BattleTech: Explorer Corps Rulebook

Table of Contents

Table of Contents

• Explorer Corps Rules
• Advanced Terrain and Weather Rules
  • Expanded Movement Cost and Terrain Table
  • Expanded Movement Cost and Terrain Table Key
  • Base Terrain
    • Jungle
    • Magma
    • Ultra-heavy Woods
    • Tundra
    • Sand
  • Terrain Conditions
    • Deep Snow
    • Geyser
    • Ice
    • Mud
    • Rapids
  • Weather Conditions
    • Blizzard
    • Blowing Sand
    • Dusk/Dawn
    • Earthquake
    • Fog
    • Heavy Snowfall
    • Rainfall
    • Winds
  • Bog Down
  • Careful Movement
  • Gravity
    • Weapon Calibration
  • Heat-Scale Modifiers
    • Expanded Heat Point Table
  • Intentional Fires
• Shipboard Combat
  • Missed Shots
  • Bulkheads and Objects
    • Ricochets
    • Damage Capacities and Thresholds Table
    • Critical Hits
    • Over-Penetration
  • Specialty Ammunition
  • Cargo and Supplies
    • Food
    • Spare Parts
    • Ammunition
    • Fuel
• Low-Tech 'Mechs
  • Choose Technology Base
  • Determine Engine Rating
  • Allocate Tonnage for Internal Structure
  • Determine Jump Capability
  • Add Extra Heat Sinks
  • Add Weapons, Ammunition and Other Equipment
  • Complete Critical Hit Table
• Special Vehicles
  • Amphibious Vehicles
  • Dune Buggies
• Explorer MechWarrior
• Optional BattleSpace Rules
  • Ramming
    • Accidental Collisions
    • Deliberate Attacks
  • Sensor Rules
    • Infrared Signature
    • Emergence Wave
    • Active Radar
    • ESM/Passive Radar
    • Drive Plumes
    • Radio Triangulation
    • Neutrino Detectors
  • Ground Units in BattleSpace
• New Equipment
  • Tele-Operated Missiles
    • Missile Types
    • Movement
    • Combat
  • Screen Launchers
  • Mobile Yards
  • Hyperpulse Generators
• Spaceflight Procedures (Life in Space, Gravity and Hyperspace)
• Gravitational Effects
• Hyperspace Procedures
  • Basic Jump Procedure
  • Double Jumping
  • Non-Standard Jump Points
  • Objects Within a K-F Field
• Drive Charging

Explorer Corps Rules

Rules section, pages 65 onward of the sourcebook.

The following rules are designed to enhance BattleTech, BattleSpace, and MechWarrior games featuring the Explorer Corps. Many of these rules will work for any type of game, but most are specifically designed for space travel and planetary exploration scenarios. All rules in this section are optional, so players and gamemasters should feel free to use only those that best fit their games.

For the purposes of official BattleTech play, all of the rules in this book are considered Level 3 (not for use in most tournaments).

Advanced Terrain and Weather Rules

Deep Periphery missions can place players on unexplored worlds where they may encounter a staggering variety of terrain, as well as harsh and unpredictable weather. The following rules, which expand the terrain rules in the BattleTech Compendium: The Rules of Warfare (BTC:RoW), are designed to simulate these unusual conditions.

The Expanded Movement Cost and Terrain Table below summarizes the Movement costs, Piloting Skill Roll modifiers and to-hit modifiers of each new terrain type and weather condition. When applying these modifiers, consider all artillery weapons, autocannons, flamers, Gauss rifles, machine guns, missile launchers and Narc pods as ballistic weapons. All lasers and PPCs are considered energy weapons.

The table also lists the types of units prohibited from entering certain kinds of terrain or functioning under certain weather conditions. When referring to these units, the term "ground" denotes wheeled, tracked and hover vehicles. It does not include infantry or BattleMechs.

The Piloting modifiers listed in the table apply to any Piloting Skill Roll a character makes while operating within the specific terrain or weather. Note that the presence of a modifier does not necessarily mean a Piloting Skill Roll must be made upon entering the terrain.

Expanded Movement Cost and Terrain Table

Base Terrain	MP Cost per Hex	To-Hit Modifier	Piloting Modifier	Prohibited Units
Building, Light	2B*	0	0	Naval
Building, Medium	3B*	0	0	Naval
Building, Heavy	4B*	0	0	Naval
Building, Hardened	5B*	0	0	Naval
Clear	1	0	0	Naval

Terrain Conditions	MP Cost per Hex	To-Hit Modifier	Piloting Modifier	Prohibited Units
Deep Snow	+1FI	+0	+1	Wheeled
Geyser	+1**	+2**	+1**	Wheeled, Infantry**
Ice	+1GIJ*	0	+4*	—*
Mud	+1FI	+0	+1	—
Rapids	+1	+0	+2	—

Weather Conditions	MP Cost per Hex	To-Hit Modifier	Piloting Modifier
Blizzard	+0	+2 ballistic weapons, +1 all other weapons	+1K**
Blowing Sand	+0	+1 ballistic weapons, +2 all other weapons	+0
Dusk	+0	+1	+0
Earthquake	+0	**	**
FireH	+0	+0	+0
Fog	+2J	+1 energy weapons	—K
Gravity

Table Key on the following page.

Expanded Movement Cost and Terrain Table Key

• * See special rules in BTC:RoW.
• ** See special rules below.
• A Piloting Skill Roll required to prevent falling.
• B Piloting Skill Roll required to prevent damage. Infantry units pay only 1 MP to enter or leave any building.
• C If traveling along road; otherwise, cost of underlying terrain.
• D Hovercraft may enter all water hexes.
• E No cost for infantry.
• F Units entering this terrain may get stuck. See Bog Down, p. 69.
• G Skidding rules apply (see p. 23, BTC:RoW).
• H See also Fire (pp. 84-86, BTC:RoW).
• I These terrain modifiers do not apply to hovercraft.
• J Does not apply to infantry units. A non-infantry unit entering this terrain may choose to ignore the additional MP cost. However, the unit may fall or crash as a result (see Careful Movement, p. 67).
• K Poor visibility. Units jumping into woods hexes must make a Piloting Skill Roll. Apply a +1 modifier if the target hex is Heavy Woods. Failure results in a fall in the target hex from a height of 1 level.

Base Terrain

Base terrain is the underlying terrain found in each hex. Every hex on every map will consist of one of the base terrain types (Buildings, Clear, Paved, Rough, Water, Light Woods or Heavy Woods). Rules for using these terrain types appear on pages 11-13 and 35-36, BTC:RoW.

The following paragraphs describe the new terrain types provided in the Expanded Movement Cost and Terrain Table.

Jungle

Jungle hexes are covered in trees and other dense vegetation. Hanging vines and thick undergrowth combine with the tree cover to make travel through these areas extremely slow and difficult. Treat jungle hexes as woods hexes of the appropriate type (Light, Heavy or Ultra-heavy), but apply the modifiers shown on the Expanded Movement Cost and Terrain Table.

When using the Clearing Woods special-case rule (p. 81, BTC:RoW), one successful clearing attack converts Ultra-heavy jungle to Heavy jungle, and a second reduces it to Light jungle. Clearing Light jungle converts it to Rough terrain.

Magma

Volcanic activity can send molten rock, or magma, flowing across a planetary surface to form burning rivers and lakes. As the magma cools, its surface solidifies, allowing units to cross.

Such magma crusts remain intensely hot, however, preventing infantry or wheeled vehicles from entering such terrain. Magma crusts are assumed to be capable of bearing the weight of all units allowed to enter them, unless those units are jumping or crashing into the Magma Crust hex.

The Expanded Movement Cost and Terrain Table includes basic information on the effects of movement across cooled and liquid magma. Any BattleMech unit jumping into or crashing onto a Magma Crust hex may bog down, and so the player controlling that unit must make a Piloting Skill Roll. If the roll fails, the unit has fallen through the crust into the molten magma beneath. In addition, players must roll 1D6 each time any unit except for a VTOL or hovercraft enters a Magma Crust hex. On a result of 6, the crust breaks and the unit falls through. All units that fall into molten magma, except for BattleMechs, are automatically destroyed.

BattleMechs that start their movement in or pass through molten magma during a Movement Phase take 2D6 points of damage to each exposed location upon entering the magma. Exposed locations are the 'Mech's legs if it is moving normally, and all locations if it is falling. Roll the amount of damage separately for each location that suffers damage. A unit that starts and ends the Movement Phase in a Liquid Magma hex takes an additional 2D6 points of damage to exposed locations.

Magma hexes also increase the heat level of a BattleMech moving into or crossing them. During the Heat Phase, a 'Mech occupying a Magma Crust hex generates an additional 5 Heat Points; one occupying a Liquid Magma hex generates an additional 10 Heat Points. A BattleMech also generates 2 Heat Points for each Magma Crust hex and 5 Heat Points for each Liquid Magma hex that it moved out of during the Movement Phase (see Heat Scale Modifiers, p. 70).

Ultra-heavy Woods

Ultra-heavy woods are covered with huge trees that grow very close together, like the massive old-growth forests found on Terra in the pre-industrial age. In BattleTech game terms, Ultra-heavy woods is a new type of terrain even heavier than Heavy woods. Ultra-heavy woods are impassable to most ground units, including BattleMechs. The Expanded Movement Cost and Terrain Table lists the MP costs and other modifiers for Ultra-heavy woods. For purposes of determining line of sight, Ultra-heavy woods rise 3 levels above the underlying terrain. A single Ultra-heavy woods hex between an attacking unit and its prospective target will block line of sight. Attacks against a target that occupies an Ultra-heavy woods hex receive a +3 to-hit modifier.

When using the Clearing Woods special-case rule, a single successful clearing attack converts Ultra-heavy woods to Heavy woods, meaning that the treetops rise only 2 levels above the underlying terrain.

Pilots ejecting (p. 83, BTC:RoW) into Ultra-heavy woods apply a +4 modifier to the required Piloting Skill Roll.

Tundra

Tundra consists of black, mucky soil over permafrost (permanently frozen subsoil). Hardy grasses and lichens grow profusely over tundra, giving it the appearance of a grassy glade. Tundra can be slippery and treacherous, and so units entering Tundra hexes may bog down (see Bog Down rules, p. 69). Modifiers that apply to tundra also apply to moorlands, bogs and quicksand.

Sand

This terrain represents the deep, shifting sands common to deserts and beaches throughout known space. Because it is difficult to maintain steady footing on sand, all Piloting Skill Rolls made in such terrain receive a +1 modifier. The Expanded Movement Cost and Terrain Table lists two MP costs for sand. The first (1 MP) applies to all units except wheeled vehicles and infantry, the second (2 MP) to wheeled vehicles and infantry units. [Transcriber's note: the printed table entry for Sand reads "1/2*" in the MP column, while this paragraph gives 1 MP and 2 MP; the paragraph is transcribed as printed.]* Jump infantry use Jumping MP, and can therefore avoid the increased MP cost. Also, wheeled vehicles can be modified to move in sand at the normal rate (see Dune Buggies, p. 80).

Terrain Conditions

Terrain conditions represent changes to a given hex's terrain caused by weather, specific geological conditions, or human intervention. Modifiers and unit prohibitions imposed by these conditions apply in addition to those for the underlying terrain. For example, a Heavy Woods hex that is also Muddy imposes an MP cost of 4 per hex (3 for Heavy woods + 1 for mud). The to-hit modifier for shooting into or through the hex is +2 (standard for Heavy woods), and a +1 modifier applies to all Piloting Skill Rolls made by units in the hex (standard for Muddy conditions). The presence of mud also means that units may bog down. Ground and naval units may not enter the hex.

If no underlying terrain is specified for a particular hex, assume it is Clear.

Road/Bridge, Rubble and Swamp represent terrain conditions. Rules for using these terrain types appear on pp. 11-13 and 35-36, BTC:RoW. Rules for additional terrain conditions are given below.

Deep Snow

Deep snow rules apply to areas covered with loose snow that is more than a meter deep. Lesser accumulations of snow have no measurable effect on battlefield units. Deep snow imposes a +1 MP cost per hex and a +1 modifier to all Piloting Skill Rolls; in addition, units entering deep snow may get stuck. See Bog Down, p. 69.

Treat hard-packed snow as either ice or Clear terrain, depending on how slippery it is. The gamemaster makes this choice unless the terrain is specified in the scenario being played.

Geyser

Geological activity common on some planets can create geysers and mud spouts that erupt without warning. Often, the only clues to a geyser's presence are small holes or cracks in the ground, easily overlooked by troops in combat. Sometimes a geyser can be recognized by a characteristic mound in the earth. When a geyser erupts, it spews steam and water into the air, obscuring line of sight and making movement through the terrain more difficult.

Before beginning the game, geysers can be placed on the map in known locations; if a gamemaster or referee is playing, the geysers' location can be kept secret. Until a geyser erupts, it has no effect on the underlying terrain. During the End Phase of each turn, the gamemaster should roll 1D6 for each geyser on the map. On a result of 1, the geyser erupts, creating the effect listed on the Expanded Movement Cost and Terrain Table. For purposes of determining line of sight for attacks, treat the erupting geyser as Heavy woods.

These effects last for a variable number of turns, which the gamemaster or referee should keep secret from the players. To determine the number of turns that the geyser continues to erupt, roll 1D6.

Geyser rules can also apply to small eruptions of magma on volcanically active planets. In this case, any unit that enters or stands in a hex where such a geyser is erupting suffers the same effects as if it had fallen into liquid magma (see Magma). After the eruption, treat the hex as Liquid Magma for the remainder of the game. A volcanic geyser can erupt again in a subsequent turn.

Ice

Standard rules for ice appear on page 89, BTC:RoW. Under these optional expanded rules, the modifier for Piloting Skill Rolls made on ice increases to +4. Also, a unit must spend extra MP when moving across ice or else risk falling (see Careful Movement, p. 69).

Mud

Slick, sticky mud can make any terrain dangerous. The optional mud rules in this section apply to mud less than a meter deep; for deeper mud, use standard BattleTech rules for Swamp terrain.

Moving into or through muddy terrain imposes a +1 MP cost per hex and a +1 modifier to all Piloting Skill Rolls. If the mud is deep enough, a unit may bog down in it (see Bog Down rules, p. 69).

Rapids

Swiftly moving currents make traversing water even more difficult and dangerous than usual. Rapids impose a +1 MP cost per hex and a +2 modifier to all Piloting Skill Rolls.

Weather Conditions

This category includes weather and other environmental and atmospheric conditions such as light and smoke. Weather conditions may prevail across the entire playing area, though particular scenarios usually note whether the condition applies to the entire map or only certain hexes.

Fire, high and low gravity, and night are examples of weather conditions in the standard BattleTech rules. Rules for using these conditions appear on pages 13 and 84-86 (fire), 90-91 (gravity) and 94 (night) of BTC:RoW. The Expanded Movement Cost and Terrain Table lists changes to the standard rules for some of these conditions; otherwise, standard rules apply. Optional rules for additional weather conditions are given below.

Blizzard

Heavy snowfall combined with high winds creates blizzard conditions, making accurate weapons fire extremely difficult. Blizzard conditions impose a +2 to-hit modifier to ballistic weapons, and a +1 to-hit modifier to all others. In addition, all Piloting Skill Rolls receive a +1 modifier.

Blizzard conditions also affect rolls on the Missile Hit table, in the same way as high winds (see Winds). Hovercraft are subject to skidding in all types of terrain during a blizzard.

Blowing Sand

In windy conditions, airborne sand or dust can obscure vision and make accurate weapons fire difficult. Sand and dust particles also tend to diffuse energy-weapons fire, making these weapons ineffective. Blowing sand imposes a +1 to-hit modifier to ballistic weapons and a +2 to-hit modifier to all others.

Dusk/Dawn

The brief half-light of dusk and dawn creates a penalty similar to that for night, though less severe; the to-hit modifier is +1 rather than +2. However, units cannot use searchlights to counter this penalty.

Earthquake

Many planets in the BattleTech universe are tectonically unstable, subject to frequent earthquakes that can affect combat. Seismic activity may hinder the mobility of BattleMechs and will cause targeting difficulties for all units.

When using Earthquake rules, assign a strength value to the tremor, ranging from +1 (mild) to +5 (severe). Apply this value as a to-hit modifier to any weapons fire that takes place during the same turn as the tremor. In addition, players must make a Piloting Skill Roll for each standing BattleMech they control at the start of each Movement Phase during which a tremor occurs, modified by the strength of the tremor. A 'Mech whose roll fails will fall, taking damage per standard rules.

The improved stability afforded by two extra legs means that four-legged 'Mechs suffer half the penalty (round up) when making Piloting Skill Rolls during an earthquake. Combine this penalty with the -2 modifier that applies to four-legged 'Mechs under standard rules (p. 87, BTC:RoW).

Fog

Thick fog reduces visibility on the battlefield to such an extent that units must move carefully through the terrain to avoid crashing. Fog imposes a +2 MP cost per hex and a +1 to-hit modifier to energy-weapons fire. For additional fog rules, see Careful Movement.

Heavy Snowfall

Falling snow normally has little effect on BattleTech combat. Heavy snowfall, however, imposes a +1 to-hit modifier to all weapons fire and a +1 modifier to all Piloting Skill Rolls. Heavy snowfall also reduces heat buildup, as shown on the Expanded Heat Point Table (below). Heavy snowfall combined with high winds creates blizzard conditions (see Blizzard, above, for applicable rules).

Rainfall

Rain obscures vision and makes weapons fire less accurate. Whether light or heavy, rainfall imposes a +1 to-hit modifier to all weapons fire. In addition, heavy rainfall makes the ground wet and slippery, imposing a +1 modifier to all Piloting Skill Rolls. Rainfall can also reduce the heat generated by a BattleMech, as shown in the Expanded Heat Point Table (below).

Winds

Windy conditions reduce the effectiveness of ballistic weapons and the accuracy of missile attacks. Moderate winds impose a +1 to-hit modifier on ballistic-weapons fire; for high winds, the modifier rises to +2. High winds also impose a +2 modifier to all Piloting Skill Rolls. When rolling on the Missile Hits Table, subtract 2 from the die roll for moderate winds, 4 for heavy winds. On a modified result of less than 2, the missile attack misses the target.

Hovercraft operating in high winds are subject to skidding in all terrain (see Skidding, p. 23, BTC:RoW).

Bog Down

Some types of terrain slow units down and may even cause them to get stuck. To simulate these effects, use the standard rules for Swamp terrain (p. 91, BTC:RoW), with the following modifications.

Liquid Magma hexes follow standard Swamp rules for getting stuck.

Tundra and Magma Crust hexes, deep snow and mud are all less likely than swampy ground to trap a unit. To reflect this, apply a -1 modifier to the Piloting Skill Roll made to determine whether a unit entering such terrain becomes stuck. Apply the same modifier to Piloting Skill Rolls made to free a stuck unit. For example, an undamaged BattleMech piloted by a Regular MechWarrior would need a Piloting Skill Roll of 4 or better to avoid getting stuck.

The -1 modifier replaces the standard +1 modifier for Piloting Skill Rolls in these types of terrain.

Jump-capable units that enter tundra, magma crust, deep snow or mud using Walking or Running movement may get stuck, but can free themselves in subsequent Movement Phases by jumping out of the terrain.

Careful Movement

The increased MP cost of entering hexes enveloped by thick fog or covered with ice represents the extra caution needed to avoid tripping, falling or crashing under such conditions. Units can cross such dangerous terrain without mishap by paying the increased Movement cost, or can trust to their pilots' skill and luck to move through it at full speed. A player attempting this feat must announce his intention before moving his unit. After the unit moves 1 hex, the player makes a Piloting Skill Roll.

If the unit is a BattleMech and the roll fails, the 'Mech immediately falls. It must stand up per standard rules before continuing its movement. If the roll succeeds, the 'Mech remains upright and the unit may move per standard rules. However, the player must make additional Piloting Skill Rolls for each non-Clear hex or elevation change through which the unit passes.

Vehicles moving through thick fog or ice must also make Piloting Skill Rolls after their first hex of movement. If a roll fails in icy terrain, the vehicle skids (see Skidding, p. 23, BTC:RoW). If the roll fails in thick fog, the vehicle crashes unless it is in Clear terrain. In Clear terrain, the vehicle hits a hole or other minor obstruction that costs the unit an additional 1 MP. In all other terrain, the crash ends the vehicle's movement, and the vehicle sustains damage to its Front facing as if it had charged.

If thick fog and ice are both present, the total MP increase per hex is +2, because the fog's effect on visibility is assumed to present the greater obstacle to safe movement. All other standard rules for ice apply, regardless of unit type (p. 89, BTC:RoW).

Gravity

Gravity can play a major part in BattleTech combat and movement, especially when Explorer Corps teams must fight on moons or asteroids with little or no gravity. Most scenarios assume Earth-normal gravity, but battles that occur in other environments require modified game rules. The following weapon-calibration rule supplements the standard rules for gravity on pp. 90-91, BTC:RoW.

Weapon Calibration

Gravity influences the trajectory of all ballistic weapons, causing shells or missiles to fall short of or fly past their intended target. Rather than forcing pilots to adapt to constantly shifting weapon ranges, the targeting systems of such weapons are calibrated to take gravity into account. On high-gravity worlds, the weapon may actually be aimed at a point considerably above the target, so that shots will fall to intersect the target at the appropriate range. Zero-gravity requires no calibration; the flight path of the projectile automatically matches the one the pilot intended. Energy weapons are not influenced by gravity, and therefore do not require calibration.

Usually such modifications are set up by technicians before a battle. However, sometimes weapons are not calibrated when they should be, or are mis-calibrated. A pilot with above-average gunnery skills can compensate for such problems, but firing a mis-calibrated weapon imposes a +2 modifier to the to-hit number. (The calibration of weapons is up to the gamemaster if not specified in the scenario being played.)

Heat-Scale Modifiers

In addition to speed of movement, number of heat sinks, and other conditions allowed for in the standard BattleTech rules, various terrain and weather conditions may influence a BattleMech's heat scale. The following table lists the applicable modifiers for various conditions that affect a 'Mech's heat, including terrain and weather.

Expanded Heat Point Table

Activity/Condition	Modifier
Walking	+1/turn
Running	+2/turn
Jumping	+1/hex (minimum of 3/turn)
Standing Up	+1 per attempt
Weapons Fire	Per Weapons and Equipment Table (pp. 104-6, BTC:RoW)
Heat Sinks	-1/operational heat sink; -1 additional per heat sink under water (6 HP maximum)
Double Heat Sinks	-2/operational double heat sink; -2 additional per double heat sink under water (6 HP maximum)
First Engine Hit	+5/turn
Second Engine Hit	+10 (total)/turn
Low Temperature	-1/turn per 10°C below -30°C
High Temperature	+1/turn per 10°C above 50°C

Intentional Fires

Many weapons can be fired into Woods or Building hexes to intentionally start fires (p. 85, BTC:RoW). Rain, thick fog, falling snow and blizzard conditions, however, make it more difficult to start fires. To reflect this, apply a +2 modifier to any fire-starting dice roll made under such weather conditions. These conditions also lessen the chance that a fire will spread, so apply a +1 modifier to all rolls made to determine the spread of a fire.

High winds hasten the spread of fires; under such windy conditions, apply a -1 modifier to fire-starting dice rolls. High winds also cause fires to spread to downwind flammable hexes at a rate of 2 hexes per turn.

Shipboard Combat

Several factors distinguish shipboard combat from routine MechWarrior combat, the most obvious being changes in gravity. Combat in zero-G offers tactical possibilities that ordinary gravity does not, but also poses several problems. Rules for simulating the effects of zero-G and artificial gravity appear on page 62 of the MechWarrior Companion. The following paragraphs expand on those rules, offering guidelines for missed shots, bulkheads and objects, and specialty ammunition for use aboard ships.

Missed Shots

In an enclosed space there is no such thing as a complete miss. A shot either hits its target or misses its target and hits something else instead, such as another person, a bulkhead, or a door. The following rules, while designed with boarding actions in mind, may apply to any fight in an enclosed space.

Whenever a shot misses its intended target, the gamemaster must determine what the shot eventually hits. In general, any ballistic weapon that misses its intended target will hit another target or ricochet among targets until its kinetic energy is spent. Energy weapons cause damage to the first target they strike; they do not ricochet. The gamemaster should use common sense in selecting targets. For example, a missed shot is extremely unlikely to hit the firer or anyone standing directly behind him. If a shot may hit multiple targets, select any victims randomly. As always, a gamemaster may fudge dice rolls or simply select a dramatically appropriate (or inappropriate) target.

Gamemasters who prefer hard-and-fast rules should follow the two steps below to determine the target of a missed shot.

Step 1. Establish the shot's margin of failure by subtracting the dice roll result from the to-hit number. For example, if the to-hit number is 8 and the dice roll result is 6, the margin of failure is 2.

Step 2. Have the firer make a second to-hit roll against the same target number as the previous roll. A success indicates that a character within a number of meters equal to the margin of failure has been hit. If no living targets happen to be standing in the indicated area, the shot hits a bulkhead. The shot also hits a bulkhead if the roll fails.

Step 3. If a shot hits a bulkhead, consult the Bulkheads and Objects rules below to see if the shot ricochets. If it does, return to Step 1, but treat the bulkhead as the origin of the shot. The firer now becomes a valid target.

Example (from the sourcebook): MechWarrior Richard fires at two Liao crewmen approaching him in a DropShip corridor. He targets the one on the left, who is armed with a pistol, and rolls 2D6 against a To-Hit Number of 8. Richard rolls a 5. This gives him 3 as a margin of failure (8 - 5 = 3). He makes a second to-hit roll against the same to-hit number, and this time rolls a 9. This result, a success, means that the missed shot hits a character within 3 meters of the targeted character. The second Liao crewman happens to be within 3 meters of his compatriot, and so Richard's shot hits him.

Bulkheads and Objects

Bulkheads and other surfaces or objects may be attacked deliberately or hit accidentally. Every bulkhead, door or object aboard a ship has two values assigned to it. The first is its damage capacity, the amount of damage it can take before being destroyed. The second is its threshold, the amount of damage needed to pierce the bulkhead or cause an object or surface measurable harm. Values for various surfaces and objects appear on the Damage Capacities and Thresholds Table. Though these rules were written for shipboard combat, the damage capacities and thresholds may be used in any setting.

To allocate damage to a bulkhead or object:

Step 1. Roll the appropriate number of dice to determine the amount of damage caused by the weapon. (See listings for individual weapons, beginning on p. 91, MWII.)

Step 2. Reduce the damage by the armor rating of the surface. Assume ballistic and energy armor ratings of 1/2 unless otherwise noted (see MWC, p. 89, for rules regarding armor). The resulting number is the amount of damage actually inflicted. Subtract the damage inflicted from the object's or surface's damage capacity. (This damage is cumulative, so repeated shots may cause a critical hit.)

Step 3. Compare the damage inflicted to the object's or surface's threshold to determine whether or not the damage was sufficient to pierce or harm it. If the damage inflicted exceeds the threshold, the bulkhead has been pierced or the object harmed.

Step 4. Determine the consequences of excess damage points (those that exceed the threshold). Excess damage points either ricochet or, if they pierce a bulkhead, cause critical internal damage (see Critical Hits). Only slug throwers or needlers ricochet; with energy weapons and those relying on contact explosives, such as gyrojets and missiles, the initial target absorbs the shot's full impact.

On those rare occasions when a shot destroys a door or bulkhead, excess damage may strike a character standing on the other side. Treat such shots as ricochets against a To-Hit Number of 8; no range or attacker modifiers apply.

Ricochets

Excess damage from slug-thrower or needler weapons may ricochet and strike other targets. To determine if a ricochet occurs, roll 1D6 (2D6 for needlers) and subtract the result from the amount of excess damage. If the net result is positive, the shot ricochets.

Resolve the ricochet as a weapon attack against a randomly determined character. The To-Hit Number for this attack is 8; no range or attacker modifiers apply. Treat a missed ricochet as hitting a bulkhead or door and repeat Steps 1-3 of Bulkheads and Objects.

Example (from the sourcebook): MechWarrior Richard's shot misses both Liao crewmen and instead hits a door. Richard was using a standard slug-throwing pistol, so he rolls 2D6 + 3 to determine the amount of damage done. He gets a 6 and a 4, for a total of 13 (6 + 4 + 3 = 13). He reduces the damage (13) by the door's armor rating (1/2), for a result of 6.5, which he rounds down to 6. He compares this to the door's threshold of 4, and finds that his shot caused 2 points of excess damage. The slug-thrower is a ballistic weapon, and so Richard must check for ricochets. He rolls 1D6 and gets a 1. Subtracting this from the excess damage gives him a total of 1 (2 - 1 = 1), a positive number. The shot ricochets, and does 1 point of damage.

Damage Capacities and Thresholds Table

Object/Surface	Shipboard Damage Capacity	Damage Threshold
Internal bulkhead (minor)	50/section	5
Internal bulkhead (major)	100/section	10
External bulkhead	200/section	20
Observation port	50	3
Door	50	4
Pressure door	100	8
Computer console	10	2
Other Objects/Surfaces

Critical Hits

Damage to bulkheads may result in critical hits. Critical hits reflect events that automatically happen or that may happen as a result of the damage done.

Shots that penetrate an exterior bulkhead, or a bulkhead between two areas that are pressurized differently, automatically cause decompression. The speed of the decompression varies depending on the amount of damage caused, but in general the pressure will decrease by 10,000 Pascals (10 percent of Earth-standard atmosphere) per round for each point of damage that penetrates. If no preventive action is taken, compartmental bulkheads will close automatically when the pressure falls to 50,000 Pascals (500 millibars).

If explosive decompression occurs (loss of more than 50,000 Pascals of pressure in 1 turn), each character present in the affected area must make a Build Saving Roll. A failed roll means the character dies from the sudden pressure drop or from being sucked into space.

Most penetrating shots have less predictable consequences. Shots that penetrate an internal bulkhead may damage various systems contained within it. Roll 2D6 and add the amount of excess damage to the result. A total of 8-10 indicates 1 critical hit; a total of 11+ indicates 2 critical hits. To determine the specific effect of the critical hit, roll 1D6 and consult the table below.

Example (from the sourcebook): MechWarrior Richard's shot hits a minor internal bulkhead. He rolls 2D6 + 3 to determine the amount of damage done. He gets a 6 and a 5, for a total of 14 (6 + 5 + 3 = 14). He divides 14 by the bulkhead's armor rating (1/2), for a result of 7. He compares this to the bulkhead's threshold of 5, and finds that his shot caused 2 points of excess damage. The shot pierced an internal bulkhead, so Richard must check for critical damage to systems behind the bulkhead. Richard rolls 2D6 and gets a 3 and a 5. Adding the 2 points of excess damage gives him a grand total of 10, a critical hit. Now he rolls 1D6 and gets a 3. His shot damaged an emergency-equipment locker behind the bulkhead.

1D6 Result	Minor Bulkhead	Major Bulkhead
1	Power line	Power line
2	Comm panel	Hydraulics line
3	Emergency equipment	Fuel line
4	Lights	Emergency equipment
5	Cable mechanism	Lights
6	No effect	Communications lines

Notes

• Power Line: A damaged power line may be a minor line serving the part of the vessel near where the shot hit, or a major line that channels power elsewhere in the ship. Damaged power lines cease functioning until repaired. If the power line is in a major bulkhead, damage to it affects the ship's fusion plant, reducing the vessel's Power Points by 1 (p. 24, BattleSpace).
• Comm Panel: Damage to the comm panel means that the panel and repeater may not be used.
• Emergency Equipment: The emergency equipment locker and its contents may not be used.
• Lights: Critical damage affects the lighting in the compartment or corridor where the shot hit. Apply partial darkness modifiers in all subsequent rounds.
• Cable Mechanism: The cable hand-line in the part of the ship where the shot hit is damaged and may not be used.
• Hydraulics Line: A damaged hydraulics line sprays fluid into the compartment or corridor where the shot hit. Apply a +1 modifier for reduced visibility. In addition, the vessel suffers control problems. Add a +1 modifier to all Control Rolls (p. 12, BattleSpace).
• Fuel Line: A damaged fuel line sprays fuel into the compartment or corridor where the shot hit. Apply a +1 modifier for reduced visibility. Also, any additional weapons fire in the affected area risks igniting the fuel and causing an explosion. If this occurs, the blast inflicts 1D6 points of damage per point of fuel leaked (1 point per turn for each fuel-line critical hit). Firing a flamer or gyrojet automatically causes an explosion; firing a primitive weapon such as a bow and arrow, which produces no spark or heat, does not. For all other weapons, roll 2D6. On a result of 8+, the leaking fuel ignites.
• Communications Lines: Comm lines fail in the area of the ship where the shot hit. This failure in turn affects the comm panels and repeaters in adjacent areas.

Over-Penetration

When a shot hits a character, the amount of damage allocated to the part of the character's body struck may exceed that part's damage threshold (see the Character Record Sheet). This effect, called over-penetration, means that the shot passes through the target character's body and may hit other characters or bulkheads.

If players choose to use this optional rule, apply the damage from the attack to the target character's Condition Monitor according to the standard rules. To determine the amount of damage that over-penetrates, subtract the value of any armor worn on the struck part of the body from any damage in excess of the character's damage threshold for the body part struck and treat the resulting points as a ricochet. Needlers and contact explosives (gyrojets, missiles and so on) do not over-penetrate.

Example (from the sourcebook): Richard's shot hits a Liao crewman, and he follows the standard MechWarrior hit location procedure. The shot struck the crewman's left arm, and the crewman is wearing no armor. The shot does 2D6 + 3 damage (the damage listed for the weapon used), and so Richard rolls 2D6. He gets a 6 and a 3, for a total of 12 (6 + 3 + 3 = 12). The crewman has BLD 3, and so the damage threshold for his arm is 9 (BLD (3) x 3 = 9). 12 - 9 = 3, so there are 3 points of damage remaining. These 3 points of damage over-penetrate and may strike other characters or objects nearby.

Specialty Ammunition

Two bullets have been developed especially for slug-throwers that reduce the chance of shots penetrating bulkheads, causing ricochets or over-penetrating. Both types of specialty rounds are Tech Level 3, Availability C and Legality B. They are readily available to characters working for the Explorer Corps, but cost twice as much as standard ammunition.

Frangible Rounds. These metal and polymer compound rounds are designed to work effectively against unarmored targets (doing the full damage listed for the weapon type) but to break up when they hit a solid surface (other than flesh). Consequently, frangible rounds do not ricochet, penetrate bulkheads or over-penetrate. However, they also cannot penetrate ballistic plate armor or battle armor.

AET Rounds. Accelerated Energy Transfer rounds are effective against all types of armor, but their concave tips prevent over-penetration and reduce the chance of a ricochet. When using these rounds, reduce the excess damage of a shot by 2D6 rather than 1D6. When checking for damage against bulkheads, reduce the damage potential of the round by 50 percent. For example, if the required dice roll indicates 12 points of damage, reduce that damage to 6 points.

Cargo and Supplies

Most spacefaring craft are designed to operate away from a home base for extended periods of time, and thus are equipped with numerous large cargo bays. These bays may contain any of the hundreds of things the vessel needs for its day-to-day operations, but the following paragraphs give players some idea as to what is likely to be taking up cargo space. These guidelines can also help a gamemaster determine the probable contents of a captured enemy ship's holds.

Food

One ton of cargo space can contain sufficient food for 200 people for 1 day. Ships on short patrols close to a base can carry relatively small amounts of food. However, a Clan vessel traveling from the homeworlds to the Inner Sphere or an Explorer Corps vessel searching for the Clan homeworlds will need to carry sufficient food supplies for many months, possibly even years.

A McKenna-class WarShip, with 578 crewmen and 296 passengers, needs at least 4.25 tons of food to feed its inhabitants each day. Such a vessel on a short, 30-day patrol would need 127.5 tons of food (4.25 x 30). By comparison, a Union-class DropShip, with 14 crewmen and 28 passengers, would need only .25 tons of food per day, or 7.5 tons for the same 30-day patrol.

Spare Parts

Every spacefaring vessel constantly undergoes maintenance and repairs, which means that a certain amount of spare parts must be kept on hand. Generally, a ship should carry a number of tons of spare parts equal to approximately 1 percent of the vessel's mass, though for long trips that number may increase to 5 percent.

Ammunition

Though the magazine of each weapons bay is usually fully stocked when an armed vessel leaves port, a battle may swiftly consume these supplies. Therefore, many ships carry additional ammunition in their cargo bays. The quantity and type of these stores varies greatly from ship class to ship class. Players designing a vessel should use their own judgment when determining the tons of extra ammunition carried.

Fuel

Most vessels carry sufficient fuel to remain fully operational for several weeks. For a craft that will spend a lot of time landed, docked or at station-keeping (meaning that it uses 0.1Gs of thrust and consumes only 10 percent of each burn-day of fuel), this "operational" period can be stretched to several months. However, unexpected circumstances, for example use of the fusion plant to recharge a K-F drive or a lithium fusion battery, may consume fuel faster. The cargo bays of some vessels may be lined with polymer fuel cells that act as additional tank space. Such additional fuel is generally consumed first, thus freeing up the cargo bays to be used for other purposes. Every ton of cargo space given over to additional tank space allows 0.9 tons of fuel to be stored.

Creating Star Systems

[Transcriber's note: the sourcebook's Creating Star Systems procedure (pp. 74-79: star type and luminosity, number of planets, life-zone planets, habitable-planet characteristics, climate zones, other planets, satellites, multiple-star systems, and the Spectral Class, Luminosity, Jump Point Distance, Star Subgroup, Planetary Characteristics, Special Features and Occupancy tables) is not transcribed in this file. It is a gamemaster world-generation procedure rather than a rule of play, and its many dice-table entries are not reproduced here. Consult the printed sourcebook.]

Low-Tech 'Mechs

BattleMechs are the best-known 'Mechs of the thirty-first century, but other types of 'Mechs still exist. During the Star League era, myomer-driven 'Mechs played a role in various aspects of life, from farming to loading DropShip cargo bays. After the fall of the Star League, these utility 'Mechs fell into disuse, their parts often scavenged to repair BattleMechs. As the Succession Wars raged on, the technology needed to build and repair 'Mechs declined, and the Successor States concentrated their dwindling technological resources on the BattleMechs they needed to continue fighting. Utility 'Mechs became a luxury, and soon a rare sight in the Inner Sphere.

The following rules allow gamemasters and players to create the rare utility 'Mechs such as AgroMechs, LoggerMechs, CargoMechs and so on. These rules also allow for the installation of internal combustion engines (ICE) in BattleMechs, an inefficient but common practice in the poorer regions of the Periphery, where fusion engines and techs who can repair them are virtually unknown. The primary advantage of creating these types of 'Mechs is to place the technology that BattleTech players want on planets that could not be expected to support any type of Mech manufacturing capabilities. It provides a reasonable explanation for finding Mechs and parts across all of known space and even in areas forgotten since the Star League, which gives players greater options for using BattleMechs in the Periphery and beyond. These rules also offer players and gamemasters a few more alternatives for building Mechs that are more precisely tailored to the type of game they want to play.

Utility 'Mechs are built using standard BattleMech construction rules (pp. 99-106, BTC:RoW) with a few minor changes, described below. 'Mechs created with these rules are Level 3 units, and so not appropriate for tournament play.

Choose Technology Base

Though utility 'Mechs may be built according to the Clan technology base, the Clans rarely use such machines. Clan technology and philosophy prevents any tech from installing an internal combustion engine in a BattleMech.

Determine Engine Rating

Determine the engine rating as for standard BattleMechs. Utility 'Mechs and low-tech BattleMechs may make use of internal combustion engines, which weigh twice as much as fusion engines with the same rating. Internal combustion engines are cheaper and more readily available, though not available in XL versions. See the Vehicle Costs Table, p. 124, BTC:RoW.

If a BattleMech equipped with an internal combustion engine will be carrying energy weapons, it must also carry power amplifiers, as if it was an ICE-powered conventional vehicle. These amplifiers take up 1 ton of space per 10 tons of energy weapons (round up to the nearest 0.1 ton).

Engine hits against ICE-equipped 'Mechs do not generate additional heat. Instead, the player checks to see if the engine explodes. At the end of the phase in which the unit's engine was hit, the player rolls 2D6. On a result of 10+, the engine and the 'Mech are destroyed. For a second engine hit, add +3 to the dice roll result. On the third engine hit, add +6 to the result. Note that a third engine hit "destroys" the 'Mech for purposes of game play (per the standard rules); the player must still determine if the engine explodes and completely destroys the 'Mech.

Allocate Tonnage for Internal Structure

Utility 'Mechs must allocate 20 percent of their tonnage to internal structure, but receive structure points per the table on page 100 of BTC:RoW.

Determine Jump Capability

'Mechs fitted with internal combustion engines may not use jump jets.

Add Extra Heat Sinks

Add extra heat sinks per standard rules. Unlike fusion engines, internal combustion engines do not come equipped with heat sinks.

Add Weapons, Ammunition and Other Equipment

Add weapons, ammunition and equipment as for BattleMechs. The following additional equipment is also available.

System	Tonnage	Criticals	Notes
Cargo bays*	Special	1 per ton	Enclosed cargo as per p. 81, BTC:RoW
Combine (AgroMech)	5	4 in each arm	May inflict 1D6 damage against infantry
Lift hoists (CargoMech)	3	3	May lift cargo equal to half the 'Mech's tonnage
Chainsaw (LoggerMech)	5	5	Logging tool, too slow for use as a weapon.

*Cargo bays may only be mounted in utility 'Mechs. BattleMechs with ICE engines may not have cargo bays.

Complete Critical Hit Table

Complete the Critical Hit table as for BattleMechs. When rolling on the Determining Critical Hits Table against utility 'Mechs, add +2 to the dice roll result. Treat a modified result of 13 as a result of 12. On a result of 14, the 'Mech's head or a limb is blown off; roll 4 critical hit locations, as indicated on the table.

Special Vehicles

The wide variety of environments on planets in the Deep Periphery often require special vehicles to traverse irregular terrain. Amphibious vehicles and dune buggies are two examples of such special vehicles.

Amphibious Vehicles

Water is one of the most common obstacles to thirty-first-century fighting forces, as it restricts the movement of conventional vehicles and BattleMechs. Many vehicles built in earlier eras, however, such as twentieth-century tanks, were capable of limited amphibious operations. They could cross rivers or land from transport craft to form a beachhead. The increasing sophistication of warfare and the resulting specialization of vehicles led to the creation of non-amphibious tracked and wheeled vehicles; amphibious operations were left to vehicles such as hovercraft, which lent themselves to such uses. Only a few types of tracked and wheeled vehicles, mainly used for exploration by civilians, retained the capacity for amphibious operations. The Explorer Corps uses several such vehicles. The following rules allow players to include them in Level 3 BattleTech games.

The necessary drive equipment takes up 10 percent of an amphibious vehicle's tonnage, and may only be fitted to tracked or wheeled vehicles. This equipment allows the vehicle to move across open water (including Level 0 water) at a cost of 2 MP per hex. However, any damage to the vehicle's drive system, such as a damaged or destroyed track, axle, or wheel, will disable this capability.

As an amphibious unit is partially submerged, the hull breaching rules (p. 98, BTC:RoW) apply to amphibious vehicles. Any unit suffering a breach to any location except its turret (which is assumed to be above water) sinks and is automatically destroyed. If all of a location's armor is destroyed, that location is automatically flooded (except for the turret).

Amphibious equipment costs 10,000 C-bills per ton and has a Combat Value equal to the vehicle's tonnage.

Dune Buggies

Normally, moving over sand slows down wheeled vehicles considerably. However, the wheels and suspension of any wheeled vehicle can be modified to make it more suitable for desert use. Larger wheels and high-riding suspension allow the vehicle to move through sand at a cost of 1 MP per hex. However, these modifications affect the vehicle's overall performance, reducing its Cruising MP by 1. As a vehicle's Flank MP is one and a half times its Cruising MP, rounded up, reducing the Cruising MP also reduces the Flank MP.

An experienced technician with the right parts and tools can convert any wheeled vehicle into a dune buggy. The process requires a Deluxe Tool Kit, a Mechanic Repair Kit, and special wheels and suspension gear costing a number of C-bills equal to the vehicle's tonnage squared, times 10. The conversion takes a number of days equal to the vehicle's tonnage divided by 10, which may be further divided by the number of techs working on the conversion. It takes a minimum of one day (16 hours) of work to convert any vehicle, regardless of its size or the number of techs assigned to the job.

Explorer MechWarrior

The vast, uncharted reaches of the Deep Periphery beckon to a special breed of MechWarrior: the Explorer MechWarrior, who has honed his skills through years of traveling the space lanes and fighting on countless battlefields. Few would call the Explorer an ace 'Mech pilot, but he has several useful secondary skills and enough unusual equipment collected on his travels to make him an ideal choice for an Explorer Corps team. Armed with his own scout 'Mech, the Explorer MechWarrior rarely waits long between contracts.

Attributes	Characteristics
BLD 4 (8+)	Athletic (9+)
REF 5 (7+)	Physical (8+)
INT 5 (7+)	Mental (8+)
LRN 5 (7+)	Social (10+)
CHA 3 (9+)

Advantages: Well-Equipped (2 pt)

Skills (MechWarrior Package):

• Communications/Conventional 1 (7+)
• Gunnery/BattleMech 3 (5+)
• Leadership 1 (9+)
• Medtech 1 (7+)
• Perception 1 (7+)
• Piloting/BattleMech 2 (6+)
• Security Systems 1 (7+)
• Small Arms 2 (6+)
• Survival 2 (6+)
• Technician/BattleMech 1 (7+)
• Tracking 1 (7+)
• Unarmed Combat 2 (7+)
• Zero-G Operations 1 (7+)

Edge: 1 Assets: 500 C-bills

BattleMech: Light

Other Equipment: Climbing Gear; Environment Suit, Light; Field Kit, Deluxe; Lock-Pick Kit, Mechanical; 2 Medkits; Noteputer; Personal Communicator, Long-Range; 3 Power Packs, High Capacity; Rangefinder Binoculars; Recharger, Solar; Respirator; Satchel Battery, High Capacity; Security Bypass Kit, Advanced; Tool Kit, Deluxe

Weapons and Armor: Bayonet; Body Suit, Flak; Helmet; Imperator SMG w/10 reloads; Needler Pistol w/10 reloads; Pump Shotgun w/10 reloads; Sonic Stunner; Vest, Plate

Optional BattleSpace Rules

During long-term space missions, Explorer Corps teams will inevitably find themselves engaged in space combat. The following optional BattleSpace rules expansions are designed to expand players' options when waging and resolving battles. These rules are appropriate for any type of BattleSpace game, but are particularly suited to Explorer Corps-related campaigns and games that combine BattleSpace and MechWarrior.

Ramming

Generally, ramming tactics have little use in naval combat. But on rare occasions, a warrior may see no other way to achieve an objective and, like the legendary Tyra Miraborg, may deliberately crash her vessel into an opposing craft. The following rules provide a system for incorporating such ramming attacks, as well as accidental collisions, into BattleSpace.

Accidental Collisions

Any time a space vessel becomes Out-of-Control, it runs the risk of colliding with other nearby vessels (see Control Rolls, p. 12, BattleSpace rulebook). To reflect this risk, a player must roll 2D6 any time a large ship (DropShip, JumpShip or WarShip) under his command enters a hex occupied by another large vessel or space station. On a result of 10 or greater, the Out-of-Control vessel collides with the "target."

To determine damage from a collision, roll 1D6. On a result of 1-5, both craft are destroyed. A result of 6 produces a glancing collision: each vessel takes 1D6 x 1D6 Damage Points. The Out-of-Control vessel takes this damage on its nose. If using the Advanced Movement rules (p. 30, BattleSpace), the Out-of-Control vessel takes the damage on the facing that was "forward" at the time of the collision. The target takes the damage in the location facing the hexside from which the Out-of-Control vessel entered the hex.

A player must also make a 2D6 roll any time an Out-of-Control fighter unit under his command enters a hex occupied by a large ship. (No roll is required if the Out-of-Control fighter unit enters a hex containing another fighter unit; the small size of such craft make the chance of accidental collisions insignificant.) On a result of 10 or greater, the fighter unit collides with the "target."

In this case, make a second 2D6 roll and consult the Fighter Hits Table (p. 19, BattleSpace). The number of "hits" achieved represents the number of fighters that collide with the target. Every colliding fighter is destroyed (remove 1 Armor row from the unit's record sheet). Additionally, each colliding fighter causes the target an amount of damage equal to the fighter's velocity. The target takes the damage in the location facing the hexside through which the Out-of-Control fighter unit entered the hex.

Deliberate Attacks

To make a ramming attack, a vessel first must end its movement in the same hex as the target. The vessel or fighter-unit commander must then convince his crew or pilots that a ramming attack is the only option left to them. To do so, the player makes a 2D6 roll. If the result is 11 or higher, the unit may attempt to ram the target. If the result is less than 11, the commander has failed to convince his crew or pilots to attempt the attack and the unit may not ram.

If MechWarrior rules are being used, the commander must make a Leadership Skill Roll to convince his crew or pilots to try the attack. The roll receives a +4 Target Modifier. If player characters are aboard the attacking vessel or are members of the attacking fighter unit, the gamemaster may apply additional target modifiers to the roll, based on roleplaying and the specific circumstances.

If circumstances are particularly dire and the crew or pilots are especially loyal to their commander, the gamemaster may allow the unit to make the attack without a dice roll.

To determine the success or failure of the ramming attempt, the attacking player makes another 2D6 roll and consults the Ramming Attacks Table. Damage from a successful attack is resolved in the same way as for accidental collisions.

Ramming Attacks Table

Target	Base To-Hit Number
WarShip	7*
JumpShip	6
Station	5
DropShip	8*

*Reduce the to-hit number by 2 if the target cannot accelerate for any reason.

Sensor Rules

The following rules expand and clarify those presented on pages 48-49 of BattleSpace. These rules assume that any military craft operating in combat conditions will not be emitting an identifying IFF signal and will be operating under EMCON (EMission CONtrol or "radio-silence") orders. Any unit broadcasting an IFF signal is automatically detected.

Infrared Signature

The infra-red (IR) signature of any JumpShip or WarShip arriving in-system will enable any other units within 50,000 kilometers of the vessel to detect the incoming ship with no Detection Roll.

A jumping vessel's IR signature appears before the vessel shows up in-system. The period between the signature's and the vessel's appearance equals the vessel's jump duration, multiplied by 2. Therefore, the IR detection period can be calculated using the following formula:

• Jump Duration = (Light-years traveled x DropShip capacity) + 2
• Detection Period = Light-years traveled x DropShip capacity

If a JumpShip carries no DropShips, simply multiply the number of light-years traveled by 1. The product equals the IR detection period in seconds.

Example (from the sourcebook): The Garibaldi, a Scout class JumpShip that can carry 1 DropShip, makes a jump of 10 light-years. Consequently, the Garibaldi's IR signature will appear 10 seconds before it makes its 5-second jump. Meanwhile, the Valley Forge, a Potemkin class WarShip capable of carrying 25 DropShips, makes a jump of 30 light-years. This means the Valley Forge's IR signature appears 12.5 minutes (30 x 25 = 750 seconds, or 12.5 minutes) before it makes its jump of 6 minutes and 15 seconds [(30 x 25) + 2 = 375 seconds, or 6 minutes and 15 seconds].

Emergence Wave

An incoming vessel's emergence wave can be detected at a greater distance than its IR signature, but identifying the emergence wave is more difficult.

Only large military craft within 15 AU of an incoming vessel can detect its emergence wave. To do so, the player controlling the large craft makes a 2D6 Detection Roll against the incoming vessel's emergence-wave target number, determined according to the formulas below (round all fractions up).

• Base Target Number = (Distance from incoming vessel + 2) + 7
• Target Modifier = (Incoming craft's K-F Drive integrity + Number of DropShips carried) + 10
• Round fractions up and subtract target modifier from base target number.

A craft may make only one Detection Roll against the target unit. The maximum detection range is 15 AU, regardless of the target number.

Emergence waves travel at the speed of light (314,000 km per second), so they take approximately 8 minutes to travel 1 AU.

Example (from the sourcebook): The DropShip John Wayne is 3 AU from the arrival point of the Waterloo, an Invader class JumpShip with K-F Drive Integrity 4 and 3 DropShip capacity. Therefore, if the John Wayne's controlling player makes a successful Detection Roll against a Target Number 8, the Wayne will detect the Waterloo's emergence wave 24 minutes after it arrives in-system.

• Base Target Number: (3 + 2) + 7 = 8.5, rounded up to 9
• Target Modifier: (4 + 3) + 10 = 0.7, rounded up to 1
• Final Emergence-Wave Target Number: 9 - 1 = 8

Active Radar

Any large craft with an active-radar system may attempt Detection Rolls against any objects within 100,000 kilometers of it. The active-radar systems of fighters and small craft are less powerful and can only detect craft within a 1,000-kilometer range.

Military DropShips, WarShips and JumpShips make 2D6 Detection Rolls against a Target Number 4. All other vessels make the roll against a Target Number 6. Increase the target number by 1 for each box of Radar Critical Hit damage the detecting vessel has taken.

Any object detected with active radar remains detected as long as it stays within the range of the detecting craft. Vessels can make only one active-radar Detection Roll against a target per hour.

Note that any craft using active radar emits a radar signature that can be easily detected by other vessels (see ESM/Passive Radar).

ESM/Passive Radar

All military craft (excluding fighters and small craft) carry electronic-support measures (ESM) systems that enable them to detect the radar signature of any vessel using an active-radar system within 150,000 kilometers. No roll is needed to detect vessels in this manner.

Drive Plumes

The drive of any accelerating vessel emits a visible drive plume. Any other craft that makes a successful Detection Roll against a Target Number 5 can see the drive plume. Add a +1 Target Modifier for every 500,000 kilometers (or fraction thereof) that separates the two vessels. A vessel may make one such Detection Roll against a target craft per hour.

A craft that observes a target's drive plume can extrapolate the heading and velocity of the target vessel, as well as the distance to the vessel.

Radio Triangulation

A target's radio and HPG communications may be detected by appropriately equipped units. Civilian craft may detect radio transmissions within 500,000 kilometers. ESM-equipped military craft may detect transmissions within 1 million kilometers.

The K-F fields created by HPG transmissions create electromagnetic pulses when they collapse, pulses similar to the emergence waves created by a jumping ship. Therefore, HPG transmissions can be detected with the emergence-wave detection rules, with the following modifications: use only the base target number, but double the distance between the signal source and detecting vessel when calculating the target number.

Neutrino Detectors

A neutrino detector can detect any fusion reactor within 4 AU of the vessel carrying it. However, neutrino detectors are fragile, complex instruments that require careful calibration. In fact, any time a neutrino detector is used, it must first be calibrated for a period of 2D6 hours. Every hour thereafter, make a 2D6 roll for every other vessel in the system. On a result of 9 or higher, the neutrino detector detects the vessel.

The neutrino emissions of every vessel are unique, with variations resulting from class and age. After successfully tracking a vessel for 6 hours without interruption, a neutrino detector-equipped vessel will have a neutrino profile of the craft that identifies the vessel class. After 12 hours of uninterrupted tracking, the neutrino profile will be sufficiently detailed to allow positive identification of that specific vessel in later encounters.

Ground Units in BattleSpace

BattleMechs and battle armor units can be used in space operations because they are environmentally sealed machines. However, both types of units are designed for planetary use. Consequently, they are ill-suited to and ineffective for most space combat, though circumstances may occasionally prompt a commander to use them anyway.

The following sections provide rules for using BattleMechs and battle armor units in BattleSpace play.

Converting BattleTech Units

To convert BattleMech and battle-armor BattleTech statistics to BattleSpace, use the rules for Converting AeroTech Craft (p. 78, BattleSpace), with the changes given below. Round fractions to the nearest whole number (round up on .5).

BattleMechs. Use a fighter record sheet for a single 'Mech, but fill in 1 Armor row only. Other unique 'Mech conversions are listed in the Mech Conversion Table.

Consult the Master Weapons Tables (pp. 69-70, BattleSpace) to convert BattleTech weapons. Use the following Mech Weapon Conversions Table to assign weapons to the appropriate firing arcs. Do not include melee weapons such as hatchets and swords. BattleMechs and battle-armor units may only attack targets within the same hex, and so may only fire at short range.

Mech Conversion Table

BattleSpace	BattleTech
Armor Value	= Armor Factor ÷ 40
Safe Thrust Value	= Jumping MP ÷ 3
Fuel Points	= Jumping MP x 2

Note: BattleMechs have no Maximum Thrust value.

Mech Weapon Conversions Table

BattleTech Location	BattleSpace Arc
Torso, leg and head	Nose
Left arm	Left Wing
Right arm	Right Wing
Rear weapons	Aft

For example, a VTR-9K Victor BattleMech would have the following BattleSpace statistics:

• Tech: Star League; Armor Value: 5; Heat Sinks: 15; Fuel: (8); Safe Thrust: 1

Arc	Type	Heat	S (Range Value)	Mounts
Nose	SRM	3	1	1
LW	Pulse	8	1	2
RW	AC	1	2	1

Battle Armor

Anywhere between 1 and 10 battle-armor troopers may be assigned to a unit. Use a fighter record sheet for a single unit; each row on the sheet represents a unit member.

Consult the Master Weapons Tables (pp. 69-70, BattleSpace) to convert battle-armor weapons. Battle-armor SRM launchers have limited ammunition, so they are worth only 75 percent of their standard BattleSpace Fire Factor. Allocate all weapons to the nose arc.

For example, a standard Clan battle-armor trooper would have the following BattleSpace statistics:

• Tech: Clan; Armor Value: 1; Fuel: (6); Safe Thrust: 1; Heat Sinks: N/A

Arc	Type	Heat	S (Range Value)	Mounts
Nose	Mixed	N/A	1	2

Battle Armor Conversion Table

BattleSpace	BattleTech
Armor Value	= Armor Factor ÷ 10
Safe Thrust Value	= Jumping MP ÷ 3
Fuel Points	= Jumping MP x 2

Note: Battle-armor units have no Maximum Thrust value.

Movement, Combat and Boarding Actions

The following rules provide additional BattleSpace movement, combat and boarding-action guidelines for BattleMechs and battle-armor troops.

Movement. BattleMechs and battle-armor troops move first in the movement sequence, before JumpShips. For movement purposes, treat 'Mechs and battle-armor units as fighter units unless stated otherwise.

A 'Mech or battle-armor unit that launches from a DropShip, JumpShip or WarShip has the same heading and velocity as the mother vessel. For example, a 'Mech that launches from a DropShip traveling north at a velocity of 10 will also be moving north at a velocity of 10.

'Mechs and battle-armor units do not have Maximum Thrust values. Whenever they expend thrust, they must make Control Rolls (Piloting Skill Rolls with a +2 modifier; use a Target Number 6 for battle-armor units). Note that BattleMechs without jump jets cannot expend thrust; therefore they cannot change heading, accelerate or decelerate.

Any time a BattleMech or battle-armor unit expends a Thrust Point, it also uses 1 Fuel Point. Generally, the propulsion systems of 'Mech and battle-armor units use plasma-heated air as reaction mass. Therefore, they must use their limited supplies of "reserve" reaction mass to propel themselves in space. BattleMechs and battle-armor units cannot be fitted with additional reserve reaction-mass tanks.

'Mech or battle-armor units may "land" on a target vessel during a boarding action (see Boarding Actions) but may perform no other special actions in space. Battle-armor units always operate in loose formation during space maneuvers.

Any 'Mech or battle armor not equipped with an ablative re-entry pod or Personal Re-entry Unit (PRU) is destroyed on entering a space-atmosphere Interface hex.

Combat Restrictions. BattleMechs and battle-armor targeting and tracking systems are designed for ground combat at ranges of a few kilometers or less. Consequently, they are ill-suited for space combat. For this reason, 'Mechs and battle-armor units can only engage units within the same hex. Additionally, they receive a +4 To-Hit Modifier for all weapons attacks (treat all firing as if at long range).

'Mechs and battle-armor units have one advantage in space combat: their relatively small size prevents naval-grade weapons from effectively targeting them.

Boarding Actions. In space combat, BattleMechs and battle armor are most commonly used during boarding actions. Typically, such units will land on a target vessel's hull and attempt to neutralize weapon turrets and other opposition to the boarding party.

To attempt a landing on a target DropShip, WarShip or JumpShip, a 'Mech or battle-armor unit must start the turn within the same hex as the target. Next, the controlling player makes a 2D6 Control Roll (as described under Movement, p. 85). Any damage that would normally modify a Piloting Skill Roll according to standard BattleTech rules applies to this Control Roll. In addition, applicable modifiers for damaged leg actuators are doubled for a BattleMech with leg-mounted jump jets.

If the roll result equals or exceeds the target number, the unit lands successfully. If the roll fails, consult the Boarding Failure Table to determine the outcome.

Boarding Failure Table

Margin of Failure	Effect
1	Hard landing. Unit takes 1 Damage Point.
2	Very hard landing. Unit takes 2 Damage Points.
3	Glancing collision. Unit bounces off the target's hull, takes 1 Damage Point and fails to land.
4	Collision. Unit bounces off the target's hull, takes 2 Damage Points and fails to land.
5	Hard collision. Unit bounces off the target's hull, takes 3 Damage Points and fails to land.
6+	Off target. Unit misses target craft and may not make any other movement for the remainder of the turn.

Boarding units land on the location of the target vessel that corresponds to the hexside through which the boarding unit entered the hex. (A boarding unit that enters through the nose hexside lands on the target's nose.) Magnetic plates built into the soles of 'Mech and battle-armor feet enable a landed 'Mech or battle-armor unit to walk to an adjacent area (for example, nose to fore-left or fore-right) as its movement during the Movement Phase.

A landed unit may attack any of the target vessel's weapon bays, doors, maneuvering thrusters or its transit drive in the location the landed unit occupies. Units in either side location may attack that side's maneuvering thrusters. Units in the target's aft location may attack the transit drive. Assume Bay 1 doors are fore-left, Bay 2 doors are fore-right and Bay 3 doors are on either aft side. Bay door attacks bypass the target vessel's armor and succeed automatically. Cross off 1 appropriate Critical Damage box for each unit attacking weapon bays, doors and thrusters, regardless of the damage the unit's weapons inflict under standard rules. (See pp. 22-29, BattleSpace, for more on the effects of these attacks.)

A landed unit may also attack the target vessel's hull in the location it has landed. Such attacks succeed automatically. Record damage by crossing out a number of Armor boxes in the location equal to the target vessel's combined nose and wing arcs. Landed units may also use melee weapons, such as hatchets and swords, to attack a target vessel's hull. Such attacks add an amount of damage equal to the weapon's normal damage divided by 10 (round fractions to the nearest whole number).

A target vessel can use four basic tactics to defend itself against landed units.

First, the target can make a high-thrust maneuver that requires a Control Roll. Any time a vessel makes a Control Roll (during high-thrust maneuvers or because of damage), any landed units on its hull must also make successful Control Rolls to remain in place.

Second, the target vessel may use point-defense weapons mounted in a location to fire on landed units within that location. However, the target vessel cannot fire at the landed unit with any other weapons.

Third, fighter units may be used to strike at landed units. Fighter units may attempt to attack landed units only if the fighter units occupy the same hex as the landed unit or an adjacent hex that faces the side of the vessel occupied by the landed units. If a fighter attack misses, it automatically hits the target vessel instead and inflicts damage on the location occupied by the target unit.

Fourth, a target vessel can deploy its own battle-armor units or 'Mechs to attack the landed units. The target vessel's 'Mech and battle-armor units may enter on the first turn after a successful landing by enemy troops. The vessel's forces may enter play on any desired location at the beginning of the turn. Battles between such "ground" units can be resolved with BattleSpace rules or with the BattleTech Hostile Environments rules (see p. 89, BTC:RoW). Vacuum conditions are in effect, but all units are magnetically affixed to the target's hull, so low-gravity rules do not apply. Furthermore, no units may use Running movement, and any units that use Jumping movement will leave the target's hull and float off into space. As with fighter attacks, any missed attacks directed against a landed 'Mech or battle-armor unit hit the target vessel instead.

If using BattleTech rules to resolve such combat, use the blank reverse side of a single BattleTech mapsheet to represent the surface of the target vessel. After the End Phase of each BattleSpace turn, play 6 consecutive BattleTech turns. Then, play another BattleSpace turn and so on, until the combat is resolved.

Converting BattleSpace Damage to BattleTech

Converting BattleSpace damage to BattleTech damage is fairly straightforward. For each BattleSpace damage box crossed off, apply 10 Damage Points to a single location on the 'Mech (or eliminate a single Elemental in a battle-armor unit). Roll on the Front column of the BattleMech Hit Location Table to determine hit location for each 10-point group of Damage Points. However, if the resulting location would destroy a 'Mech still functional under BattleSpace rules (2 head hits, for example), re-roll that location.

Drive-System Malfunctions

The BattleSpace rulebook describes the effects of combat damage and quick-charging on a JumpShip's K-F drive, but it provides little information on other drive-system malfunctions, which may certainly occur any time a JumpShip jumps in hyperspace. The following drive-system malfunction rules enable players to simulate the risks and dangers of drive-system malfunctions in BattleSpace or MechWarrior campaigns.

First, the controlling player of a jumping vessel makes a 2D6 Malfunction Roll to determine whether a drive malfunction occurs. Any appropriate modifiers from the Malfunction Roll Modifiers Table apply. The player makes the roll before the ship jumps (for roleplaying purposes, assume this roll occurs at the end of program initiation but before the ship actually jumps).

If the Malfunction Roll yields a result of 12 or higher, a mishap has occurred. In such cases, the player makes a 2D6 Effect Roll. On a result of 12, make a 1D6 roll and add 11 to the result. Add any appropriate Malfunction Roll modifiers to the final result and consult the Drive-System Malfunctions Table to determine the specific malfunction and its effects.

Malfunction Roll Modifiers Table

Ship Condition	Modifier
Jumped within past hour	+4
Jumped within past 1-6 hours	+3
Jumped within past 7-12 hours	+2
Jumped within past 13-36 hours	+1
K-F drive charged from reactor	+2

Drive-System Malfunctions Table

Roll	Result Effect
2-8	No noticeable effect.
9-11	Micro-fractures develop in drive. Reduce K-F Drive Integrity by 1.*
12-13	Seal blows on the K-F drive's helium tank; all drive charge is lost and jump aborts. Cross off all helium tank boxes.
14-15	Static discharge causes drive failure. Jump aborts.
16-17	Static discharge causes drive-controller failure. Roll on Failed Jump Table (p. 46, BattleSpace).
18+	Static discharge causes catastrophic drive-controller failure. K-F field misformed, but jump continues. Vessel misjumps. Gamemaster determines fate of vessel.

* A vessel may not jump if its Drive Integrity falls to 0. Enemy ships attempting to detect the vessel still use the vessel's full (undamaged) K-F Drive Integrity value.

Overburn

To simplify bookkeeping in the BattleSpace game, all units have traditionally operated on the "zero-net heat principle": the number of Heat Points a unit generates cannot exceed the number of heat sinks the unit possesses. Though this general principle works well for most of the larger and newer ship classes, it effectively prevents players from exploiting the full performance capabilities of certain fighter designs.

Under the Overburn rule, however, aerospace fighters may temporarily generate Heat Points that exceed their heat sink limits, a practice known as overburning. Any time a fighter overburns, however, the stress of the excess heat reduces the effectiveness of other systems on the fighter and may even destroy the craft.

To simulate this phenomenon, calculate the overburn of a fighter unit during the End Phase of each turn using the following formula:

Heat Points - Number of heat sinks = Overburn

Then consult the Overburn Effects Table. All overburn effects begin at the start of the following turn and remain in effect until the overburn level changes or is reduced to 0.

No fighter may overburn by more than 15 Heat Points. Additionally, any Heat Points that a fighter does not dissipate are carried forward to the next turn. As in BattleTech, unused heat-dissipation capacity cannot be carried forward into the next turn.

Example (from the sourcebook): A Lightning (equipped with 12 heat sinks) generates 26 Heat Points during a turn. During the End Phase of the turn, the gamemaster calculates its Overburn at 14. The Lightning suffers the appropriate penalties during the following turn (+3 Target Modifier on Control and To-Hit Rolls), but the fighter generates no additional Heat Points, and so its heat sinks reduce its Overburn to 2 during the End Phase of the second turn. During the third turn, the fighter receives a +1 Target Modifier on Control and To-Hit Rolls. By the fourth turn, the fighter's heat sinks have reduced its Overburn to 0, so it suffers no overburn effects.

Overburn Effects Table

Overburn	Effect
1	None
2-4	+1 Target Modifier on Control and To-Hit Rolls.
5-7	+2 Target Modifier on Control and To-Hit Rolls.
8-10	+2 Target Modifier on Control and To-Hit Rolls. Roll 1D6; fighter unit shuts down on a result of 6.*
11-13	+3 Target Modifier on Control and To-Hit Rolls. Roll 1D6; fighter unit shuts down on a result of 5 or 6.*
14-15	+3 Target Modifier on Control and To-Hit Rolls. Roll 1D6; fighter shuts down on a result of 4 or 5. On a result of 6, 1 fighter is destroyed (cross off one Armor line on record sheet, determined randomly) and remaining fighters in unit shut down.*

* A "shut down" fighter unit may not fire weapons or expend Thrust Points (heat sinks continue to operate, however). The fighter unit remains shut down until its Overburn drops to 0.

Non-Standard Jump Points

Non-standard, or "pirate," jump points are transient points of gravitational equilibrium that JumpShips can use to jump to a star system (see p. 41, Non-standard Jump Points, for a full description).

Using non-standard jump points involves three separate steps: plotting the non-standard point, the jump itself, and arrival. The following rules are additions to those provided on pp. 42-46, BattleSpace.

Step 1: Plotting the Point

To plot the non-standard point, the jump officer overseeing the maneuver makes a Navigation Skill Roll (p. 19, MechWarrior Companion), adding a +4 Target Modifier. Additionally, plotting the point requires 2D6 x 30 minutes, whether the roll succeeds or fails.

If the roll fails, the jump officer has failed in his or her task. If the roll succeeds, he or she has correctly calculated the coordinates of a suitable non-standard point. Record the Margin of Success. Note that the coordinates are correct only for a specific, stated time (chosen by the captain or navigator, who decides when he or she wants the ship to jump, before the Navigation Skill and transit time rolls are made).

If the ship is jumping out of a gravity well, the officer must make an additional dice roll to determine the distance to the jump point (the transit time from the ship's location to the jump point may render the navigational information useless). If the ship is in "deep space," the distance is 3D6 - 3 million kilometers. If the vessel is near a planet with at least one moon, the distance is 3D5 - 300,000 kilometers. [Transcriber's note: the printed formula reads "3D5"; transcribed as printed.] (See System Transit, p. 52, BattleSpace, for instructions on calculating transit times.)

Step 2: The Jump

Rules for the jump are provided on page 45 of BattleSpace and page 19 of the MechWarrior Companion.

Step 3: Arrival

When the vessel arrives in the new system, the jump officer makes another Navigation Skill Roll. Add the Margin of Success from Step 1 as a modifier for this roll.

If the roll succeeds, the ship has made a "clean" jump. If the roll fails, the jump officer has miscalculated or based his or her computations on faulty data. Consequently, the jump may damage or even destroy the ship.

For each point in the Margin of Failure, apply 1D6 Damage boxes to each Armor facing of the JumpShip and any DropShips it is carrying. Reduce the JumpShip's K-F Drive Integrity by the Margin of Failure as well. If the Drive Integrity is reduced to 0 or lower, the K-F drive and the vessel are destroyed.

Effects of Gravitational Forces on Characters

Though most aerospace fighters and spacecraft can withstand incredibly high gravitational (G) forces, such forces can impede the mental processes of human pilots and crew members or even cause them to black out. The following rules enable players to simulate these effects in BattleSpace and AeroTech games.

G-Force Thresholds Table

[Transcriber's note: the printed table's column layout is hard to resolve from the scan; the entries are given in the order printed.]

• Character condition, with G-suit: primary threshold 6 Gs (12 Thrust Points per turn) for extended periods, or 11 Gs (23 Thrust Points per turn) for short periods.
• Character condition, no G-suit: primary threshold 6 Gs (12 Thrust Points per turn).
• Secondary threshold: aerospace pilots, 6 Gs for 1 or more turns; DropShip, JumpShip and small-craft crews, 3 Gs for 1 or more turns.

G-Force Thresholds

Any time a character is exposed to G-forces that exceed his primary G-force threshold, he blacks out and remains unconscious until the End Phase of the next game turn. While a character is unconscious, his craft will continue on the same heading and at the same velocity at which it was moving when the character blacked out.

Lower G-forces are unlikely to cause blackouts, but they do cause discomfort and fatigue. Any time a character exceeds his secondary threshold, apply a +1 penalty to all To-Hit and Piloting Skill Rolls made by the character during the remainder of the turn. If the character exceeds his secondary threshold for several consecutive turns, increase the penalty by 1 for each turn.

The G-Force Thresholds Table lists thresholds for crew members and passengers on aerospace craft and space vessels. Note that a G-suit enables a character to withstand additional G-forces before passing out. (Aerospace pilots nearly always wear G-suits; DropShip and JumpShip crews rarely wear them.)

Tactical Use of Unexpected G-Forces

G-forces have certain tactical uses as well. Most commonly, the crew of a vessel that has been boarded by enemy troops may suddenly accelerate rapidly or make a tight turn to generate sudden low-level shifts in the G-forces within the vessel. Anyone caught unaware by the maneuver will fall and may sustain serious injuries.

If using the MechWarrior rules, make a roll against the REF attribute of each unaware character to determine the results of such tactics. If the roll fails, the character receives 1D6 points of bruise damage per point of Thrust Point expended by the vessel.

If using the BattleSpace boarding-action system, shift the combat ratio 2 columns to the left (in the defender's favor) and subtract 2 from the dice roll result. The table does not allow for a result of 1 or 0, so treat results of less than 2 as 2.

New Equipment

In recent years, most of the Successor States, as well as ComStar, have gradually resumed producing WarShips. The reappearance of these powerful vessels has prompted the development of new equipment to supplement their firepower and also to fight against them. The following information describes some of these new items available to agents of the Explorer Corps.

Tele-Operated Missiles

The sophisticated guidance computers used in naval missile systems have long limited the availability and battlefield effectiveness of such systems. Remotely piloted, or tele-operation, guidance systems represent the most significant alternative to computer guidance yet devised for naval missile systems. Currently, only the ComStar and Draconis Combine militaries possess such systems.

A tele-operation guidance system consists of a coded laser link that provides secure communication between the missile and its operator. Such a system enables an operator on a launching vessel to direct a missile toward a target, managing its fuel and correcting its course as necessary. Many existing naval missiles can be fitted with tele-operation systems, which also provide greater versatility than computer guidance systems.

For example, a computer guidance system typically directs a missile toward the pre-designated target at maximum acceleration. Consequently, the missile can make only a single pass at the target. A tele-operation system, however, enables an operator to control the missile's direction and velocity. This allows the operator to direct the missile to make multiple passes at a target, or even switch targets in mid-flight. If he wishes, the operator can re-direct the missile's path until it exhausts its fuel supply.

However, this advantage is somewhat offset by the inherent time lag created while the missile sends telemetry information to the operator and the operator sends commands to the missile. Consequently, control-response time may take up tenths of seconds or even whole seconds, which makes tele-operated missiles virtually useless against highly maneuverable craft such as fighters.

The following rules enable players to incorporate tele-operated missiles into BattleSpace games.

Missile Types

At present, four types of naval missiles have been fitted with tele-operation systems. These are described in the Naval-Grade Missile Types Table. (The "-T" suffix distinguishes tele-operated variants from the standard computer-guided versions of each missile type.) These missile systems are the only naval-grade weapons eligible for use on a DropShip or conventional JumpShip.

Naval-Grade Missile Types Table

Naval Weapon	Type	Heat	Fire Factor	Max Range	Fuel	Tons/Shot	Tons	Cost	Ammo Cost	MPV
Killer Whale-T	Capital Missile	20	4	Extreme	30	50	160	165,000	17,000	1,100
White Shark-T	Capital Missile	15	3	Extreme	40	40	140	145,000

*Tele-operated Barracuda missiles do not receive the -2 to-hit bonus. **There is no "standard" version of the Kraken, only the tele-operated version.

Movement

Tele-operated missiles move as if they were fighters or small craft, though they move immediately before such units in the turn sequence (after DropShips). They follow the standard rules for turning and acceleration, with the following exceptions.

Missiles are not subject to G-effects. Missiles may not decelerate, but unlike piloted vessels, tele-operated missiles do not have Maximum Thrust values. The only limit on thrust is the amount of fuel available. For example, a missile with 20 Fuel Points may expend up to 20 Thrust Points of thrust.

Only two factors limit the maneuverability of a tele-operated missile: the missile's fuel and the operator's line of sight (LOS) to the missile. For every Thrust Point a missile expends, whether for turning or acceleration, the missile loses 1 Fuel Point. If the missile expends all of its Fuel Points, it cannot maneuver or accelerate.

A clear line of sight must be maintained between the operator and missile to facilitate the transmission of data between the two. All objects that block LOS and inflict LOS-related to-hit penalties, such as asteroids, debris or screen launchers, prevent the operator's commands from reaching the missile. Consequently, the missile may not expend thrust, and thus it cannot accelerate or turn. Once LOS is re-established, the missile can maneuver normally. A missile that loses contact with its operator will continue on the last heading and velocity it received, until it receives further instructions. Additionally, all tele-operated missiles contain small targeting computers that assume control of a missile once it enters the same hex as its target. Thus, a tele-operated missile lacking LOS to its operator may still strike its target if it ends the turn in the same hex as the target.

Whenever a tele-operated missile is launched, place a marker representing the missile in the firer's hex, with the same initial heading and velocity as the firing unit.

Combat

Tele-operated missiles are not "fighter capable" and may not attack fighters.

For the purposes of combat, however, treat tele-operated missiles as fighters or small craft in most other respects. They may be attacked by any weapon system capable of engaging fighters. The "Armor" value of a tele-operated missile equals the amount of damage the missile can inflict. For example, a Killer Whale has an Armor Value 4, while a Barracuda has an Armor Value 2. Missiles are not destroyed until all their armor is destroyed, though intermediate levels of damage will adversely affect their performance.

If a missile ends the Movement Phase in the same hex as an enemy unit, the missile's targeting computer assumes control of the missile and attempts to hit the "target" vessel. Consequently, Gunnery/Piloting Skill is not used for the To-Hit Roll. Instead, a tele-operated missile uses a Base To-Hit Number 2. Add a +1 Target Modifier for each Thrust Point used during the turn and for each Armor box crossed out on the missile's record sheet. If the missile has no Fuel Points left, add a +6 To-Hit Modifier.

Tele-operated missile hits are resolved after all other weapons fire. Any missile destroyed by defensive fire does not hit its intended target. A missile that is not destroyed by defensive fire but misses its intended target remains in the target hex. The missile's operator may continue to maneuver the missile until it hits a target, is destroyed, expends all its fuel or leaves the mapsheet.

Screen Launchers

Faced with the overwhelming firepower of Clan WarShips, the Inner Sphere powers began searching for ways to neutralize the advantage the Clans' superior weaponry afforded them. The Inner Sphere militaries have explored several approaches, but so far only one system, produced by the Draconis Combine's Omodaka research facility, has seen service. That system is the XP1 Kamen "screen launcher."

The XP1 is an explosive obscurant, designed to detonate and block LOS between a firer and target. Commonly known as a screen launcher, the system consists of a short-range missile, or "canister," that detonates at a pre-designated point and scatters particle obscurants, chaff and wide-band radio noisemakers. These items effectively block LOS in the area immediately around the detonation point and provide a certain measure of concealment from enemy fire. However, the cover provided by the obscurant usually lasts only a few minutes.

[Transcriber's note: the screen launcher's statistics block, which the text introduces as "the following statistics," is not legible in the scan transcribed here and is omitted. Consult the printed sourcebook, p. 92.]

Screen launchers can be installed like any other weapon system and may even be fitted on DropShips and conventional JumpShips. Like other weapons, a screen launcher must be allocated to a specific firing arc.

Each screen launcher may fire 1 canister per turn, and each canister may be targeted on any hex in the appropriate firing arc within 6 hexes (short range). No to-hit roll is needed to detonate a canister. Once a canister detonates, place a screen marker in the hex.

Screen-launcher canisters lack the targeting systems and explosive power needed to damage a DropShip or larger target, but may damage fighter units in the detonation hex. Roll 2D6 for each fighter unit in the hex. On a result of 9-11, each fighter in the unit takes 1 Damage Point. On a result of 12, each fighter takes 2 Damage Points. After the detonation, units may pass through the screen hex without taking damage.

A detonated canister creates a screen that blocks LOS through the target hex. Any units within the hex may fire out of it, but they receive a +2 To-Hit Modifier. Any unit that fires also enables units outside the hex to target it, however these units also receive a +2 To-Hit Modifier.

During the End Phase of each turn, roll 2D6 for each screen on the mapsheet. On a result of 7 or greater, remove the screen marker. On any other result, the screen remains.

Mobile Yards

Mobile maintenance/construction/repair ship yards may be installed in any WarShip, but their size precludes their installation in DropShips and standard JumpShips. (Currently, the Faslane-class support vessels recently deployed in the Deep Periphery are the only space vessels equipped with maintenance/repair yards.)

Pressurized facilities may be built with 100,000-ton capacities, but nonpressurized facilities may be built even larger. However, no more than 10 percent of a vessel's mass may be dedicated to such facilities.

A maintenance/repair facility occupies Cargo Bays 1 and 2 on the vessel's Critical Damage chart. Any damage taken to such locations is applied in direct proportion to the bay and its contents. For example, if 10 percent of a cargo bay's boxes are crossed out, 10 percent of the bay and its contents are damaged. If all the boxes are crossed out, the bay and its contents are destroyed.

Any time a ship expends Thrust Points while another vessel occupies the repair bay, the repair bay sustains severe structural damage. In such cases, cross off 1 box of repair facility/cargo for each Thrust Point expended.

Hyperpulse Generators

Though some Star League-era mobile HPG systems weighed as little as 9 tons, the modern-day mobile HPG systems carried by certain DropShips, JumpShips and WarShips weigh 50 tons and require dedicated links to a ship's power plant.

To activate a ship-board HPG, a vessel must dedicate at least 4 Power Points to the HPG (these points cannot normally be allocated to weapons, life-support or drive systems). The HPG transmission, consisting of an electromagnetic pulse, temporarily "blinds" the vessel and all other craft within 1,000 meters of the transmitting vessel, and the vessel cannot fire on any other ship, and cannot be fired on by another ship within that range, during the turn that the transmission is taking place.

Ships that form part of an HPG chain operate under additional limitations. Such vessels are bombarded by the EMP effects of communications from neighboring vessels and cannot use their sensors, fire their weapons, maneuver or jump. Fortunately, any other vessel within 1,000 meters of the HPG emergence point experiences the same effects.

Recovering from EMP bombardment can be a lengthy process: the ship's crew must check and re-initialize every circuit on the vessel. This process takes approximately 5 minutes per minute of communications.

Note that "firing" an HPG at another vessel to blind its sensors is not possible. HPGs are designed to aim at very distant, relatively stationary targets. Aiming an HPG transmission at a target within the same star system, even a stationary target, accurately enough to "blind" the vessel is virtually impossible.

Spaceflight Procedures (Life in Space, Gravity and Hyperspace)

Transcribed from the "Life in Space" chapter of the sourcebook (pp. 37-43). Daily routine, food, recreation, quarters, docking narrative, internal atmosphere and psychological-effects passages are background and are omitted; the rules below are retained.

Gravitational Effects

The effects of gravity in non-terrestrial environments represent the most ubiquitous and potentially disconcerting feature of space travel. Generally, these effects fall into two classifications: microgravity and high gravity.

Microgravity ("zero gravity") denotes the effects of gravity in a field well removed from any large gravitational bodies. In microgravity environments, the lack of strong gravitational forces makes people and objects "float" as if suspended in water.

High gravity is the level of gravity on a planetary surface or caused by extreme acceleration. Most humans can bear up to 1.5 Gs (1.5 times Terra's gravity) for extended periods, though overweight people and those who have heart defects or have experienced prolonged exposure to microgravity may experience noticeable discomfort at this level. A normal, healthy human can withstand G-forces up to 5 Gs for short periods, such as during the lift-off of a DropShip. (Forces within launch-acceleration of spheroid vessels may reach 4 Gs, whereas aerodyne ships lifting off from runways rarely exceed 2 Gs.) Higher G-forces are usually encountered only during battle maneuvers performed by DropShips or aerospace fighters. The Inner Sphere Achilles and the Cian Noruff class DropShips are both capable of performing 6-G maneuvers, and the Star League-era Swift light aerospace fighter can reach 10.5 Gs.

Without any sort of special equipment, a human may experience up to 6 Gs before suffering blackout and falling unconscious, though redout can occur at levels as low as 2 Gs, given the appropriate circumstances and orientation. G-suits, which inhibit the circulatory system as G-forces increase, enable humans to withstand up to 9 Gs and remain conscious. Such suits dramatically reduce mobility, however, and the reduced circulation they are designed to create may actually harm the wearer if maintained for more than a minute. In a DropShip, acceleration pulls occupants toward the floor and blood pools in the lower limbs and trunk (blackout). Redout occurs when G-forces pull the subject from above, pooling blood in the upper torso and head.

Hyperspace Procedures

Kearny-Fuchida hyperdrive systems (commonly known as K-F drives) enable JumpShips to instantaneously travel distances of up to 30 light years. Drive malfunctions or improperly executed jumps can result in disastrous consequences.

Basic Jump Procedure

The first step in performing a jump is charging the K-F drive (see Drive Charging, below). Next, the JumpShip navigator enters the destination's jump point coordinates into the vessel's navigation computer, which calculates the field parameters needed to move the JumpShip and any connected DropShips from their current location to the destination. Because gravitational forces affect the K-F fields produced by K-F drives, JumpShips travel between predetermined points in space that feature insignificant gravitational forces. The most stable and commonly used jump points (also known as proximity points) are situated directly above and below the gravitational poles of the destination system's star. At these points, the gravitational forces of the star and any planetary bodies in the system are in a state of virtual equilibrium. Other points of arrival exist away from these zenith and nadir points, but these non-standard jump points are difficult to calculate and may prove hazardous to use (see Non-Standard Jump Points, below).

As soon as the navigational calculations are complete, the ship's jump officer (the designated officer in command during the jump) alerts the crew to secure all fittings, and then initiates the jump program with a single command. Initiating the program triggers warning klaxons and beacons, which alert the ship's crew and passengers to the upcoming jump. The K-F drive requires several minutes to reach ready status. Ten seconds after ready status is achieved, the drive-generated K-F field expands and the vessel makes the hyperspace transition known as a jump.

The jump itself "blinds" the vessel's sensors, which recover approximately 30 seconds after the vessel arrives at its destination, and causes mental disorientation among crew and passengers. The extent of this disorientation varies, generally ranging from a few seconds to fifteen minutes or more. As a precaution against hostile attack during this period of disorientation, many military JumpShip crews go to Code Red/battle stations status before jumping.

To verify its location after the jump, the vessel's optical sensors triangulate the ship's position in relation to charted stars and compare its data to the planned destination. Most JumpShips arrive within 5,000 meters of their planned destinations, and some modern military JumpShips are capable of arriving within 500 meters of their intended destinations.

Not all jumps are completely successful. Drive problems, navigational errors or natural phenomena may cause a JumpShip to arrive at an unplanned destination, commonly termed a misjump. On some occasions, the ship arrives only a short distance off course and the vessel can maneuver to the correct position. On other occasions, a vessel may end up somewhat further afield and need to make a second jump to reach its objective. A severe misjump may damage a vessel's drive core, forcing the ship to perform emergency repairs in order to return home.

Double Jumping

Some JumpShips are equipped with lithium-fusion battery systems. These systems store extra charges for a ship's K-F drive, enabling a vessel to make a second jump within a relatively short time period. (Efforts to fit ships with multiple battery systems to achieve multiple-jump capability have resulted only in major losses of drive efficiency and increased recharge times.)

The main operational limitation concerns the minimum time between jumps. Two factors influence this time: the period required to bring a ship's navigational array back online after its first jump, and the period required for the first K-F field to contract. Normally, a vessel's navigational sensors recover within 30 seconds after a jump. An operational navigational array is a primary requisite for a controlled jump, and so 30 seconds is the absolute minimum time a ship must wait before performing a second jump.

The contraction period of a ship's K-F field depends on two factors: the distance traveled on the first jump, and the JumpShip's DropShip load. The K-F field of a small JumpShip traveling a short distance may contract completely before the ship's navigational sensors come back online, but ships making longer jumps and larger vessels may have to wait for their K-F fields to collapse before making a second jump. On the largest WarShips, the K-F field may require up to six minutes for complete collapse.

Double jumping doubles the stresses inherent in a single jump and does not provide a JumpShip crew with adequate time to inspect their vessel for jump-related damage. The accumulation of static electricity during double jumps presents the most dangerous hazard. Normally, static charges dissipate naturally following a jump. Double jumping provides little time between jumps for static charges to dissipate, however, so such charges may build to dangerous levels. A discharge of static electricity during the second jump may disrupt operating systems in the vessel and disrupt the jump process. Micro-fractures and drive-core helium leakage are also more common, and double jumping considerably increases the likelihood of seal failures. Double jumping also increases the severity and duration of the disorientation suffered during a jump.

To minimize the strain on ship and crew, most JumpShips wait several hours or even days between jumps, except when the risks of delay outweigh these potential hazards. Many vessels equipped with lithium-fusion batteries jump no more than once every three days, alternately powering their jumps with their batteries and jump sails.

Non-Standard Jump Points

The most common type of jump points, called standard jump points, are located above the two gravitational poles of a star (see Basic Jump Procedure). Because these points do not shift, they represent by far the safest type of jump point.

Non-standard jump points, commonly called pirate points, include any points of gravitational equilibrium within a star system other than the system's standard zenith and nadir points. (The most commonly used type of non-standard points are Lagrange points.) Unlike standard jump points, non-standard jump points do not have fixed locations. The complex gravitational interaction of the system's stars, planets and other astronomical bodies means that non-standard points are constantly moving, appearing and disappearing at irregular intervals. This characteristic makes calculating such points extremely difficult even with powerful computer systems and accurate astronomical data. Additionally, vessels using non-standard points stand far less chance of being rescued in the event of a malfunction than those using standard points. For this reason, non-standard points are generally used only in emergencies or by JumpShip crews seeking to conceal their arrivals in star systems (such as pirate vessels).

Objects Within a K-F Field

Any object within a JumpShip's K-F field (a vessel's K-F field normally extends up to 1,000 meters from the vessel) is exposed to considerable gravitational and electromagnetic stresses and is likely to sustain damage. An object within a ship's field produces opposing effects, but generally these are too weak to affect the arriving or departing JumpShip, unless that object is another JumpShip.

In such cases, the drive coil of the second vessel will distort the jumping ship's K-F field, with serious consequences for both vessels. Typically, the initiating vessel's drive controller will automatically abort a jump in such a situation, losing the drive's charge but saving both craft. If the controller is malfunctioning or the vessel's crew overrides the controller, however, the vessel may misjump and suffer extensive damage. Most such vessels are lost. Consequently, JumpShips commonly observe strict protocols when operating in the vicinity of other vessels. Usually, a fleet commander designates an entry/exit zone, which all departing and arriving vessels use. All recharging or waiting vessels take up stations well away from this designated zone.

The field-interaction problems of multiple JumpShips also prevent JumpShips from transporting disabled jump-capable vessels, forcing crews to repair damaged JumpShips in the field. Vessels that cannot be adequately repaired to ensure safe travel must be abandoned.

Drive Charging

All JumpShips must recharge their Kearny-Fuchida hyperdrives and/or lithium-fusion batteries before they can perform a jump. Most JumpShip crews prefer to remain near a jump point and perform such recharge operations immediately after completing a jump. K-F drives and batteries may be recharged with a vessel's jump sail or power plant. If a JumpShip contains a lithium-fusion battery, the crew normally will use both the sail and the power plant to charge the vessel's battery and drive core simultaneously. Crews rarely use either the jump sail or power plant to simultaneously charge drive cores and battery systems, because this practice causes a drastic reduction in the recharge rate and places a severe strain on the vessel's power system.

To perform solar-sail recharging, the JumpShip's crew must first align the vessel's nose to the system's star. Normally, the alignment operation takes only a few minutes, during which the entire vessel crew is placed on maneuver alert. Once the ship is properly aligned, the vessel crew begins to deploy the ship's jump sail, an operation that may take up to 90 minutes. Once the sail is deployed, the recharge operation can begin, though the pressure on the sail caused by the light energy from the star (the so-called stellar wind) immediately begins to slowly push the JumpShip away from the star. To counteract this force, the vessel's station-keeping thrusters are fired through the hole in the center of the sail.

The base charging time for both drive-core and lithium-fusion systems is 150 hours. (Using a vessel's reactor for recharge operations will lower this base time, but this practice may damage the ship's drive system and the vessel itself.) If using a jump sail to recharge a system, the charging time may range from 151 to more than 200 hours, depending on the class of star in the system. However, jump-sail charging conserves fuel and minimizes the risk of damage to a ship's drive.

Drive cores and battery systems may be charged more quickly, but faster charging rates place considerable stress on these systems. The level of stress, and consequently the chance of damage or failure, are inversely proportional to the time taken to charge the system. At the base charging rate of 150 hours, the chance of damage is negligible. A rate of 100 hours produces a 16-percent chance of failure and damage. A 75-hour rate increases the chance of failure to 27 percent, and a 24-hour rate yields a 50-percent chance of damage. The potential for system failure increases considerably below this rate, and any attempt to charge the drive in less than 16 hours inevitably results in severe damage.

Drive damage or failure ranges from the simple loss of a stored charge, through various component failures, to complete destruction of the drive. Such failures may strand a vessel in space, but they will not affect the vessel's life-support systems. Fast-charging a lithium-fusion battery may have far more dire consequences: fast-charging such batteries generates large quantities of heat, which may cause a battery system to explode and severely damage a JumpShip.