Long story short, I am currently writing an adventure for my dark heresy group in which the PCs get sent to an exploratory/research moonbase that sent out a request for assistance some 200 years ago. (The message was delayed by Administratum Bureaucracy the whole time). Basically, I was wondering if anyone has any ideas for cool/thematic/interesting locations/structures/etc. that would be in a moon base in 40k. Any input is appreciated.

Thanks.

(If anyone is interested in the plot, I can post some of that too.)

A moon as in not Luna? (Terra's moon) because that is the base for the Imperium Navy.

It would have an Astropath , maybe a small choir (posibbly in a seperate building), Admech stuff: censorium, reactors, machine shop, research facilities . I guess that's all kinda ordinary. If it's not just the admech it could very well have a (small) chapel so that the crew can worship the emperor. Maybe the base has an imperial guard security detail , in wich case you'll find baracks, arsenal and bunkers/ defensive weapons . If the moon is large enough it might warrant a garage for a small vehicle pool of moon buggies or low-G sentinels . It should have a landing zone for shuttles. Their could be an extensive network of underground chambers and corridors hewn from the moon's bedrock. (safer from meteor impacts and radiation)

And then you can go overboard with hidden Inquisition/Deathwatch facilities (armouries, laboratoriums, cells, library full of exotic tomes, chained-op dark mechanicus experiments, vaults full of xeno-tech, etc...)

And the old standbies of Chaos artifact/ Necron vault/ Eldar webway portal burried under the surface. Maybe there are tyranid sleeper organisms hybernating on the moon's cold surface.

A small elevator leads down deep underground to a massive vault door. Behind it is a cavern easily twice the size of the base that sits on top. It is completly empty (as far as you can see) Except in the middle stand stand 50 rectagonal shapes. As you come closer you see these are boxes. Each is labeled with "Experimental Earth."

One box has a yellowed vellum parchment attached to it. It's barley readable. On it you can make out the following: " Ships log -EMETER. 50 -xes of expe- -arth. Des-ation: Cair- abbey, London Eng-"

Just remembered the base from Space: 1999 was called moonbase Alpha .

Thumbs up for "dug in" solution. Radiation should be considere a problem, just to add SOME "hard" scifi into this unreal 40k universe

I would vote for hydroponic gardens and perhaps an arboreum . Those things provide food AND air, and are thereby very good to have. Plus, a dead space garden makes for a good setting piece to bring about a feeling of death long before the first corpse is seen. An untended garden, with lots of fungus of different kind, is a good red hering in 40k (the characters will think NURGLE immediately). Oh, there is a VERY old scifi horror movie about some fungus infection of the nasty, intelligent kind running rampart on a deep space station [Mutiny in outer space / 1965]

There should be large water vaults as well as giant underground air tanks. A base on an airless moon would be screwed without them, as soon as the first supply vessel comes later then scheduled. Really, go all the way with that in regard to "40K huge", but make sure there are dozens of smaller units separate from another instead of just one huge unit: this makes sure that, if one vault/tank is broken or "infected", not all of the water/air is lost. Series of emptied, linked vaults/tanks make for nice set of room to hunt characters through as well.

With the outside being below zero, water could be kept as artifical icebergs instead of keeping it liquid, so. The turndown is, if you don´t have means to get it in and perhaps speed up the melting by heating it, you are screwed as well.

For energy, there could be large fields of solar panels , either as stand alone or as additional source to whatever kind of reactor you happen to have included.

And yes, it would be nice to hear of your plot

EDIT: Corrected some of my gramma. Sorry for such, folks, I type in a hurry during my lunch break, with sometimes horrible results

Good point about the gardens. I can see them looking more like a gothic greenhouse (as in "The Haunting") than more scientific hydrophonic gardens. (It's 40k after all.)

I'll add a Recyling plant/waste reclamation facility if only because nothing sais "grimdark" than drinking your own urine for decades.* Oh and maybe a trash compactor to recreate the Dianoga scene from Star Wars.

A graveyard ! Now hear me out: The way the imperium rolls (skulls everywhere in architecture?) is that the crews of the stations are probably there for quite a long time. (if not generations) So the valiant crew have the right to buried properly in small mausoleums on the lunar surface. Yes underground catacombs are an option to and make more sense but...

Imagine a graveyard-crater full of ornate tombstones glinting in the harsh light of distant stars, casting stark and deep shadows. Then a small asteroid comes crashing down, smashing the mausoleums and scattering fragments of stone and mangled corpses all over the place, slowly raining down in low G. - Man I love 40k!

@ Nihilius: Oh yeah I also wanna hear about your plot.

* That and an eternity of war in a galaxy devoid of hope )

Oh oh oh! If you are gonna include Gregorius' hydrogarden/arboreum, could you have it crewed by 3 Servitors nicknamed Huey, Dewy and Louie?* (Feel free to make them sound more 40: Huon, Due and Lucius for example)

* Silent Running 1972

No operation like this will come without a Med Bay , and I consider a medical servo skull or servitor to be a must have. This will not be a replacement for a real 40k medic, but still one would like to have one at hand, just in case that the medic needs help with surgery or if it is the MEDIC that had an accident. Plus, players tend to be get very cautious when they enter a Med Bay with a Servitor during the search of a station... they will always expect it to attack.

Personally, I like having Zero G Shafts for movement. In 40K, gravity is artificially generated by some tech-magical plates the floor is made of. If you just leave them out in ONE shaft, that shaft will be Zero G (or whatever gravitiy the moon actually is). If your group isn´t having a voidborn, and nowbody passes an easy(+30) Intelligence test, you can have some fun with the first one stepping in, proppeling himself up unexpectedly and bumping his head. Don´t dish out serious harm, so, that would be to much.

Talking gravity and living in space for a long period of time, you should have a gym in the station. If you life on limited space for a prolonged period of time, you NEED some possbility to exercise, not only for your physical well being but for your mental health as well. Lack of physical activity is known to make you more likely to grow depressiv, and being on a space station can be oh so very depressive. Being on one found in the 40K universe is not helpful here, either.

That being said, you should have a chapel , just for it being 40k to emphasize the role of religion in this setting (the f***ing society is founded on it). Having some smaller shrines in the personal quarter of the crew isn´t bad, either. Make sure to place at least one flail at one of such personal shrines... there is always somebody who feels the need to attone for something the harsh way. ...erm, the right and proper way!

A wall of memory is a nice touch as well, where the name of everybody who ever served here is engraved. A room with a view is good for mental health, too. If that view is an artifical landscape where people can linger and relax off-shift or if it is the literal view of the stars above is up to you.

Talking overall structure , how about having the moon being heavily cratered, with "domes" build in all the craters? This gives you a "hall by hall" approached, linked with narrow, tube like corridors. It makes sense to use what was already dug by astoroids ages ago, as it sparse you a look of heavy digging into solid stones. Well, if the craters are lager enough, deep enough and within reasonable reach of another.

Oh wow! Thanks for the input guys! I had begun compiling a list of location to include, but I think now it just doubled in size. I really like the idea of the gothic hydroponics garden to through the PCs off the trail (suspecting Nurgle) for a while. That is a definite addition. In all honesty, I will probably include just about everything you guys mentioned. I'm thinking of having the surface layer of the base be built into craters as Gregorius mentioned, and then including deeper levels that were mined out of the moon. Perhaps the original function of the base was a mining outpost, and then the tunnels constructed for that purpose were repurposed for other uses. I was actually planning on physically mapping out the entire base and then giving the PCs unmarked copies of the map to fill in themselves as they went through. (If I get the maps done anytime soon I'll try to post them in some way.) Overall, I was aiming at part exploration/part scifi horror for the theme of this investigation.

So here is the plot as it currently stands. (Feel free to point out plot holes or suggestions as well!) The PCs Inquisitor receives a memo that had been sent over 200 years previously to his predecessor, which includes a request for assistance in a suitably cryptic manner to get my players interested. Basically, the overseer of the base suspects some foul heresy at play. Cue PCs traveling to the base.

Now here is the important part: A Rogue Trader was responsible for the initial construction and operation of the base, with the intent of utilizing it for some greater profit scheme. Inadvertently, the moon upon which the base was constructed was the sight of some ancient alien ruins and artifacts deep beneath the surface. These alien ruins/artifacts had a mysterious effect on the mind, driving those who manned the base insane, unbeknownst to anyone.

This is actually where I have yet to nail down the details. I've considered using the Yu'vath (I think their tech tends to do that, right?), but I might make up my own species, unless you guys happen to know of another race of aliens active in the Askellon sector that might have a similar effect?

Continuing on, the Rogue Trader quickly became aware of the insanity rampant within the moon base, but decided to do little to nothing about it (it would cut into his profit margin too much. Besides, people are the cheapest resource in 40k). Operations continued for some time, until some of the laborers started doing strange rituals and such. This was when the memo was sent. Unfortunately for those left on the base, shortly there after mass insanity spread through the bases population, which resulted in the death of everyone on the base (life support was turned off, bulkheads sealed leading to starvation, crew stabbing each other etc.)

Flash to current timeline. A descendant of the Rogue Trader who founded to base hears of the request around the same time as the PC's Inquisitor, and being a contact of the Inquisitor, also hears of the PC's mission to investigate. He does a bit of research on his own (well, his seneschal does) in the family archives, and realizes something serious went down on the base. He then sends a message to the PC's, to "retrieve a critical piece of the bases reactor, that is quite valuable" (the STC template was probably lost for it or something), which he would pay highly for. Unknown to the players, the removal of this piece would cause the reactor to go critical, and explode, wiping the base, the PCs, and all incriminating evidence off the map in one fell swoop.

I'm planning on leaving clues all over the base that mention the Rogue Trader family's name to clue in the players a bit, in addition to having several pieces of evidence (books/memos/something) that state concern about that piece of the reactor and the consequences of its removal. Nearly every member of my party has the mechanicus background, and so they should be able to piece together the consequences of the Rogue Trader's request.

Furthermore, I'm planning on secretly rolling willpower checks for the PCs as they descend deeper into the base, and upon failure I will describe various hallucinations as if they were real, but only to one of the PCs at a time. Overall, my desire is for the PCs to discover the alien ruins, or at least signs of them, and then deal with them any way they see fit. What do you guys think? Would this work? What should the alien race be?

Thanks again for all the input!

I'd say Eldar since their entire race is psychic. Maybe its some type of wraithbone comunication device hooked to a mini infinity circuit (you know the thing the eldar use as operating system/power source/soul storage. And the halucinations are actually the toughts of dead eldar being broadcast straight into their brain. But since its all alien mind stuff and mythological symbolism they have no clue what's going on, and you can literally have anything "happen" to them. Some examples:

Soul of an eldar aspect warrior > The avatar> halucinations of bloody handprints or blood streaming from your fists, feelings of uncontrollable anger.

Soul of an eldar child who wanted to become a harlequin* > Visions of a masked child, uncontrollable fits of laughter, watching your face turn into a blank mask when you look in the mirror.

Eldar Autarch who lost fis life fighting against the forces of Nurgle: Halucinations of slime dripping from the walls or you hear the drone of millions of flies. (This should come in handy for the Hydrophonic-garden-Nurgle-fakeout. )

* you can't have actual harlequin souls in a infinity cirquit.

Sticking with the Yu´vath isn´t a bad choice. They make for nice, creepy, cthullu-style "enemies".

So, I have to say , I am not keen about the RT & Reactor thing you mentioned. No matter how influential an RT is, I never got it why that should mean that acolythes on a mission should be inclined to do him or her favours. Sure, they have a ship, but so does the Imperial Navy, and they don´t need to be pampered to heed the call. Or, a lot less then an RT.

That being said, how about turning this into a "Nega-Dungeon" or "Negative Dungeon"? A place where everything around them urges them to investigate more, but the more they delve into the matter, the more horrible things happen. Note that in this scenario, NOTHING should hinder them from simply getting back to the shuttle and leave. I found that, conversely, the perceived freedom of being able to turn round and leave at any given point actually binds the players stronger then any plot-shackles could bind the player characters.

With your style of plot and structure, the upper levels would be kinda horrible, but just "unnerving". The hints that are there and are pointing down into the forma mine structures are a different matter. Down in the mines, things get more twisted, hallocinations get worse (the effect of the alien artifacts further below), and some clues point more and more to the nature of the things further below. Then, there is this "below" with the actual alien atrifacts present. Here, the mind starts to warp. and the players are up for insanity and will need to turn at some point or lose their mind. To bad that, from this point on, what they steer up there does steer up the corpses they have seen in the "mine level"..and it does not matter if they were hacked to pieces or not.

If you would still like your self-destruct device, how about a DIFFERENT Inquisitor having sealed the lowelst levels (or , his acolytes). How will the PC react if their Inq just told them "find out, leave no stone unturned" and are faced with the sigils of an all different Inquisitor telling them "do not cross"? It is not like they could fly back and ask for more detailed instruction..well, they can, but the story ends there

If this works out as I hope it would, you will have players on your table asking out loud "bedamned..what have WE done!", which is far better then them being gruntled about "what did this plot made us do"

EDIT: Correct some of my messy gramma

On my part, I agree with Gregorius.

I second the Yu'Vath's implication in the matter.