So, is there a way to prove that someone is a sanctioned psyker? I know many look like it (hollow, lifeless eyes, maybe warmed over death, perhaps missing their teeth, or hair), but is there a legitimate way to tell? The records keeping of the Imperium is as arcane, byzantine, and full of dead ends as every other facet of the organization, and I often see getting info reliably from any other world, certainly sector, as problematic, at best (no dedicated Internet), so asking Holy Terra if this psyker came through their program seems unlikely. If your crew found a young psyker, living on the streets of Footfall, or among the populations of numerous worlds that don't pay official tithes to the Imperium, and they decided to scoop him up, would anyone be the wiser? I doubt there's any identifying tattoo, as much as I doubt one couldn't fake it, if it did exist. I see plenty of Inquisitors who are psykers, and none of them have the harrowed look of a sanctioned psyker, even having seen all the additional things that should unhinge even an Inquisitor's mind. How might you be found out? That might be the work of rejuvenants, or surgeries, but a Rogue Trader could afford those, too, if they were of a mind, leaving some to question if the individual has been tested.

If you did pick one such psyker up, and you happened to have an astropath, or some such, aboard your ship, who might be as loose with his organization's rules as many other individuals who also serve a Rogue Trader, could they "test" this new acquisition? They've been through everything, so they have some idea what to look for, if they don't just flip, and say "we must report this psyker to the Black Ships!"

While I know that the Imperium is very grimdark, and many petty crimes might be punishable by death, just because the Imperium can't afford to be less severe, what would the actual fine/punishment be, to the Rogue Trader, for making use of an unsanctioned psyker, assuming it is discovered prior to that psyker, intentionally, or otherwise, starting a calamity psykers are feared and reviled for being able to cause?

As a last bit, if your ship found itself without any astropaths, say something went pear-shaped, on the last run, what might be the official means of resupplying this particular resource?

Kind of curious about all this because, if say one of your group's members had a kid, in game, and they developed the psyker gene, it might not be convenient to have to send them off to Holy Terra, wait forever for them to arrive there, wait 10-30 more years for the training to conclude, hope that they survive that, and then maybe get them back, if you grease enough cogs. If you just said "screw it! Way out here, beyond most of the Emperor's sight, who'll know? And besides, Ostius can look after them, for that aspect. He's a great, old guy, as astropaths go, and definitely been through the whole song and dance about what it means to be a psyker. It'll be like he has a grandson!" If the kid doesn't make civilians have stray nosebleeds, or blizzardy winds, out of the blue, are they likely to be caught, and can the great power of their RT benefactor shield them?

I would assume a sanctioned psyker comes with documentation when they are turned over to their new handlers (because few, if any psykers, even the top members of the AAT don't answer to somebody). If they lose this paperwork, they will likely need to send away for it. The process might be byzantine, but it'll get around to completion eventually.

As far as a sanctioned psyker meeting another, I'm sure they have enough shared experiences that they can know if each other are genuine or not, and each has certain types of training and education that ONLY AAT psykers know, which an unsanctioned psyker can't fake unless they learn these things somehow from a sanctioned psyker.

As to hiding an unsanctioned psyker, or just not turning them over to the AAT, that is grounds for death, no matter how powerful you are, and generally not a good idea unless you can somehow arrange a state of plausible deniability that you actually knew you had an unsanctioned psyker in the first place.

Edit: If you have enough pull, and you have sanctioned psykers in good standing with the AAT, you MIGHT be able to get away with them teaching a young unsanctioned psyker someplace other than Terra, provided they have the capabilities and resources to do so, but they and you would have to be some pretty trusted individuals. You might be able to get them sanctioned and properly trained in this way, but thems grounds for massive favors and campaign adventure plots.

For the fun of conversing, then, give a try to Inquisitor Victoria Aldrich? I'm a big fan of Inquisitors, Psykers, and stuff like that, as characters, and one of the reasons I like this one so much is simply that they statted her out (BC, p.367), in comparison to other things of the same setting. Deathwatch has numerous opportunities to meet an Inquisitor, but no stats, as they don't expect you to play one, likely even fight one, and the other lines, when they do, can't often keep up with the higher-end monsters, such as daemons, Space Marines, and such. She can, though. She's a potent psyker, a consummate daemon-hunter, and empowered with all the capacity of any Inquisitor.

Blah, blah, her master found her when she was young, and kept her around, maybe even planning on having her succeed him, but nothing in there, or in many psyker Inquisitors, for that matter, reference a long, arduous journey to Earth, where the benefactor must hope they can survive for over a decade (DH1 psyker references this time frame, at least), a decade where their "Inquisitorial training", and use to that master, are null, and hope to get them back, and yet these are often the psykers they trust the most, with the worst secrets, and nightmares, to keep the Imperium safe. What happens with all of these, beyond "the Inquisition answers to no one!", which is a flimsy excuse, and one many Rogue Traders, while beyond the Imperium's bounds, might also use? It just seems that, within a certain scope, your own "sanctioned" should be able to use their experience to monitor others, and things do blow up in their face, it's grimdark, and that was going to happen, anyway.