Many warp-capable ships have an Astropath in their crew (Rogue Trader and Dark Heresy). Can they send and receive their messages while the ship is in warp transit?

Somehow I think it would only work in normal space, otherwise it would be much easier to brave the dangers of the warp and not get lost/cut off/missing for longer times.

The Laughing God said:

I believe there no differences sending and receiving astrophatic messages while in the warp than in the real universe. Because your are closer to the medium that the message travel I belive it is also easier to send or receive messages.

Would active gellar fields inhibit this? imho when a ship is in the Warp, you really don't want the warp to talk to you as it would say things you don't really want to hear. Any legit Astropathic messages could be drowned in a cacophonous wailing of the howling warp and have a high risk of madness and possession.

guest469 said:

But gellar fields are less an obstacle than the normal boundary between the warp and normal universe(because of the need for navigators to guide the ship) so it is less of a hassle for astropaths to receive and send messages through a gellar field than to send and receive messages through the barrier between the warp and the normal universe.

The cacophonous wailing of the howling warp and have a high risk of madness and possession is already present for the astropaths when sending or receiving messages in normal space. It is like background noise a danger that is already there. What changes is that the astropath expends less energy sending and receiving messages through and active gellar field than through the normal barrier between the warp and the normal universe.

But then why do ships get lost in the warp and arrive sometimes in another time than when they left? when astropaths could continue to update their position and trajectory with colleagues in realspace, they should at least be able to stop everyone from being so surprised when this happens.

The Laughing God said:

Imagine the warp and real space like the bottom of the ocean and the surface. There are little corelation between the direction inside the warp and direction in real space. The ship must avoid all kinds of dangers like currents,zones of calm,whirlpools,warp storms,etc.. There is also the fact that moving in one direction in the warp does not necessary coresponds with the same direction in real space.

In principle it what you said I believe is used in cognitar assisted navigation. The ship astropaths use the astropathic choirs in real space to update their positions. But astropaths cannot discover the vast majority of the dangers that make the warp so dangerous. That is the job of navigators,phyhicher trained for warp navigation,phyhicher devices and cognitors, deamons and even them can fail and found themselves trapped by a danger of the Ewarp. Cognitars for the IOM even during the period between 30k(Great Crusade) and 41k cannot accurately predict those dangers that is why navigation with a cognitar is done in short hopes of 4-5 ly. Astropath in the IOM lack both the trainning ,knoledge, experience, and power to do the navigation themselves. Astropaths are some of the weakest phyhichers that are in the employ of the IOM.

EDIT:Ships get lost in the warp and arrive sometimes in another time than when they left because of the sudden dangers of the warp that trapped the ship and send them into the past and not found by ship sensors,phyhichers,navigators until it was too late and not because they don't know their position in real space before the ship went missing.

I could be wrong, but I seem to recall reading references to receiveing astropathic messages during warp travel in Black Library books.

@The Laughing God

But then why do ships get lost in the warp and arrive sometimes in another time than when they left? when astropaths could continue to update their position and trajectory with colleagues in realspace, they should at least be able to stop everyone from being so surprised when this happens.

Why wouldn't they?
An astropath can send messages and receive them. That's all. He hasn't necessarily got any idea about where messages come from, meaning he can't triangulate his position, and there's no guarantee that messages require any specific amount of time to get from A to B. Thus, staying in contact with other astropaths doesn't change matters at all.

When you want to know where you are in relation to the rest of the galaxy, you ask a Navigator, because that's the guy with the third eye capable of seeing the one important thing in the Warp that allows you to determine your position: the Astronomican.

I've not read any 40k fiction but Eisenhorn/Ravenor, and haven't followed RT closely, but the issue is possibly addressed on Disciples of the Dark Gods pg 15. It refers to temporal anomalies noticed in astropathic transmissions. The writer of the document says that such errors sometimes occur around warp anomalies or "during times of tempestuousness in the immaterium."

This quote in itself doesn't necessarily mean 'while in the immaterium', but following sentences go on to say "But we are not subject to such conditions now... the light of the Throne waxes strong here and our vessles make good speed and steady progress." That may, or may not, imply that they are travelling in the Warp since there's where most long-range, sustained periods of travel take place.

According to the Rogue Trader entry on astropaths "Relying as heavily as the Imperium does on the warp for galactic communication...", "There he learns to send his thoughts singing across the galaxy via the medium of the warp", and on page 310 in Communication it says "However, as with everything associated with the warp, astrotelepathy is an erratic process. Like the Astronomican, an astropathic message is affected by the currents and storms of the warp."

Since the warp is specifically mentioned as the medium astropathic messages travel through, I think it's likely that astropathic communications are not at all affected (and who knows, might be even more easily transmitted) by an astropath travelling in the warp itself.

I think another valid point is if the Gellar Fields interfere with the astro-path, to which the answer is no.

Apparently Hexagrammatic Wards are related to Gellar Fields somehow, but the Fields do not block psychic powers, astro-pathic communication or even demonic entities once they have manifested inside the field's area. There are plenty of reports of demonic entities remaining active inside a ship after a Gellar Field failure or flicker. So apparently all the field does is establish a boundary similar to the one keeping the warp and the materium separate.

All in all, that means there's really nothing to inherently impact astropathic communications while in the warp.

This question has been asked a few times before. If it helps, the last time this question was asked, I e-mailed Sam Stewart to ask. According to him, astropathic messages can be both received and transmitted whilst in warp transit.

About astropaths updating trajectories and position: That's actually not their job, IIRC. That's the work of the Navigators (though I may be wrong).

Anywho, I think that it would be much less stressful for the astropath in question to send or receive signals in the warp, since the Gellar Field is weaker than the normal space/warp space boundary. However, this works both ways: Would that not make it easier for the perils of the warp to take hold of the psyker or the ship? Essentially, it's easier but it's more dangerous, at least that's what I believe.