It's not dissimilar from mechanics in other games, implicit in my comment is that none of the 3 EV games had any sort of stealth mechanic. (ETA: Actually, they had cloaking devices, but they were special unique items that you couldn't transfer if you upgraded your ship. Not sure if that exists in Naev, I haven't gotten very far into the main story.)
You can go into stealth, and other ships have a bubble around you can see on your radar (the radar is also much better than in EV). If you get inside that bubble you'll fall out of stealth. The size of the bubbles scales with the mass of your ship, so a shuttle or an interceptor can hide very effectively, but massive cargo ships simply cannot.
This makes being a criminal or smuggler much more interesting. In EV there was nothing more to it than being super fast and staying ahead of the patrols trying to scan you. In Naev it's the similar, but stealth gives you more options. It feels very cool to be drifting silently in space, waiting for patrols to move away so you can reach the jump point undetected. Feels more deliberate and clever.
Another cool thing is that the AIs use it too. So it feels much more like you've been accosted by a highwayman when you're a little Terrapin trying to finish a mission, and suddenly pirates appear out of the blue (black?).
So does stealth involve shutting down systems / power output etc.?
I always like a stealth system in space that involved not radiating, as well as avoiding active radar, too many sub sims in my youth :D
My favourite thing about The Expanse was when incoming radar stealth ships were finally identified by their bright drive plumes as they slowed for an attack.
No unfortunately (or not that I've noticed), though you drop out of stealth if you open fire or use your afterburners. It would be cool if you came out of stealth at half power; that would make it pretty costly, since power and power regen are the stats that dictate how long you can sustain your weapons in a firefight (missiles not withstanding).
That's very cool re: The Expanse. Alastair Reynolds, an astronomer turned sci-fi author, explores "weaponized astronomy" a lot in his books, especially the opening chapters of "Inhibitor Phase". Without too many spoilers, there's a ship that cools it's hull close to absolute zero and uses cryogenic gasses for thrust in order to maneuver, so that it isn't radiating IR. And they have to time their operations so that they aren't seen occluding the sun.
Another author who explores stealth in space combat is Greg Bear in 'Anvil of Stars' (the successor to 'Forge of God'). This is nothing like The Expanse, instead the galaxy is a hostile jungle full of predators just waiting for a young techno civilisation (like humanity) to naïvely broadcast its presence.
Jack Campbell's "The Lost Fleet" starts with Dauntless, and is reasonably good at considering light speed issues in combat, tactics, and moving fleets of ships at low fractions of the speed of light, eg .1c
However, if I remember correctly, stealth in particular is not really considered and is dismissed as impossible. Campbell does a good job of demonstrating tactics to hide ships, though.
You can go into stealth, and other ships have a bubble around you can see on your radar (the radar is also much better than in EV). If you get inside that bubble you'll fall out of stealth. The size of the bubbles scales with the mass of your ship, so a shuttle or an interceptor can hide very effectively, but massive cargo ships simply cannot.
This makes being a criminal or smuggler much more interesting. In EV there was nothing more to it than being super fast and staying ahead of the patrols trying to scan you. In Naev it's the similar, but stealth gives you more options. It feels very cool to be drifting silently in space, waiting for patrols to move away so you can reach the jump point undetected. Feels more deliberate and clever.
Another cool thing is that the AIs use it too. So it feels much more like you've been accosted by a highwayman when you're a little Terrapin trying to finish a mission, and suddenly pirates appear out of the blue (black?).