Sci fi RPG systems

Stars Without Number is a fun system. Traveller can be a bit complex but the character generation is the best.

Questions since you seem to have experience :)

Stars Without Number looks interesting -- been poking the free basic ruleset PDF. I don't like the focus on psionics and teleportation and other sci fi tropes that are not as hard. If one were to run a zero-psi game, would the system still work?

Which "edition" of traveller have you used, and how do you even pick an edition? Are there inter-edition and inter-publisher compatibility?
- From my limited investigations, I think the modern version from Mongoose is the one to go with
  
  The character generation system is amazing but from my POV its a bit Star Trek instead of Star Wars or the expanse, if that makes sense?
  
  My only experience of it is listening to bits of it on the Glass Cannon so I may have a skewed perspective
- Psionics is the reason there is FTL in the default setting, and also why it's a post-apocalyptic setting. You don't need psionics to travel, like in 40k, but I reckon removing psionics from the setting is taking away some of its flavor.
  But from a gameplay point of view, I really don't think it's a problem. You could probably search the Reddit sub for Kevin's word on it, but from what I recall, it's a non issue, because it's OSR and the game isn't "calibrated" for a particular party, like say DnD3.5. You could always leave psionics in the background, something dreadful and not known to the public, like in Babylon 5 or Firefly. Even in SWN itself, like I said, psionics is the reason for the whole mess the universe is in, so they're definitely not omnipresent, and more likely to be a trouble magnet, if present in the party.
- The easiest Traveller version is definitely the one from Mongoose.
  
  Also, you should check out Seth Skorkowsky’s overview videos:
  
  https://youtube.com/playlist?list=PL25p5gPY6qKVUg6ys5N1oRlsBI7DTByyI

I'm surprised no one has mentioned the expanse rpg. Link

I like Green Ronin, in general, and love The Expanse as a setting. However, I want to be in a homebrew setting rather than in The Expanse. I suppose I should have said that in the original post.

The Expanse started as an RPG setting, which is an interesting bit of trivia :)
- The Expanse started as an RPG setting, which is an interesting bit of trivia :)
  
  I had no idea! That's so cool!
  
  Anyway, it looks like you wouldn't be interested in Firefly RPG either.
- I was thinking use the rule system and home brew the story and setting. I rarely use the written setting for a game system, I don't want to have to become an encyclopedia of someone else's fictional universe, lol.

I recently picked up Scum and Villany which is made to do exactly what you describe. I havent had a chance to run it yet though so the advertised use and actual game feel may be a bit different.

There is also Vast Grimm, a scifi reskin of Mork Borg. It is more locked into its setting than Mork Borg but with the expansion books that just came out it has plenty of options for space combat added in.

I played a Mork Borg one-shot a few weeks ago and didn't like the system at all -- for my playstyle. I think it would be an excellent rogue-like system though, if that was your cup of tea. But that means I probably avoid Vast Grimm.

Scum and Villany may be a good choice -- one that I wasn't aware of. I'll poke it :)

I did something like this with Fate because I had specific ideas about my setting and the aliens, corporations, and organizations I wanted in it. I added some of my own mechanics for ships and stuff, giving them their own attribute tracks and letting players make rolls during space battles based on their position in the crew. It worked well enough for what I wanted, which was more of an action, space opera feel, like Outlaw Star. It won't have a lot rules for all the hard sci-fi stuff you may be looking for if you prefer crunch.

Although recommending a generic system like Fate makes me feel like the kind of guy who suggests GURPs every time a question on a recommended system pops up lol.

Although recommending a generic system like Fate makes me feel like the kind of guy who suggests GURPs every time a question on a recommended system pops up lol.

I was thinking of Fate but decided I'd better not recommend such a generic system, but you beat me to it!

Fate is great with the right players, but it's not crunchy.

We did have a fun little game that was sort of "Shadowrun in space" where we statted up the ships. The players' ship was a stolen evil-fedex-in-space shuttle. It had a stunt "just doing my job" for a bonus to deceive, and "built for bad drivers" to reduce stress from impacts. Fun stuff, but real life ended the group before we got too far.
- We got close to the end, but then everyone ended up moving away. I still have people ask me when we'll finish that because it was so fun, so I really need to go ahead and cut 75% of my planned end game content and then arrange one final online game day to wrap it up. Only issue now is real life, jobs, kids, and time zones...
So, have you tried using GURPS? Hey at least no one has recommended d20 Future yet ;)

I appreciate the recommendation nevertheless. Sometimes it does feel better to roll your own with a basic framework. In so many RPGs, the system and setting are inextricably linked, and disentangling them becomes far to tiresome. (Try playing D&D5e in a non-forgotten realms setting -- as much as you try to avoid references...) Rolling your own lets you start entangled, but in a way that fits your universe.

What're the odds you have some favourite details on what you did that made it feel right for you?
- I am that guy that recommends GURPS, which I'm actually using right now to run a sci-fi campaign. 3d6 is a great system, there are tons of sci-fi skills baked right in, Ultra Tech is a great resource for laser guns and robots and all sorts of fun tech, and there are like half a dozen supplements full of ship stat blocks. Yeah the crunch can be a lot, if you want it to. You can also ignore most of it if you want, or slow-drip it to your players.
  
  I think the broad nature of sci-fi means that, when it comes to systems, your choices are to either find a system that fits the exact universe you're running, or build it piece by piece.
- If you like The Expanse because of the hard sci-fi and you don't know about GURPS Transhuman Space, you absolutely need to check it out. It will blow your mind. Even if since then, the transhuman sci-fi movement has evolved, it's still choke-full of inspiration, imho.
  I dream of combining that setting with Stars Without Number...

I've been enjoying Starforged since it came out. The PDFs are available of course, but it sounds like they're also getting another reprint here in a month or two.

Ah, yet another PbtA sci fi game. Between it and Impulse Drive (from another comment), I have some reading to do. Appreciate the recommendation :)
This needs to be at the top. Starforged is amazing, because Ironsworn is an amazing system. All the influences you mentioned in starting post are also mentioned as influences for the making of Starforged. The only problem I see, is that your focus on mechanical system for the ship stuff.

Ptba is inherently not as mechanical as other meta systems. But I highly recommend checking it out.

Second suggestion would be Stars without Numbers, Crawford is praised for almost every release he does. You can't go wrong for Sci Fi with his system, it offers quite more crunch than Starforged (from my knowledge, I didn't read or play SWN myself!). But it offers, similar to Starforged, amazing tools for building worlds in a scifi setting, which can be used in any other system you might prefer.

You could check out Hyperspace D6. It is a rules light reimagining of the old West End Games Star Wars D6 system. You wouldn't have to use the Star Wars setting for it.

https://drive.google.com/drive/mobile/folders/1LjVQZVHLKtEaJO_XGe8VDRy6IWVk1sKt?usp=sharing

Death in Space is essentially Mörk Borg in space so has enough room for you to decide how hard you like your sci fi

I have been playing Genesys, and I LOVE it. I'm not playing in a sci-fi setting, but the whole premise behind Genesys is that is is adaptable to any setting, and from what I have seen of the system, it would be great for something like that. There are tons of rules for vehicle stats, combat, etc. and it has guidelines for how to design and balance your own vehicles.

If you are interested in making and playing in your own setting I would definitely recommend Genesys.

If you are wanting something with an existing setting that matches that vibe, then I'd first check and see if some of the community made settings will fit that, and if not, then maybe look elsewhere.

There are a ton of community made resources for Genesys on DriveThruRPG and also in a dropbox maintained by one of the community members, and that dropbox has some resources for an Expanse setting and other sci-fi stuff that would be a good starting point: https://www.dropbox.com/sh/raqr7usuzwizglm/AACMnwsNyT5DPHyjokWZwQLOa/Community Content?dl=0&lst=&subfolder_nav_tracking=1

I would also say you should definitely get the core rulebook AND the expanded players guide, as that has tons of good resources and better guidelines for creating vehicles, as well as other useful things. It's really a fantastic GM toolkit.

EDIT: Also regarding the dice, which can be kind of hard to get, they have an app that you can use, as well as charts for converting normal polyhedral dice to the Genesys symbols, and what I personally do is just use the Star Wars dice, which are the same (with slightly different look to the symbols) and are more available, at least where I am.

Check out the Alien TTRPG. Super easy to learn from a player perspective. It discusses ships. But I don't believe there are mechanics for it. Maybe check out FATE? Or the Firefly TTRPG?

Ironically, FATE is probably the best, because it is divorced from setting. But would require some additional work.

Unlike heroic fantasy, there isn't one big sci fi games.

At the moment, I see mostly people playing Alien and Coriolis. I played only a couple of one shots, so have no strong opinion on them. But Alien's tension mechanic is neat.

Eclipse phase has an amazing lore, However, the system sucks, if you like the lore get the FATE of the eclipse version, not even that FATE is great, but it's a functional system unlike the D100 one

Have you looked into Starfinder at all?

Starfinder's more sci-fantasy than sci-fi, no?
Running starfinder now, and I love it... But it is a lot more fantasy sci-fi than the IPs OP mentioned. It's a great "dnd but in space" setting, but it is mostly based on og Pathfinder so it's quite a crunchy system and ship battles can be a slog and kinda unbalanced from a "what each player gets to do" perspective. Really sucks to be the engineer or science officer as far as excitement goes compared to the pilot or a gunner.

We've had good luck with atypical ship encounters though, like trying to chase down and board a ship before they escape or some people are on the enemy ship during the fight. Having to be fast and loose with the rules about ship roles though when you've only got 2 or 3 people on the ship. It feels like it is really designed to have a minimum of 5 people strictly RAW. We've also played with concepts from other systems, like allowing the Bard equivalent to use influencing spells on enemy ship crew despite being wildly out of range (but not being able to use ship actions in the same turn).
My experience as a GM is that starship combat in Starfinder is a bit of a slog. It has loads of cool mechanics but the main issue is that the rules are so different from regular encounters that generally you don’t have much of a chance to internalise them.
- also GMing Starfinder. I love starship combat but it is a slog. Any time my players get into starship combat it is almost garanteed to take the entire 3 hour session if not more. Its difficult for players to switch over to the different gameplay. for my current campaign I ended up just giving them a ship that can outrun just about anything so they wouldnt complain about starship combat anymore.
As others have suggested, it doesn't fit the more grounded sci fi feel. I'd end up having to redo a bunch of stuff. Was rather hoping that a system was just ready to use and get people's comments on it :)

What about Rogue trader? It uses the Warhammer 40k system.

Looking to roll my own setting, and this one is too attached to the 40k universe. Which is awesome, just not what I want. Too much mysticism and woo :)

If you like Altered Carbon then Eclipse Phase does the "you can change your body" transhumanist-cyberpunk-sci-fi thing pretty well. It's pretty hard sci-fi, but that means it doesn't really have much in the way of ship combat, so not sure if it's what you're looking for!

I've played a Fate game set in the Traveler universe with some of the GMs tweaks sprinkled in. It's awesome.

Using extras for certain types of equipment (like power armor); weapon damage rating; scale... You can have a pretty realistic and complete system while still maintaining the narrative focus of Fate.

Of course the more options you add, the crunchier it gets, but you don't need a lot and some things, like scale, only matter if you have a difference of scale at play (say a fighter vs a destroyer).

Mothership 1E is shipping soon. I enjoy the ship mechanics. I’m not 100% it goes where you want it to go, though, because it’s way more grimdark than those series.

I think Traveller is probably your best starting point. You just missed a Traveller Bundle of Holding. From there you’ll have a good foundation to understand other games and how they address different things. MCC (from DCC) and Starfinder (from Pathfinder) are both great general purpose games if you’re looking for a 3.5 feel.

Jovian Chronicles has a good base system that you can divorce from the setting pretty easily. (The same system is used in a planet-bound SF game—Heavy Gear—and an apocalyptic fantasy game—Tribe 8.) It has a pretty simple system for making vehicles which scratches your "statted ships with ship to ship combat" itch.