GURPS Spaceships for THS conversions?

[thrakkemarn]

Well, after reading this still a lot is left unanswered. It seems TS uses TL9-11 stuff from spaceships. Diamondoid armor for example is TL11 in 4e, but is explicitly in the core TS book.

Is there any sort of standard or guide to using Spaceships to build TS ships? I like the system but so much detail is lost... so I'm hoping for a compromise.

[thtraveller]

Originally Posted by thrakkemarn

Well, after reading this still a lot is left unanswered. It seems TS uses TL9-11 stuff from spaceships. Diamondoid armor for example is TL11 in 4e, but is explicitly in the core TS book.

Is there any sort of standard or guide to using Spaceships to build TS ships? I like the system but so much detail is lost... so I'm hoping for a compromise.

As far as I know the only hint we have for now is, from this thread, that drive performance is TL9 for fusion rockets, and fusion pulse is maybe TL10.

We may have to wait for the Spaceships for Transhuman Space book for the full details. Was that book 8?

I am guessing that while TS is mature TL10 that materials tech (nano based?) is early TL11 and engine tech is late TL9 (engineering based?).

[Tzeentch]

Spacecraft Tech Assumptions
See Transhuman Space: Changing Times for detailed coverage.
- TL9 for older spacecraft (old modules, built before 2080 or so)
- TL10 for newer spacecraft
- All drives use TL9 performance. Some particularly old designs may use TL8 performance (Horus I from Spacecraft of the Solar System, for example.
- As TL9 and TL10 designs exist together you may wish to give a cost break to old designs (maybe treat as a used ship, see Spaceships 2, pp. 27-28).

Conversion Notes
Some quick eyeballed notes. See Transhuman Space, pp. 173-190 for detailed module descriptions.

Major Rules of Thumb
- ALL THS designs use the Exposed Radiators design switch (Spaceships, p. 31).
- Converted designs are often starved for space (module slots). This means most craft will use both core slots (also, see Storm Shelters, below), lack Engine Rooms, and take advantage of steerage and scaled weapon battery cargo.
- The nature of THS space warfare means Defensive ECM and Stealth is rarely employed.
- You will probably not be able to exactly match DR, delta-V, and cargo capacity. The important thing is that the design feels right in comparison with the others.

Picking a SM
1. Note the LMass (Loaded Mass) of the THS design and pick a hull size that roughly corresponds to that. You can adjust this up or down one SM as the situation requires. For example, the Meizi, with LMass 11,213 (p. TS191), is SM+10 (10,000 tons). Note that the actual measurements of the ship do not necessarily need to differ from what THS says. Also see Changing Times, p. 67 for a discussion of Size Modifiers.
2. Note that in Spaceships, most THS craft are not streamlined. As a general rule, only apply streamlining (Spaceships, p. 9) to Streamlined Deltas (p. TS173)
3. Some Combination Hull designs (p. TS175) may be easier to replicate using Upper Stage (Spaceships, p. 26).

Armor
Armor, Ice and Stone: Use these for Asteroid Hulls, p. TS175.

THS Material		Spaceships
Slag		             Rock
Steel Alloy		Steel
Aluminum Alloy		Light Alloy
Titanium Alloy		Light Alloy
Foamed Alloy		Light Alloy
Carbon Composite		Metallic Laminate
Metal-Matrix Composite	Advanced Metallic Laminate
Nanocomposite		Nanocomposite
Diamondoid		Diamondoid

Control Rooms: Note that THS Basic Bridges have 4 control stations; THS Command Bridges have 8. In addition, many designs are completely automated. Take advantage of the cost breaks for removing control stations (Spaceships, p. 14).
Sensors: In general, most designs will use the control room bundled sensors. Use special Arrays (Spaceships, p. 15) only in unusual cases.

Drives
Note that Spaceships uses the realistic delta-V calculations (p. TS189).

<Edit> THS designs list their delta-V with turnover. Double that to get full one-way delta-V as Spaceships lists.

Conversion Note: It can sometimes be useful to determine the mass fraction of a THS design used for drives. Multiply #modules * 4 to get mass of THS drive. Each of the five Spaceships engine (rear) slot available is about Loaded Mass /20 tons.

THS		Spaceships
Chemical Rockets (all)		Chemical Rocket
Laser Rocket		None
Mass Driver Engine		Mass Driver
Fission Drive		Nuclear Thermal Rocket
Fusion Pulse Drives		Fusion Pulse Drive/Advanced Fusion Pulse Drive
Antimatter Pulse Drives		None. Use Antimatter Thermal Rocket
Fusion Torch Drives		Fusion Rocket
Nuclear Light Bulb		Nuclear Light Bulb
Plasma Sail		Magsail
Ion Drive		Ion Drive
Fission Air-Ram		Antimatter Thermal with Ram-Rocket option
Turbo-Scramjet		Jet Engine

Weapons
Do not be too concerned about matching exact beam outputs. You may wish to use the RF and VRF options to bring things more into THS ranges.

Lasers: Use lasers with the ultraviolet option. Most are turreted.
Coilguns: Use electromagnetic guns.
Particle Accelerators: Use lasers with the particle beam option. Note that most are best represented by Major Batteries, not Spinal Mounts.

Crew and Passengers
Most crew modules translate over directly. Exceptions are noted below:

Passenger Seats: THS modules hold 16 seats.
Storm Shelters: To replicate these, place the Control Rooms and sheltered habitat areas in the [core].
Habitat: Be careful with these, but most correspond to Open Space and Factory. Vatfacs have no direct Spaceships module. For Housing, use Luxury Cabins. These modules may be Reconfigurable (Spaceships p. 24).

Accessories
Most of these are obvious. Note that entry modules are subsumed in Spaceships.

External Cradle: One External Clamp can represent several THS cradles.
Robot Arms: These may be purchased as design options. They are NOT the Spaceships Robot Arm in most cases.
Surgery: These are sickbays with automeds (Spaceships, p. 18).
Vehicle Bay: Use the optimized option in Spaceships 4.

Power Systems
Spaceships drives do not generate Power Points, it is subsumed into the system.

Solar Panels: Most solar arrays are subsumed into the Spaceships system.
Energy Banks: These do not exist per se any longer, and would be hell to mix with the variable length Spaceships turns. Use Fuel Cell or MHD in cases where you need the power and can't justify a reactor conversion.

Surface Features
Liquid-crystal skin is a design feature and subsumed into the system.

Other Notes
Gravity Generation (p. TS176): Use Spin Gravity (Spaceships, p. 30) for all types. The THS derived spin gravity can be kept as a design feature.

[thtraveller]

Originally Posted by Tzeentch

Spacecraft Tech Assumptions

Thanks for this. Very useful.

- All drives use TL9 performance.

This seems to contradict what David Pulver said in post 10 of this thread.

Originally Posted by David L Pulver

Many ships in THS use "Fusion Pulse" and these are probably best repped by the TL10 fusion pulse drives.

Though this was over a year ago. Has the position changed?

[Tzeentch]

-- I've just been sticking with straight TL9 across the board right now. It forces some very severe restrictions on spacecraft performance that (in my opinion) actually helps accentuate the "flavor" of THS designs (bare bones, almost entirely fuel tanks and engines). At least with the designs I've done quick conversions of, it works out ok.

-- If the official word becomes TL10 is allowed, it's easier to rebuild or modify a Spaceships design than a Appendix A one :)~

------------------
Example Conversion
This example converts the "Sudbury 4000" design by thtraveller, available at http://www.transhuman.talktalk.net/ts/tsSudbury4000.htm

The design uses a 10,000 ton (SM+10) unstreamlined hull.

Example 1: Using standard fusion drives
- As we can see, the cargo capacity is sacrificed to get the rough amount of delta-V in the original. Note the amount of steerage cargo (THS designs run very crew-light) and the scaled weapon batteries to also juice some extra cargo while still keeping it armed with a light defense laser.

Example 2: Using advanced fusion pulse drive
- Note the steep increase in cost (+$100M per drive slot), but it's easier to get the originals other performance features.


Sudbury 4000: Fusion Pulse Drive Edition (TL9)

Front Hull System Notes
1 Light Alloy Armor (dDR 15).
2-4 Cargo Hold (500 tons capacity each).
5 Control Room (C7 computers, comm/sensor 8, only four control stations).*
6 Habitat (four cabins, one minifac fabricator, one-bed sickbay with automeds, and 270 tons cargo).*

Central Hull System
1 Light Alloy Armor (dDR 15).
2 External Clamp.
3! Tertiary Battery (one turret with 1 MJ VRF ultraviolet laser and 435 tons cargo).*
4 Fuel Cell (one Power Point).
5-6, core Fuel Tank (500 tons nuclear pellets providing 6 mps delta-V each).

Rear Hull System
1 Light Alloy Armor (dDR 15)
2 Fusion Pulse Drive (0.02G).*
3-6, core Fuel Tank (500 tons nuclear pellets providing 6 mps delta-V each).

* One technician mans each system.

It has a spin hull (0.2G) and exposed radiators.

TL Spacecraft dST/HP Hnd/SR HT Move Lwt. Load SM Occ dDR Range Cost
PILOTING/TL9 (Low Performance Spacecraft)
9 Sudbury 150 -4/5 13 0.02G/48 mps 10,000 2,205.8 +10 8ASV 15/15/15 0 $178.3M


Sudbury 4000: Advanced Fusion Pulse Drive Edition (TL9)

Front Hull System Notes
1 Light Alloy Armor (dDR 15).
2-4 Cargo Hold (500 tons capacity each).
5 Control Room (C7 computers, comm/sensor 8, only four control stations).*
6 Habitat (four cabins, one minifac fabricator, one-bed sickbay with automeds, and 270 tons cargo).*

Central Hull System
1 Light Alloy Armor (dDR 15).
2 External Clamp.
3! Tertiary Battery (one turret with 1 MJ VRF ultraviolet laser and 435 tons cargo).*
4 Fuel Cell (one Power Point).*
5-6, core Cargo Hold (500 tons capacity each).

Rear Hull System
1 Light Alloy Armor (dDR 15)
2-3 Advanced Fusion Pulse Drive (0.005G each).*
4-6, core Fuel Tank (500 tons nuclear pellets providing 20 mps delta-V each).

* One technician mans each system.

It has a spin hull (0.2G) and exposed radiators.

TL Spacecraft dST/HP Hnd/SR HT Move Lwt. Load SM Occ dDR Range Cost
PILOTING/TL9 (Low Performance Spacecraft)
9 Sudbury 150 -4/5 13 0.01G/80 mps 10,000 3,705.8 +10 8ASV 15/15/15 0 $466.5M

[thrakkemarn]

Thanks for the replies! Very useful information.

I haven't gotten into doing conversions and have no experience with the 3e combat system to really compare, so I'm just wondering if the armor vs damage conversions work out.

It seems that in THS in general, armor is very powerful compared to weapons tech. From what I understand of the old combat system, it was pretty easy to have some high armor ratings which small ships couldn't really punch through. However, with this new system you can slap a heavy or secondary battery that can tear through even heavy ship armor. This seems very unreasonable for a THS setting.

Again, I'm just getting into this stuff, so maybe my interpretation is way off. Have any of you guys addressed this situation? I was thinking that maybe dDR should scale with ship size, or some across-the-board boost to dDR. Any thoughts?

[thtraveller]

Originally Posted by Tzeentch

Sudbury 4000: Fusion Pulse Drive Edition (TL9)

3! Tertiary Battery (one turret with 1 MJ VRF ultraviolet laser and 435 tons cargo).*
4 Fuel Cell (one Power Point).

This is an issue with Spaceships. Having to use a whole module for a power point when all that is needed is a thirtieth of a power point in the Battery module is not right. Possibly just use a double size weapon to simulate this?

It has a spin hull (0.2G) .

Interesting. Given the relative low cost of spin hulls compared to original TS would you give all large TS ships spin hulls?

Generally
I would favor the advanced fusion pulse drive as the more economical one. The NP fuel price is a serious problem though for any commercial operation. It needs to be at least ten times cheaper to be a potential commercial choice. NP did seem to be artificially under priced in the original TS.

Given the capabilities of the fusion rocket in spaceships, the fuel price _and_ availability, I expect to see it being favored over NP based drives in new TS designs.

Note that the TL10 advanced fusion pulse drive is close to being commercially competitive with TL9 fusion rockets as you need less fuel modules.

[Tzeentch]

Not sure if it would make sense to give all larger ships the spin gravity option. I imagine most travellers can get by just fine in microgravity most of the time.

Fuel costs are probably going to have to be altered somewhat for the setting. I don't know if that means using the values from the THS core book (although those were set at values that justified a certain level of intrasystem trade).

The weapons thing is kind of annoying, but you can use the hack of 3x SM-1 systems in one slot to get around it.

SDVs and maybe all THS ships in general could maybe make use of Greater Survivability options in Spaceship 3 (p. 35).

[thrakkemarn]

I'm thinking that the only way to even closely represent THS ships is to use the 3-in-1 hack.

[Crakkerjakk]

Originally Posted by thrakkemarn

I'm thinking that the only way to even closely represent THS ships is to use the 3-in-1 hack.

Or wait for Spaceships 8 (or whichever one it is that is the TS supplement, I think it's 8).