In some cases, this is justified by having the missile silos oriented up (or down) to allow for more surface area-and, in turn, more missiles. Occasionally, this is explained in Space Opera as the effect a ship's energy/force/gravity field has on the missiles. The missiles often follow artistic curving trajectories for no apparent reason, though strategically it may simply make them more difficult to dodge (or intercept, if there's any usable point defence).
A tactic wherein a military vehicle or craft - often a Humongous Mecha - launches a massive salvo of missiles at a target (sometimes more missiles than you'd think the craft would be able to hold).
