Spaceship construction is done via GURPS Spaceships, an e23 sourcebook for GURPS Fourth Edition. Any changes to the rules are found below.

With the changes in the new edition, conversion of existing SSDs is difficult, so the designs listed here are more concerned with the look and feel of ships rather than an exact SSD conversion. In addition, until later supplements are brought out, these rules will largely concern themselves with freighters, shuttles and fighters, not the larger capital warships.

Basic notes:

All ships are TL 10.
Military ships use Nanocomposite armour, civilian ships use up to Advanced Metallic Laminate armour.

Power plants are Fusion or Antimatter.
The engine of choice for is the Antimatter Plasma torch, although Antimatter Thermal Rockets and Antimatter Plasma Rockets are available.
All ships that are capable of Hyperdrive should install a Stardrive (see below). Fuel is required for stardrives (see below).

All ships should have artificial gravity.

Ships weapons are Particle weapons or Launchers. Launchers use Warp Missile Launchers for space combat, but normal missile launchers are available for ground attack. 1 ph-3 is roughly equal to two 10 MJ particle beams.
I allow ships to mount smaller weapons than their size allows. In this case, use the cost and weapon statistics from the smaller mount, but use the Unistalled value from the larger size.

Items not used:

Cloaking devices. While some experimental models might exist, cloaking devices are not in use.
Force screens and Stasis Web are not in use at all.

Write up:

The only change to the write up is with the Spacecraft Table. For Range, insert the Travel Time Modier (see below).
Shuttles and fighters are NOT included in the price!

All prices are in cubits, however the price of the spaceship is still the same as that generated in the design process.

Notes:

All sensors are FTL capable without additional cost, space, mass or power. These sensors include FTL communications as no extra cost.

Stardrives:

Stardrives drives are treated as warp drives. Stardrives require fuel. This fuel is the same fuel that the reaction drives use (tylium) and the two drives can share fuel from the same tanks.

A spaceship consumes an amount of fuel equal to 1/6 the amount of fuel in a single fuel tank per centar of travel. For Antimatter thermal rockets this works out to 0.3 mps per centar of travel, while antimatter plasma rockets and antimatter plasma torches use 20 mps per centar of travel.

To calculate the Travel Time Modifer of the ship, add up the amount of stardrives that the ship has and consult the following table.

Ships cannot exceed a modifier of x0.75.

Fuel:

While antimatter drives and fusion power plants are used for spaceship construction, all craft actually use Tylium as their fuel and reaction mass. In game terms, all engines use Jet Fuel for fuel, and Tylium should be treated as that substance, with the same cost and weight. Because all drives use the same fuel, all fuel may be used for both the stardrive and manoeuvre drives.

So how much fuel should a spaceship carry? Civilian vessels will generally have three fuel tanks. Using an antimatter plasma torch, this allows them to make a basic hyperspeed journey of 6 centars (at a travel time modifier of x2.00 that makes 120 mps fuel per trip), have some fuel to manoeuvre and then return. Shorter range vessels could lose fuel for a return trip if they are sure that they will be able to refuel at their target destination.

Military vessels will have more. All ships need fuel for their target destination and a return trip. Then they will need fuel to manoeuvre and fight. This means that military vessels need at least 3 fuel tanks - more if the ship is a smaller fighter.

Cylon Spaceships:

In game terms, Cylon ships follow the same rules as Colonial vessels above.
Cylons do not require cabins and bunks for themselves on ships, but they do require space for repair and storage as such. Cylons should be given bunks for all crew, and in addition, a minifac should be bought for every 25 Cylons. This accounts for the repair facilities that they need. Cylons must buy life support for their ships though.