Sensor/Stealth Test

Sensor/Stealth interaction test

A sensor sweep is rolled at D10 + sensor power, rerolling and adding all 10s. Normally a sensor sweep rolls 1 dice at Long range, one additional at Medium and a third at Close. All targets with a stealth rating below the roll(s) must make a saving throw for each detection success made.

If the save is successful, the sweep has detected a 'contact' which can be further followed; if the save is failed there is sufficient accuracy on the sensor solution to enable weapons fire, though the target's Evasion may recieve a bonus. A ship may fire on a non-targeted contact by Blindfiring, however this is guaranteed to provide a substantial bonus to the target's evasion.

Sensors

The following are the default sensors that is free on all ships, ranked 1-5.

+0 Telescopes and Lookouts
Sensor Power: +0
Sensor Ranges: 5/10/20
Doubles all Star Way effects.

+0 Simple Magnetic Sensor Array
Sensor Power: +2
Sensor Ranges: 8/15/30

+0 Simple Search Radar
Sensor Power: +3
Sensor Ranges: 10/20/40

+0 Simple Gravitometer
Sensor Power: +4
Sensor Ranges: 12/25/50

+0 Simple Quantum Flux Detector
Sensor Power: +5
Sensor Ranges: 15/30/60

Permutations

High-frequency sensors; high sensor power but small medium/long ranges.
Low-frequency sensors; moderate sensor power with extended long ranges.
Towed sensor arrays; disabled if ship is forced to make an evasion roll.
Wake detectors; bonus for being in star ways.

More esoteric things

Over-The-Starway sensors; for detecting from star systems into star ways. Big, for use in forts and large warships?
Star Way cloud generators, for mobile concealment.

Stealth

All ships have a default stealth value, as well as a stealth coefficient which modifies the cost/space of stealth systems depending on the size of the fitted equipment. Many stealth systems also reduce the slots available for weapons/armor, on top of their cost in Option slots.

Stealth has two routes; Passive Stealth and Active Stealth. Passive stealth tends to have lower bonuses and inferior saves, however it is more effective at increasing effective range. Active stealth has generally better bonuses and saves, but does not provide as much of a penalty to enemy sensor ranges. Also, some active stealth systems may interfere with the host vessel's own sensor systems.

Examples

+2X Simple Passive Stealth
Weapon/Armor reduction: X
Stealth +5
Stealth Save: 7+
Range Increase: +10 This adds to the actual range, making the stealthed ship act as if it were more distant
Evasion +1 Evasion bonus is doubled if the target is attacked with Blindfire.

+3X Simple Active Stealth
Weapon/Armor reduction: X
Stealth +8
Stealth Save: 6+
Range Increase: +5
Evasion +1

Concepts

Running Silent

While as a matter of course warships at war minimize their emissions, in many cases stealth ships go beyond this, eliminating all emissions as humanly and technologically possible and essentially becoming 'holes in space'. This typical results in deactivation of shield systems, reducing speeds to limit scatter and relying solely on passive sensors. The upside of course is that this makes them even more difficult to detect, but a ship caught in this state is particularly vulnerable.
Running Silent allows stealth saves to be re-rolled, but halves speeds, deactivates any shield, ECM and other active systems and reduces all sensor rolls by 1 dice.

Tracking targets

A contact that has not been successfully targeted but is tracked for consecutive rolls recieves a -1 cumulative penalty to its stealth saving rolls. A contact that successfully breaks contact removes all such penalties.

The Layer

'The Layer' is the colloquial term for the often shifting, stormy boundary between the relatively clear inner star way and the dense, stormy outer layer. As a general rule, it reflects and refracts energy, making detection across the Layer notoriously difficult.
Detecting targets on the other side of the Layer penalizes sensor rolls.

Space Mines

While not strictly speaking derived from stealth technology, mine warfare is related, particularly in the use of extremely high-frequency (and thus high fidelity) sensors to detect mines. The small size of space mines (rarely significantly larger than a human in a bulky spacesuit) means that even relatively unsophisticated weapons can be difficult to detect.