Why didn't Vland expand coreward or spinward?

[McPerth]

Maybe it's on some version/supplement I have not read, but, where is the problem to jump into empty space?

AFAIK its quite in canon the possibility to just do so, refuel from deep space stations (or use extra fuel carried) and jump again, and there are many canon sources that support this (from CT and MT):

• In the Fat Trader description (Seeker Games, for MT) it's stated it cah have dismountable tanks just for this pourpose
• In he CT Yacht description it has fuel for two jumps, Best guess is that is just for this pourpose too
• In CT:AM1 Aslan is stated they built deep space refuelling stations to croos the Great Rift on Riftspan Reaches (until they achieved J5 and didn't them anymore)
• There are various references in Challernger TNS about Margaret building a deep space refuelling base in the Hinterworlds to ease the route to Hiver space
• IITR (sorry, not hard references here) that the Zhodani fleet appearing in Ruie at the start of the FFW was suspected to have used deep space refuelling depots to reach it undetected

 

[GypsyComet]

Maybe it's on some versión/supplement I have not read, but, where is the problem to jump into empty space?

It has been given as one of the reasons the Terrans were able to outflank the Vilani three thousand years ago. It is not a problem in the modern age of Traveller.

Presumably it has to do with navigation solutions for initiating jumps. Knowing where you are is just as important as where you want to go, and is a bit more involved if you don't have a world nearby to have done the math for you.

 

[Condottiere]

Vilani - half astrogation skill

 

[mike wightman]

Maybe it's on some versión/supplement I have not read, but, where is the problem to jump into empty space?

It is a holdover from the jump rules in Imperium and Dark Nebula that only allow jumps between systems with mapped jump lanes. Empty hex jumps are forbidden, although STL travel through empty hexes is possible... at 0.9c no less.

During a game of Dark Nebula one of the research outcomes is the ability to make empty hex jumps.

AFAIK its quite in canon the possibility to just do so, refuel from deep space stations (or use extra fuel carried) and jump again, and there are many canon sources that support this (from CT and MT):

• In the Fat Trader description (Seeker Games, for MT) it's stated it cah have dismountable tanks just for this pourpose
• In he CT Yacht description it has fuel for two jumps, Best guess is that is just for this pourpose too
• In CT:AM1 Aslan is stated they built deep space refuelling stations to croos the Great Rift on Riftspan Reaches (until they achieved J5 and didn't them anymore)
• There are various references in Challernger TNS about Margaret building a deep space refuelling base in the Hinterworlds to ease the route to Hiver space
• IITR (sorry, not hard references here) that the Zhodani fleet appearing in Ruie at the start of the FFW was suspected to have used deep space refuelling depots to reach it undetected

All of these are post discovery of empty hex jumps.

 

[McPerth]

TY for your answers. As I suspected, I have never seen Dark Nebula (though I own Imperium).

 

[JBRocky]

I am a big believer that the Vilani stuck to the J1 Mains for the most part till they discovered J2. Now this doesn't mean they didn't but while the Vilani are not the most innovative bunch they are efficient. So why make a jump to empty space or a random refueling stop when you can continue down the main? After all creating a refueling stop can take up a lot of time and effort.

Now when they did hop between mains there was most likely a reason. It could be a short cut to get to a desired world faster, or if something caught their attention. Would they use it to outflank an enemy? I doubt it since it was probably against SoP, and Vilani do follow procedure.

Doing a quick edit since I took some time to see where the Vilani Main and Lishun Main went. The Vilani Main is in the following Sectors, Vland Lishun, Rimward part of Corridor, Reft, Gushemege, Dagudashaag, handful of worlds in Core, Verge and Ilelish. While the Lishun Mains goes places like Lishun, Antares, Meshan, Amdukan, in fact a large portion of the Asimikigir Confederation is on it, and it continues up into Gashikan and Trechans. That's a lot of area that only two mains cover, so plenty of places to go just using J1.

 

[Garnfellow]

Somewhere I had sketched out a more finely graduated tech progression of jumps. Everyone knows J-1 is TL 9, J-2 is TL 11, J-3 is TL 12, and J-4 is TL 13. So shorter jumps are clearly easier than longer jumps. (Duh.)

But I think there are many other degrees of difficulty between these major milestones: jumping into a system with a large stellar object like a main sequence star is probably easier than jumping into a system with a smaller one like a brown dwarf. Jumping into a system with a brown dwarf is easier than jumping into a system with a comet, which is easier than jumping into a truly empty hex. Jumping into a system with established coordinates is easier than jumping blind into a new system. Jumping a single ship is easier than coordinating a jump with several different ships.

As the TL progresses these different types of jump become more reliable, less dangerous, and easier to use. So at TL9 one might be able to jump one parsec into an uncharted system with only a brown dwarf, but it's dangerous and not something you would do casually. By TL 11 maybe this is fairly routine, but jumping blind into an empty hex is extremely risky and not something you would try to do consecutively or for farther than one parsec at a time. Somewhere in the TL 12 continuum 1-parsec blind jumps into empty hexes become reliable enough that the Aslan cross the Great Rift using this technique.

Similarly, J-1 might be TL 9 but being able to coordinate a fleet jump of multiple ships one parsec might not be feasible until TL10, and even then it's very risky. You might not be able to do it reliably until TL 11. A J-2 fleet jump might not become standard practice until TL 13.

These are all just hypotheticals, and I'm sure there are canonical exceptions to these examples. But hopefully the principle makes sense – I think it potentially reconciles a lot of old flamewars over empty hex jumping.

 

[Garnfellow]

So here's the table I had sketched out:

Tech Level, Distance, and Types of Jump

	1 Parsec		2 Parsecs		3 Parsecs		4 Parsecs		5 Parsecs		6 Parsecs
	Possible	Reliable	Possible	Reliable	Possible	Reliable	Possible	Reliable	Possible	Reliable	Possible	Reliable
Single Ship Jump, Large Stellar Object	8	9	10	11	11	12	12	13	13	14	14	15
Single Ship Jump, Small Stellar Object	9	10	11	12	12	13	13	14	14	15	15	16
Single Ship Jump, Empty Hex with Coordinates	10	11	12	13	13	14	14	15	15	16	16	-
Single Ship Jump, Empty Hex Blind	11	12	13	14	14	15	15	16	16	-	-	-
Fleet Jump, Large Stellar Object	9	10	11	12	12	13	13	14	14	15	15	16
Fleet Jump, Small Stellar Object	10	11	12	13	13	14	14	15	15	16	16	-
Fleet Jump, Empty Hex with Coordinates	11	12	13	14	14	15	15	16	16	-	-	-
Fleet Jump, Empty Hex Blind	12	13	14	15	15	16	16	-	-	-	-	-

The "Possible" columns show the TL at which a jump of the corresponding type becomes achievable on an experimental basis; this would be dangerous and uncertain.

The "Reliable" columns show the TL at which this type of jump becomes standardized enough for regular, commercial deployment.

So based on this, the TL 10 Ziru Sirka could have bridged 1 parsec gaps by identifying a rogue planet, brown dwarf, comet, or the the like. This would have been reasonably safe and reliable, but until they reached TL 11 crossing a 2 parsec gap would have been beyond their capabilities to do so on a regular basis.

 

[McPerth]

So here's the table I had sketched out:

Tech Level and Types of Jump

	J-1		J-2		J-3		J-4		J-5		J-6
	Possible	Reliable	Possible	Reliable	Possible	Reliable	Possible	Reliable	Possible	Reliable	Possible	Reliable
Single Ship Jump, Large Stellar Object	8	9	10	11	11	12	12	13	13	14	14	15
Single Ship Jump, Small Stellar Object	9	10	11	12	12	13	13	14	14	15	15	16
Single Ship Jump, Empty Hex with Coordinates	10	11	12	13	13	14	14	15	15	16	16	-
Single Ship Jump, Empty Hex Blind	11	12	13	14	14	15	15	16	16	-	-	-
Fleet Jump, Large Stellar Object	9	10	11	12	12	13	13	14	14	15	15	16
Fleet Jump, Small Stellar Object	10	11	12	13	13	14	14	15	15	16	16	-
Fleet Jump, Empty Hex with Coordinates	11	12	13	14	14	15	15	16	16	-	-	-
Fleet Jump, Empty Hex Blind	12	13	14	15	15	16	16	-	-	-	-	-

The "Possible" columns show the TL at which a jump of the corresponding type becomes achievable on an experimental basis; this would be dangerous and uncertain.

The "Reliable" columns show the TL at which this type of jump becomes standardized enough for regular, commercial deployment.

Just to comments against your theory (that is quite interesting otherwise):

1: Aslan crossing the Great Rift:

As you say, Aslan began crossing the J5 gap in the Great Rift at TL12. My guess (But not supported) is that they did it at this TL because is the only one that allows to make it in just 2 jumps, with a refuelling base in the empty space between the ends.

To do so at J1 (that is what you put s posible, though not reliable , at TL12) would require to mount 4 refuelling bases and to have enough life support in your ship for the 5+ weeks needed...

2: Solomani:

Terra has no adjacent world. So, to reach Barnard Star requires either J2 (so TL 11) or stop at mid point (either into a refuelling base or carrying fuel for 2 consecutive jumps).

According timeline in MT:S&A (pages 20-21), Solomani developed jump drive in -2431, and first interstellar war began in -2408. I have serious doubts they reached J2 (so 2 full TLs) in less than 23 years, so I'm afraid this means they reached it by making 2 consucetuve humps, and so stopping in deep space.

It is a holdover from the jump rules in Imperium and Dark Nebula that only allow jumps between systems with mapped jump lanes. Empty hex jumps are forbidden, although STL travel through empty hexes is possible... at 0.9c no less.

During a game of Dark Nebula one of the research outcomes is the ability to make empty hex jumps.

I'm afraid this makes this explanation in question too...

 

[mike wightman]

The canonical explanation from GT:ISW is that they found a brown dwarf to use as the bridging point between Sol and Barnard's Star.

 

[Garnfellow]

2: Solomani:

Terra has no adjacent world. So, to reach Barnard Star requires either J2 (so TL 11) or stop at mid point (either into a refuelling base or carrying fuel for 2 consecutive jumps).

According timeline in MT:S&A (pages 20-21), Solomani developed jump drive in -2431, and first interstellar war began in -2408. I have serious doubts they reached J2 (so 2 full TLs) in less than 23 years, so I'm afraid this means they reached it by making 2 consucetuve humps, and so stopping in deep space.

Canonically the Terrans develop J-2 after the First Interstellar War in -2398 per the Referee's Companion (34). But yeah, 33 years seems like a stretch.

CT Alien Module 6 - Solomani states "The range of the jump-1 drives first developed by UNSCA was insufficient to reach the nearest star- Alpha Centauri. It took several years before a US Space Force team based on Luna tried a mission which, in several trips, established an intermediate stopover and refuelling point about one parsec out" (4).

GURPS Traveller: Rim of Fire builds on this: "At first, the prototype jump drive was extremely limited in range. It was used only within Sol system, as a fast means of reaching the outer planets or the cometary cloud. After several generations of improvement, the United States Space Force first tried an interstellar expedition. Jump-drive ships operating from a base at Luna made several trips to a point in deep space, about 1 parsec coreward of Sol. After a makeshift fuel depot had been established there, the Americans launched a full-scale expedition to Barnard’s Star. The expedition spent a year at the target star, returning in -2424" (40).

GURPS Interstellar Wars 22-23 also discusses this connundrum, but takes it in a very different direction:

Even after the UNSCA produced a true jump-1 drive (in 2092), there seemed to be little practical application for the technology. No other star systems were within a parsec of Sol, and the mathematics of jump navigation seemed to imply that a jump into empty space was not possible. . . . The first step was to locate a “jump point,” a wandering planet or brown dwarf star located at a convenient point in interstellar space. . . . Here the American mission planners were lucky – a candidate rogue planet was found, located so that jump-1 starships could reach it from both Sol and Barnard’s Star.

Either explanation works with my table *. If you follow GT:IW, I suggest a rogue planet jump might be possible at TL 9. If you follow the CT Alien module or GT:RoF, setting up a deep space depot after many many trips is probably like jumping into an empty hex with coordinates, which I suggest could be possible at TL 10. Both are defensible: If the Terrans were at TL10 at the start of the First Interstellar War, it would explain (1) how they survived and (2) how they hit J-2 so quickly after.

* And these explanations aren't necessarily incompatible. The Terrans could have found a rogue planet and established the fuel depot either on or in orbit there.

 

[mike wightman]

After the first Interstellar war the Terrans had lots of TL11 Vilani equipment to reverse engineer.
Oddly enough in the intervals between wars Terran traders were allowed to enter Vilani space and buy stuff - so a quick boost from TL9 to TL10 is a no-brainer. The jump to TL11 for military equipment would rely on espionage and reverse engineering.

Once Vilani worlds started falling to Terra, granting total access to Vilani universities and the like, then Terra actually moved above the Vilani on the TL scale.

 

[Garnfellow]

1: Aslan crossing the Great Rift:

As you say, Aslan began crossing the J5 gap in the Great Rift at TL12. My guess (But not supported) is that they did it at this TL because is the only one that allows to make it in just 2 jumps, with a refuelling base in the empty space between the ends.

To do so at J1 (that is what you put s posible, though not reliable , at TL12) would require to mount 4 refuelling bases and to have enough life support in your ship for the 5+ weeks needed...

Again, we have contradictory canonical sources. I don't believe the CT alien module or S&A state how the aslan first crossed the Rift, just when (-1044).

Traveller's Digest 17 describes the first crossing of the Great Rift as using deep space refueling but does not specify the jump drive or tech level used at the time. The captain of the first expedition, Ktouwaatritoikh, used "large fuel pods equipped with beacons, and sufficient extra tankage in the ships to make the return jump."

GURPS: Traveller Alien Races 2 says "In 1185 (-1044 Imperial), one of the Cisrift clans was persuaded by a charismatic explorer to build a long-range survey craft capable of five successive Jump-1s. He led it on a three-year mission across the Great Rift" (p 20). My table would allow this at TL 12.

The Mongoose Traveller Aslan alien module, though, states that the Rift was crossed using J-5, which would not require deep-space refueling (62). This is also consistent with my table -- J-5 is possible at TL 12 and reliable at TL 13.

Personally, either way I much prefer my Aslan to be TL 12 in -1044. When the TL 13 Imperium starts to encounter Aslan around 200, they have a decided technological advantage. If the Aslan had reached TL 13 1,500 years earlier, it doesn't seem like the Imperium would have any advantage.

 

[aramis]

Again, we have contradictory canonical sources. I don't believe the CT alien module or S&A state how the aslan first crossed the Rift, just when (-1044).

Traveller's Digest 17 describes the first crossing of the Great Rift as using deep space refueling but does not specify the jump drive or tech level used at the time. The captain of the first expedition, Ktouwaatritoikh, used "large fuel pods equipped with beacons, and sufficient extra tankage in the ships to make the return jump."

GURPS: Traveller Alien Races 2 says "In 1185 (-1044 Imperial), one of the Cisrift clans was persuaded by a charismatic explorer to build a long-range survey craft capable of five successive Jump-1s. He led it on a three-year mission across the Great Rift" (p 20). My table would allow this at TL 12.

The Mongoose Traveller Aslan alien module, though, states that the Rift was crossed using J-5, which would not require deep-space refueling (62). This is also consistent with my table -- J-5 is possible at TL 12 and reliable at TL 13.

Personally, either way I much prefer my Aslan to be TL 12 in -1044. When the TL 13 Imperium starts to encounter Aslan around 200, they have a decided technological advantage. If the Aslan had reached TL 13 1,500 years earlier, it doesn't seem like the Imperium would have any advantage.

It's canonical that the Aslan reverse engineered their Jump Drives from a crashed ship. So it could have been better than Jump 1.

 

[Garnfellow]

It's canonical that the Aslan reverse engineered their Jump Drives from a crashed ship. So it could have been better than Jump 1.

Sure. The Mongoose Aslan module has them developing J-2 around -1699 (p 58), so I wouldn't be surprised if they had J-3 or better by -1044.

My theory is that the TL that gives you J-X allows you to reliably make a single X parsec jump into a charted system with a main sequence star.

But it requires a higher TL to reliably jump into an empty, uncharted hex X parsecs away. That this feat represents an inherently more difficult task.

 

[JBRocky]

Love the table Garnfellow makes pretty good sense on how different groups could or might do things. However its been brought up the Solomani needing J2 to get anywhere, and the Aslan crossing the Great Rift, both most likely using fuel depots in deep space. Well if you use Garnfellow's table the Solomani would take the risk because they had to, and the Aslan would take the risk in their drive for more land. But the question is why would the Vilani not take the risk? Simply put they didn't need to since they had better options available to them.

Now did the Vilani eventually take some risk, sure they did but only in limited situations when risk was not as great. By this time they could be closer to TL10 so by the chart is much easier, and not against procedure. They saw a reason to do it like go from the Vilani Main to the Lishun Main so they can have a captive audience, and other reasons which they could get permission through channels. In the end they discovered J2 which made the whole sticking to the mains a moot point and procedure had already been established to go in a certain direction.

 

[Condottiere]

If I remember ISW correctly, microjumping is maxed out at a quarter parsec, so in theory, they'd need eight jumps to get to the next system.

 

[aramis]

If I remember ISW correctly, microjumping is maxed out at a quarter parsec, so in theory, they'd need eight jumps to get to the next system.

ISW's jump restrictions are superseded by T5's lack thereof. A J0 drive can make 0.9 Pc, given that H0 can make 9 Pc, S0 can make 90, etc.

They could be considered to be specific to the setting era, but given the robust tech rules of T5, that feels more like a cop-out.

Note also: The only way to make a J0, H0, S0, L0, B0, or V0 is to be building a prototype of J1, H1, S1, L1, B1 or V1, respectively.

 

[McPerth]

Well if you use Garnfellow's table the Solomani would take the risk because they had to.

Agreed the Solomani were wiling to risk with unreliable jumping to explore space, but, could them with such unreliable drives conduct (and even win) a war?

 

[kilemall]

Agreed the Solomani were wiling to risk with unreliable jumping to explore space, but, could them with such unreliable drives conduct (and even win) a war?

Plucky earthers ALWAYS do dangerous jumps.