FTL Communications?
- Thread starter MasterGwydion
- Start date
ProfGrizzlyJon
Cosmic Mongoose
ProfGrizzlyJon
Cosmic Mongoose
You are correct.
ProfGrizzlyJon
Cosmic Mongoose
As long as they were paired, and delayed by the difference between entering jumpspace
Cool. Mostly ships jumping as a group won't really have much need to communicate during jump. Plans should have been discussed before they enter jump space and not much usually changes during jump that would affect that.
But a fleet or squadron sending a paired scout, then jumping at an agreed time as the scout jumps back is very useful. The fleet gets relatively recent information about the destination before arrival. And if the scout doesn't transmit, they at least know things have likely gone pear shaped. (And that's one situation where they would need to discuss things during jump; something HAS happened during jump that might affect plans).
But a fleet or squadron sending a paired scout, then jumping at an agreed time as the scout jumps back is very useful. The fleet gets relatively recent information about the destination before arrival. And if the scout doesn't transmit, they at least know things have likely gone pear shaped. (And that's one situation where they would need to discuss things during jump; something HAS happened during jump that might affect plans).
Condottiere
Emperor Mongoose
They're in separate bubbles of reality.
Sigtrygg
Emperor Mongoose
I like it, but do have some devil's advocacy...
Mesons and neutrinos are not exotic, they are part of the standard model and are part of what we class as matter within our universe (at least for now)
Since jump space destroys normal space matter how do mesons and neutrinos avoid this?
What if you switch on a meson screen in jump space? Do meson guns work in jump space? Where do the neutrinos spewing forth from your fusion reactor go to while in jump space?
Mesons and neutrinos are not exotic, they are part of the standard model and are part of what we class as matter within our universe (at least for now)
Since jump space destroys normal space matter how do mesons and neutrinos avoid this?
What if you switch on a meson screen in jump space? Do meson guns work in jump space? Where do the neutrinos spewing forth from your fusion reactor go to while in jump space?
ProfGrizzlyJon
Cosmic Mongoose
I am not arguing against that point. The threadcaster simply connects those bubbles (like a string-can telephone)
ProfGrizzlyJon
Cosmic Mongoose
Where is your advocate licensed to practice? Jumpspace is not hell (that's 40k),,,
1) Correct. In realspace, mesons and neutrinos are not exotic—they are normal, well-characterized components of the Standard Model. However, in the context of jumpspace physics, the term "exotic" refers to field behavior, not particle classification. Threadcaster systems do not emit real mesons or neutrinos. Instead, they manipulate the jump envelope's internal harmonic field to mimic the signal profile of those particles—much like how radar mimics motion by timing reflected pulses. The term "exotic" is retained in technical jargon because the simulated particle behavior exists within an exotic field domain, even if the particles themselves do not.
2) They don’t. Normal matter—including mesons and neutrinos—cannot survive unshielded in jumpspace. Any particle not contained within the ship’s jump envelope would be immediately absorbed, scattered, or decohered by the transition field. This is why no actual mesons or neutrinos are transmitted by the Threadcaster. Instead, localized harmonic phase shifts are induced within the jump envelope—similar to encoding vibration into a sealed chamber. These shifts are reconstructed on another vessel with a synchronized envelope, rather than being physically sent across space.
3) Meson screens rely on realspace field coupling to prevent meson penetration. In jumpspace, the physics that meson screens depend on do not apply in the same way. Turning one on inside jump would likely do nothing functional, or in some theories, destabilize the jump field by introducing unpredictable energy gradients. While the internal systems of a meson gun might cycle, the projected mesons would not behave predictably, and their decay path would be distorted by the jump envelope. Meson guns rely on precisely decaying mesons within a target’s armor in realspace. In jump space, neutrinos emitted by onboard systems are retained within the jump envelope. Since no particles can escape the field, these neutrinos do one of the following: continue through the ship harmlessly, as they do in realspace (they are weakly interacting), dissipate into the envelope as background energy or get reabsorbed or scattered by the envelope boundary in a way that renders them undetectable
MasterGwydion
Emperor Mongoose
This is a huge can of worms. Before this, you were totally cut off in jumpspace, now there is a method for communicating while in jump. Seems like a TL issue to me. If it can be done at lower TLs, the method will be refined to allow matter teleportation to eventually cross the jump bubble. Basically, this technology allows for sending a signal to other universes. Has anyone thought of the implications and complications those implications may cause? Unless dimensional travel is set to become a thing in Traveller outside of the psionic dimension drive ships. Psionics allows the communication between dimensions, but psionics cannot travel outside of a jump bubble. So, lots of very complicated cans of worms just to allow something that no one really thought they needed in Traveller anyhow, the ability to send and receive messages while in jumpspace.
ProfGrizzlyJon
Cosmic Mongoose
That is an unexpectedly flippant answer.
The Traveller Core Rulebook Update 2022, under the Jumpspace section (p. 142), states:
It further states:
It stands to reason that:
- Jump Isolation is Not Absolute Across All Frames
- Signal ≠ Matter
- Jump Space ≠ Alternate Universe
- “No One Needed This” Is Not a Valid Objection
There is no rule prohibiting communication within jumpspace, or between synchronized ships already in jump. Nor is there any restriction on psionic talents, resonance-based systems, or other intra-bubble mechanisms, provided they remain confined to the bubble and do not reestablish contact with realspace. Traveller’s rules establish a sealed environment—not a metaphysical void. Internal systems remain viable, and tightly scoped jump communication does not violate the system’s logic.
The leap from “signal can cross jumpspace” to “matter teleportation becomes inevitable” is a textbook slippery slope. Traveller technology maintains a hard boundary between information and mass. Even psionic Teleportation is spatially constrained and line-of-sight dependent. There is no mechanism—psionic, technological, or narrative—that allows for the transmission of matter into or out of a jump bubble. Claiming otherwise ignores the strict energy requirements and physical constraints embedded in the jump drive model.
The assertion that communicating through jumpspace equates to cross-dimensional messaging is unfounded. Jumpspace is not a separate universe—it is a topologically folded region of our own spacetime. It is exotic, hostile, and largely unmapped, but it remains part of the same reality.
The suggestion that limited jump-bubble communication is unnecessary—and that “no one really thought they needed it”—is not a technical argument, but a rhetorical dismissal. Traveller has never been a one-size-fits-all setting. It supports naval campaigns, scientific expeditions, exploratory missions, and emergent horror—all of which may benefit from tightly constrained communication capabilities during jump.
The feature in question does not bypass jump mechanics, erase delay, or undermine narrative isolation. It adds a controlled option for referees who need it—nothing more.
MasterGwydion
Emperor Mongoose
It states very clearly,
"No communication is possible with a ship in jumpspace. It is effectively cut off from the universe for the week it is in jumpspace."
As you stated above and I will accept that they are part of the same universe. Therefore, no communication is possible because they are "effectively cut off" from the universe.
You also say that clearly this only applies to realspace, but this is you changing the meaning of the words used. You need to decide. If jumpspace is within our universe, then no communication is possible because, "The Mongoose Traveller Core Rulebook (2022 Update) states that a vessel in jumpspace is “completely isolated from the rest of the universe.” It says that the vessel is completely cut off from the rest of the universe. So maybe you can communicate from inside jumpspace, you just have to go outside of the ship to do it. lol. Rest of the universe is anywhere other than where you are at currently. In this instance, your current location would be in a jump bubble in jumpspace.
If I am swimming in the Atlantic Ocean off of the cost of Iceland and I use the phrase "rest of the planet" am I referring to everything on the planet where I am not? Or am I only referring to anything that is not the Atlantic Ocean, meaning I would not be counting the Atlantic Ocean just off the coast of Brazil as part of the "rest of the planet" since I consider them both to be part of the same location? Common usage would seem to indicate the former as opposed to the latter.
So, my previous reply was intended in all seriousness. I apologize if you felt it was flippant. That was not my intent. So, for the misunderstanding, I apologize.
"No communication is possible with a ship in jumpspace. It is effectively cut off from the universe for the week it is in jumpspace."
As you stated above and I will accept that they are part of the same universe. Therefore, no communication is possible because they are "effectively cut off" from the universe.
You also say that clearly this only applies to realspace, but this is you changing the meaning of the words used. You need to decide. If jumpspace is within our universe, then no communication is possible because, "The Mongoose Traveller Core Rulebook (2022 Update) states that a vessel in jumpspace is “completely isolated from the rest of the universe.” It says that the vessel is completely cut off from the rest of the universe. So maybe you can communicate from inside jumpspace, you just have to go outside of the ship to do it. lol. Rest of the universe is anywhere other than where you are at currently. In this instance, your current location would be in a jump bubble in jumpspace.
If I am swimming in the Atlantic Ocean off of the cost of Iceland and I use the phrase "rest of the planet" am I referring to everything on the planet where I am not? Or am I only referring to anything that is not the Atlantic Ocean, meaning I would not be counting the Atlantic Ocean just off the coast of Brazil as part of the "rest of the planet" since I consider them both to be part of the same location? Common usage would seem to indicate the former as opposed to the latter.
So, my previous reply was intended in all seriousness. I apologize if you felt it was flippant. That was not my intent. So, for the misunderstanding, I apologize.
Sigtrygg
Emperor Mongoose
I think it is the fact that the rules don't mention ships in jump space communicating with each other by some mechanism is all the wiggle room needed for this, which also makes me wonder if two ships jumping along similar jump lines are in the same jump dimensions...
"JUMP THEORY
There are several differing theories of jump space*, and although jump technology has been used for star drives for thousands of years, a precise understanding of it is not necessarily a prerequisite; high quality data on jump space is difficult to obtain.
The basic concept of jump space is that of an alternate space**. Theoretically, jump spaces are alternate universes, each only dimly understood from the standpoint of our own universe***. Within jump space, different physical laws apply****, making energy costs for reactions and activity different and imposing a different scale on size and distance."
* this is in setting and metagame
** alternative space, different universe, alternative dimension is often substituted here
*** jump spaces, note the plural, are alternative universes
**** different physical laws that have a very sever interaction with matter and energy from our universe, yet somehow the jump field protects...
"JUMP THEORY
There are several differing theories of jump space*, and although jump technology has been used for star drives for thousands of years, a precise understanding of it is not necessarily a prerequisite; high quality data on jump space is difficult to obtain.
The basic concept of jump space is that of an alternate space**. Theoretically, jump spaces are alternate universes, each only dimly understood from the standpoint of our own universe***. Within jump space, different physical laws apply****, making energy costs for reactions and activity different and imposing a different scale on size and distance."
* this is in setting and metagame
** alternative space, different universe, alternative dimension is often substituted here
*** jump spaces, note the plural, are alternative universes
**** different physical laws that have a very sever interaction with matter and energy from our universe, yet somehow the jump field protects...
ProfGrizzlyJon
Cosmic Mongoose
As a scuba diver, I would take that to mean "the rest of the planet not covered by water". Surface swimming blurs that edge, because you are at the cusp of transition. "No communication is possible with a person diving underwater. They are effectively cut off from the universe for the week they are underwater.". 50 years ago, that was true. We have eventually learned to use acoustic, photonics and other tech to allow for communications between divers, and even recreational divers might be found with beacons and wireless intercoms.
I can see your perspective, but the nuance of "effectively" should not be interpreted as "explicitly and immutably"
Lots of discussion about this in canon.
From the Starship Operators Manual (emphasis added by me):
JUMPSPACE
Many believe jumpspace comprises the ‘bulk’ in which our universe is embedded. A common, if trite, analogy is of viewing our universe as a 2D sheet in a 3D space, with jumpspace all that is above and below it. It is unclear whether jumpspace is part of our universe, another universe, a series of universes parallel to our own, or something external to our universe altogether. This uncertainty gives rise to different nomenclatures denoting the reality in which we live, with the most common being ‘realspace’. Critics regard this term as a misnomer, pointing out that jumpspace is very much as real as the space in which we live, irrespective of how alien it might be. This book uses the term because it is how most of our audience already refers to it.
When performing a jump, ships translate from the ‘surface’ of realspace to a certain ‘height’ in jumpspace, called the jumpspace level. Studies prove jumps of different distances correlate to different levels, with the longer the jump in realspace the deeper a depth travelled through jumpspace. No other correlation is found between realspace and jumpspace, and studies suggest that scientists will not ascertain any. When jumping, a ship is removed altogether from realspace, such that the concepts of its ‘position’ and ‘speed’ are meaningless for the duration, until reemergence. It is possible that the ship might have position and speed within jumpspace but these do not map to realspace equivalents and there are no perceptible external reference points within jumpspace, making determination of location and velocity impossible.
JUMPSPACE
Many believe jumpspace comprises the ‘bulk’ in which our universe is embedded. A common, if trite, analogy is of viewing our universe as a 2D sheet in a 3D space, with jumpspace all that is above and below it. It is unclear whether jumpspace is part of our universe, another universe, a series of universes parallel to our own, or something external to our universe altogether. This uncertainty gives rise to different nomenclatures denoting the reality in which we live, with the most common being ‘realspace’. Critics regard this term as a misnomer, pointing out that jumpspace is very much as real as the space in which we live, irrespective of how alien it might be. This book uses the term because it is how most of our audience already refers to it.
When performing a jump, ships translate from the ‘surface’ of realspace to a certain ‘height’ in jumpspace, called the jumpspace level. Studies prove jumps of different distances correlate to different levels, with the longer the jump in realspace the deeper a depth travelled through jumpspace. No other correlation is found between realspace and jumpspace, and studies suggest that scientists will not ascertain any. When jumping, a ship is removed altogether from realspace, such that the concepts of its ‘position’ and ‘speed’ are meaningless for the duration, until reemergence. It is possible that the ship might have position and speed within jumpspace but these do not map to realspace equivalents and there are no perceptible external reference points within jumpspace, making determination of location and velocity impossible.
From Traveller 5, Book 2:
Multiple Jump Spaces
Multiple Jump Spaces
Jump Space is a continuous series of alternative spaces, each with a slightly different set of different physical laws.Each of the Jump Spaces is infinite, but smaller (often muchsmaller) than Real Space.Jump Space is classified by the distance it tolerates.Jump-1 allows a ship to move about a parsec in about aweek. Jump-2 tolerates a ship moving two parsecs in abouta week. The maximum Jump-9 tolerates nine parsecs.
Jump Space.
Jump Space is an alternative space in which the laws of physics from the true universe do not apply. JumpSpace itself is truly alien: inimical to life and even to matter; it is only the special protections of the jump field that protect a hull and its contents from immediate destruction. Jumpspace exists in multiple levels which are exploited by jump drives to produce different distances travelled. More specific names for portions of jumpspace include hopspace, skipspace, leapspace, boundspace, and vaultspace.
3 IN JUMPSPACE
3 IN JUMPSPACE
A ship in Jump Space is totally isolated from Real Space.
It is Undetectable. A ship in Jump Space is undetectable. There is no known system available to detect the presence of ships in Jump Space.(Some psionicists claim to be able to detect ships injump, but test results are inconclusive.)
It Is Almost Unstoppable. A ship in Jump Space is theoretically unstoppable. It remains in Jump Space until it exits at its planned destination. A ship cannot voluntarily terminate jump early. If its drives are destroyed, it still exits Jump Space at the end of the Jump time period (rather than immediately). If the Jump Field is breached, much of the matter is destroyed by Jump Space. What matter that remains exits Jump Space at the end of the time period.
Movement Vector Can Be Changed
A ship can change its speed and direction while in jump space. Vector change requires non-gravity-based drives or devices; gravity-based drives (due to their need to interact with gravity sources) are generally ineffective.
Sigtrygg
Emperor Mongoose
I reiterate Marc's comment from his article:
There are several differing theories of jump space
Have we been told the one true way? No. And that is the way I like it. Dave Nilesn was going to explain jump dimension in more detail and promote their interaction with psionics. I am so glad that never came to pass in a way since it means I am free to do what I want rather than what is dictated from on high. Yes I know we are all free to change stuff, but there is a reason we still discuss HG80...
I disagree with much that was fanon that is now considered canon with regards to jumpspace, and also pick nits at the two SOMs.
So I like that Marc left it vague, it means people can come up with stuff like your comms...
There are several differing theories of jump space
Have we been told the one true way? No. And that is the way I like it. Dave Nilesn was going to explain jump dimension in more detail and promote their interaction with psionics. I am so glad that never came to pass in a way since it means I am free to do what I want rather than what is dictated from on high. Yes I know we are all free to change stuff, but there is a reason we still discuss HG80...
I disagree with much that was fanon that is now considered canon with regards to jumpspace, and also pick nits at the two SOMs.
So I like that Marc left it vague, it means people can come up with stuff like your comms...
ottarrus
Emperor Mongoose
Sorry, Lt. Uhura. No answers on hailing frequencies. 
The whole point of there being no FLT commo in Traveller is to give the players agency. They have to make decisions and take action without having a superior or advisor to blame when it all goes hairball. Change that and you might as well play Star Trek.
[Which is no hack against Star Trek... I've had good Trek games, though I don't like the current 2d20 rules much]
The whole point of there being no FLT commo in Traveller is to give the players agency. They have to make decisions and take action without having a superior or advisor to blame when it all goes hairball. Change that and you might as well play Star Trek.
[Which is no hack against Star Trek... I've had good Trek games, though I don't like the current 2d20 rules much]
MasterGwydion
Emperor Mongoose
It wasn't even true 50 yeras ago.
MK V Diving Rig - U. S. Naval Undersea Museum
The Mark V diving rig was used by the U.S. Navy for deep sea and salvage diving from 1916 through the early 1980s. Designed for intensive diving operations and to provide maximum physical protection, the Mark V allowed divers to work at much deeper depths than had previously been possible. With...
navalunderseamuseum.org
Also, even before electronic communications, you were not "effectively cut off". The guy in the boat could signal the guy underwater by banging on the boat or on a night dive by flashing a light into the water. I live in the Caribbean and moved down here to open a dive resort. (resort is still a work in progress, but we still have a dive boat.
) So, your analogy doesn't really work. You can't "bang on a boat" and have it be detected in jumpspace.As far as "effectively" goes, it means "the same result as" being cut off. So, any result that connects from jumpspace to normalspace, means that you are no longer "effectively cut off" as you have a point of contact and a method of doing so.
If communication can pass through jumpspace, even if it is only to another ship in jumpspace, it proves that jumpspace can be used as a transition medium for "stuff", information, or whatever. It stands to reason, that if we can send "signals" through jumpspace, then what else does that open the door to?
Or maybe jumpspace doesn't exist within Canon and all of the rules in the rulebooks are lies since Canon is just a collection of historical texts and therefore can be wrong or fabricated. A laser can't do 2d6 damage if lasers don't exist and we can only take the word of Canon that it does exist.
