Do you see torpedo boats?
Kamchatka frigate of the Russian navy 1903
Missiles span everything from small 50 kg ones that are fired and either hit or miss in a single turn all the way up to 5 ton beasts that move and behave almost like a ship. Larger missiles than 5 ton should be built as unmanned ships and use the ramming rules when attacking, this is far outside of the scope of this post though.
This post will walk you through a missile attack step-by-step referring to The rulebook as we go along. In order to fire at missile you must have a missile launcher (we assume a turreted one here) and a missile in the launcher (we assume standard 50 kg missile, the only ones normally allowed for Traveller characters). In fact, we assume you are Jamison, the Free trader captain in the space combat example on pages 18-19, we’ll skip right to Jamison retaliating with his missile launcher, on page 19.
Two traders disagreeing over something leading to hostilities. Let’s call the aggressor Grant and let’s call the defender Jamison. Grant has an Empress Marava class Far trader, Size 8 with 2 computer dice pool, their crews are both skill 2 in all departments. The ship has two turrets mounted left and right, each holding a 20 MW laser and a sandcaster. Jamison has a Beowulf class Free trader, Size 7 with 1 computer dice pool. The ship has two turrets mounted top and bottom, each holding one 10 MW laser, one small missile launcher and one sandcaster.
Jamison retaliate
The situation is that Mr Grant won the initiative and fired upon Jamison with his two lasers taking out his powerplant, Jamison is about to retaliate but cannot use his laser because of the damaged powerplant, damage effects takes place immediately in Intercept. Jamison will attack using his missile launcher because that requires no running powerplant. Let’s follow the rulebook step by step
We must determine the range so we know what to roll to hit and we need the attack vector to know how hard we hit.
Launch position
Launched missiles use the Drift position from the launching ship instead of the actual position of the launching ship. We simply assume that the missiles were launched at the start of the turn and have been thrusting during the turn free from the launching ship.
Jamisons drift is 4 squares away from Grants ship, don’t forget that diagonals count as 1.5.
Attack vector
The missiles in Intercept use kinetic energy for damage, as would any space combat missiles in the real world. This means that what relative speed the missile impacts the target affect whether it will penetrate and how much damage it delivers, it also affects the likelihood of hitting as well as the likelihood of any point defense lasers stopping it. Our friend Newton would say this will require some vector algebra but thankfully I have come up with a really nifty way of avoiding all that, hang on.
The attack vector is simply the separation the attacker and target had last turn. Think about it, the two where separated that distance the last turn and now there are at the same position therefore the two of the somehow must have closed that distance in one turn and thus we have the speed, nifty! Just by coincidence the separation from the last turn was also 4 squares. It doesn’t matter in what order you do the straights and diagonals as long as you count the diagonal 1.5, and drop any final .5 from the distance measured.
The figure above shows the steps taken for missile combat, it’s taken from page 12 of the rulebook. All right let’s quickly go through each step of the sequence. Grant has already attacked using his lasers so these are the steps for Jamisons retaliation.
Missile attacks are performed after beam attacks for the current ship
Jamison cannot fire his 10 MW beam laser because Grant just scored Critical on his power plant.
Snap missiles launch during the attacking ship’s combat phase
Jamison is a civilian and is only allowed the small 50 kg Snap missiles.
Regular and Cruise launch and move during the missile movement phase
We’ll cover Regular and Cruise missiles in an upcoming post.
Missiles outside of launcher range at the end of the movement phase are lost
This only affect Regular and Cruise missiles and will be covered in an upcoming post.
Missiles need only be within launcher arc when attacking
The target must be inside the attacking mounts launcher arc when attacking ie the missile gunner must ‘see’ the target. Intercept missiles are operator guided, homing missiles may be covered in a future post. Grant is in the top turret launcher arc when attacking so the attack is allowed.
Targets in a thrusting attackers aft centerline cannot be attacked
A thursting ship has narrow arc to the rear where they are blind on all sensors and this means that the ship cannot use its lasers to defend against missile attacks originating from the aft centerline squares. Attack position here is the missile Launch position as mentioined above. Jmaison as far from Grant’s aft centerline so Grant would be able to use lasers defensively against the attack but Grant has already used these lasers offensively so that is not allowed. Lasers can eiker attack or defend in a single turn but not both.
Missile attack
We have previously determined that the range (from Launch position to target) is 4 squares and that the attack vector also is 4 squares. The basic target number for missile attacks is a whopping 19+ but this is before we have applied the modifiers. Let’s go through each of the DMs and see whcih apply:
Target Size
This is the most important DM, Grant’s ship is Size +9 as seen from his datacard.
Target drifting
Grant thrusted this turn so we skip this DM.
Gunner skill
Jamison’s Gunner has skill level 2 so this gives us +2.
Crew damage Light / Severe
If the crew area has suffered damage the crew performance goes down of course, if crew damage is Critical they may not attack at all (nor defend or even pilot the ship). No crew damage, at least not yet, so no DM here.
Surface damage Light / Severe
A ships weaponry and sensors are in the Surface location so their performance suffer when they take damage. There is no damage on Jamison’s Surface location so there is no DM here.
Dual role sensor task
Naval vessels typically have dedicated crew for sensors and gunnery but merchants typically have them serving dual roles. Dual role sensor/gunner crew suffer -3 on attacking/defending if they performed a sense task prior in the turn and they suffer a -3 on sense tasks if they attacked/defended in the previous turn. Jamison was already tracking Grant this turn so there is no DM here.
Vector DM
We previously determined the Attack vector to be 4 and this will determine the Vector DM as well as modifiers to PEN and DAM if we hit. A faster relative velocity makes the target harder to hit but also has more penetration and damage as Intercept missiles (the non nuclear ones) cause damage by kinetic energy. At a spped of just 1 a missile would inflict ten times more damage than if the missile was entirely made of TNT! Attack vector of 2-4 gives a Vector DM of 0.
Volley units
The number of missiles in the attack volley increase the likelihood of a hit, DMs from multiple missiles is on page 9 in the rulebook. Only the top turret have Grant in its arc, so there will be only one missile in the volly and thus no DM.
Remaining thrust
A missile uses its thrust to close the distance to its target but also to aim for the target. If more thrust remain the missile has a larger chance of hitting. For each remaing G of thrust the missile gain a +1 DM up to +3 for 3 remaining Gs. Jamison’s missiles are 5G and the range was 4 so he gets a +1 from remaining thrust.
So, +9 for target size, +2 for gunnery skill and +1 for remaing thrust: +12! Jamison must roll 19+ with +12 DM which is 7+.
Before rolling sense, attack or defense tasks ships can add dice from their computer dice pool to the roll. Jamison has just one die in his dice pool and he decides to use it now. He rolls 3 D6 and pick the 2 highest D6. In the example in the rulebook Jamison has already used up his single die of computer pool for sandcasters against Grant’s attack. Jamison roll 5, 6 and 2. His 2 highest D6 are 5 and 6 so his 11, three higher than the required 8, a Good hit.
Grant has already used his lasers for attacking so he cannot use them in defense against the missile, the missile stays a Good hit.
Hitlocation
Hitlocation is based upon where the attack is coming from using the diagrams above. The Launch position is clearly in the front area so hitlocation rolls 2 D6 and picking the lowest D6. Jamison roll a 3 and 5 so 3 is used;
Core. Jamison scored a Good hit and this allows him to move the hitlocation one step up or down on the table, he can pick Crew or Surface instead of Core if he wants to. Jamison decides on Surface, to possibly take out Grant’s lasers.
Penetration
In order to score any damage the attack must penetrate the targets armor first and this is done by comparinmg the PEN of the attack versus the ARM of the target location. Jamison’s missile has PEN 28 and DAM 28, these are modified by the ATtack vector but the previously determined Attack vector of 4 give no modifiers tp PEN and DAM (had the Attack vector been 5 PEN & DAM would add +3 and if the Attack vector was 1 PEN & DAM would be modified by -3). The Surface location has two ARM values, the left lower one is for opped out and the right one is for popped in), 13 / 19 for Grant.
Grant has his weapons and sensors popped as he is attacking so we’ll use the left 13 value for ARM. Looking at the Penetration table above we see that with a PEN – ARM of 15 the hit will penetrate regardless of the hit being a Fair, Goo or Very Good hit. Jamison has hit and penetrated the Surface location of Grant, let’s get on with dealing damage.
Damage
Damage is determined by subtracting the DAB of the ship from the DAM of the attack and adding a die roll that is rolled differently based on the hit task result. After the degree of damage has been determined shift one row up if the hit location is Surface, Power or Thrust or two rows down for pass-on damage.
Fair hits roll 2D6 and use the lowest of the two, change of rolling a 6 is one in 36.
Good hits roll 2D6 and use the highest of the two, chance of rolling a 6 is 11 in 36, much better.
VGood hits don’t roll, you simply treat the result as if you rolled a 6, 36 in 36, as good as it gets.
If the result of the roll was a 6 you also roll Exploding Dice or ED for short. Roll 1D6 and add half the result rounded down, if that roll was a 6 you roll another ED dice and so on. If the result of the roll was a 1 you suffer Continuing Damage or CD for short, mark the CD checkbox on the ship paper.CD means that at the end of each turn, including this turn, by rolling 1D6 and increase damage if a 1-2 was rolled, the CD fizzles out on a roll of 6 so remove the CD check, rolling 1-5 and the CD remain. Whenever Repair Crew manages to Jury-Rig a damaged location the CD fizzles out too.
The missile has a DAM of 28 and the attack vector of 4 does not change this as we saw on the Missile attack image far above. Grants Far Trader has a DAB of 22 so the resulting damage is 28 – 22 = 6 to which we will add the damage roll. Jamison scored a Good hit so he rolls 2D6 and use the highest value. Jamison rolls a 2 and 3 so the damage roll is treated as 3. 6 + 3 = 9 and looking up 9 on the damage table gives us Severe damage. Surface location hits are treated one row worse so the damage is actually Critical! This means that Grant can no longer use his sensors or weapons until his Repair Crew manages to Jury-Rig the damage down to Severe.
Summary
So there you go, an overly wordy description of missile combat. A brief summary would go something like this:
Lauch position Determine the missiles launch position (same as Drift position for Snap missiles). This will determine how hitlocation is determined.
Attack vector Determine the attack vector which is simply the separation between the ships from the last turn. This determines Vector DM when rolling to hit and Vector PEN & DAM modifiers if a hit was scored.
Attack roll Roll to hit and note the task result. Don’t forget the DMs from the attack vector.
Defense roll Defender if tracking the attacker may use lasers to defend, but obly if lasers haven’t already been used offensively in the turn. This defense roll reduce the degree of success of the attack, possibly down to a miss.
Hitlocation VGood hits pick hitlocation, Good roll but maybe pick adjacent and Fair attacks simply roll. How the roll is made depends on the where the launch position is versus the target.
Penetration Determine Penetration by comparing the PEN of the missikle and ARM of the hitlocation. PEN is heavily modified by the attack vector and ARM depend on hitlocation but also on wether weapons and sensors where popped out or the powerplant was running.
Damage roll Roll damage based on the degree of success. Note damage and possibly CD if a 1 was rolled.
So there, that is all there is to it, remember to watch your aft centerline and scan near yourself as missiles are deadly.
We have guided missiles and misguided men.
Martin Luther King Jr
Vector movement 