Subspace Transition

The Fabury Gate is located in planetary orbit far inside the planet's shunt limit. Besides the obvious convenience of having the gate just above the planet this location also means that no raiders or other enemies can simply shunt in to attack the gate, though this far inside the Highland such attacks are almost completely unknown.
As Trinity approached the man made interface between real and subspace gate control requested the craft follow a specific vector and set its autopilot on the far-side beacon. Through the gate the swirling photon field of subspace shown like an abstract masterwork. As the schooner penetrated the interface her measured forward velocity seemed to be reduced, as if she had dived into a body of syrup. Darvis reconfigured the drive for subspace service, reducing its output until the vessel sprang forward.
Outside, the tunnel like aspect of the conduit, the hyperdrill stabilized gravity structure which allowed vessels to reach the orbital gate-portal without being torn apart by the gravitational shear plane generated by Faury's planetary plateau, surround the vessel. Darvis could see another vessel ahead. The gravscanner showed two more vessels beyond his vision, hidden in the fog like photon field of subspace. 
The VORN showed the conduit end-beacon as the schooner left the conduit behind. The beacons for St. Pilimon up road and Grendmouth down road blinked on the display, as the automatic piloting computer awaited his verification. Darvis acknowledged the Grendmouth beacon icon and the Trinity's pilot computer turned the ship to follow the series of beacons. The counter showed 6 days estimated flight time until Grendmouth. 
The gravscanner showed the gravity plateau of Fabury falling behind, and the very much larger plateau of Fabury's primary beyond the curved display of the routing beacons. Below and above the shear planes of subspace waited for anyone unwary enough to leave the well marked Major route.
Darvis made sure the computer was monitoring the DOR storm watch channel, broadcast from the hypercable links on the beacon stations. He then left the bridge computer to its work.

Proximity Detectors

Proximity Detectors are short range, commercial grade, gravscanners which are used by light spacecraft for the purpose of collision avoidance and subspace navigation. The range of proximity detectors is much lower than even the lightest gravscanner. A proximity detector does not have an active mode.

Proximity Detector	Volume(cuft)	Mass	Cost	Power	Scan	Range
Proximity Detector/D	1000	25	11	neg.	35	10,000
Proximity Detector/C	2000	50	20.4	neg.	39	50,000
Proximity Detector/B	2000	50	20.2	neg.	42	100,000

Sensors - GURPS extended rules.

Neither Multiscanners, nor Gravscanners are given detail rules in GURPS Space equivalent to the detail given for AESA, PESA and Radscanners in GURPS Traveller Starships. In that rule book sensors are given stats for a wide range of sizes from Flt. for the very lightest to Ult. for the ultra-heaviest. In GT the very largest used on a space craft, for the super-sized Tigress Dreadnought, is Shv. (Super-Heavy), leaving the very largest for use in stations and planetary arrays.
For purposed of New Diasporia Tech Levels Gravscanners became available at TL D, the same level as the Barnes-Gutierrez Hyperspace Engine. Multiscanners became available one TL sooner, at TL E. That makes both these technologies well established, with well known capabilities and limits.
Specs for each device is based upon GURPS VE 2nd Ed. Volume is in cubic feet. Mass is in tons. Cost is in MegaParliments. Scan is the standard GURPS sensor scan value. Range is in miles.

New Disporia Multiscanners	cuft	Mass	Cost	Power	Scan	Range
Flt. Multiscanner/E	2800	50	.202	neg.	35	100,000
Mlt. Multiscanner/E	3000	75	.302	neg.	36	150,000
Ult. Multiscanner/E	4000	100	.402	neg.	37	200,000
Slt. Multiscanner/E	6000	150	.602	neg.	38	300,000
Elt. Multiscanner/E	9000	226	.902	neg.	39	450,000
Lt. Multiscanner/E	14,000	350	1.402	neg.	40	700,000
Md. Multiscanner/E	20,000	500	2	neg.	41	1,000,000
Hv. Multiscanner/E	30,000	750	3	neg.	42	1,500,000
Ehv. Multiscanner/E	40,000	1000	4	neg.	43	2,000,000
Shv. Multiscanner/E	60,000	1500	6	neg.	44	3,000,000
Uhv. Multiscanner/D	90,000	2250	9	neg.	45	4,500,000
Elt. Multiscanner/D	2500	56.2	.226	neg.	39	450,000
Lt. Multiscanner/D	3500	87.6	.35	neg.	40	700,000
Md. Multiscanner/D	5000	125	.50	neg.	41	1,000,000
Hv. Multiscanner/D	7500	187.6	.75	neg.	42	1,500,000
Ehv. Multiscanner/D	10,000	250	1	neg.	43	2,000,000
Shv. Multiscanner/D	15,000	376	1.5	neg.	44	3,000,000
Uhv. Multiscanner/D	22,500	562	2.26	neg.	45	4,500,000
Md. Multiscanner/C+	1000	25	.1002	neg.	41	1,000,000
Hv. Multiscanner/C+	1500	37.6	.1502	neg.	42	1,500,000
Ehv. Multiscanner/C+	2000	50	.2	neg.	43	2,000,000
Shv. Multiscanner/C+	3000	75	.3	neg.	44	3,000,000
Uhv. Multiscanner/C+	4500	112.6	.45	neg.	45	4,000,000

Multiscanners are indirect sensors. An indirect sensor can perceive multiple targets in a virtual 360 degree sphere around the sensor.
A single multiscanner can only operate in a single mode at any one time. Military vessels usually have more than one so that they can scan for radiation, biological and chemical data at the same time. This does not mean that a single vessel will have more than one multiscanners of the same capability. After all, in space radscanner mode is generally much more useful at long ranges than bioscanner mode. So most military or exploration ships will have a long range multiscanner supplemented by a couple of shorter range scanners.
In chemscanner and bioscanner mode a multiscanner is an active sensor and can be detected by a multiscanner in radscanner mode for double its effective range. An active force field will block a multiscanner.

New Disporia Gravscanner	Volume	Mass	Cost	Power	Scan	Range
Flt. Gravscanner/D	10,000	250	1.01	neg.	35	100,000
Mlt. Gravscanner/D	15,000	375	1.51	neg.	36	150,000
Ult. Gravscanner/D	20,000	500	2.01	neg.	37	200,000
Slt. Gravscanner/D	30,000	750	3.01	neg.	38	300,000
Elt. Gravscanner/D	45,000	1125	4.51	neg.	39	450,000
Lt. Gravscanner/D	70,000	1750	7.01	neg.	40	700,000
Md. Gravscanner/D	100,000	2500	10.01	neg.	41	1,000,000
Hv. Gravscanner/D	150,000	3750	15.01	neg.	42	1,500,000
Ehv. Gravscanner/D	200,000	5000	20.01	neg.	43	2,000,000
Shv. Gravscanner/D	300,000	7500	30.01	neg.	44	3,000,000
Uhv. Gravscanner/D	450,000	11250	45.01	neg.	45	4,500,000
Elt. Gravscanner/C	18,000	450	1.804	neg.	39	450,000
Lt. Gravscanner/C	28,000	700	2.804	neg.	40	700,000
Md. Gravscanner/C	40,000	1000	4.004	neg.	41	1,000,000
Hv. Gravscanner/C	60,000	1500	6.004	neg.	42	1,500,000
Ehv. Gravscanner/C	80,000	2000	8.004	neg.	43	2,000,000
Shv. Gravscanner/C	120,000	3000	12.004	neg.	44	3,000,000
Uhv. Gravscanner/C	180,000	4500	18.004	neg.	45	4,500,000
Md. Gravscanner/B	20,000	500	2.002	neg.	41	1,000,000
Hv. Gravscanner/B	30,000	750	3.002	neg.	42	1,500,000
Ehv. Gravscanner/B	40,000	1000	4.002	neg.	43	2,000,000
Shv. Gravscanner/B	60,000	1500	6.002	neg.	44	3,000,000
Uhv. Gravscanner/B	80,000	2000	8.002	neg.	45	4,000,000

Gravscanners are also multi-mode devices. In passive mode a gravscanner can detect artificial and natural gravitational fields. That is it can detect the natural mass of matter and it can detect devices which artificially manipulate gravity. Object such as stars, planets and massive planetary objects can be detected at system wide ranges. Smaller objects such as vessels, adrift people, and stations require that the object be within the range of the gravscanner and that a successful sensor roll be accomplished.
Using standard GURPS sensor rules:

Detection; Reveals the objects bearing, its ~ mass to the ton, and its speed within 10 mph.

Recognition: Reveals the objects range to within the nearest mile and gives an idea for the approximate size. Reveals the kind of gravity manipulation technology in use.

Identification: Reveals the exact mass of the object and details of the gravity manipulation technology used.

Modifiers for Gravscanners is as follows: Object is using: TLC Basic Emission Cloaking -8 TLC Radical Emission Cloaking -16 TLB Distortion Field -18 TLA Distortion Field -20 Object is using a tractor beam +5 As a (GAD) Gravity Anomaly Detector a gravscanner can be used to detect and map large scale gravitic phenomenon, such as a subspace portal or the subspace/real space interface created by a vessel when it shunts into or out of subspace. In this mode a gravscanner can also be used to map the topology of subspace and detect gravity shear planes. Ranges in subspace are more or less equivalent to ranges in real space, except of course that subspace is much smaller than real space so effective ranges are much greater. This only applies to GAD mode. Normal gravscanner operation is much more limited in subspace. Ranges beyond 1 light second (186,000 miles) is about maximum for even the best gravscanner as far as detecting normal matter. In active mode a gravscanner can be used as a gravitic-imaging device. Range in this mode is 500 miles at TL C, 1250 miles at TL B, and 2500 miles at TLA. In this mode the gravscanner is very susceptible to disruption by varying fields of artificial gravity and of course it cannot see through an active force field, not even the structural integrity fields used by modern starships. Also another gravscanner in passive mode can detect an active gravscanner at twice that gravscanner's normal range. As can be seen this mode is most useful in scanning dead ships or ancient ruins, rather than active powered vessels

Space Combat - Movement

Generally speaking there are two broad types of space combat scenarios in New Diasporia: Individual ship actions and fleet actions.
Individual ship actions can be done using the abstract combat rules from GURPS Space by converting the standard GURPS statistics of New Diasporia to GURPS Space statistics (which in most cases means dividing them by 100.) Any other space combat system  can also be used, provided the game master/story teller/referee is willing to convert the ship statistics to that game system.
Fleet actions are divided into a strategic and a tactical phase. In the strategic phase fleet assets are moved to the target using the stellar maps. Movement on the star system scale should be calculated using the proper calculations. I use those given in the Space Travel and Combat appendix of the GURPS fourth edition Sourcebook Vorkosigan Saga, specifically the Newtonian Space Flight box. All of these formula are derivable from real world sources. As for many other calculation used in the game I use a spreadsheet which allows me to plug in the values rather than having to calculate them by hand during the game. That keeps the game moving.
At the tactical level I use the modified GURPS Traveller hex map rules already referenced. That is hex distances are 1 hex = 10,000 miles. Time scale is 1 min. This is a two dimensional playing field instead of a three dimensional field. Yes a three dimensional field is more accurate, it is also very difficult to play. Playability thumps accuracy in this case. For game purposes movement can be rounded such that 100 Gs of acceleration will equal 1 hex per minute movement. So a ship with 100 Gs acceleration will move 1 hex in its first movement phase 2 hexes in its second movement phase. 3 hexes in its third movement phase, etc.
To calculate how many miles a vessel will move use the formula:

Travel time [hours] = SQRT(0.0000508)*((Distance[Miles])/Acceleration [Gs])

This gives the time require for the spacecraft to travel longer distances.

Men O'War -Vessel Classes

The smallest standard warship class is the Corvette, also known as the patrol ship. Corvettes are usually no more than four to five hundred thousand cubic feet in size. They have a small crew and are used for custom and policing duties, by both the Legion and Rangers. Other space navies use them for equivalent duties. Corvettes are lightly armed and armored.
The Pinnace is an even smaller vessel. Typically between 250 thousand and 400 thousand cubic feet, pinnaces, though they have hypershunting capability, are typically carried aboard other vessels to provide couriers, engage in scouting tasks and provide messenger services. A Pinnace is typically an armed vessel. They are capable of landing on world, which larger combat ships are not, as well as operating in hyperspace.
The Schooner is a lightly armed, swift courier vessel which often accompanies fleets and tasks forces. Like the Pinnace they are small enough to be embarked on major combatants as auxiliary vessels. most Schooners are in the fifty thousand to hundred thousand cubic foot range.
Frigates are more heavily armed ships designed for independent duty. The typical frigate is from 5 to 8 million cubic feet in size, though some Midland forces are known to field frigates in the ten million cubic foot size. Frigates range from medium to heavily armored and are usually outfitted to provide for planetary combat support as well as space combat. This means they embark a number of space and planetary combat craft, as well as having sufficient personnel to man them.
The Destroyer and its even smaller cousin the Destroyer Escort are ships in the 5 to 6 million and 3 to 5 million cubic feet range respectively. Unlike the Frigate, Destroyers and Escorts are designed to provide support to larger warships or convoys of merchant craft. They are neither designed for independent action, nor capable of supporting planetary combat.
A Battlerider is a small vessel in the 50 thousand to 400 thousand range optimized for space combat. Unlike the Pinnace they lack passenger facilities and though shunt capable and landing rated, they are seldom used for any other purpose than space combat. Most battleriders are specialized with a specific weapons mix or sensor package. They most often operate in groups which consists of craft of varied capabilities.  Like most large space combatants they are typically roughly spherically shaped.
A third-rater or Battleship is a ship of the line usually in the 10 million to 50 million cubic foot range. Battleships are the lightest of the ships of the line. They are armored with heavy force fields. Like all ships-of-the-line a battleship will have a large troop contingent, as well as combat support craft, including many battelriders.
A second-rater or Dreadnought is a ship of the line usually in the 100 to 200 million cubic foot range.
A first-rater or Superdreadnought is a ship of the line usually in the 200 to 250 million cubic foot range.

Space Combat - Framework

Generally speaking New Diasporia is about the background, not about the game system. But for aspects of the game which are either central to the concept or describe technology unique to the game universe it is very difficult to present the background in a way which will allow use of the material without adding game mechanics to the mix. If your preferred game system already has rules or a way in which to incorporate these concepts by all means use them. Game mechanics included here are for those who wish to have a set of rules ready made for the background.
The native game rule set of New Diasporia is GURPS 3rd Edition. Any rules present here are based upon or are variants of that rule set.
The area in which New Diasporia has the largest set of applicable rules is in space combat. Space combat rules are always almost entirely driven by the technology of the game universe. Often that in game technology is driven by the feel of the space combat experience desired by the creator. So for example, Traveller most closely resembles the age of battleships, while a game like Full Thrust or Star Wars D6 fulling incorporates fighter combat, like modern naval warfare.
As for GURPS, over the years GURPS has incorporated a number of different space combat rule sets. GURPS Compendium II introduced the Space Opera Combat System and the Abstract Space Combat System. GURPS Space has its own, slightly more detailed abstract space combat system. GURPS Traveller used a hex grid based combat system, optimized for the Traveller universe. GURPS Space has a sidebar conversion to allow the use of the GT hex system with GURPS Space. All of these systems are predicated on very low spacecraft acceleration, 6 Gs or less for GURPS Traveller.
I find the GURPS Traveller Rules the most useful after modifications. Each hex is 10,000 miles across. Time scale for each round is reduced from 20 minutes to 1 minute. Vessels traveling at >50 Gs acceleration tend to pass outside of effective combat range very quickly. Capital ship energy weapons have ranges in the 40,000 to 80,000 mile range. Missiles tend to have longer ranges, in the 1,000,000 mile range for a single stage missile and many times that for a multiple stage missile.
Classes of combat ships follow.

Nanomaterials & Game Mechanics

In the universe of the New Diasporia nanomaterials have been around for a long time. The field of nanomaterials encompasses a materials- based approach to nanotechnology. Unlike the nanite based microelectronic field of nanorobotics upon which later tech levels are based nanomaterials are not strictly speaking nanomachine based. Most nanomaterial properties are based on quantum mechanical effects. Novel material properties become apparent in the nanoscopic region. For example opaque substances become tranparent (copper), stable materials become combustible (aluminum), isulators become conductors (silicone), solids exhibit the characteristics of liquids (gold). Many of these properties are used in the construction of nanomachines, however many materials such as ceramics, alloys and fixed powders can evidence properties which are unattainable at larger sizes, but do not require a mastery of advanced nanorobotics.
In the game mechanics of New Diasporia nanomaterials are sometimes invoked as a mechanism to alter the GURPS 3ed. rule set for the background or as an in universe explanation for how some of the tech works.
A particular example is spacecraft "skin." New Diasporia spacecraft at the TLA technology level have two characteristics which are not standard GURPS properties.
The first is stealth. In GURPS VE 2nd Edition rules only streamlined vehicles can be stealthy. This is an extension of existing stealth designs which are based on LO or low observable technology. This technology depends on both surface shape and composition. In the New Diasporia rules a nanomaterial stealth coating allows even unstreamlined vehicles to have basic or radical stealth characteristics. Stealth reduces a vehicle's chances of being detected by active sensors. Typically only military vessels will have radical stealth. Naturally such nanomaterial stealth like other crystal skin properties is adjustable, so a ship with stealthy "skin" can be unstealthy at will.
The second is solar cells or rather solar power accumulating skin. VE 2nd allows, at TL11+ for direct surface mounting of solar cells using the formula solar cell sqft = hull area/2. New Diasporia allows total coverage to be equal to any skin area not occupied by weapons or sensors. Even windows can absorb sunlight in the non-visible spectrum. Calculate output of the solar absorbtion system by calculating the square footage of "skin" and use the TL9+ value of .08 kW per sqft. pwr = hull area x .08. Actual effective output is typically one-half of that number since typically only one side of the craft can face the sun. It is possible of course to sit between binary suns and get maximum output, but that is a special case.  The craft skin can still have stealth, infrared or liquid crystal skin.
Broadly speaking TLA is roughly equivalent to GURPS TL14. Nanomaterials first become widely available at TLF, so are widely used on even fairly obsolete vessels. Standard Tech Level GURPS rule relationships between sensor and stealth/emission control effectiveness are used. So sensors from higher Tech Levels are more effective against sensor masking techniques of lower Tech Levels.

Sensor Systems - Advanced

It should come as no surprise that military and advanced commercial sensor systems far outstrip the capabilities of the standard sensor systems available to the general public in the kinds of commercial vehicles typically used on the Major Routes or Blue Highways.
Sensor are typically divided into Active Electromagnetic Sensors (AESA), Passive Electromagnetic Sensors (PESA), Advanced Multi-mode Sensors, (Multiscanners) and Gravity Detectors (Gravscanners).
Generally speaking AESA and PESA sensors are line of sight sensors which require mounting either in a turret or multiple units with fixed antennas must be installed. Military craft typically have 6 long range fixed array units of each type to ensure total sensor coverage.
Multiscanners and gravscanners are indirect sensors. They do not require line of sight to operate.
Multiscanners have three operational modes. A single multiscanner unit may only be used in one mode at a time. Civilian vessels will often mount a single multiscanner. Military vessels will almost always have multiple multiscanners, to allow operation in all modes simultaneously. Multiscanner may be set to chemscanner, bioscanner or radscanner mode. In chemscanner and bioscanner mode the multiscanner is an active sensor and may be detected by other vessel's radscanners at 10x their operation range. Radscanners are passive detectors. Radscanners may operate in multiple modes simultaneously. Radscanners function as an advanced radar/laser/maser locator. That means they can locate a ship that is using broadband EM communication, electromagnetic, including light or x-ray based weapons, (though highly collimated energy, like lasers will only be detectable by the intended target.) Plasma weapons are extremely easy for a radscanner to detect. A radscanner can also act as an energy scanner, capable of locating the output of a fusion or MHD based power plants. The ability to detect such sources is very dependent on the output of the power plant as well as the range and whether or not the plant is shielded by a force field or emission masking.
Gravscanners are also multi-mode devices. In passive mode a gravscanner can detect artificial gravity and contrgravity fields, such as those developed by an operating B/G engine. Force fields which are not being operated in distortion mode and gravity field weapons, such as gravity rail guns or gravity pulse weapons can be detected. Tractor/pressor beams can also be detected. Gravity emission masking technology is available.
In passive mode a gravscannor can also be used to detect natural gravity fields and the distortions in real space caused by the movement of an object which has mass through those naturally occurring gravitational fields. This means that a gravscanner can determine the bearing and approximate mass and speed of an object. It can also be used as a gravity anomaly detector (GAD) detecting areas where subspace has intruded into real space, such as happens when an hypershunting capable ship enters or leaves subspace.
In subspace a gravscanner can be used to detect the gravity planes which make up subspace topology, detect subspace storms, and intrusions of real space, such as a subspace portal. The gravity manipulation fields of an operating hyperspace drill can also be detected by a gravscanner in GAD mode.
In active mode a gravscanner can operate as a densitometer, a gravitic-imaging sensor which  can be used to map the interior of objects. In active mode a gravscanner is itself detectable to another gravscanner at 10x its own range. A gravscanner cannot penetrate active force fields, including the structural integrity fields of most TLA and B space vessels.

Men O' War - Force Fields

The Major Roads have made interstellar travel through the use of very small craft so common in the Highlands that it is easy to forget the vast difference in capabilities necessary between a major combatant and a hyper utility vehicle (HUV) or brake.
Highland combat spacecraft tend to be built rather lightly armored. Force field technology provides the greatest amount of protection to a modern warship. It is also a standard building technique to include planar force fields within bulkheads and at the center of struts. Such fields allow for greater structural integrity, that is the structural integrity field allows a bulkhead to resist stress and compression damage as if it were made of a much stronger, heavier material. Structural integrity fields also prevent simple penetration from depressurizing compartments, as the field can retain the atmosphere.
Of course relying on such technology to increase the durability of such large structures as a battleship or dreadnought means that without structural integrity force fields intact and operational such a vessel is vulnerable to structural failure. Of course since failure of inertial compensators and the life support system would result in the death of everyone aboard anyway, such vessels have many layers of backup systems to ensure such systems do no fail.
It is also standard for passageways and large compartments to include a system of planar force fields to allow sections to be segmented both for security and emergency damage control. Such ubiquitous application of force technology make modern warships quite unlike vessels built at lower technology. Much of the Midlands, and almost all of the Wilds construct most of their vessels at TLC and below, and lack even the most basic force field technology. In the Highlands even the plebeian HUV contains internal force field segmentation and an external, though light power force field.