Jump Drive
- Thread starter BackworldTraveller
- Start date
creativehum
SOC-14 1K
Thank you. That makes a heck of a lot more sense.
BackworldTraveller
SOC-13
It would seem not:
What is the frame of reference for "moment"? It sort of implies that time in jump-space maps to realspace time along the entire route at V=n-parsecs per 168 hours
creativehum
SOC-14 1K
Per the clause quoted from T5, the frame of reference for the "moment" is when the "jump begins." It says it right there. I'm not quite sure how this ambiguous.
The reference to "at any point along the course" referee to the jump line, not the duration of the journey. (Course: "The route or direction followed by a ship, aircraft, road, or river."). If the sentence was supposed to be about the duration of the journey, it would have said that.
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AnotherDilbert
SOC-14 1K
I would say it implies the opposite: The blockage can be at any point of the course line, yet is only checked at the beginning of the jump, hence the ship is at all points of the course line simultaneously.
creativehum
SOC-14 1K
With this reading, which I think is cool, the jump within jump space is instantaneous, but in real space the ship is gone for a week. The jump bubble (or whatever handwave tech*) allows the crew and contents of the ship not to be stretched into the infinite, creating a pocket of real space within jump space.
That is mind-bending and worth of a SF conceit.
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* I have no idea if that logic fits within 40 years of evolving, often contradictory canon material. But I really do like it.
For myself, I like the idea that jump drive both pierces jump space, allowing the ship to enter the "channel" of jump space the navigator has plotted, but also drags a bit of real space along with it, to allow the physics of real space to contain the ship and crew.
Or, to put it another way, all of the parameters of the jump (from beginning to end) are determined by the all of the conditions at the instant the jump is initiated.
Condottiere
SOC-14 5K
That's why we hire Vogons to clear hyperspace routes.
Marc's TU - it's at any point during the jump.
So, you have to have a weeklong clear window.
IMTU? I don't use masking for the EC setting.
For the OTU as I use it IMTU, I only do so for the start and end parsecs... Start at initiation, end at exit, so as to prevent dropping people out by accident.
My biggest issue with full week full run? it means the smaller transports will be dropping out in close proximity to the demand-feeder large ships.
Straybow
SOC-14 1K
That is assuming the orbital path of Jupiter is anywhere near the line of travel to the destination, which is overwhelmingly likely to be well out of the plane of the ecliptic.
At conjunction, Jupiter is 630M km away. The 100D shadow (201D diameter) covers only 201×0.143 = 28.7M km, a 2.6° arc. If not in conjunction the arc is even smaller. A path to a random destination would have less than 0.01% chance to be occluded. But actual destinations from a known origin (Earth, in this case) would not be random. AFAIK, none of the neighboring destinations are close enough to the plane of orbit for Jupiter to be of concern.
:xh:
Okay, head doing the spinny thing now. Let's bring back the Jupiter example and postulate heading for a system with a Jovian world we shall name Doppelgangr, that happens to lie along the plane of travel, out in that system's outer reaches. We are about to jump to a world in the habitable zone of that system. At the moment of jump, Doppelgangr does not occlude our jump. However, Doppelgangr will occlude our jump while we're three days into jump space (and will occlude direct-line jumps for about 3 weeks after that) and we, being egregiously neglectful after a night of heavy drinking and a morning evading law enforcement, failed to take that into account.
So, we precipitate out somewhere near Doppelgangr ... on day 3? On day 7?
I presume my jumpline is not blocked if a Plankwell shows up at my planned exit point after I've departed my origin point but moves on before I've arrived at my destination.
It appears that jump space is a plane, and I'm not familiar with Sol subsector's systems, so I don't know how they lie with respect to Sol's equatorial plane. It would be rather convenient, however, if we could assume that the odds a particular system's equatorial plane lay parallel to the jump plane were low.
mike wightman
SOC-14 10K
This rule has changed as T5 has changed editions.
If I am understanding the current rule correctly:
a ship initiates jump - the universe is now frozen in time and you draw a line between your start point and destination, if there is anything on the jump line bigger than the ship it will precipitate at that object rather than at the target.
the ship jumps - it now doesn't matter what happens in the rest of the universe, in one week's time the ship will precipitate out of normal space either at its destination or the point it was pulled out of jump space.
If I am understanding the current rule correctly:
a ship initiates jump - the universe is now frozen in time and you draw a line between your start point and destination, if there is anything on the jump line bigger than the ship it will precipitate at that object rather than at the target.
the ship jumps - it now doesn't matter what happens in the rest of the universe, in one week's time the ship will precipitate out of normal space either at its destination or the point it was pulled out of jump space.
Straybow
SOC-14 1K
You mean, draw a line between the start point and where the destination will be in one week... and if anything is on the jump line at a point in time proportional to the distances... yeah, it doesn't get any simpler.
BackworldTraveller
SOC-13
But the target 100D sphere isn't always in place when the ship jumps...It too moves. If the timeframe was instantaneous, you's potentially miss entirely!
mike wightman
SOC-14 10K
You aim your jump line for transit to a given location in spacetime with an accuracy of within a few thousand km. If you know what you are doing that arrival point will be close to the 100D of the target world in a week's time.
AnotherDilbert
SOC-14 1K
We have two rules:
1) Blockage at the start of the jump will stop the jump at the 100 D limit (roughly?), ending the jump in ~168 h as usual.
2) A jump ending within the 100 D limit of a larger object at the end of the jump time will end the jump at the 100 D limit (roughly?)
Of course this is simplified from some more complex reality, just as the 2D map is a simplification of the 3D reality.
creativehum
SOC-14 1K
I appreaciate you saying "current"... but even that is tangled by stray reports arriving.
We have the way this all worked in the 70s and 80s (jump ending early only upon arrival), 2D map as a game tool. Which changes by T5 to jump ending early due to 100D shadow anywhere along the jump at the instant of jump, with no mention of 2D space. But adding to the mix, reports that Marc's universe is 2D (!!!! -- I still can't wrap my head around this), along with jumps ending earlier if any 100D shadow falls across the jump line at any point during the jump's duration.
Obviously none of this squares and we are left with -- as has always been the case -- each group's setting will work differently and have different "physics"* based on whatever the table finds most reasonable to interesting.
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* Scare quotes on purpose, since the physics of a made up technology based on an alternate space defined as being not-physics can never be tested, and can behave exactly as one wants.
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@Another Dilbert,
Your 2 rules are the "common knowledge" of Traveller grognards, but the second one is no longer true based on the T5 RAW
Because the stars aren't obriting the galaxy at the same speed, your target system is moving relative to your system on the order of 10s of km/sec. Over the course of a week long jump, that is some multiple of 6M km - far more than the 100D limit of a planet we can roll up. So now you have a situation where you could jump in as close to a planet as your accuracy because the 100D limit won't be anywhere near that target when you initiated.
For me, I ignore this T5 stuff and stick with the "common knowledge" of how jump works. If I want to dump a ship out of jump for some reason, I have other tools for that (misjump, secret advanced tech, etc.)
Your 2 rules are the "common knowledge" of Traveller grognards, but the second one is no longer true based on the T5 RAW
Because the stars aren't obriting the galaxy at the same speed, your target system is moving relative to your system on the order of 10s of km/sec. Over the course of a week long jump, that is some multiple of 6M km - far more than the 100D limit of a planet we can roll up. So now you have a situation where you could jump in as close to a planet as your accuracy because the 100D limit won't be anywhere near that target when you initiated.
For me, I ignore this T5 stuff and stick with the "common knowledge" of how jump works. If I want to dump a ship out of jump for some reason, I have other tools for that (misjump, secret advanced tech, etc.)
AnotherDilbert
SOC-14 1K
?
T5.10 said:
T5.10 said:
Note the current 100 D limit is used, not where the 100 D limit were a week ago when you initiated jump.
