Astropaths

By ColArana, in Dark Heresy

How effective is communing by Astropaths really? Obviously it's really the Imperium's only means of long range communication, but how useful is it for communications as far as a band of Acolytes would be concerned? Specifically:

1. How reliable is it (assuming there aren't any warp storms in the vicinity)?

2. How fast is it?

3. (Most importantly) How secure is it? How easy would it be to intercept communion between Astropaths?

Also, the one thing I never quite got is how the messages necessarily get relayed. Presumably you tell one psyker/group of Astropaths the message you need to be sent, they send it to another group at the destination point and then... what, one of them walks off to the recipient of the message? Or do they write it down and then send it off that way? Or what?

I treat Astropathic communication in my campaign as being akin to the telegraph in the 19th century American frontier. If that helps...

Due to 40k's lack of uniform canon, details such as these are left to the personal preferences of writers and readers everywhere, which is why a singular "true" answer is not possible for cases such as these.

However, personally, I've aligned my interpretation of the setting mostly with the material published by the Games Workshop studio itself -- and perhaps the following excerpt from the 6E tabletop rulebook can at least provide one possible inspiration to adopt or dismiss as you wish:

"[...] It is said that the Emperor, the greatest of all pyschic minds, once held full telepathic conversations with Malcador the Hero, himself a mighty telepath. Though they were on opposite ends of the known galaxy, there was no time delay to speak of, and they may well have been in the same room. Although human psykers of such extreme potency no longer stride among the stars, the most powerful Astropaths can single-handedly send messages across several star systems with some accuracy.

If all goes well, Telepathic communications travel quickly through the Warp, crossing many thousands of light years, becoming fainter and fainter, before eventually fading out altogether. Still, such communications vary wildly based on the mental strength of the sender, the ability of the receiver to absorb such incoming messags, and, perhaps most of all, the unpredictable nature of the Warp itself. When the galactic distance required of a transmission is so great that a single Astropath proves insufficient, it is common for them to work in relays, sending messages to various beacons, hubs and Imperial substations to pass along. It is also possible to boost a message by using an Astropath Choir - a group working in synchronicity to broadcast or receive complex messages over unimaginable distances.
It is too complicated and variable to list all of the methods and processes involved in Astropathic communications, but the following generalizations should help even a novice understand some of the difficulties of the medium. There are, after all, dozens of types of Trance Broadcasts alone, to mention nothing of Station Reception, Astral Projection or the nearly infinite styles of Divination practiced by Astropaths within and beyond the purview of Imperial Sanction.
Using mesmeric chants to enter a deep trance, a typical Astropath forms the message within his mind and sends it through the Warp. The progress of the message is rather like a stone dropped into a pool, as it creates a series of ripples that extend outwards through the Immaterium. Some psychics are able to project the message so that it travels only in a desired direction, but even then, some echoes are likely to lap outwards. Once projected, a message hurtles through the Warp until its energy is lost and it fades away, typically a gradual process, but the Immaterium is anything but predictable.
A communication of this kind has many restrictions; they are brief in length, perhaps comprising only a few images and sentences depending on how the Astropath works, for psychics are as likely to work in abstract pictures and emotions as they are in words. As with all things, the very Chaos of the Warp can alter the form of the message, if only rarely its intent. Unless powered by a mighty source, longer or more complex messages risk getting unravelled in the ripples of the Warp, arriving in a jumbled order and risking further if not complete distortion. Warp interference is common, as messages can be delayed, altered or contaminated by any number of fluctuations, such as shifts in Warp tides or the intermingling of multiple telepathic signals. Raving Warp storms can redirect or simply swallow and destroy messages, blocking communiques for centuries.
Any Astropath can pick up Trance Broadcasts, although in general it can be said that more discipline is needed to receive messages than to send them. With outgoing messages, an Astropath can concentrate on the clarity of thought, on the message itself, pushing such deliberations deep into the Warp. Astropaths in such a trance and actively receiving incoming messages are particularly vulnerable - their minds must open to the eternal noise of that erratic and highly dangerous realm. Not only must an Astropath attempt to sift out the senseless static of passing currents, they must also contend with the residue of ancient messages that sometimes, for no logical reason, drift endlessly, not losing power as is usually the case but continuing to call out from some distant past, faint waves of energy lapping gently across the void. The repercussive Warp-waves of major events or cataclysms can also be picked up, sometimes unintentionally, sending more sensitive Astropaths into fits or burning out their minds altogether with the unexpected onslaught.
Ominously, some telepathic impulses attract unwanted attentions - mischievous Warp entities that attempt to alter messages, making them misleading or obscene, redirecting them to the wrong recipient, or perhaps even attaching themselves to the mental transmissions, piggybacking on the message to its final destination. Although rare, it is possible for Daemons themselves to become aware of and attracted to the psychic signals hurtling through their realm. On occasion, they will even trace them back to their source, searching for a way to establish a claw-hold into realspace.
An Astropath who wishes to send a singular message to a specific location - whether it is a particular spacecraft, planet, hive or even an individual - must be able to concentrate his mind to a degree that is unimaginable to a normal human. These messages are launched into the Warp not as ripples extending outwards into all directions, but as a single bolt of pure thought. The recipient must be prepared to receive such powerful transmission, though it is still possible for those in Sweeping Trance Reception to pick up snippets of such messages if they happen to pass through the area of their psychic awareness on the way to their destination. Success of this kind is linked more to random chance than any degree of skill or accuracy on the part of the erstwhile recipient. [...]"
-- 6E BRB, p407: Dark Millennium Appendix, Astropath Communications
The comparatively extreme lack of reliability in Astropathic communications mentioned in the above-quoted text is reinforced by the same source's description of Imperial timekeeping (page 406), where the first digit of a full date (a prefix before year fraction, year, and millennium) is actually a dedicated check number whose sole purpose is to track the reliability of any events or messages attached to that date, as determined by proximity and directness of the Astropathic transmission. For example, a prefix of 2 means the sending Astropath was in direct contact with Terra, whereas prefix 3 means usage of a single substation relay along the way. Apart from describing the respective account's general level of accuracy, this is also a way of narrowing down potential time differences, meaning how much the recorded date may actually differ from the true event.
Hope that helps! But again, all of this is optional and merely to be treated as a suggestion. In the end, it's up to you. :)
Edited by Lynata

1. Not very. all messages are encrypted, and most do not use the exact same language as each other, so some messages are misread or even never translated, nor are most messages clear as day.
2. Not very fast. Planet wide is instant, but it gets slower as you go out. within system would be minutes, near by systems/within the sector anywhere from a few hours to a day or so, and trying to send a message across the galaxy could take months to get there. For the purpose of DH, which usually dont go much out of a single sector or subsecrtor, most messages will be a few hours or a day
3. Its not exactly clear how secure they are, but if they weren't at least relatively secure, chaos would have had the imperium dead years ago. They can attract attention of the warp, although It would probably be random and pretty infrequent. The weaker the astropath, the high chance of it getting read or attracting the daemon.
4. The astropaths that are not personal astros likely have some form of staff working under them, which look into contacting you when they get a message, although who you sent it to, who you are, and which group you sent it to would all affect that. For example an astro working for a powerful noble might tell their master who will then decide if he cares enough to look for you, others might not do anything, and expect the recipient to come and get it, while others may use even far more bizarre methods.

Haven't we some kind of table in one of RT books?

For reliability I would say it depends on the complexity of the message.

Giving a full breakdown of enemy troop dispositions across a planet would be incredibly complex and unreliable if the astropath tried to send it with speed, however saying

'Ork Warlord Gruzzak the Destroyer attacking Fylack IV. Send Help'. That would be pretty easy to send.

2. Speed. I would say pretty fast. The point is though that your caveat of warp storms is important. The further you send something the more likely you are to hit a warp storm.

3. I would say Astropathic messages are generally very secure. I don't think it would impossible for an enemy to intercept them but such a feat should be a minor plot point and would be a reasonably big deal for the Inquisition. e.g If the PCs reported that there was an Eldar Farseer who could reliably and consistently intercept astropathic messages I don't think it would be far fetched to think the Inquisition would dispatch an Officio Assassinorum agent to kill said Farseer as a matter of course.

On the other hand I don't think it would be so preposterous as to have the Inquisitor scoff and say 'That's ridiculous'.

Edited by Visitor Q

1. Astropathic communication is only moderately reliable: it can be crypted, but it is often difficult to interpret (it is often sent as dreams, impressions, and symbolic visions by weaker psykers).

2. It can take anything from a few minutes intra-system to a few months between Segmentums (for a very powerful psyker).

3. You want to check the Navis Primer Rogue Trader book for that - it has tables and detailed rules for all that, along with some pretty good fluff. But basically yeah, loads of stuff can intercept and modify messages - hence why they are hidden and crypted.

I repeat, check the Navis Primer. It answers all your questions in about 2 pages (including tables).