Impact of Warp Drive on Pirates of Drinax

[Balfuset790]

Hey all,

I'm contemplating starting to run the Pirates of Drinax campaign for a group, but making a few modifications to the OTU to fit my own vision of how I want things to work.

One of these modifications is using Warp Drive instead of the standard Traveller Jump Drive. I've done the calculation and worked out that this would let the Harrier - using its standard statline - travel 8 parsecs in 4 weeks on a full tank of fuel, as well as having sufficient fuel to operate the ship itself at sub-light for those 4 weeks. This would, of course, have a major impact on Adventure 1 - making Theev more easily accessible from Drinax/Borite right out of the gate. This is something I'm working on making trickier to explain the lack of Naval presence and the need to rescue Krrsh in order to get details - I'm contemplating some sort of stellar anomaly that needs exact up-to-the-minute course data which Krrsh can provide or something similar.

Are there any other implications - assuming all ships use their standard Traveller statlines - that this change would cause that I might be missing? Would it, for example, make piracy more difficult if ships have to stop less frequently to refuel? My theory would be that a ship would have to drop out of warp in each system enroute to pass through the hundred diameter limit of the local star or mainworld to permit time to ambush ships along the trade routes - that and merchants may make stops to trade at planets along the way even if not to refuel.

Does the above work or make sense? Are there other things I need to consider when making these changes? Any insight is welcome!

 

[simonh]

It might help if we understood why you want to use warp drive instead of jump drive?

Bear in mind that havign warp drive does not have to also mean the presence of any kind of FTL radio. You can still require that messages have to be physically carried by warp ships.

Warp drive also doesn't imply FTL sensors either. If they have to fly blind, they will still need detailed up to date navigation charts. In fact they will need them much more than Jump drive ships would. A jump drive allows a ship to completely bypass intervening space so you don't have to worry about obstacles. On the other hand with warp drive things can still get in the way.

Simon Hibbs

 

[Balfuset790]

Really it's mostly an aesthetic choice. While there's nothing wrong with Jump Drive in principle, I find it difficult explaining why a Jump-2 (or Jump-3/4/5 etc.) ships still needs one week in Jump space in order to travel only a fraction of the distance that the drive is capable of. There's also the possibility of, given warp-capable ships are able to be interacted with in the real world, of giving the players the opportunity to pursue fleeing ships in the hopes that their warp drives are more powerful and they can beat them to their destination, which makes acts of piracy a little easier to justify or explain than in the standard Traveller continuity.

And it might also lead to the possibility of adding in some sort of interdiction technology that can be used both by and against the players that can either prevent them from warping, or drag a ship out of warp and abck to sublight velocities.

As said though, mostly it's a purely aesthetic choice. I do think I'd stick with there being no FTL comms or sensors though.

 

[Tom Kalbfus]

Really it's mostly an aesthetic choice. While there's nothing wrong with Jump Drive in principle, I find it difficult explaining why a Jump-2 (or Jump-3/4/5 etc.) ships still needs one week in Jump space in order to travel only a fraction of the distance that the drive is capable of. There's also the possibility of, given warp-capable ships are able to be interacted with in the real world, of giving the players the opportunity to pursue fleeing ships in the hopes that their warp drives are more powerful and they can beat them to their destination, which makes acts of piracy a little easier to justify or explain than in the standard Traveller continuity.

And it might also lead to the possibility of adding in some sort of interdiction technology that can be used both by and against the players that can either prevent them from warping, or drag a ship out of warp and abck to sublight velocities.

As said though, mostly it's a purely aesthetic choice. I do think I'd stick with there being no FTL comms or sensors though.

What if the pirates invented the warp drive, how would they operate in the OTU then if everyone else uses Jump Drive? They'd have a tactical advantage over those jump drive users, as they could get some place in less than a week! Rob a ship on one system, and then fly to another before the first jump ships can get there and catch the next merchants by surprise!

 

[simonh]

Really it's mostly an aesthetic choice. While there's nothing wrong with Jump Drive in principle, I find it difficult explaining why a Jump-2 (or Jump-3/4/5 etc.) ships still needs one week in Jump space in order to travel only a fraction of the distance that the drive is capable of. ...

That's entirely fair enough. I'm not particularly trying to persuade you to use Jump Drive, there's nothing wrong with warp drive and it might well suit your purposes better, but here's how I explain it.

I think of it as being a bit like a pendulum. For a pendulum with a fixed weight and fixed length of cord, the period of the swing is always the same. It doesn’t matter if you deflect the ball a few millimetres or several centimetres, the time it takes for the pendulum to complete one swing does not vary. So it is with trajectories through jumpspace. You can vary the length of the jump (the width of the pendulum’s swing) but the jump still always takes the same amount of time.

Perhaps the properties that set the length of each jump, equivalent to the properties of the mass and length of a pendulum, are determined by physical laws or constants of our universe. Speed of light, Planck length, universal gravitational constant, etc. Because they never change, the length of a jump never changes. But in theory if someone from a different spacetime to ours with different physical constants could use jump space, the time taken for their jumps might be different from ours.

Simon Hibbs

 

[AndrewW]

Really it's mostly an aesthetic choice. While there's nothing wrong with Jump Drive in principle, I find it difficult explaining why a Jump-2 (or Jump-3/4/5 etc.) ships still needs one week in Jump space in order to travel only a fraction of the distance that the drive is capable of. There's also the possibility of, given warp-capable ships are able to be interacted with in the real world, of giving the players the opportunity to pursue fleeing ships in the hopes that their warp drives are more powerful and they can beat them to their destination, which makes acts of piracy a little easier to justify or explain than in the standard Traveller continuity.

You could also modify the jump drive. So that for every jump where the drive is overrated you shave a day off travel time for each number over. So say you have a Jump-3 drive and are making a Jump-1, shave two days off the travel time. (with a minimum travel time). Just a thought, use whatever works for you.

 

[Reynard]

Remember the warp drive eats twice the fuel. That's coming out of somewhere else on the ship.

The other problem is jump ships normally don't face all those gravity wells within a system as you head for your destination. The rules don't take into consideration all the angles and distances needed to enter and leave a system above or below the solar plane. I believe warp drives are still under gravity restriction just like jump. That means warp ships need to pass by whatever masses obstruct their path and the simplest way is by dropping out of warp at the system's outer orbit and fly in under maneuver drive the reverse leaving a system. Simple rules again say there's so little matter between worlds and won't affect something bending realspace.

 

[Tom Kalbfus]

Really it's mostly an aesthetic choice. While there's nothing wrong with Jump Drive in principle, I find it difficult explaining why a Jump-2 (or Jump-3/4/5 etc.) ships still needs one week in Jump space in order to travel only a fraction of the distance that the drive is capable of. ...

That's entirely fair enough. I'm not particularly trying to persuade you to use Jump Drive, there's nothing wrong with warp drive and it might well suit your purposes better, but here's how I explain it.

I think of it as being a bit like a pendulum. For a pendulum with a fixed weight and fixed length of cord, the period of the swing is always the same. It doesn’t matter if you deflect the ball a few millimetres or several centimetres, the time it takes for the pendulum to complete one swing does not vary. So it is with trajectories through jumpspace. You can vary the length of the jump (the width of the pendulum’s swing) but the jump still always takes the same amount of time.

Perhaps the properties that set the length of each jump, equivalent to the properties of the mass and length of a pendulum, are determined by physical laws or constants of our universe. Speed of light, Planck length, universal gravitational constant, etc. Because they never change, the length of a jump never changes. But in theory if someone from a different spacetime to ours with different physical constants could use jump space, the time taken for their jumps might be different from ours.

Simon Hibbs

What if someone initiates a jump while travelling at 99% of the speed of light?
At 99% of the speed of light, the gamma factor is about 7. So relative to the crew of the spaceship, 7 parsecs in the direction of travel will look like 1 parsec, and lets suppose the system ahead which they want to get to is 7 parsecs away, and they have only a Jump-1 drive, the ships sensors tell them the system is only 1 parsec away, so they make the Jump 1 jump to that System, they are in Jump Space for 1 week, their time, and they emerge in the system traveling at 99% of the speed of light. Now lets say there was a ship watching the other starship enter Jump space at 99% of the speed of light, they make two jump three's and arrive at the destination system 2 weeks later, the other starship arrives 7 weeks later in that single space dilated Jump-1 with a maneuver-6, the ship takes 2 months to slow down from 99% of the speed of light, so if they allowed space to slow down, it would take 7 weeks to make the Jump at 99% of the speed of light, and 2 months of maneuvering at maneuver-6 to slow down to match velocities with the system they want to visit. Travelling at 99% of the speed of light doesn't help much - unless the ship is equipped with a bussard ramscoop, and a fuel processor, in which case the ship could gather interstellar hydrogen to refuel its jump drive instead of having to slowdown and skim a gas giant, in this case rifts could be easily crossed as there is no need for there to be any systems between jumps Probably if the Imperium wanted to send a mission to the Galactic core, it might want to accelerate a Scout ship to 99% of the speed of light, equip it with a bussard ramscoop, and it could keep on jumping all the way to the Galactic center, in this case it would be able to Jump 14 parsecs with its jump-2 as seen by a stationary observer, each jump would take 7 weeks, and the referee will have to decide how long it takes to refuel the jump drive with the ramscoop. A fuel processor can convert 20 tons of fuel in a day, so that is a day and a half for a scout ship, so that is about 11 days of refueling from the interstellar medium. 11 days + 7 weeks to go 14 parsecs. this means the scout ship is traveling through the galaxy at 1.64 parsecs a week, but the crew sees it as 1.5 days for each refueling and 1 week for each jump, and each jump gets them 14 parsecs further on, so its 8.5 days for every 14 parsecs jumped or 1.64 parsecs per day, not bad! It would therefore take them 5,611.25 days to travel the 9,202.45 parsecs to the Galactic core, that is 15 years for the crew, 30.75 years round trip, the Imperium doesn't see the mission they sent out until 215.23 years later, the thing it, the scout ship doesn't slow down, and uses the black hole at the center of the Galaxy to make a 180 degree turn and head back towards the point it started at. Probably its mission would be to chart the stars between the Imperium and the center of the Galaxy, it could probably catalog a number of planets the Imperium might want to colonize someday.

 

[simonh]

What if someone initiates a jump while travelling at 99% of the speed of light?
At 99% of the speed of light, the gamma factor is about 7. So relative to the crew of the spaceship, 7 parsecs in the direction of travel will look like 1 parsec, ...

I like it. Yes, due to lenth contraction the effective range of the jump drive should stay constant in their inertial frame of reference, which means it would be extended relative to the rest of the universe. The same goes for the time it takes for them to complete the jump.

A J-6 ship able to reach 0.99c would have a theoretical range of 42 parsecs (an entire sector!), but as you point out, to an external observer it would take the ship 7 weeks to complete the jump. Still, that's hugely faster than doing 7 jumps because there's no messing about landing on planets, fueling up or taking R&R. It would also handily beat the X-Boat relay network, mainly because you travel in a straight line and can completely bypass all the intervening astrography and any kinks and detours in the X-Boat route.

So why hasn't this been done in OTU history? Have to think about that. Maybe there's an inverse relationship between length contraction and time dilation in our universe, and the equivalent effects in jump space. That's the easiest way to hand-wave the whole idea away, which is a shame because it's tons of fun.

Simon Hibbs

 

[Balfuset790]

While the science of near light speeds is fascinating, I fear that it's a little beyond my expertise and something I'm probably unlikely to make a point of in any game I run Though thanks for the reading, wrapping my head around astrophysics is certainly one way to wake up in the morning!

In all seriousness though, if I make the assumption that warp-capable ships need to stop to pass the hundred diameters in any system or sector of space with a sufficiently massive body - which allows me to throw in the odd 'encounter in deep space' with something not on the group's charts if I so desire, which could make for some interesting scenarios - and that most traders and official vessels stick to the established trade routes if only to unload cargo, take shore leave and so on, is there a major impact to the nature of any of the campaigns assumptions?

As I mentioned above, reaching Theev from Borite in Adventure 1 is the only major concern I have encountered so far - as the Harrier will be able to cross the rift between Borite and Theev without refuelling using a warp engine. Are there any other scenarios within the currently published adventures that I should be wary of, anything that capitalises on the restrictions of Jump travel preventing the Harrier, or NPC ships, from crossing the Jump 3+ routes between isolated systems?

 

[locarno24]

No, but there a case where someone 'dropping out of jump' in a specific spot is a relevant thing (it happens in "Treasure Ship") - a ship at warp which isn't 'locked into' a course couldn't be predicted the same way.

 

[Balfuset790]

I think that should be easy enough to compensate. I'd probably say that you have to lock in a course for a warp drive anyway, so still requiring an astrogation check and not allowing that course to be deviated from until you drop out of warp, though I think I'd allow that to happen prematurely.

And, again, with ships following established 'warp lanes' that follow the standard trade or communication routes it's easy to predict, or be given intel on, standard commercial traffic. That should hopefully avoid any messiness of course corrections mid warp.

 

[Tom Kalbfus]

While the science of near light speeds is fascinating, I fear that it's a little beyond my expertise and something I'm probably unlikely to make a point of in any game I run Though thanks for the reading, wrapping my head around astrophysics is certainly one way to wake up in the morning!

In all seriousness though, if I make the assumption that warp-capable ships need to stop to pass the hundred diameters in any system or sector of space with a sufficiently massive body - which allows me to throw in the odd 'encounter in deep space' with something not on the group's charts if I so desire, which could make for some interesting scenarios - and that most traders and official vessels stick to the established trade routes if only to unload cargo, take shore leave and so on, is there a major impact to the nature of any of the campaigns assumptions?

As I mentioned above, reaching Theev from Borite in Adventure 1 is the only major concern I have encountered so far - as the Harrier will be able to cross the rift between Borite and Theev without refuelling using a warp engine. Are there any other scenarios within the currently published adventures that I should be wary of, anything that capitalises on the restrictions of Jump travel preventing the Harrier, or NPC ships, from crossing the Jump 3+ routes between isolated systems?

Depends on what sort of warp you use. It is possible to go into warp and drop out at any point in the journey and get a fix on the local stars to find out where you are so you can stay on course.

 

[Reynard]

I was assuming Traveller's alternate warp locomotion was being referenced or are other warp concepts being thrown out?

 

[Balfuset790]

I was assuming Traveller's alternate warp locomotion was being referenced or are other warp concepts being thrown out?

How so? My intention is to use Warp drive as presented in the CRB

 

[Reynard]

Ah, okay. The descriptions here were sounding off from the CRB.

 

[Tom Kalbfus]

I was assuming Traveller's alternate warp locomotion was being referenced or are other warp concepts being thrown out?

Well the description doesn't say you need a gravity well to shut off the Warp Drive, so I assume you can shut down the warp at any point in your journey and get a fix on the stars to determine whether you are on course or not.

 

[Reynard]

That is one of the advantages of warp, you can stop and start but there would also need to be a complex set of rules for navigation from system to system which Traveller circumvents with a drive that avoids everything between Point A and point B. Since the Traveller universe is on a parsec wide two dimensional plane, that usually means you pass into each system from its outer region pass all the possible system bodies. Doing that at warp speed is flying a jet at 600 mph through a city at ground level. You need to slow down to speeds sensors, your computer and the pilot and navigator can react to.

Done properly, and I used it to describe the IXS Enterprise and it's mission, warp is a fine alternate.

 

[Tom Kalbfus]

That is one of the advantages of warp, you can stop and start but there would also need to be a complex set of rules for navigation from system to system which Traveller circumvents with a drive that avoids everything between Point A and point B. Since the Traveller universe is on a parsec wide two dimensional plane, that usually means you pass into each system from its outer region pass all the possible system bodies. Doing that at warp speed is flying a jet at 600 mph through a city at ground level. You need to slow down to speeds sensors, your computer and the pilot and navigator can react to.

Done properly, and I used it to describe the IXS Enterprise and it's mission, warp is a fine alternate.

I don't know, You have a 3-d map of stars in the ship's computer database, then you stop the ship and site the stars, match those with the stars in the database and the computer determines where the ship is, and take doppler readings to determine how fast and in what direction its going. Doesn't sound too complicated to me.

 

[Reynard]

Sorry, I meant the Traveller rules would need a more complex set of rules so you could create a path above and below the system plane. Again, warp speed is lousy within a system with all those objects coming at you like driving faster than your car headlights at night at top speed.