Point Defense

Point Defense

See Ship Combat on how to set up weapons and fire controls on your ships.

See the Anti-Missile Tutorial for an introduction to defending against missiles.

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Point defense is using missiles and beam weapons to automatically defend a ship, a fleet or a colony against incoming missiles, small attack craft or fighters; basically anything that comes too close for comfort.

While it is possible to attack missiles with fighters, an effective point defense system usually relies on an outer 'umbrella' of anti-missile missiles and an inner 'screen' of turreted guns to catch anything that slipped through the outer barrier.

Note: to understand the different modes of point defense fire, keep in mind that positions of ships and missiles are updated in five-second increments, so a missile moving at 22,000 km/s actually moves in 110,000 km "hops". That's why your sensors almost never detect objects at maximum theoretical range: they are just outside of detection range in one turn, and already some way inside it the next turn.

Anti-missile Missiles (AMM)

Generally these are small (size 1) missiles with high speed and agility values to increase their hit chance, while damage and fuel are of secondary importance.

See the Anti-Missile Tutorial and Missiles for details.

In the Ship Combat window, you set their fire control to automatically engage any incoming threats within a given range with a number of one to five AM-missiles, depending on how lucky you feel. Higher numbers mean better chances to hit all threats but you might run out of ammunition quickly.

Ship Mounted Turrets

With small lasers, gauss cannons, and meson cannons mounted on a turret, a high tracking speed short-mid ranged weapon for Missile Interception is possible. They can be used both as short range weapons against enemy fighters or ships that dare close in with Point Defense mounted ships.

Ship Mounted Turrets can actually provide an inner 3 layers or more of PD fire for the fleet by staggering weapon ranges.

A basic example of fleet defensive turrets for use against missiles:

Twin 10cm C3 Near Ultraviolet Laser Turret

Damage Output 3x2      Rate of Fire: 5 seconds     Range Modifier: 3
Max Range 90,000 km    Turret Size: 8    Armour: 0    Turret HTK: 2
Power Requirement: 6    Power Recharge per 5 Secs: 6
Maximum Tracking Speed: 10000km/s

Twin Gauss Cannon R4-100 Turret

Damage Output 1x6      Rate of Fire: 5 seconds     Range Modifier: 4
Max Range 40,000 km    Turret Size: 15    Armour: 0    Turret HTK: 4
Maximum Tracking Speed: 10000km/s

Twin R3/C3 Meson Cannon Turret

Damage Output 1x2      Rate of Fire: 5 seconds     Range Modifier: 3
Max Range 30,000 km    Turret Size: 8    Armour: 0    Turret HTK: 2
Power Requirement: 6    Power Recharge per 5 Secs: 6
Maximum Tracking Speed: 10000km/s

If you increase the size of the laser focal size to 12cm you gain another 30,000 range, so you can have multiple laser hit ranges and stratify your Point Defense layers even more.

Point defense modes for beam weapons

In the Ship Combat window you can select a fire control, assign weapons to it and set it to one of several automated Point Defense firing modes:

Area Defense

Area defense occurs during the normal weapons fire segment of a 5-second increment. If a missile crosses the engagement range of a weapon set to Area Defense during a single movement then it will not be engaged.

Example: a laser turret has its mode set to "(Area PD Mode 19)", i.e. automatically fire at anything within a range of 190,000 km. If a missile moving at 45,000 km/s (thus traveling 225,000 km per 5-second turn) begins the turn 210,000 km away, just outside that range, it will never "stop" inside the weapon's range and will not be fired at before impact.

Use this when you want a beam weapon to fire at maximum range. For example, a combination of laser and fire control that has a range of 400,000 km might be able to fire several times at a missile salvo. Or you might split off defensive ships and order them to fly ahead of the main task group, where they can engage incoming missiles before they reach the high-value units.

Final Defensive Fire

Final defense occurs at the end of the last movement segment, when the missile intercepts any ship in this task group. Range to the missile is 10,000 km, the smallest unit of distance in Aurora, thus assuring maximum hit chances at point-blank range.

Final Defensive Fire (self only)

Like above, but only if the missile attacks the ship carrying the fire control and not a different ship in this task group. Use this when you want to reserve this weapon to protect the high-value ship it is mounted on.

Close-In Weapon Systems

CIWS are a weapons category of their own and are designed as a ship component. They are fully autonomous, automatic gun turrets that contain their own weapons, sensors and fire controls. They always operate in "Final Defensive Fire (self only)" mode, so they do not protect other ships and cannot be used offensively. All you have to do is stick them on a ship and wait. They count as commercial components and can be mounted on any ship.

Point Defense setup within a fleet

A widely used doctrine for combat fleet defense consists of a AMM-equipped missile ship (long range), Area Defense beam-weapons ship (medium range) and a Final-Fire-laser ship (short range).

You want your PD missile launchers to be able to fire at the incoming missiles multiple times before they strike, but not waste too much ammo. Anything that gets through the missile screen gets attacked by the Area Defense ship with long range lasers. Finally, your Final-Fire ships will fire one last time at 'leakers'.

Comments

Ideally, any PD weapon would have a rate of fire of 5 seconds. Missile PD can get away with 10 or even 15 seconds, but most likely not more than that. However if you happen to know that this particular enemy fire salvoes of very fast missiles every 40 sec you may want to have some burst Final Fire capability every 30-40 sec rather than wasting short ranged turret RoF when there are no missiles in range 80% of the time.

For an in-depth analysis of area defence in Aurora, see this thread: http://aurora2.pentarch.org/index.php/topic,5197.msg53720.html#new