The primary function of the Navigation Deflector Array (NDA) was to clear a path ahead of the ship. It did this by generating a deflector beam in front of the ship that pushed debris out of the way. Most recent Starfleet vessels have been equipped with an auxiliary deflector dish. While the secondary deflector on Intrepid-class or Nova-class starships are more obvious, some like on the Galaxy-class are built within the hull.

At warp, or even impulse speeds, anything, from micrometeoroid particles to asteroids, posed a major navigational hazard. Even repeated collison with stray hydrogen atoms could cause damage to the ship. The significance of the deflector system cannot be overstated; the NDA is an absolutely vital part of the ship. The beam itself is a graviton beam that was focused and manipulated by a series of subspace field coils. This powerful tractor/deflector emission sweeps thousands of kilometers ahead of the ship, pushing aside not only small particles, but also larger objects that could present a hazard. The navigational sensors detected any object that were too large to displace and made automatic course corrections. In addition to the actual deflector beam, the dish generates a series of parabolic shields that extended approximately two kilometers in front of the ship; these low-level fields were relatively static, and were designed to deflect stray hydrogen atoms and any submicron particles that the main deflector beam may have missed. The deflector system is powered by three redunant high-powered graviton polarity source generators. These fed  two 550-millicochrane subspace field distortion amplifiers, with the resulting energy being focused by the subspace coils through the deflector array.

The array, which is made up of a series of molybdenum-duranium mesh panels, is mounted on a duranium framework. The NDA, and therefore direction of the beam it emitted, could be steered by the navigational computer system. Its movement was controlled by four high-torque electrofluidic servos, which could move it as much as 7.2 degrees from the ship's X-axis. Because of the large amounts of power required by the deflector beam, the system generates significant subspace and electromagnetic radiation. such fields sometimes affect the ship's sensor systems.

To avoid this potentially dangerous interference, the long-range sensor equipment is located directly behind the main deflector dish. The emitters from the sensors and the deflectors were aligned in such a way that both of their fields issued outward from virtually the same point, effectively allowing the sensors to look straight through the interference generated by the deflector systems. A significant increase in power to the deflectors could still affect some of the systems, notably the subspace field stress and gravimetric distortion sensors, so the balance was carefully maintained unless there was an emergency. If an unusual or dangerous situation occurred, the sensor dish could perform functions for which it was not specifically designed. Various fields can be channeled with great effect through its broad aperture, and these could be used as weapons or to remove anomalies.