Engines, Drives, and Power

Space is not fast. The distances between stars are genuinely vast, and even the distances inside a single star system are large enough to make simple travel a meaningful decision. The technologies that move ships through both kinds of distance are the most important engineering aboard any vessel, and understanding how they work and how they fail is the foundation of operating a ship at the table.

This chapter covers everything that makes a ship move: sublight engines for normal-space travel, Slipstream drives for interstellar transit, power systems that keep it all running, and the heat management problem that defines what any ship can sustain under pressure.

Sublight Engines

Sublight engines handle everything inside normal space: leaving a Slipstream seam arc, crossing a system to reach a planet, running down a target, matching a station's orbital vector, and surviving the part of transit where being chased is a real possibility.

Two drive technologies dominate civilian and military use.

Fusion Drives

Fusion drives are the working standard of commercial space. They are cheaper than antimatter drives, maintainable at most frontier ports, legal everywhere, and well understood by mechanics across known space. A fusion drive can be repaired with available parts, fueled from sources that do not require military supply chains, and operated by crews who have not received specialized training.

What fusion drives cannot do is be fast. A fusion engine runs at Cruise 1, 2, or 3 (see Cruise Ratings below), and Cruise 3 is the fusion ceiling. A working ship at Cruise 2 makes a Standard approach in two days. A bulk hauler at Cruise 1 takes six. Fusion ships make route geography matter: the time between Slipstream exit and destination is measured in days, and it is never zero.

Antimatter Drives

Antimatter drives are fast, expensive, politically significant, and loud.

They are fast because the energy density of antimatter annihilation produces thrust that fusion cannot match. A ship burning antimatter at high cruise covers distances in hours that would take a fusion ship days. When an antimatter drive lights its torch, every ship in the system with functioning sensors notices. The heat signature, the drive bloom, the thrust-to-mass ratio: all of it reads as military capability or corporate investment that most independent operators cannot afford.

Antimatter drives are expensive in three ways: the fuel costs more, the maintenance costs more, and the political cost of operating one without the right credentials can be significant. Fuel containment, safety systems, regulatory tracking, security seals, and maintenance records create hooks for customs, insurers, military auditors, and competitors. A civilian vessel with an antimatter drive is worth investigating.

An antimatter engine runs at Cruise 4 or 5. A Cruise 4 patrol ship makes a Standard approach in twelve hours; a Cruise 5 interceptor makes it in six. Any ship running an antimatter engine at Cruise 4 or higher is detectable at Extreme by any sensor grade for as long as the drive is lit.

In-System Travel

Every ship carries two speed ratings. Speed is tactical: it governs Range Band movement per Maneuver in ship combat and chases (Chapter Fifteen). Cruise is strategic: it governs the time to move between Travel Bands in normal space. The two are independent. A courier can be Speed 5 and Cruise 3. A bulk freighter can be Speed 2 and Cruise 1. A hull with high Speed and low Cruise is nimble in a fight and slow across a system.

Cruise is a property of the Sublight Engine. Swapping the engine changes Cruise, and engine damage reduces it (see Engine Damage below). Every hull profile in Chapters Sixteen and Seventeen lists both ratings.

The GM does not compute distances. In-system travel is resolved from three values: the ship's Travel Band, its Cruise rating, and the destination system's Approach.

Travel Bands

A ship in normal space is always in exactly one Travel Band, measured from its destination: the port, station, planet, wreck, or rendezvous the crew is heading for. When the destination changes, the GM restates the band.

Travel Bands use the same names as combat Range Bands because they are the same abstraction at a different clock. When two ships in the same Travel Band begin an encounter, switch to the ship combat rules in Chapter Fifteen and open at Long combat range unless the situation dictates otherwise.

Legs and Intervals

Moving from one Travel Band to the next is a leg. A leg costs a number of Intervals: one for the near bands, two for the far bands, mirroring the Maneuver cost for range movement in combat.

A full run from a Standard seam arc to dock is 6 Intervals. Departure uses the same legs in reverse, plus the drive charge at the seam (see FTL Transit Procedure below). The length of an Interval in hours is set by the ship's Cruise rating.

When the crew travels between two bodies inside a system rather than from the seam to a port, the GM states the leg count using the same band logic: a planet to its own moon or orbital station is 1 Interval, one inner world to another is 2, an inner world to a gas giant is 4, and a gas giant to the seam arc is 2 or the Extreme leg cost if Approach is Far. A precise figure is not required; a consistent one is.

Cruise Ratings

The reference speed column exists only for consistency with the drive descriptions above. Do not use it at the table.

Cruise 4 and 5 require an antimatter Sublight Engine. Antimatter engines are Restricted or Military availability, tracked, and expensive to fuel. A civilian hull with Cruise 4 or higher is corporate, ex-military, or illegal. Engine grades and their Cruise values are in Chapter Ten.

Approach

Approach is a system stat. It states which Travel Band a ship occupies when it emerges from the standard exit arc, and how many Intervals the outermost leg costs. Every system record in the Sector Atlas carries an Approach value. When a system record has no Approach value, use Standard.

Approach is a property of the seam arc, not the ship. A Cruise 1 hauler and a Cruise 5 interceptor emerge in the same band; they arrive at dock five and a half days apart. An offset exit adds Intervals to the Extreme leg; the modifiers are in the Offset Exits table under Slipstream Drives below.

Approach examples:

Hard Burn

A ship may push its Sublight Engine to cover ground faster.

• Trigger: The pilot declares Hard Burn at the start of a leg.
• Effect: Treat Cruise as one higher for that leg only. A Cruise 5 ship cannot Hard Burn.
• Cost: 1 additional Supply Unit for the leg. At the end of the leg, the engineer makes an Average Craft Trial. On failure the Sublight Engine suffers 1 System Damage. Each consecutive leg under Hard Burn increases the difficulty by one step.
• Signature: A ship under Hard Burn is detectable at Extreme by any sensor grade for the length of the leg. Signature Management does not offset this.

Hard Burn is not the Overburn action. Overburn is a per-round combat action with its own Heat cost, covered in Chapter Fifteen.

Detection on the Approach

Travel Bands line up with the sensor detection bands in Chapter Seven. A watcher detects an approaching ship when it enters the outermost band the watcher's sensor grade reaches: Basic at Short, Standard at Medium, Extended at Long, Military at Extreme. Two exceptions apply at any range. A ship broadcasting a transponder is known to traffic control from emergence wherever relay or beacon coverage exists. A ship on Hard Burn, or any ship running an antimatter engine at Cruise 4 or higher, is detectable at Extreme by any sensor grade. Pursuit across Travel Bands is resolved by comparing clocks; the procedure is in the GM Guide.

Engine Rating and Availability

A sublight engine answers two separate questions, and the answers do not depend on each other.

Rating is Speed and Cruise, tracked as separate steps. Each step of Speed rating is +1 Speed above the hull's Scale baseline, and each step of Cruise rating is +1 Cruise. Speed ratings are open-ended; what stops a freighter buying a warship's acceleration is the operator tier cap for its Scale in Chapter Thirteen, not a ceiling on the hardware. Cruise is capped by drive class: a fusion engine cannot be raised past Cruise 3, and Cruise 4 or 5 requires an antimatter engine fitted as a full replacement. The engine grade table is in Chapter Ten.

Availability is who may legally own the drive. This is where the fusion and antimatter split does its work: the technology sets what is on open sale, and the paperwork follows the technology.

There is no such thing as a better engine because it is a military engine. There are engines with more rating steps, and there are engines a civilian may not legally hold. The two travel together often enough to look like one axis, and they are not.

Overburn: An engine at Restricted or Military availability adds +1 Speed while Overburning, because its injectors and containment sustain a push the commercial article cannot. It also draws attention, requires restricted parts, and typically triggers inspection when found on a civilian hull.

Component condition, salvage, and integration are in Chapter Ten. Build point costs and tier caps are in Chapter Thirteen.

Engine Damage

When a ship's sublight engine suffers System Damage, the effects depend on severity:

• 1 System Damage: Reduce Speed by 1 and Cruise by 1 (minimum 1) while the damage persists. Heat costs for Overburn increase by 1. Hard Burn is unavailable.
• 2 System Damage: Reduce Speed by 2. Cruise is 1 regardless of rating. Overburn is unavailable until repairs are made.
• 3 System Damage: The engine is offline. The ship cannot maneuver beyond minimum attitude control. Speed drops to 1 (maneuvering thrusters only). The ship drifts and cannot change Travel Band without assistance.

Engine damage reduces both ratings at once. A disabled sublight engine does not prevent Slipstream transit if the drive is intact, but the ship cannot reach the seam arc without external assistance.

Table Hooks

The difference in sublight performance creates natural pressure at the table.

A Cruise 2 freighter that emerges at a Far system through a Distant offset faces an Extreme leg of 10 Intervals and a total of 14 to dock: four days and sixteen hours of fuel, food, crew patience, and deadline pressure. A Cruise 4 military cutter emerging on the standard arc of the same system docks in twenty hours, and everyone in the system sees its drive from the moment it lights.

Whether the navy corvette has the antimatter budget to keep burning at full Cruise is a real tactical consideration.

Slipstream Drives and FTL Transit

Slipstream corridors are naturally occurring channels in folded space, anchored between distant black holes and accessible at seam arcs where local gravity weakens the boundary between normal space and Slipspace.

The Slipstream drive generates the field required to cross that boundary and sustain transit within a corridor. It is the most complex and expensive system aboard any interstellar ship, and its failure is the kind of emergency that turns a routine transit into a campaign event.

Corridor Classes and Transit Times

Corridor class governs capacity: which ships the corridor tolerates and how much traffic it carries. It does not set speed.

Transit time is set by the length of the journey and the route's traits. Every published route record in the Sector Atlas carries a travel time; use it when one exists.

A Fast or Slow route trait moves a journey toward the low or high end of its band. A superior Slipstream drive does not make every corridor faster, but it makes the worst corridors less dangerous.

FTL Transit Procedure

Use this checklist at the table when a ship attempts Slipstream transit.

Step 1: Identify the seam arc. On an established corridor, this requires no Trial under normal conditions. The navigation AI and traffic control both have current arc data. On a frontier or degraded seam, an Astrogation Trial may be required (Average for Maintained seams, Hard for Frontier seams, Severe for New or Fading seams).

Step 2: Reach the approach zone. The ship must travel to the outer system where the seam arc lies. This is the in-system travel discussed above: the legs from the ship's current Travel Band out to Extreme, at the ship's Cruise rating.

Step 3: Charge the Slipstream drive. A functioning Slipstream drive requires a minimum charge time of 10 minutes under normal conditions. A drive at Restricted or Military availability charges in half this time. A drive at less than full System Points increases charge time proportionally.

Step 4: Entry. On an established seam, entry is routine and requires no Trial. On a frontier or degraded seam, entry requires an Astrogation Trial at the same difficulty as identifying the arc. Success enters the corridor normally. Failure with Banes may result in a rough entry, drive stress, or temporary sensor loss.

Step 5: Transit. The ship moves through the corridor at the drive's rated transit speed. Standing directives handle navigation in a clean corridor. Active hazards (saturation, turbulence, damage) may require Trials during transit.

Step 6: Standard exit. The navigator follows the charted stream and allows the drive to push the ship back into normal space at the expected exit arc. No Trial required under ordinary conditions. Standard exits are monitored; authorities know when a ship arrives.

Offset Exits

An offset exit takes the ship out of the corridor before or after the standard exit arc. This is the smuggler's tool, the military scout's technique, and the desperate escape option when the expected exit is hostile.

The farther the ship exits from the reinforced seam, the more difficult the transition becomes, and the farther the ship emerges from the standard track. An offset exit adds Intervals to the Extreme leg of the approach. The ship also chooses its own emergence direction, so a patrol sitting on the standard arc is not in its path.

This is the only copy of the offset-exit modifiers in this book. Chapter Seven and Chapter Nineteen point here.

Offset exit failure table (d6):

A near-miss on an offset exit does not automatically destroy the ship. It makes the exit messy, visible, or expensive. Offset exits are dangerous and not subtle: an experienced customs officer does not need proof that a ship used an offset exit; the arrival pattern tells them enough.

Forced Entry

A ship in normal space cannot enter Slipspace where no seam exists. The boundary is not thin enough without local gravity assisting.

A forced entry, tearing through the boundary outside a seam arc, is possible in theory and catastrophic in practice. It requires suitable coordinates, a functioning Slipstream drive, an Advanced or Military Directive AI running a navigation package, and a navigator willing to attempt something that almost never works.

Possible outcomes include catastrophic drive damage, severe System Damage across multiple systems, crew casualties, emergence in an unintended corridor, uncontrolled phase exposure, or destruction. A forced entry is not a routine technique. It is an act of desperation or deliberate military recklessness.

Forced Entry is not the exploration procedure. Finding a new seam is covered in Chapter Seven under Corridor Trace, and the full six-step expedition procedure is in the GM Guide.

Drive Damage

A drive that takes System Damage mid-transit may force an immediate emergency punch-out at the GM's discretion.

Power Systems

Power capacity is how much the ship's reactor can sustain simultaneously. Power load is how much the ship is currently drawing. When load exceeds capacity, the engineer must act.

Power Capacity

Power Capacity is the reactor's maximum sustainable simultaneous output. Routine systems (life support, basic sensors, environmental controls) are always active and are assumed included in baseline calculations. Only high-output choices require tracking during encounters.

Common high-output draws:

When active Power Load equals Power Capacity, the engineer is managing a system at maximum sustained demand. When load exceeds capacity, the engineer must immediately choose a response.

Overload responses:

The ship can sustain minor overload (1 above capacity) for 1 round without consequence if the engineer immediately declares a response. Sustained overload or overload of 2 or more above capacity escalates immediately.

Power Boost

A ship's engineer can push the reactor beyond its rated output as a deliberate action. This is called Power Boost, and it provides temporary additional Power Capacity at the cost of Heat.

Power Boost requires an Average Craft Trial. On success, treat Power Capacity as 2 higher for one round, but generate 2 Heat immediately. Each round the Boost is maintained requires another Trial. A Bane on this Trial generates 1 additional Heat. A Calamity generates a cascade failure affecting the reactor or power distribution.

Emergency Power

Some ships carry emergency battery reserves: separate power sources that activate when the main reactor is damaged, shut down, or overloaded.

Emergency power provides enough capacity to sustain life support, basic maneuvering (Speed 1 from thrusters), distress beacon, and minimal communications. It cannot power weapons, screens, high-output sensors, or the Slipstream drive. Duration depends on the ship's battery capacity: most commercial ships have 4–8 hours of emergency reserves.

A ship running on emergency power is a ship that has lost.

Heat Management

Heat is the accumulation problem that cannot be managed by turning off the right switch. It builds over time as weapons fire, engines push, screens absorb hits, and the reactor works beyond comfortable limits. The ship dissipates Heat passively at the end of each round. Under sustained pressure, Heat accumulates faster than it dissipates, and when it crosses the Threshold, the consequences compound.

How Heat Builds

Heat Dissipation

At the end of each round, the ship removes Heat equal to its Heat Dissipation value. This is passive and automatic under normal conditions.

Commercial hull Heat reference:

The tier baselines these hulls are built from, by Scale and operator tier, are in Chapter Thirteen, Step Five.

Improving Thermal Performance

Power Capacity, Heat Threshold, and Heat Dissipation are all reactor stats, and they are bought the way every other system stat is bought. One step of reactor rating yields +2 Power Capacity, +3 Heat Threshold, and +1 Heat Dissipation. Steps accumulate as far as the hull's operator tier caps allow and no further.

Heat Dissipation is the one exception. It has a tier baseline set by Scale rather than a purchase price at zero, and a design may raise it at most 2 steps above that baseline. Beyond that the hull needs radiator area it does not have.

A better reactor is therefore a better reactor, not a military reactor. Availability governs whether the crew may legally hold it; rating governs what it does. A Restricted reactor pulled from a wreck runs exactly as well in a tramp freighter as it did in the corvette, which is the whole appeal and the whole problem.

Rating steps for every system are in Chapter Ten. Build point costs, tier caps, and the Heat Dissipation baselines are in Chapter Thirteen.

Engineer Heat Management Actions

Heat Threshold Escalation

Heat below the Threshold is manageable. At Threshold and above, consequences escalate in bands. Each band stacks all penalties from the bands below it.

At Threshold: Warning

The ship is running hot. No mechanical consequence yet, but the signature bloom has begun.

• Signature Bloom: all Signature Management Trials add 1 Bane Die.

Threshold +1 to +3: System Strain

Thermal stress is affecting weapon cooling, targeting stability, and engine performance.

• All Strain penalties continue.
• All weapon attack rolls add 1 Bane Die.
• All Pilot Trials to push engines, Overburn, or execute Combat Thruster maneuvers add 1 Bane Die.
• At the end of each round: Average Craft Trial. On failure, Heat Dissipation is halved for that round.

Threshold +4 to +6: Critical Strain

Thermal systems are in distress. Power routing is becoming unstable.

• All previous penalties continue.
• At the end of each round: Hard Craft Trial. On failure, the ship suffers 1 System Damage to Reactor, Power Distribution, or Defensive Control (GM selects).
• Active screens absorbing hits generate 1 additional Heat per hit beyond listed values.
• Heat Dissipation is automatically halved; a Hard Craft Trial is required to maintain normal Dissipation.

Threshold +7 to +9: System Failures

Components are failing. The hull is beginning to take thermal stress.

• All previous penalties continue.
• At the end of each round: Hard Craft Trial. On failure, one non-essential active system shuts down automatically (weapons, screens, ECM, or modules; GM selects).
• The ship takes 2 Hull Damage per round from internal thermal stress.
• Power Capacity is reduced by 2 until the ship cools below this level.

Threshold +10 or more: Emergency Shutdown

The ship is in thermal crisis. Automated shutdown protocols are engaging.

• All previous penalties continue.
• At the start of each round: Severe Craft Trial to prevent emergency shutdown (must be declared before any other actions).
• On failure: all weapons, screens, modules, and ECM go offline. Engines drop to Speed 1. Life support switches to emergency reserves.
• On success: emergency shutdown is held off for this round. Each Boon may keep one named system online, but each kept system generates 2 additional Heat at the start of next round.
• Recovery: the ship must cool below Threshold +3 before systems can be restarted. Each restart costs 1 action and an Average Craft Trial.

Heat Escalation Quick Reference:

Gravity Systems

Every ship above Scale 2 carries artificial gravity generators. They are as standard as life support and nearly as critical: a crew operating in microgravity cannot fight effectively, maintain systems under pressure, or function across long transits without significant physical cost.

Standard Artificial Gravity

Ship artificial gravity systems maintain 0.8g–1.2g across the inhabited sections of a ship. Within this range, no mechanical effect applies. The gravity is normal.

Standard commercial AG systems affect the entire ship equally. They cannot apply different gravity to different sections. Changing the ship's gravity level requires an Engineering action and a Craft Trial; the change takes effect over 2 rounds.

Disabling AG requires only a simple Engineering action or emergency cutoff. The ship immediately drops to microgravity throughout all affected sections.

In microgravity, unsecured crew must spend 1 additional action each round to maintain position or reorient after strenuous actions. Melee attacks without anchoring add 2 Bane Dice. Mag boots eliminate the anchoring penalties on compatible surfaces.

AG as a Tactical System

Ships with AG systems at Restricted or Military availability, and Funtari designs at any availability, can apply differential gravity to locked compartments. This is covered fully in Chapter 14 (Crew Stations and Actions), but the basic principle matters here: a crew with hover suits can set ship gravity to 3g and operate freely while boarders are crushed.

Zone AG requires a closed, pressure-sealed section, an Engineering action (Hard Craft Trial), and an ongoing Power Load of 1 per isolated zone.

Sudden gravity changes (shifting from 1g to 3g in one action) require all unprepared characters in the affected area to make a Hard Athletics Trial or fall prone.

Funtari Hover Integration

Funtari-built ships above Scale 3 typically integrate localized antigravity technology into their interior design. This means hover-only access points: control stations and secure areas placed across open interior gaps that authorized hover-equipped crew cross easily. Standard artificial gravity handles crew comfort. The hover architecture handles access control.

The gravity rules that govern what happens to crew in non-standard environments are covered in full in the Void Drifters Player's Guide. The relevant ship systems reference is this: a ship's AI can control ship gravity as a system, the power load is tracked normally, and the tactical use of gravity manipulation is a legitimate play option with full mechanical support.

Gravity on Planetary Approach

When a ship transitions from space to atmospheric or surface operations, environmental gravity becomes a factor for the crew aboard. Most ships maintain their artificial gravity throughout atmospheric approach, maintaining the normal range regardless of planetary surface gravity.

A ship with a disabled or damaged AG system that enters a high-gravity planetary environment subjects its crew to that environment's gravity band, with all associated penalties, until the system is restored or the ship departs.

The ship's Speed and Handling in atmospheric flight are handled by the atmospheric flight package rules. The crew's physical condition under variable gravity is handled by the gravity rules from the Player's Guide.