"Mission Kill" Odds
in 2300AD Starship Combat

Copyright © 1997, 1998, 2002 by Kevin Clark.  All Rights Reserved.
Disclaimer

Introduction

I am confident, that in your mind's eye, you have the image of the Kafer warship becoming an expanding cloud of space dust.  This is the normal way everyone envisions a starship battle ending, but every decisively victorious fight does not have to end with all of the loser's side atomized.

Being "vaporized" is legitimately one possible result of combat; a starship can be destroyed by losing all of its hull points, in Star Cruiser.  When it gets to "zero", the hull's structural integrity fails and the ship either tears itself apart or it is vaporized.  It is now an ex-ship, and definitely out of the fight, and naturally unable to finish its mission.

What is a "Mission Kill"?

There are three vital hit locations, in Star Cruiser, that are critical to almost every mission:

1) Computer

Having your computer network go down leaves you stationary, blind, unable to aim and fire weapons, or run your remotes.  Your shields are also ineffective, just like if you were at "all stop", but without the reductions in signature ( unless you also throttle down your power plants, and shut off the "noisy" screens).

This is the most deadly hit location in the game, since it leaves you totally vulnerable, floating hulk, possibly powerless.  You are the space equivalent of a roadside sign in hunting season, or the proverbial sitting duck.

The biggest toughest battleship in the game can be brought down by this hit.  This is the "David versus Goliath" killing shot in Star Cruiser.

In my own campaign, you are also left with only battery/emergency power, since your powerplant's safeties triggered a plant shutdown to prevent power surge damage ( created by the nearly instantaneous, huge drop in power load/demand).

2) Stutterwarp

This hit also renders you stationary.  You cannot pursue a departing opponent, control the orientation of your ship versus your opponents ( if you move first in the sequence of play), or depend on your shields for any protection.

One gripe of mine with Star Cruiser is that when you are completely "stationary" ( not using your stutterwarp), your opponent should get a bonus to hit you.  I've tried a '+2' bonus, and/or scoring two actual hits ( two location rolls -- each doing the normal damage for that weapon system) per successful roll to hit.  I'm still not perfectly happy with this fix, and still need to do a more detailed statistical analysis of it.  I'll keep you informed if I come up with something better.

3) Life Support

If you run Star Cruiser's rules as written, then this hit means that unless your Crew Quality is '+3' ( Elite) you will never fix any damage to your ship while the battle is still raging.

This critical hit, when combined with continuing damage and a less than elite crew ( or if all of the damage control personnel are dead), will always destroy your ship, if the battle drags on for too many turns.  I've lost numerous Kafer warships ( and several Human civilian starships) to this combination of events.

The odds of taking damage to one of these vital locations in Star Cruiser is 2% per successful hit.  Since there are three vital locations, the total chance of a "mission kill" is 6% per successful hit.

Large Starship Table

Note: This table ignores the effect of shields -- so it only accurately shows the odds for successful hits, which also gets past the shield ( or automatically through after the shields are worn down to zero).

                             Any Large Starship
                                 Armor Level
       0      1      2      3      4      5      6      7      8      9
Hits --------------------------------------------------------------------
  1   6.0%   5.4%   4.8%   4.2%   3.6%   3.0%   2.4%   1.8%   1.2%   0.6%
  2  11.6%  10.5%   9.4%   8.2%   7.1%   5.9%   4.7%   3.6%   2.4%   1.2%
  3  16.9%  15.3%  13.7%  12.1%  10.4%   8.7%   7.0%   5.3%   3.6%   1.8%
  4  21.9%  19.9%  17.9%  15.8%  13.6%  11.5%   9.3%   7.0%   4.7%   2.4%
  5  26.6%  24.2%  21.8%  19.3%  16.7%  14.1%  11.4%   8.7%   5.9%   3.0%
  6  31.0%  28.3%  25.6%  22.7%  19.7%  16.7%  13.6%  10.3%   7.0%   3.5%
  7  35.2%  32.2%  29.1%  25.9%  22.6%  19.2%  15.6%  11.9%   8.1%   4.1%
  8  39.0%  35.9%  32.5%  29.1%  25.4%  21.6%  17.7%  13.5%   9.2%   4.7%
  9  42.7%  39.3%  35.8%  32.0%  28.1%  24.0%  19.6%  15.1%  10.3%   5.3%
 10  46.1%  42.6%  38.9%  34.9%  30.7%  26.3%  21.6%  16.6%  11.4%   5.8%
 11  49.4%  45.7%  41.8%  37.6%  33.2%  28.5%  23.4%  18.1%  12.4%   6.4%
 12  52.4%  48.6%  44.6%  40.2%  35.6%  30.6%  25.3%  19.6%  13.5%   7.0%
 13  55.3%  51.4%  47.2%  42.8%  37.9%  32.7%  27.1%  21.0%  14.5%   7.5%
 14  57.9%  54.0%  49.8%  45.2%  40.1%  34.7%  28.8%  22.5%  15.6%   8.1%
 15  60.5%  56.5%  52.2%  47.5%  42.3%  36.7%  30.5%  23.8%  16.6%   8.6%
 16  62.8%  58.9%  54.5%  49.7%  44.4%  38.6%  32.2%  25.2%  17.6%   9.2%
 17  65.1%  61.1%  56.7%  51.8%  46.4%  40.4%  33.8%  26.6%  18.6%   9.7%
 18  67.2%  63.2%  58.7%  53.8%  48.3%  42.2%  35.4%  27.9%  19.5%  10.3%
 19  69.1%  65.2%  60.7%  55.7%  50.2%  43.9%  37.0%  29.2%  20.5%  10.8%
 20  71.0%  67.1%  62.6%  57.6%  52.0%  45.6%  38.5%  30.5%  21.5%  11.3%
 30  84.4%  81.1%  77.1%  72.4%  66.7%  59.9%  51.8%  42.0%  30.4%  16.5%
 40  91.6%  89.1%  86.0%  82.0%  76.9%  70.4%  62.2%  51.6%  38.3%  21.4%
 50  95.5%  93.8%  91.5%  88.3%  84.0%  78.2%  70.3%  59.7%  45.3%  26.0%
 60  97.6%  96.4%  94.8%  92.4%  88.9%  83.9%  76.7%  66.4%  51.5%  30.3%
 70  98.7%  97.9%  96.8%  95.0%  92.3%  88.1%  81.7%  72.0%  57.0%  34.4%
 80  99.3%  98.8%  98.0%  96.8%  94.7%  91.3%  85.7%  76.6%  61.9%  38.2%
 90  99.6%  99.3%  98.8%  97.9%  96.3%  93.6%  88.8%  80.5%  66.3%  41.8%
100  99.8%  99.6%  99.3%  98.6%  97.4%  95.2%  91.2%  83.7%  70.1%  45.2%

Large Starship Example

Situation #1: The Kennedy sends 4 SIM-14 detonation missiles in against the Improved Alpha.  The Kafer crew shoots down two of them, in the terminal phase.  Both surviving SIM-14s detonate and hit.  What are the odds of taking out the Kafer ( crippling him, getting a "mission kill")?

The first SIM-14 is unlucky, all ten pulses hit the level 9 screens and are stopped, but at least the screens are now "down".

Be advised that official errata, from GDW, in a Traveller's Digest article, stated that since all the pulses from a single detonation missile strike the target simultaneously, the shield level is reduced only after you have rolled for the penetration of all the pulses.  This means that someone with level 1 screens versus a 3x5 detonation warhead could get very lucky ( by rolling a '1' three times in a row) and stop all three pulses.  Only after all the screen penetration rolls for that one missile are done, then the screen level is lowered by the number of hits stopped, as described in the rulebook.  If more than one missile detonate, each is handled separately.

Now all 10 pulses ( each doing 'x2' damage) from the second successful missile hit the Kafer.  Since the screen is "down", we now consult the table.  We cross reference 10 hits ( pulses) versus the Kafer's 9 armor to get a 5.8% chance of this missile causing a "mission kill".

(Note: If you are instead using the optional armor penetration rules, found in the Invasion sourcebook ( sidebar on page 53), then the 'x2' pulse gets a +1 to bonus to armor penetration.  This +1 is the same as checking against armor that is one level weaker. So using this optional rule, 10 pulses versus armor 8 is an 11.4% chance of causing a "mission kill".)

Situation #2: The Kennedy Captain, after making a tactical error, is attacked by two Kafer X-ray detonation missiles.  Unfortunately the Human crew only shoots down one of them, in the terminal phase.  The surviving X-ray detonates and hits.  What are the odds of taking out the Kennedy ( crippling him, getting a "mission kill")?

Well the X-ray has 14 pulses ( each doing 'x2' damage), so cross referencing 14 hits ( pulses) versus the Kennedy's level 1 armor to get a 54.0% chance of this missile causing a "mission kill".

( Note: Using Invasion's optional armor penetration rules, then this is 14 pulses versus one level weaker armor ( so is treated like it was armor 0) which would be a 57.9% chance of a "mission kill".)

The Kennedy-class actually has armor level 1.  For a hull made of advanced composite, an unarmored hull will mass the same as a level 1 armored hull, so it is treated as armor level 1( If you were the Captain, you would want every "free" advantage you could get).

The moral of the story is that if you are relatively unarmored, stay far, far away from those X-ray missiles.

Smallcraft/Fighter Table

It is the continuing damage hit location, which happens 6% of the time.  Adding this 6% to the above 6% that all star vessels have, then the total chance any one successful hit will create a "mission kill" on a smallcraft is 12%.

                             Smallcraft/Fighters
                                 Armor Level
       0      1      2      3      4      5      6      7      8      9
Hits --------------------------------------------------------------------
  1  12.0%  10.8%   9.6%   8.4%   7.2%   6.0%   4.8%   3.6%   2.4%   1.2%
  2  22.6%  20.4%  18.3%  16.1%  13.9%  11.6%   9.4%   7.1%   4.7%   2.4%
  3  31.9%  29.0%  26.1%  23.1%  20.1%  16.9%  13.7%  10.4%   7.0%   3.6%
  4  40.0%  36.7%  33.2%  29.6%  25.8%  21.9%  17.9%  13.6%   9.3%   4.7%
  5  47.2%  43.5%  39.6%  35.5%  31.2%  26.6%  21.8%  16.7%  11.4%   5.9%
  6  53.6%  49.6%  45.4%  40.9%  36.1%  31.0%  25.6%  19.7%  13.6%   7.0%
  7  59.1%  55.1%  50.7%  45.9%  40.7%  35.2%  29.1%  22.6%  15.6%   8.1%
  8  64.0%  59.9%  55.4%  50.4%  45.0%  39.0%  32.5%  25.4%  17.7%   9.2%
  9  68.4%  64.2%  59.7%  54.6%  49.0%  42.7%  35.8%  28.1%  19.6%  10.3%
 10  72.1%  68.1%  63.6%  58.4%  52.6%  46.1%  38.9%  30.7%  21.6%  11.4%
 11  75.5%  71.6%  67.1%  61.9%  56.0%  49.4%  41.8%  33.2%  23.4%  12.4%
 12  78.4%  74.6%  70.2%  65.1%  59.2%  52.4%  44.6%  35.6%  25.3%  13.5%
 13  81.0%  77.4%  73.1%  68.0%  62.1%  55.3%  47.2%  37.9%  27.1%  14.5%
 14  83.3%  79.8%  75.7%  70.7%  64.9%  57.9%  49.8%  40.1%  28.8%  15.6%
 15  85.3%  82.0%  78.0%  73.2%  67.4%  60.5%  52.2%  42.3%  30.5%  16.6%
 16  87.1%  83.9%  80.1%  75.4%  69.7%  62.8%  54.5%  44.4%  32.2%  17.6%
 17  88.6%  85.7%  82.0%  77.5%  71.9%  65.1%  56.7%  46.4%  33.8%  18.6%
 18  90.0%  87.2%  83.7%  79.4%  73.9%  67.2%  58.7%  48.3%  35.4%  19.5%
 19  91.2%  88.6%  85.3%  81.1%  75.8%  69.1%  60.7%  50.2%  37.0%  20.5%
 20  92.2%  89.8%  86.7%  82.7%  77.6%  71.0%  62.6%  52.0%  38.5%  21.5%

This table works the same way, and since there are currently no smallcraft which have shields ( except for the British Donovan fighter), you can use it almost all of the time.

If five turrets engage an incoming fighter, and three manage to hit.  Then cross reference the "3" hit row versus the fighter's armor level.  If the fighter had armor 4, then the fighter is crippled ( "mission killed") 20.1% of the time.

A note to all those starship designers out there.  You can use these tables to predict how well your starship will hold up under attack by various detonation missiles, or when "under the lasers" of an enemy starship.

If you have any questions about the above, please email me.

Revision History