Star Cruiser missiles are not very realistic. For a start unlike turret weapons (with a large 6m diameter focal array and monochromatic X-Rays) the beams are not focused. The beams are at best collimated, and thus at even a few thousand km (far less than a SC hex) are meters across and essentially a warm wind rather than ravening beams of death. The same also applies to submunitions and particle beams.
The fix of course is to make everything that isn't a turret laser a sub-range 0 weapon. With these weapons a very close range detonation that hits (on the order of km) is likely to literally tear the target to pieces. However, of course this increases the amount of time defensive fire has to shoot down the incoming vampire. However, stutterwarp is so fast that a warp 3 missile is traveling roughly 3.36 million m/s, so there's not a huge amount to be gained by increasing the range of detonation. The time taken to go from the hex-side to the middle of a hex at warp 3 is 89 seconds, and it crosses "1 hex" in 179 seconds (say 3 minutes). Ignore the so-called "1 minute turns"; there were always a typo.
This means the difference in defensive fire a missile receives between ineffective detonation (1,000 km) and effective detonation (1 km) is miniscule. As far as SC is concerned the missile literally has to travel through the target hex and "impact" the target. This is a strong argument for why submunitions aren't that effective, and why perhaps nuclear mines are also ineffective.
Guidance
Realistically we have three possible forms of guidance:
1. Full control
2. Semi-active
3. Fully independent
1. Full Control
Basically the missile is being flown by a remote pilot onboard the mothership (usually). The implication for lag is enormous. At close range (like the same hex) the missile can be fire essentially as a turret weapon, but as the range opens the lag is roughly the same as a turret weapon.
The missile thus should be treated roughly as a very long range turret, but we don't have range tables beyond one hex (-2). Personally (since I'm also in favour of large focal arrays and longer range turrets) I'd restructure the range modifier to - 2x range (i.e. -2 at 1 hex, -4 at 2 hexes, -6 at 3 etc.), and should probably get the TC and RP skill as bonuses (which partially offsets the penalties at medium ranges).
2. Semi-active
Once the missile has a seeker head (i.e. a sensor) but not the full package of processing equipment then semi-active is possible. The mothership probably maintains a datalink to the missile, but aims by pointing the active sensor array at the target and the missile watches for reflections and fires on them.
The advantage is that lag is essentially eliminated - the missile when it reaches detonation range is milliseconds or less away from the target, but has to generate the target solution on more limited equipment.
In game terms apply the -3 penalty for an independent weapon, and no TC or RP bonus, but no range penalty. To determine whether the missile can track add the target reflected signature (as appropriate), motherships active sensor value (dedicated or not) and deduct range. Roll d10, if less than the result then the missile is "locked on" and can make an attack.
Example: A Kennedy (active-15 with SIM-14 missiles = 8) is firing at a Hamburg (lat ref = 7) 25 hexes away. The target number is 5, at this range the missiles will achieve a lock on to attack on 50% of attempts. Roll for each missile in the salvo after any defensive fire.
3. Fully independent
The missile is constructed as a full starship. No examples. No rules given.
Ranges of the passive sensors (likely radar only receivers given the tiny size, none has 30 m^2 of passive array) of SC missiles are:
Ritage-1: 5
Ritage-2: none
EM-1: 0
EM-5D: 0
AAS-2: 1
AAS-2B: 2
AAS-4/5: none
SR-9: none
SR-10: 0
Fantan: none
Glowworm: 3
SIM-14: 8
Silka: none
Kafer Whiskey: none
Kafer X-Ray: 2
The missile with no sensors are thus close range weapons, and given the above at 3-4 hexes with modern ships are advantaged over SA missiles (which fits the errata limiting all missiles to 4 hexes from the controlling ship). Those with sensors are designed for "long shots" with the Ritage and SIM-14 capable of some quite long shots upwards of 20-30 hexes, but most capable of 10-15 hex shots.
Cost
SC missiles were mostly constructed with NAM, but for some reason prices are divided.
An alternative is to simply make all use OC drives, which IMC implies a single coil rather than multiple coils of OM and NM drives.
The missiles using NM modifiers will have speeds 83% of the original, and OM 92% of the original.
A Silka could thus be a OC Fuel Cell, OC Drive (which it had anyway) a nav array (inc. comms) and a 5x2 warhead massing 1 ton and costing MLv1 - total cost MLv 3.02 per missile.
A SIM-14 would be a 0.07 MW NM Fuel Cell, 0.07 OC drive, nav, directional passive-8 (1 m3, 0.1 tons, MLv 0.08 say) and a 10x2 (2 tons, MLv2) = MLv4.3 (with NM drive =MLv11.1). Warp = 2.94 (slow as large warhead on a small drive).
Big missiles
MikeJ wrote up for his Russians an equivalent of a Sunburn - 0.3 MW drive missile giving a very high warp speed with a big warhead. Of course the darn thing will cost about MLv15 per pop.
That said, the original boxed set Kafer X-Ray is clearly more like a Sunburn, with a move of 11 and 2 power plant hits (implying a very large drive). That's rather different, and makes Kafers a bit scarier. One wonders if this was changed when the Kennedy kept getting slaughtered.
Damage
A turret (x1) puts out roughly 1/3,500th of a kiloton per turn (20 minute). Ergo a moderate nuke puts out at least 10,000 "hits" in energy, but it is not very concentrated. The x1 laser has an impulsive density of about 3 MJ/cm^2 (at 20% efficiency), whereas a 100 kT nuke without shaping 250 m away has a density of 0.05 MJ/cm^2. However, with shaping it's very hard to get the pulse intensity as high as a focused weapon unless very close - 1 cm beams occur around 180 km, but efficiency is low. By low I mean that 1980's estimates that we might get 0.1% of the X-Rays coming out of the rods seem high.
Since the best rod is 1.4 nm wide, and for a 1 m device each rod is 4.456x10^-10 of the diameter. If we generously say 10% of the radiated X-Rays (i.e. 7% of the total energy) are in the region adjacent to the physics package with the right angle then each rod will emit (for a 10 kT device) 1.3 kJ. Thus either the bomb needs to be bigger, or each "pulse" must be come from a large number of rods (about 5,000 for a x2 pulse).
Let he note here that the bomb is likely a simple fission device, since fusion produces fast neutrons rather than X-Rays (which in a modern thermonuclear warheads are used to inefficiently fission U-238 boosting the explosive power but at the cost of a much dirtier bomb). So megaton nukes are out.
Ergo I think a reasonable case can be made that the damage levels are reasonable, especially since the pattern of sewn pulse will be much wider than a ship and most will miss.
However, better would be to have a roll for the number of pulses that hit. In fact instead of a general hit/miss roll like turret lasers instead a better model would be a "no. of hits" roll that allows for a result of zero.
That said, I think that turret lasers should allow for multiple hits. Perhaps for each "level" (4 points) the to hit roll is passed by an extra hit is inflicted. In this case the missile should make multiple to hit rolls equal to the "no. of pulses".
So for example, a spread of 4 SIM-14's against an Alpha at long range will roll 40 times, with rolls of 8-10 inflicting a hit, but at range = 2 rolls of 3-7 will hit once, but 7-10 twice. The average numbers of hits are 12 and 48 respectively. We should use a table converter to determine actual numbers of hits.
Submunitions of course are essentially range-0 missiles, so against an Alpha with FC+2 and CQ+2 rolls of 1-2 hit once, 3-6 twice and 7-10 thrice. A 5 pulse Big Clip hits 11 times on average. Hence one can see just how dangerous a reimagined fighter with many submunitions launchers could be to a capital ship.
