Faster Than Light Communications

Posted: 2023-03-28
Word Count: 1293
Tags: rpg space settings

Table of Contents

As of this writing I’m working on a longer article on faster-than-light travel1. For now let’s tackle a simpler aspect of star-spanning science fiction games and fiction: communications across light-years. All those I could think of break down to the following cases.


In Classic Traveller no “FTL radio” exists. One of the rulebooks likened it to the Age of Sail wherein all communications required a courier.

Coriolis has the same trope: no EM communications can cross the portals between star systems. The mass media outlets of Kua have to ship their broadcasts to other worlds on the equivalent of hard drives. Aiwas or Hamura might see “broadcasts” a day or two late; Menkar might see one weeks late, if at all.

Most free trader / pirate / murdertrucker2 campaigns will see little difference since they have no larger organization to call. Representatives of an interstellar organization, on the other hand, will have no way to call for supplies or reinforcements short of turning tail and running back home. (If they can.) An interstellar financial or literal Empire will likely keep an outpost or garrison in each star system they claim, but the resources and level of cooperation may vary from outpost to outpost. Scouts, ambassadors, and patrol ships in transit will lack such recourse.

Low Bandwidth

In the early to mid-20th century ships at sea could communicate with each other or their home bases through wireless telegraph, invented by Marconi around the turn of the century. Much of Ursula K. LeGuin’s work assumes communication only through a planet-bound text-based device called an ansible. Other stories from the Golden Age of SF have assumed communications only through something like a teletype. The Confederation setting posited something similar, only between possessors of Jump drives or complex stationary devices that can send to and receive from them.

While some communication beats none, a text only or low graphics channel reduces interaction between planetary authorities … and between a starship and the admirals who issue orders. It means the Star Patrol can receive orders and send reports, but depending on transmission speed they cannot call for immediate backup. Captains must interpret brief and sometimes vague orders according to the best traditions of the Patrol, their understanding of the situation, and their instincts. Good admirals in turn recognize that captains must bend some regulations to get things done; bad admirals will use those bent regulations to change victory to a court martial.

Similar dynamics apply to diplomats, troubleshooters, merchants in an interstellar corporation, and similar leaders with authority to act on their own discretion and responsibility when things go wrong. (And they do go wrong, or there’s no story.)


A step up from Low Bandwidth, asynchronous FTL communications resemble transmissions during the moon landing and later missions: each party can send video and audio freely, but the other party won’t receive it for minutes, hours, days, or possibly weeks depending how far out they are. A few reasons spring to mind:

Communication approaches real time, but instead of captains and admirals arguing dramatically in front of viewscreens we get only angry phone calls or email exchanges. Brief requests for aid – and automated alerts – get back to Central Command fairly quickly; detailed video and reports travel less quickly. Captains must not only learn how to handle situations quickly they must know how to phrase bulletins so as to encourage exactly the right amount of haste while setting expectations.


This resembles communications in Star Wars, Star Trek, Babylon 5, Battlestar Galactica, The Orville, and other media franchises: two people on viewscreens talking. Sometimes, like a Zoom meeting, the focus shifts from each others’ faces to exterior footage, diagrams, or complex technical presentations. Perhaps instead of viewscreens people talk remotely to 3D holograms sent across the stars, or drop into a virtual space created and maintained by computers on both sides.

Whatever the audio-visual setup, conversations across an interstellar empire resemble conversations between people across a room. Occasionally the distances reduce bandwidth, increase lag, or impose static; sometimes the communications array goes down on one or both sides. Nevertheless, smooth communications are the norm. Spotty or downed comms become rare dramatic moments.


The only step beyond “real-time” is guaranteed communication, no matter the distances, conditions on either end, or quantity of data sent. We have yet to achieve this in the real world, but hey, it’s science fiction.

On the other hand, this assumption yields no dramatic possibilities, no flaw a writer or GM can exploit. Thus we must turn to the nature of the communication itself.

Distributed Mind

In Ann Leckie’s Imperial Radsch series, the supreme ruler of the Empire cloned herself3 tens of thousands of times, and each clone formed a node in a brain distributed across the entire Empire. Only an Emperor could make that kind of galaxy-spanning project work.

Yet (SPOILER ALERT) subsequent events revealed a critical flaw: synchronization lagged and the distributed mind’s internal debate manifested as two or more factions of these supposedly mentally identical clones. Obeying one faction – ostensibly a manifestation of the Supreme Ruler – became treason to another faction.


As in the last chapters of Charles Stross’s Accelerando, communication becomes instantaneous and flawless because travel becomes instantaneous and flawless through ubiquitous portals across light-years. One’s living room may rest on Earth, one’s bedroom on Mars, one’s parlor in Alpha Centauri.

Exploring all the implications of bending space this far, and all the other technologies the civilization must have invented, exceeds this article’s scope. Read Accelerando or the Krakoa era of X-Men comics, starting with the House of X/Powers of X collection (2019).


Only telepaths achieve this level of communication between each other, and only when both sides know each other well. Mundanes must use more prosaic tech to hold their conversations. And perhaps in some worlds telepathy is the only way to communicate across the stars … and only images or sounds the telepath can see or hear can pass through the mind-link.


Flawless communication requires a wormhole (or Stargate) connecting both ends. This implies either one side initiates the connection with hard-to- comprehend technology or both sides open their ends at a pre-arranged time. There’s no time limit, but the link is expensive: power drained, time to set up and/or tear down the connection, other wormholes blocked while this one is open, etc.

If the connection is expensive, it creates extreme pressure to present one’s situation concisely and precisely, and avoid fruitless arguments or chit-chat over the channel.

  1. “Grand Unified FTL” … eventually. ↩︎

  2. Like murderhobo, but PCs have their own long-range vehicle. ↩︎

  3. The series uses female pronouns almost exclusively, as our narrator’s native language has no gendered pronouns. ↩︎