Table of Contents

• Executive Summary
• Introduction
• Scope
• Definitions
• Turret Missile Derivation
• USP Table
• 7.84 Derivation
• Battery Round Derivation
• Magazine Size Derivation
• Rules Clarifications and Additions
• Heresies
• Resupply Issues
• Sample Ships
• Conclusion
• References
• Appendices
  • Turret Missile Derivation
  • USP Table
  • 7.84 Derivation
  • Magazine Size Derivation

Executive Summary

This article covers rules for High Guard second edition (published in 1980) missile magazines. Rules for adding missile magazines to ships were included in High Guard first edition (published in 1979), but are missing from High Guard second edition. Alternatives are given to cover universes where turret and bay missiles are the same and where they are different sizes. In my Traveller Universe I have chosen: to use bay missiles that are larger, to have different numbers of launchers for different size bays and tech levels, and to require a separate 36 battery round magazine for planetary bombardment. In my Traveller Universe missile magazines are XXX tons and MCr XXX for the initial installation, and XXX tons and MCr XXX per missile in the magazine.

Introduction

In the High Guard first edition, rules for adding missile magazines were included. They were not very detailed on what magazines represented, how they affected the rules, or how many missiles were included. This article expands and details my concept for missile magazines for the second edition of High Guard (in which the magazine rules were removed).

Depending on which Traveller design system you work with, turret and bay missiles may be defined as the same size or different sizes. I present one case where they are the same size, and another where the bay missiles are several times as large. The number of launchers in a bay was never made clear in Classic Traveller, though MegaTraveller specified two and Mark Miller's Traveller gave different numbers of launchers for various tech levels and bay sizes. I present three cases for the number of launchers in bays, one assuming turret and bay missiles are the same, another assuming bay missiles are larger, and a third assuming there are only two launchers.

Scope

This article includes exploration of two missile sizes, three launcher number variations, and two magazine capacity options, all relating only to High Guard. This article excludes major changes to missile launch rates or turret missile sizes, and does not consider sand caster magazines.

Definitions

Definition: Missile magazines are automated storage for large numbers of missiles. Magazines can be added to support missile bays or turrets on a ship, or added to supply vessels to replenish missile armed ships. Magazines are designed in units of battery rounds.

Definition: A battery round contains the same number of missiles as there are launchers in the bay or turret battery.

Turret and Bay Missiles Compared

High Guard second edition turret weapons USPs are found by cross-referencing the number of weapons with a USP number (High Guard second edition p25). This contrasts with High Guard first edition in which a point value was assigned to each weapon (turret or bay), and the points totaled (turret missiles plus bay missiles), and the point total divided by the number of kilotons displacement of the ship, then the adjusted point total referenced to a USP table.

The use of a point system for the various weapons in High Guard first edition made the relationship between turret and bay missiles easy to grasp, as well as making the design of missile magazines straightforward. High Guard second edition is much less clear on the relationship between turret and bay weapons. To clarify the relationship, I put turret and bay missiles on a single table comparing USP to tech level.

This table suggests we should be able to come up with the number of turret missile racks that would be equivalent to the various bay missile installations. Regression analysis yielded an equation that fits the turret data and extrapolates to cover bays in a satisfactory manner (see appendix 1 for more details).

The canonical Book 2 triple missile turret can hold three missile racks, each having three missiles (one ready to fire and two reloads). A turret missile is 0.05 tons, so a launcher at twice that size is 0.1 tons, and a reload cradle is half again as large as a missile, which comes to 0.075 tons. When we group a missile launcher and two reload cradles, we come up with a weapon that is 0.25 tons. Three of these fit into a one-ton turret with 0.25 tons left over, which is space enough for a crew seat, some controls, and traverse/elevation mechanisms.

7.84 Conversion Derivation

Of the four Classic Traveller sources on missiles, two (Striker and Special Supplement 3) indicate that bay missiles are larger than turret missiles. Book 2 only deals with turret missiles, and High Guard is silent on the question. All the later design rules have missiles that are much larger than those in Classic Traveller turrets. The first step in coming up with larger bay missiles is to decide how much bigger they are, and Striker gives some clear information on this. Striker indicates that turret missiles are 15 cm rounds, and that bay missiles are 25 cm rounds. Dividing the area of bay missiles by the area of turret missiles, we come up with a ratio of 2.8. It seems reasonable that a missile with a larger area would have a greater length as well, and I chose 2.8 times as long. Multiplying the original 0.05 ton volume of the turret missile by the 2.8 ratio of the area and the 2.8 ratio of the length, we get 0.39 tons which I round to 0.4 tons.

Bay Battery Round Derivation

Magazine Design

To be considered capable of surface bombardment, a ship must have enough magazine capacity for a 12-hour shift of firing (which is 36 battery rounds). A bay missile magazine costs MCr 5 and 5 tons for the initial installation, plus MCr 0.0001 and (0.075 or 0.6) tons per reload cradle (depending on which size missile you use). A ship design capable of surface bombardment should include one magazine per missile bay.

Magazines for turrets are possible, but cost MCr 0.25 and 0.25 tons per turret in addition to the cost for the initial installation while eliminating the possibility of local control in the turret (as well as precluding the use of loader crew members). This cost per turret is in addition to the cost of a missile magazine to service these turrets (at MCr 5 and 5 tons for initial installation plus MCr 0.0001 and 0.075 tons per reload cradle).

To create non-standard magazine sizes (whether smaller or larger), multiply the size of the ready missile rack (0.075 or 0.6 tons) by the number of launchers (2, 5, 42, etc.) and then multiply by the number of battery rounds desired.

Rules for Magazine Use

Missile Parameters: Missiles can vary widely in their capabilities as well as in their physical descriptions. It is possible for missiles to be small enough to fit in the hand, or large enough to rival small craft. A standard has been established for turret missiles, however, which allows interchangeability of many different types of missiles and an ease of procurement as well. Standard turret missiles must be able to fit into a standardized shipping/launch container. The launch container is fitted directly to the launch rack and the missile is fired from it. The container includes integral test circuitry, provides protection from extremes of temperature and weather, and is isolated from the corrosive effects of atmosphere and moisture. The standard container is a cylinder with interior dimensions of one meter in length and 15 centimeters in diameter. Sealed for safety and security, the containers can be opened and the contents examined, removed or exchanged -- an important feature when components are to be custom assembled for specific missile types.

Magazine capacity (to allow use of missile racks in large scale bombing) may be specified. Planetary bombing is not available to ships without missile magazines.

Planetary Bombardment: Missiles may be used against planetary surface installations, specifically starports or cities, provided a magazine is installed in the attacking ship. Attacks are made using the missile attack table; each successful penetration of the defenses present results in an automatic hit. The referee is responsible for the determination of the city or starport's defenses, and for determination of the number of hits required for capitulation and destruction.

An otherwise unused bay may also be used to carry deadfall ordnance for planetary bombardment; such a bay is useless in battle, but is used to bombard worlds. Empty weapons bays may be put to a variety of purposes, from holding additional missile ammunition for other bays to housing vehicles such as air/rafts, shuttles, or ATVs.

Turret-mounted missiles have warheads equivalent to 15 cm CPR gun rounds; bay-mounted missiles have warheads equivalent to 25 cm CPR gun rounds. Ship missiles have the same guidance system types as tac missiles: they may be target designated, homing, or drone. A launcher may fire one missile per turn, in the friendly fire phase.

At TL21+, missiles gain an additional USP rating per break point in the weapons matrix. Thus 1 turret launcher will give a USP of 3, two launchers will give a USP of 4, and so forth.

Launch facilities for missiles from spacecraft are comparatively simple. Each launch facility consists of a standard crew workstation, a 300,000-kilometer-range laser communicator, and one or more launchers. Missile launchers may have their own active or passive sensors and master fire directors installed, but are not required to do so, as they are able to use target locks obtained by sensors mounted elsewhere on the ship, and hand off control of their missiles to MFDs elsewhere on the ship. A launch facility may (but need not) also contain a mechanical reloader and one or more reload cradles.

Note that missiles carried in launchers and reload cradles do not count against the volume of the launch facility, as the launchers and reload cradle volumes include the vacant spaces for the missiles.

To be considered capable of surface bombardment, a ship must have enough missiles for a 12 hour shift of firing (12 hr x 3 turns/hr x 1 missile/launcher/turn = 36 battery rounds). [An alternative is to require 24 hours worth of missiles, or 72 battery rounds, but this seems excessive to me.]

If using magazines in your designs, I suggest keeping track of rounds expended (on both sides of the battle).

On larger ships with missile turrets and no magazines, I suggest having one gunner per turret to keep it stocked from the cargo space.

Carrying missiles in cargo spaces uses the same space as a ready rack does (for packing) - 0.075 ton for turret missiles and 0.6 ton for bay missiles. Reloading rates can match those specified in Book 2 if you have the crewmembers for it.

Imperial Navy ships that use nuclear missiles will normally have an Imperial Marine group on board, partly to safeguard those missiles during loading operations at starports and bases.

Ships must designate whether the missiles they carry (regardless of how many) are nuclear or HE. Nuclear missiles can be fired in an HE mode (?) but HE missiles can't be fired in a nuclear mode.

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Reloading

Book 2 crew requirements include a gunner per turret. This gunner is the primary reloader for turret launchers, though the rules mention having helpers for the gunners (to transfer munitions from cargo). HG crew requirements include a gunner per battery. A battery can contain up to ten turrets. There are no munitions reloading rules in HG. I propose that a ship using HG crew rules that does not have a turret magazine can fire for three turns from each launcher before the launchers require reloading. The three turns of firing need not be consecutive. Reloading occurs at the same rate as in Book 2, with the gunner responsible for reloading all launchers in all his turrets. If sustained firing is desired from HG turret launchers, an additional crewmember should be added for each unit of three launchers (or portion thereof). These additional crewmembers are considered gunners for purposes of Book 2 compensation. The additional crewmembers are not normally firing the launchers, so they are able to reload at the faster Book 2 rate (keeping up with normal firing rates). In partial compensation for the additional crew required, ships crewed at this higher level will treat weapon -n damage results where n is greater than 1 as weapon -n+1 for those batteries (so weapon -4 becomes weapon -3, etc., while weapon -1 remains the same). This represents the additional damage control available, as well as the ability to fire turrets individually in local mode if fire control to the battery is disrupted.

Bay weapons can benefit from additional crewmembers as well when magazines are not installed. If bay missiles are the same as turret missiles, assign one crewmember per three launchers. If bay missiles are larger, assign two crewmembers per launcher. Assigning these additional crewmembers will allow reloading to keep up with normal launch rates and confer the benefit against weapon -n damage results.

Magazines are heavily automated; they only require one crewmember per 100 tons (or fraction thereof). Ship designers will normally choose either extra crewmembers or magazines (when they deal with reloading issues at all), but designers who choose both will have ships where the magazines can be restocked from cargo at the rate of firing, and which receive the benefit against weapon -n damage results.

Damage Results

If the battery to which a magazine is attached is reduced to USP of 0, the magazine is also made non-functional. A separate damage control repair roll must be made to restore the magazine to functioning status. A functional magazine attached to a non-functional battery may transfer missiles to other magazines in the ship (assuming the missiles are the same size). Ships having magazines which receive a Critical Hit of 11 (Spinal Mount/Fire Control Out) must roll again on the Critical Hit table with a DM of -12, which DM becomes less serious by one for each factor of armor around the magazine itself.

High Intensity Missile Fire

High Guard first edition p41: High Intensity Missile Fire: A ship armed with missiles may attempt to overwhelm its enemy by firing all of its missiles at once. This maneuver may be performed only once, but allows a DM of +4 to penetrate any and all defenses operating, including to hit the hull of the target.

ln (36) = 3.58, rnd 4

ln (18) = 2.89, rnd 3

ln (9) = 2.20, rnd 2

ln (5) = 1.61, rnd 2

ln (4) = 1.39, rnd 1

ln (3) = 1.10, rnd 1

ln (2) = 0.69, rnd 1

ln (1) = 0.00, rnd 0

5 and 4 are both listed because they are both reasonable roundings for half of 9. From this list I would strike 5 and 2 as redundant, leaving high-intensity fire of 36 rounds getting a bonus of +4 to hit and penetrate, 18 rounds getting +3, 9 rounds getting +2, and 4 or 3 rounds getting +1. Perhaps this could be extended to making the damage roll that much lower on the damage table? This would mean that a missile bay firing conventional missiles in 36 round high-intensity fire would roll 2D6, +armor of defender, +6 for being less than USP A, -4 for high-intensity fire.

Notes on Possible Heresies

(If allowing group defense against fighters?) Combine multiple ships into a single USP for attack and defense (but not screens) (this would apply to turret weapons only?)

Individual launchers (or small groups of launchers) in bays might be able to bear on different targets. This might require a special program and/or a larger computer and/or more crew (gunners). This would match up with variable turret groupings (USP) heresy.

Resupply Issues

Resupply is a serious issue when using expendable munitions (missiles and sand canisters). Once the munitions run out, those launching facilities are useless. Vessels that are likely to be away from supply sources for an extended period often minimize the number of launchers installed for this reason (this is especially true of exploration vessels). The three main ways to get around the problem of expendable munitions are; 1. not using them, 2. magazines, and 3. resupply vessels. Magazines increase the internal storage volume for munitions, and supply vessels ferry munitions from bases.

Resupply vessels can come in many sizes, from the common free trader to large special purpose military vessels. Regular cargo vessels will carry munitions in their cargo holds (sometimes as individual munitions, but more often in standard cargo containers). Special purpose military vessels might carry munitions as cargo, but more often they carry them in magazines. Normally magazines are designed with an armored reloading hatch, which can mate with similar hatches on resupply vessels or at bases. Connecting the hatches in this way allows very rapid transfer of munitions from one ship to another. this is normally done between battles, but could conceivably be done while both ships are in the reserve during a battle, or during orbital bombardment.

GMs can adjust the severity of resupply problems in their universe by choosing among several options:

1. Are bay missiles the same as turret missiles? If not, then two or perhaps three different sizes of missiles will need to be transported, and magazines will only work with one size of missile.

2. Are sand canisters the same dimensions as turret missiles? If they are the same, magazines can be used interchangeably for missiles or sand.

3. Are sand canisters able to be fired by missile racks? If so, why are there separately listed missile racks and sand casters?

4. What is required for resupply of space vessels beyond missiles and sand canisters?

Other Magazine and Missile Size Articles

Another way of looking at missile bays (and turrets) is to view them more like Multiple Rocket Launchers in modern day (TL7/8) Earth in which there are a number of missiles each in a tube, and they can be fired singly or in any combination, but when expended they need to be reloaded one by one. This appears to be the approach taken by Derek (aka Tyranian on the CT-Starships list), as well as the Traveller: the New Era turrets (and possibly bays).

Capital missiles have been proposed that would be one ton each (two and a half times as large as my bay missiles, twice as large as Marc Miller's Traveller missiles, and 20 times as large as Classic Traveller turret missiles). These would be much more powerful. I don't pursue this option in this article since there has been no canon suggesting this case.

Sample Ships

Missile bay armed ships (one using each style of bay and magazine?)

resupply vessels with magazines (one with and one without missile bays?)

Conclusion

The GM has to decide on the size of missiles in bays (and turrets), the number of launchers in bays, and the number of battery rounds required for planetary bombardment before magazines can be used in his universe.

My recommendations are (IMTU):

Notes to Think on

Investigate cost for nuclear dampers for magazines.

Calculate number of missiles or sand canisters in a standard cargo container.

Search for cargo transfer rates at various tech levels.

Size of Stiker crew seats.

Check Striker and FF&S for auto loader changes over different TLs. - FF&S doesn't change autoloader sizes by TL for space missiles.

Consider reworking high intensity missile fire in terms of the HG2 battery system rather than porting it from the HG1 aggregate system.

Could a nuclear missile be fired as an HE missile?

Appendices

My compiliation of sources related to Missile Magazines

Turret Missile Derivation

Turret missiles are 50kg in Book 2, so they are 0.05 HG tons (50kg per missile, and 1000kg per SI [mass] ton; 50kg/1000kg=0.05, therefore a CT missile is 0.05 dton - this is a big step, but I have to have someplace to start from). Turret missile launchers are 0.1 tons empty. Each reload cradle is 0.075 tons. Launchers and reload cradles include space for one missile each. A turret missile rack is 0.25 tons (one launcher plus two reload cradles). Triple missile turrets can accommodate three weapons, and a control couch for local control of the turret, so couch plus turret machinery is 0.25 tons (this fits with Striker's volume for a crew seat).

Bay weapons require a crew of two (0.5 tons for two couches as derived in the turret paragraph). Part of the bay machinery is auto-loading equipment connected to whatever storage space is on the ship. The autoloader can keep up with a normal rate of fire (1 missile per launcher per HG turn).

By doing regression analysis on the USP data relating to turret weapons, I came up with an equation that gets quite close to the data. Using y as the number of weapons, and x as the USP, use the equation: y = 1.125 x^2 - 2.2659 x + 2.55 and then round to the nearest whole number divisible by 3. This will get the same numbers as are in the USP table for turret missiles. Extending the USP series beyond 6 gives 42 launchers required for USP 7, 57 for USP 8, and 72 for USP 9 (with TL13+ getting a 1 USP boost - essentially requiring fewer launchers per USP).

Using assumptions of 0.05 tons per turret missile, 0.1 tons per turret launcher (includes space for 1 missile), 0.4 tons per bay launcher for bay support hardware (including connections to magazines and an autoloader), 0.5 tons for the bay crew of two, and 0.075 tons per missile per launcher for ready missile rack (includes space for 1 missile):

The MegaTraveller Referee's Guide vehicle design sequence suggests that there are two missile launchers per bay (though it also suggests that turret and bay missiles are interchangable, and that there are 50 missiles in a 50 ton bay and 100 missiles in a 100 ton bay). Using my calculations for turret missiles, I have determined the characteristics of bays with only two launchers.

7.84 Conversion Derivation

Area = pi * r^2. Striker says turret missiles are 15cm rounds, thus r = 7.5 and area = 176.7. Striker says bay missiles are 25cm rounds, thus r = 12.5 and area = 490.9. 490.9 / 176.7 = 2.8. 2.8 x 2.8 = 7.84. Striker indicates a turret missile is equal to a 15cm CPR round, and a bay missile is equal to a 25cm CPR round. The cross sectional area of a bay missile is thus 2.8 times that of a turret missile. It is not unreasonable (based on TL 7/8 missiles) to assume that a missile with almost three times the area would have a greater length as well, and 2.8 times the length is a convenient number. 2.8 x 2.8 x 0.05 = 0.39 tons.

For the case where bay missiles are larger than turret missiles, using assumptions of:

The MegaTraveller Referee's Guide vehicle design sequence suggests that there are two missile launchers per bay (though it also suggests that turret and bay missiles are interchangeable, and that there are 50 missiles in a 50 ton bay and 100 missiles in a 100 ton bay). Using my calculations for larger bay missiles, I have determined the characteristics of bays with only two launchers.

Magazine Size Derivation

To be considered capable of surface bombardment, a ship must have enough missiles for a 12 hour shift of firing (12 hr x 3 turns/hr x 1 missile/launcher/turn = 36 battery rounds). [An alternate thought would be to require 24 hours worth of missiles, or 72 battery rounds, but this seems excessive to me.]

5 tons and MCr0.5 per 30 tons of magazine (or fraction thereof) for equipment, crew stations, and passages for missiles.

To create non-standard magazine sizes (whether smaller or larger), multiply the size of the ready missile rack (0.6t) by the number of launchers (2, 5, 42, etc) and then multiply by the number of battery rounds desired.

Ready missile racks cost in MCr what they displace in tons: MCr 0.075 for turret reload cradles each and MCr 0.6 for bay reload cradles, and the machinery and connection cost to setup a magazine is 5 tons and MCr5. Create one magazine per missile bay. When drawing deck plans, magazines can be drawn one to a battery or bay, or all together in one spot but the initial cost remains a "per battery" charge.

Magazines for turrets are 0.5 tons and MCr0.5 per turret served. Ready missile racks cost MCr0.005 each. Create one magazine per battery.

If using magazines in your designs, I suggest keeping track of rounds expended (on both sides of the battle).

On larger ships with missile turrets and no magazines, I suggest having one gunner per turret to keep it stocked from the cargo space.

Carrying missiles in cargo spaces uses the same space as a reload cradle does (for packing) - 0.075 ton for turret missiles and 0.6 ton for bay missiles. Reloading rates per Book 2 if you have the manpower for it.

To find the complete size of a magazine: multiply the number of launchers by the reload cradle size by the number of rounds which will give you the reload cradle tons; for armor, use the formula in HG to find the tons of armor required to protect the reload cradles plus base tonnage and add it to the total.

Example: a 100-ton TL 7 missile bay magazine where turret and bay missiles are the same and containing 36 battery rounds would cost MCr 5 and 5 tons for the initial setup, plus MCr 113.4 and 113.4 tons for the reload cradles, plus MCr 37.9 and 37.9 tons for armor factor 7 protecting the magazine. The totals are: MCr 156.3 and 156.3 tons.

Assuming a separate 36 battery round magazine is required for bombardment, and assuming bay missiles are the same as turret missiles:

Tons for armor levels at the TLs for 100-t bay missile magazines - assuming a separate 36 battery round magazine is required for bombardment, and assuming bay missiles are the same as turret missiles.

Tons for armor levels at the TLs for 50-t bay missile magazines - assuming a separate 36 battery round magazine is required for bombardment, and assuming bay missiles are the same as turret missiles.

Assuming a separate 36 battery round magazine is required for bombardment, and assuming bay missiles are the same as turret missiles, and assuming there are only two launchers per bay:

Assuming a separate 36 battery round magazine is required for bombardment, and assuming bay missiles are larger than turret missiles:

Assuming a separate 36 battery round magazine is required for bombardment, and assuming bay missiles are larger than turret missiles, and assuming there are only two launchers per bay:

Assuming a total of 36 battery rounds for the magazine and bay combined is required for bombardment, and assuming bay missiles are the same as turret missiles:

Assuming a total of 36 battery rounds for the magazine and bay combined is required for bombardment, and assuming bay missiles are the same as turret missiles, and assuming there are only two launchers per bay:

Assuming a total of 36 battery rounds for the magazine and bay combined is required for bombardment, and assuming bay missiles are larger than turret missiles:

Assuming a total of 36 battery rounds for the magazine and bay combined is required for bombardment, and assuming bay missiles are larger than turret missiles, and assuming there are only two launchers per bay:

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