Fuel Dumps

[Vormaerin]

Yes, you can just declare that. But there's no way to actualy make that a feature of the geography and not just an arbitrary declaration of the GM.

Also, it's basically impossible for that to be the case unless the world is inside the sun's jumpshadow, which is already a thing unrelated to the straight line. Because if I just need to jump to escape and the GM tells me "Oops, the Sun is directly between you and Alpha Centauri, I'll just figure out which of Neptune, Uranus, or some ice asteroid out around Pluto is not blocked and jump there. Yes, you could then be like 'Ooh, they have the jump tracking fancy devices and they'll just radio ahead'. All fine if you do the work to establish this stuff in advance but there is no methodology to bring it into play.

Mechanics that the player can't actually use proactively and just exist as GM gotchas are kind of meh to my mind.

 

[Sigtrygg]

There is so much wrong with the concept of jump lines that I ignore them completely.

Every object in the galaxy is in relative motion, and everything has its own relative time too, it is not as simple as imagining that at the instant you plot the jump everything is in a "fixed" place and time that you can draw a straight line between point A and point B. Then there is the jump duration uncertainty, the motion of objects between A and B, and their movement relative the the jump line during the week.

It is much simpler to say you jump from point A to point B, it takes once week, and during that week your ship is in an alternative hyperspace separate from our universe. Our universe can only affect jump when you are trying to enter or leave jump space - which is what the MWM article said.

 

[MasterGwydion]

There is so much wrong with the concept of jump lines that I ignore them completely.

Every object in the galaxy is in relative motion, and everything has its own relative time too, it is not as simple as imagining that at the instant you plot the jump everything is in a "fixed" place and time that you can draw a straight line between point A and point B. Then there is the jump duration uncertainty, the motion of objects between A and B, and their movement relative the the jump line during the week.

It is much simpler to say you jump from point A to point B, it takes once week, and during that week your ship is in an alternative hyperspace separate from our universe. Our universe can only affect jump when you are trying to enter or leave jump space - which is what the MWM article said.

This is as complicated as I need it to be. It works well, so I don't look for a deeper explanation.

 

[Fresnel]

Yes, you can just declare that. But there's no way to actualy make that a feature of the geography and not just an arbitrary declaration of the GM.

Also, it's basically impossible for that to be the case unless the world is inside the sun's jumpshadow, which is already a thing unrelated to the straight line. Because if I just need to jump to escape and the GM tells me "Oops, the Sun is directly between you and Alpha Centauri, I'll just figure out which of Neptune, Uranus, or some ice asteroid out around Pluto is not blocked and jump there. Yes, you could then be like 'Ooh, they have the jump tracking fancy devices and they'll just radio ahead'. All fine if you do the work to establish this stuff in advance but there is no methodology to bring it into play.

Mechanics that the player can't actually use proactively and just exist as GM gotchas are kind of meh to my mind.

On the 'how likely' point:

The Sun is 1.393 Million km in diameter: So it's shadow is 139.3 million km.
The Earth's mean orbit 149.6 million km.

So a ship leaving Earth is about 10 million km from a 139.3 million km sphere. This shadows about 40% of the potential directions. So it will be a very common case that the local sun will shadow the jump path. However, as Referees we don't bother with this fact unless it is adds to the story. i.e. when you need to escape from a fight you are unlikely to win. Or you are the chaser.

Being forced to do an in-system jump, play hide and seek while trying to refuel, sounds like good drama to me - ymmv.

And story set-up is not a GM gotchas. When the players arrived in the system they will know the planet they want to visit is shadowed. They might have to do an in-system jump or a long sub-light path to arrive. So it will not be a surprise when they are escaping/chasing the BBEG from that planet.

 

[Vormaerin]

Yeah, if you make all this information available to the PCs every time they arrive in a system because you have some kind of system for figuring out where various stars are in relation to the current orbits of planets in a system, then it's fine. Players can determine these things in advance.

Traveller certainly doesn't provide anything remotely like this and maintaining it with any consistency is a hassle. Since where the various planets are relative to the sun is going to vary from visit to visit.

That's a huge workload for little payoff, imho.

 

[Nelphine]

Starfire has a straightforward system for determining that.

Star is in a hex, everything gets placed in a hex or on a line between hexes, and things move one hex per time period, so you determine a start point, and then you just count how many time periods its been (and more accurately, depending on which orbit you're in, you figure out how many time periods is a full rotation, and then you just need to figure out how many time periods you are from the full rotation value.)

While Starfire does this with a map since its based around tactical space battles, you could just give everything a coordinate value, and do the same thing. And for the coordinates, you'd do something like the first number indicates how many hexes is one rotation (which orbit you are in), and the second number is which coordinate you're currently in, and you'd have a straightforward conversion for which set of numbers in one orbit is in the same arc as another set of numbers in another orbit.

 

[Vormaerin]

I might do that if I'm running a single system campaign. I'm sure not doing that for the two dozen systems in regular interstellar campaign.

 

[Fresnel]

I don't run a galactic model, I run a TTRPG. If I say a planet is on the wrong side of the sun - then it is. If it is important to the story I will take a note of the planets orbital period. No great effort. No inconsistency.

The setting serves the story.

 

[Vormaerin]

And my preference is not to create situations where I need to know the relative locations of planets and stars in the first place. Because once I make it a plot point that sometimes you have to do spatial geometry to calculate the real time to a jump point, it becomes reasonable for players to want to know this information on a regular basis so they can create situations that advantage them or avoid situations that disadvantage them.

Just a personal preference. As I pointed out in my original post on the topic.

 

[collins355]

Just chipping in on the man-drive issue. I think this may have originated in MegaTrav where, as some will remember, you could in the ship design sequences purchase TL9 antigrav maneuver units for your starship (which were comparatively cheap) or more expensive thruster plates. The thruster plates were the man. drive we know and love. People then asked DGP what was the difference. In Traveller's Digest No.21 and in the MegaTrav 3rd printing DGP clarified that if you took the cheap antigrav units you would find that their performance dropped off at 10 diameters and beyond from a planet because "they require a gravity well to push against".
If you paid for the proper man-drive you didn't face this issue.

 

[Vormaerin]

One last comment on the subject of the straight line jump occlusion. I think this is a world building issue. If there are certain times of the year that a direct jump from Prometheus (aka Alpha Centauri) to Terra is not feasible because of the location of the respective stars blocking those planets, that is something that will absolutely affect the flow of trade between them.

If some portion of the year the travel time is 10 to 14 days instead of the usual 6-8, then either freight rates and passenger tickets are going to be higher at that point or the Alpha Centauri merchants will use that time to do annual maintenance or visit Persapera instead. ESPECIALLY if these are less developed worlds where that substantial increase in real space travel would increase piracy risks significantly. Or perhaps they jump to Mars or Jupiter if those are available and let the Solar system space barges take it from there.

And there will definitely be a Poor Spacer's Almanac that lays these things out. "Sorry, we don't leave for four days because that's when Terra will be clear of Sol and we can jump straight there instead of spending that same time flying around the sun."

Regardless, this will be a well known factor that everyone accounts for and there's just nothing indicating this is a thing in Charted Space. And its just a personal pet peeve of mine when some potentially interesting thing that has obvious impacts on the world is just declared and it has no effect on anything. Doubly so when there is no actual mechanical support for the GM to use it in a consistent fashion.

 

[MasterGwydion]

One last comment on the subject of the straight line jump occlusion. I think this is a world building issue. If there are certain times of the year that a direct jump from Prometheus (aka Alpha Centauri) to Terra is not feasible because of the location of the respective stars blocking those planets, that is something that will absolutely affect the flow of trade between them.

If some portion of the year the travel time is 10 to 14 days instead of the usual 6-8, then either freight rates and passenger tickets are going to be higher at that point or the Alpha Centauri merchants will use that time to do annual maintenance or visit Persapera instead. ESPECIALLY if these are less developed worlds where that substantial increase in real space travel would increase piracy risks significantly. Or perhaps they jump to Mars or Jupiter if those are available and let the Solar system space barges take it from there.

And there will definitely be a Poor Spacer's Almanac that lays these things out. "Sorry, we don't leave for four days because that's when Terra will be clear of Sol and we can jump straight there instead of spending that same time flying around the sun."

Regardless, this will be a well known factor that everyone accounts for and there's just nothing indicating this is a thing in Charted Space. And its just a personal pet peeve of mine when some potentially interesting thing that has obvious impacts on the world is just declared and it has no effect on anything. Doubly so when there is no actual mechanical support for the GM to use it in a consistent fashion.

The way I run it is that you do not travel in a straight line in jump space. Navigating jump space is part of the Astrogator's job and all of it must be done pre-jump, since you can't control anything while in jump space. Then I do not have to ever worry about Jump Shadows, unless of course, the Starbase in inside 100Ds of a star. Then the PCs get to hoof it in real space for a bit too. This keeps things simple, and the players always know beforehand if they are travelling somewhere that is "in shadow".

 

[agentwigggles]

I like the limitation of the mdrive. Gives more structure to everything, reduces the possibility spaces and allows for better assumptions.

 

[Vormaerin]

I'm not sure how it does those things? It just means that travel to the outer worlds of a large solar system like ours means a jump instead of a more interactive real space journey. And makes a number of deep space locations really improbable without adding a rogue planet or some other gravity well that wasn't already there.

If you want empty hexes to actually be impassible, it has some value in that. But I think you could do that easier by just saying jumping into the middle of nowhere is a Bad Thing because "space magic".

What does it let you do that you couldn't do before? Or what undesirable things that do exist does it eliminate?

 

[Terry Mixon]

I'm not sure how it does those things? It just means that travel to the outer worlds of a large solar system like ours means a jump instead of a more interactive real space journey. And makes a number of deep space locations really improbable without adding a rogue planet or some other gravity well that wasn't already there.

If you want empty hexes to actually be impassible, it has some value in that. But I think you could do that easier by just saying jumping into the middle of nowhere is a Bad Thing because "space magic".

What does it let you do that you couldn't do before? Or what undesirable things that do exist does it eliminate?

Hard to find Grandfather's pocket universe if you can't jump into an empty hex.

 

[Vormaerin]

There's a number of Traveller adventures that have that problem if you enforce the 1000D limit. The fact that they bypassed the rule by introducing the Deep Space Maneuvering System so Deepnight Revelation works says a lot.

 

[Nelphine]

does anyone know what the other T5 engine types do? why they aren't affected by the 1000D, what they cost?

 

[tytalan]

A corporation want to exploit a system accessible to jump-3 craft. However, they want to allow jump-2 ships easy access the system.

They use a Subsidized Liner to jump to a point 1 parsec closer to the system of interest. They then leave 120 tons of fuel in deep interstellar at a secret location. The liner then jumps home.

Is this already a thing?

The biggest issue is that you have to use the deep space M-Drive ( see deepnight revelation) since you can’t jump in to being docked to the fuel dump. Probably the more common and inexpensive way to go in attaching drop tanks to fuel the first jump drop them jump than you already have fuel for the second jump

 

[tytalan]

But 30,000 km is not a long way at Thrust 1...

Even worse since outside of a 1000 DMs of a gravity well the M-Drive only works at 1% so it’s a really long way at .01 thrust

 

[agentwigggles]

I'm not sure how it does those things? It just means that travel to the outer worlds of a large solar system like ours means a jump instead of a more interactive real space journey. And makes a number of deep space locations really improbable without adding a rogue planet or some other gravity well that wasn't already there.

If you want empty hexes to actually be impassible, it has some value in that. But I think you could do that easier by just saying jumping into the middle of nowhere is a Bad Thing because "space magic".

What does it let you do that you couldn't do before? Or what undesirable things that do exist does it eliminate?

Well the most literal example was from a pod game I was involved in for a little bit, we were chasing someone and the mdrive limited, to where in a system they could have gone to. Limited which gas giant they could have gone too.
As a gm, the 1000d limit tells me where the bulk of outspace activity is in a certain system. Currently, making a bounty hunter game set in one system, and the 1000d limit informed me where activity through the system would be.
For a game I ran, one of the major set pieces was set above the galatic plane, and due to them having r-drive on struts from a previous adventure, allowed to navigate the area, which allowed them to escape the ship graveyard they found. Those ships couldnt escape without an rdrive.