Are Mass Relays inhabited?

Question

When you look at the various depictions of the Mass Relays in the Mass Effect series, they appear to depict them as if they were inhabited by a crew.

http://masseffect.wikia.com/wiki/Mass_Relay

Lighting certainly suggest that there is a suitable environment present in the Mass Relays for organic lifeforms.

Furthermore, when you look at other space stations that do in fact support a crew of some sort, you'll note that certainly are similarities.

http://masseffect.wikia.com/wiki/Lazarus_Research_Station

However, it is never mentioned anywhere, that I could find, that Mass Relays have a crew or a population of some kind.

So, are there people living on Mass Relays? And if they do, does this not cause some problems for some story elements of the Mass Effect series?

Surely these people living there would notice and alert the council of the Geth ships / Sovereign entering the star cluster of Eden Prime (Mass Effect 1), or alerting the Alliance leaders that a massive Reaper fleet is inbound (Mass Effect 3)?

Answer 1

As you said yourself, it is never mentioned anywhere. So you won't get a definitive answer.
At least not until Mass Effect 4 is released or you ask a dev yourself.

I’m going to go with no, however, and I will tell you why.

1. Your assumption is - in my opinion - invalid. Just because something has lights and does kind of look like a space station it doesn’t have to be one. The lights could be pretty much anything and their presence alone tells us nothing.
   Also, similarities are certainly by chance or by influence. Lazarus Station was built by humans. The relays by Reapers who might have followed a totally different design philosophy.

2. If there is a sort of crew aboard the relays, they’re most likely not people. There might be an organic maintenance crew of sorts, but then they are most likely like the Keepers or they are Keepers.
   But if I recall correctly, the Keepers were charged with maintaining the citadel because organics are more comfortable with other organics around. They would not have trusted and relied on a robot crew as much as they do on the Keepers.
   So most likely no organic crew (see also reason 3). At any rate I think the crew would not care at all for what happened in the universe.

3. The Reapers wanted to keep the relay technology a secret as long as possible. So it’s unlikely they would just let people into the relays. The relays are nearly indestructible. So there’s no forcing your way into them if they didn’t leave a door for people to use. Which I doubt.

4. The relays are clearly remotely operated. Ships communicate with the relays all the time in order to inform them of the transit mass.
   The Citadel, as the hub of the relay network, can control gates in the network. In ME Saren used it to close the gates in order to stop reinforcements. Shepard opened the relay again to allow the Alliance fleet to join the fight. So there doesn’t seem to be any need to go into the relays themselves.

5. (The most plausible reason why not, in my opinion)
   The relays are described as cold objects. This means they don’t emit heat or radiation. Being what they are, giant mass effect engines, this is impossible. There must be intense heat and radiation. So, where does it go? It stays inside.
   The Normandy’s stealth systems allow her to “go cold”. But that only works for a limited amount of time because the ship can only keep that much heat and radiation inside until the crew gets cooked alive. That is why the Normandy has to vent heat and radiation after using it's stealth system.
   The relays apparently don’t vent heat or radiation so it’s most likely very dangerous for organics inside the relays. You wouldn’t want live inside a nuclear reactor either, would you?

Answer 2

As revered of Prothean technology as the Counsel races and non-Counsel races were, I would think that the Reapers and the Leviathans would have had some means to keep the Relays from being tampered with. We know that some were activated and deactivated (Relay 319, and the one that led to the Rachni's system), but who would have the means to do so? Obviously the Prothean beacons probably had some idea as to how, otherwise the early pioneers (such as the Asari and Salarians) would probably have dismantled the things to figure out how they tick.

If they are inhabited, something like the Keepers or the Reapers would make sense, as would AI's or even embodied AI's. I can't forsee any organic species living upon them, as the Relays are incredibly old, and it would be a stretch to think that such a species could live upon one without any reasonable logistical support, not to mention some sort of colony for breeding/internments/etc. Plus would each Relay have its own government, or its own Counsel themselves? It is more likely that it is run off an AI with some sort of worker-bee droids or robots for maintenance.

Besides, where did they get all that Eezo? I'd crack one open for the fortune!