability, and certainly had normal shields for high impulse situations.

Because the star drive section can go to warp, it makes sense for the main deflector to be attached to that section.

I suspect it may also be easier to defend from that position.


Since it is a "SHIP", applying analogies of current sea faring warships to any space faring ship, we can have the following observations:

1) Today's warships face threats from all angles, 360 degrees along the water level, and from above and below. Yet, their armor / hull is thickest at the front or the bow, near the waterline, since threats from enemies will be less common(only during war, and specifically in battle), as compared to threats from flotsam / sandbars / other waterborne objects. The latter type of threat will be encountered daily, as the ship sails on regular, non-combat duty.

2) The ship will more often than not, travel in the forward direction(the control deck faces that direction in the USS Enterprise as well), at whatever speed. Remember that today's ships can also move sideways, at a very slow speed, for navigation inside harbors. However, the dangers of waterborne objects at this speed is less, compared to dangers at any high speed whence the ship will be traveling forward.

3) As far as today's ships are concerned, there are anti missile systems (fast firing multi-barrel mini guns) installed, generally in groups of two. These face various directions (6, in a certain class of battleship / carrier totaling 12 guns, can't remember which, but read on wikipedia), and are radar guided. Why such a system was not adapted for space faring ships, is beyond me.

Also, corollary to the observations about current day ships, you may also analyze the current day soldier. Modern soldiers wear combat armor, in the form of vests. These vests have ceramic + Kevlar (maybe both, maybe either) plates which perform the task of stopping enemy bullets and other projectiles. Guess which plate is the thickest? The chest plate. There is another plate at the back, but it is not as thick as the one in the front.

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