The 1.6 kilometer-long Imperial class Star Destroyer is instantly recognizable for its iconic wedge shape and prominent conning tower on the dorsal side, at the rear of the wedge. The conning tower is the area from which the Star Destroyer is piloted. While top and bottom have no meaning in zero gravity, the design of the ship clearly suggests that the side with the conning tower is the nominal "topside" of the ship, and in the films Star Destroyers are almost always show with the conning tower side "up." On top of the conning tower are two spherical shield generators, which power the energy shields that protect the destroyer from enemy fire. The docking bays are set amidships along the keel line on the ventral side of the destroyer, and the engines are at the rear of the wedge.
An Imperial Star Destroyer carries 60 turbolaser batteries for combat with capital ships, 60 ion cannons, and 10 tractor beam projectors, as well as numerous smaller weapons for point defense and combat against small craft such as fighters. Ion cannons are used to paralyze a ship and disable its systems without harming its infrastructure or the crew. The powerful tractor beams create a gravitational field that is able to draw captive ships into the capturing ship's cargo bay.
Aside from the crew, an Imperial Star Destroyer carries a full division of stormtroopers, 20 AT-AT walkers---hulking four-legged ground attack vehicles---and 30 AT-ST walkers, a smaller and more nimble two-legged ground attack vehicle. In terms of space vehicles, a Star Destroyer's complement includes six squadrons of TIE fighters, eight Lambda-class shuttles, and 12 landing barges for ground assault. Lambda-class shuttles are the white, three-winged transport ships seen in the films.