Point defense was the term for any method used by a ship to actively defend itself from missile attack. In the 20th Century PD, two forms of point defense were generally used: counter-missiles and laser clusters.
The first line of active defense was the counter-missile. Countermissiles were used to intercept incoming missiles at ranges of 1 to 4 million kilometers. Countermissiles had no warheads; they merely attempted to overlap their impeller wedges with those of the attacker's missiles. This overlap was mutually destructive as the gravitic stress vaporizes the nodes of both missiles. Countermissiles were much much smaller than ship-killers.
Laser cluster Edit
If an attack missile managed to break through the countermissile engagement zone, the last line of active defense was the point defense laser cluster. A laser cluster was a grouping of a number of individually weak lasers, much weaker than an anti-ship laser. While this reduced the range, it allows for a higher refire rate per cluster. A laser cluster typically had enough time for 1 shot before the attack missile could engage the ship. Supplementing the point defense clusters was the ship's energy armament. Anti-ship lasers and grasers could also be tasked to engage incoming missiles.
Manticoran clusters as of 1920 PD contained eight emitters, each capable of firing once every sixteen seconds. This resulted in one shot every two seconds from each cluster mounted on a ship.
Clusters had an additional use, that of low-power offensive weaponry, mostly for use against vessels that decided to resist while boarding parties approached. Edward Saganami-class cruisers had an automated program which took control of the clusters, targeting them at weapons, sensors and impeller nodes. This allowed a ship to be crippled, without resulting in the devastating damage that a shot from a regular broadside weapon would entail, which could nearly destroy an average merchant vessel. (SI1)
Laser cluster systems of the Republic of Haven Edit
- P/16x3 Laser Cluster - This laser cluster system was developed during the mid-1860s PD and put on the Charles Wade Pope-class light cruisers. (JIR2)
The autocannon was the predecessor to the laser cluster, throwing up curtains of metal fragments with which the missile would collide and destroy itself. Older autocannons were based on electromagnetic propulsion (i.e. railguns or gauss guns), while newer versions used more powerful grav drivers. (Companion)
With the advent of the laser head and later the missile pod, autocannons were considered too inefficient to provide a worthwhile antimissile defense and were replaced with laser clusters.