Jovian Chronicles Conversions: Pathfinder and Syreen

Even though Dammann and I are the only people interested, I've decided to write up some conversions from Jovian Chronicles to GURPS. I'm going to start by writing up the two original iconic exo-armors, the Jovian Pathfinder and the CEGA Syreen, pretty much using the stock GURPS Spaceships rules. I am using the sub-sized system rules from Transhuman Spacecraft, since that allows me to do some interesting tricks with the Syreen.

The only other optional rule I'd consider using is the Armor and Volume rules from Pyramid 3.34 (Alternate Rules). That would nearly double the armor on the Syreen and make it a SM+4 craft for targeting, which would incidentally make it nearly immune to Pathfinder's particle cannon. So for now, it's probably best that I don't use that rule. Though if I did, I could drop the Syreen's armor to Metallic Laminate and save $0.36M, which is tempting.

Read about these ships in action in this sample combat, and again, slightly modified, in this sample combat.

EAL-04A Pathfinder Alpha (TL10^)

The main light exo-armor of the Jovian Confederation, the Pathfinder is both fast and heavily armed, while still possessing a respectable electronics suite. The Pathfinder's armament is basic but effective. A Jovian Optics 652 particle beam cannon provides the main firepower; it is backed up by a pair of plasma lances concealed in the exo's hips for quick access. 

Pathfinders have an unstreamlined 45-foot tall hull massing 30 tons (SM +5) and are crewed by a single pilot assisted by an AI autopilot and gunner's aid.

Front Hull	System
[1]	Hardened Nanocomposite Armor (dDR 7)
[2]	Hardened Nanocomposite Armor (dDR 7)
[3]	Hardened Nanocomposite Armor (dDR 7)
[4]	Defensive ECM
[5]	Tactical Array
[6]	Handheld Major Battery (10 MJ Particle Beam)
[core]	Control Room (C6, Comm/Sensor 4, 1 Control Station)
Central Hull	System
[1]	Hardened Nanocomposite Armor (dDR 7)
[2]	Hardened Nanocomposite Armor (dDR 7)
[3]	Hardened Nanocomposite Armor (dDR 7)
[4]	Medium Battery Battery (16 cm Missile Launcher; 3 MJ Antiparticle Beam; 30 KJ Improved VRF Laser)
[5]	Robot Arm
[6]	Robot Arm
[core]	Fusion Plant (two Power Points)
Rear Hull	System
[1]	Hardened Nanocomposite Armor (dDR 7)
[2]	Hardened Nanocomposite Armor (dDR 7)
[3]	Variable Thrust Fusion Torch Engine (3G acceleration)
[4]	Robot Leg
[5]	Robot Leg
[6]	Fuel Tank (1.5 tons water with 5 mps delta-V)

TL	Spacecraft	dST/HP	Hnd/SR	HT	Move	LWt.	Load	SM	Occ	dDR	Range	Cost
PILOTING/TL10 (HIGH-PERFORMANCE SPACECRAFT)
10	Pathfinder Alpha	20	0/4	12	3G/2.5mps	30	0.6	+5	1SV	21/21/14	0	$4.22M

Weapon	sAcc	Type	dDmg	Range	RoF	Rcl	Shots
652A Particle Cannon (10 MJ Particle Beam)	-3	burn rad sur (5)	4d	C/S	1	1	Infinite
MMJ-4 Missile (16 cm Missile Launcher)	2	cr exp (2)	6dx4	L	1	1	2
PL4 Plasma Lance (3 MJ Anti-Particle Beam)	-3	cr exp rad sur (3)	6d	R	1	1	5
Arclight-3 PDS (30 KJ Improved VRF Laser Beam)	0	burn (2)	1d-2	C	200	1	inf

Design Notes

There's very little strange here. This is a pretty straightforward adaption of the Spartan (Spaceship 4 p. 27) to TL10 superscience. The variable thrust fusion torch can accelerate at 1.5G while only using half as much delta-V but the Move value is given for its maximum thrust. 

The plasma lances were the only thing that were difficult to translate into GURPS Spaceship terms. Making them anti-particle beams with a maximum range of R (Rendezvous only!) seemed like a good compromise: they do very good damage, but the low accuracy and difficulty of achieving a Rendezvous course means they're mostly going to be used against spacecraft, not other exo-armors.

Incidentally, 100 burn points in Jovian Chronicles exactly equals 1 mps of delta-V in GURPS Spaceships. So that worked out very well.

The MMJ-4 launcher should have 7 shots, but in the original JC, Pathfinders only carry 2 missiles. So they only have 2 here.

In playtest, I discovered that a PDS turret in the central hull is mandatory. So I added one and swapped the locations of the main and medium batteries. This is the same PDS array used by Hector variant of the Pathfinder.

CEA-01 Syreen (TL 10^)

Essentially a retro-fitted orbital transfer vehicle, the Syreen was merely intended to be a short-term stopgap measure. Much to nearly everyone's surprise, it has outlasted all expectations and has become CEGA's mainstay light exo-armor. While reasonably well armored, the Syreen suffers from a number of structural faults. It does have the ability to stay out of reach of its opposite in the JAF, the Pathfinder, however, which has led to the unit's popularity, both with its pilots and with CEGA's propaganda machine.

Syreens have an unstreamlined 45-foot tall hull massing 30 tons (SM +5) and are crewed by a single pilot assisted by an AI autopilot and gunner's aid.

Front Hull	System
[1]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[2]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[3]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[4]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[5]	2x SM+4 Robot Arms; 0.5 tons cargo space
[6]	Defensive ECM
[core]	Fusion Plant (two Power Points)
Central Hull	System
[1]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[2]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[3]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[4]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[5]	Medium Battery (16 cm Missile Launcher; Turreted 8 cm Electromagnetic Gun; Turreted 30 KJ Improved VRF Laser Beam)
[6]	Turreted Major Battery (10 MJ Improved Laser Beam)
[core]	SM+4 Control Room (C5, Comm/Sensor 3, 1 Control Station); 2x SM+4 Fuel Tank (1.0 tons water with 3.5 mps delta-V)
Rear Hull	System
[1]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[2]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[3]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[4]	Hardened Advanced Metallic Laminate Armor (dDR 5)
[5]	Variable Thrust Fusion Torch Engine (3G acceleration)
[6]	Defensive ECM

TL	Spacecraft	dST/HP	Hnd/SR	HT	Move	LWt.	Load	SM	Occ	dDR	Range	Cost
PILOTING/TL10 (HIGH-PERFORMANCE SPACECRAFT)
10	Syreen	20	-1/3	12	3G/1.7mps	30	0.6	+5	1SV	20/20/20	0	$2.45M

Weapon	sAcc	Type	dDmg	Range	RoF	Rcl	Shots
ACDLS (10 MJ Improved Laser Beam)	0	burn (2)	4d	S	2	1	Infinite
CSH-4 Missile (16 cm Missile Launcher)	2	cr exp (2)	6dx5	L	1	1	2
A3 Missile (8 cm E-Mag Gun)	-7	cr exp (2)	6dx2	S	1	3	8
ACDLS Screen (30 KJ Improved VRF Laser Beam)	0	burn (2)	1d-2	C	200	1	inf

Design Notes

The Syreen was a lot more complicated. In Jovian Chronicles, it's clearly intended to be a mecha for mooks, inferior to the Pathfinder in nearly every way (despite what the blurb above would say). In Spaceships, though, the smaller arms and the lack of legs should make it superior to a Pathfinder, since it has 2-3 extra systems worth of stuff.

I finessed the issue by using inferior armor materials and smaller arms and a smaller control room. The smaller control room gives it worse sensors and worse maneuverability, meaning that it should be fairly vulnerable to a Pathfinder despite a longer ranged and more accurate primary gun.

Happily, this also makes the costs of the two craft roughly equivalent to the JC versions. My Pathfinder is $4.2M (vs $3.9M in JC) and the Syreen is $2.5M (vs $1.7M in JC).

Again, the missile and electromagnetic gun should have more shots, but I'm using the JC ammo values.

Other Comments

I have some media wiki templates for correctly formatting GURPS Spaceships craft, which really simplified putting this post together. I recommend them for anyone else blogging about GURPS Spacecraft. Why doesn't blogger have a good GUI for creating tables?

Although I'm reasonably pleased with these conversions, I still want to experiment some with my intermediate size rules. Cannonically, a Pathfinder weighs 37 tons and a Syreen weighs 52 tons. Pushing them both into the SM+5, 30 ton range is annoying enough, but it'll get very odd with the medium and heavy exo-armors. The 70 ton Vindicator can be SM+6 without any issue, but the 45 ton Retaliator  really wants an intermediate size between 30 tons and 60 tons.