All this data is potentially out of date, and should be taken with a truckload of salt
Alpha damage is the amount of damage dealt by a ship when all guns and launchers on that ship fire at once. Alpha damage, also known as strike damage or alpha strike damage.
Calculating alpha damage
The damage dealt typically calculated includes the damage dealt by a missile from each launcher hitting at the same time as guns. This is not accurate, as missiles will take time to reach the target. However it simplifies calculation of the damage dealt and so is often used. This makes the calculation simple, where N is the number of modules:
This could more accurately be termed the peak damage output of a given ship and fitting.
DPS is an accurate definition of the total damage per second average that is given out by a ship/fitting. Alpha strike records the highest amount of damage that this ship/fitting will ever produce at any one moment. As such alpha strike can be useful as a general indicator of damage performance on ships, particularly smartbomb platforms or other slow-refiring weapon users.
Pilots of cruise missile ships (battleships) often refer to alpha damage as salvo damage, as it records the total damage it is possible to put on a target if all the missile launchers are fired at once. However, DPS time takes into account refire time. It is for this distinction- that missiles take time to hit and thus have a lower aggregate DPS- that makes missile ships less versatile in fleet engagements. Often targets will have time to warp out before missiles have reached them where traditional turrets will have already hit several times.