How Hard Do You Like Your Sci-Fi TTRPGs?

[CharonsHelper]

I recently came across this - TV Tropes about Sci-Fi Hardness Scale - and I was curious if the taste in TTRPGs is different from other media. I'd guess that most are a good bit lower on the scale due to many TTRPGs being somewhat kitchen sink in nature.

I like stories all around the scale - though #s 2-3 with too much technobabble can get annoying.

Frankly though - I can't think of any TTRPGs harder about a 3 on the scale which are truly sci-fi.

[Knaight]

In practice I've run mostly 3-4 or a solid 5.5 depending on whether I want space opera or science fiction proper.

[CharonsHelper]

In practice I've run mostly 3-4 or a solid 5.5 depending on whether I want space opera or science fiction proper.

Which systems?

[Vitruviansquid]

I don't really see it that way. There are fun 1's, fun 2's, fun 3's, fun 4's, fun 5's.

The question to me isn't what they're trying to be, it's how good they are at what they tried to be.

Whatever it is we play, though, I'd want it to be an actual game instead of the GM and players playing "gotcha" with each other on science trivia.

[Knaight]

Which systems?

Fudge mostly. Generics and I get along.

[martixy]

For reasons unknown to me soft as f... 1.

Which is unusual in that, in all other aspects, I take my sci-fi as hard as I can get it.

[Pleh]

For me, TTRPGs are about fantasy first, science later.

I usually don't give the science a second thought until someone finds it hard to accept the fantasy ( e.g. how does the Rogue Evade the Fireball without moving?). I'll throw down a few pseudo science theories that seem plausible enough to take us there, but I'll drop it like a snake if it inspires needless nitpicking debate about the science (does Shocking Grasp get blocked by insulating apparel?).

Science is always a supporting actor in my games, helping Protagonist Fantasy save the day.

[Kaptin Keen]

I recently came across this - TV Tropes about Sci-Fi Hardness Scale - and I was curious if the taste in TTRPGs is different from other media. I'd guess that most are a good bit lower on the scale due to many TTRPGs being somewhat kitchen sink in nature.

I like stories all around the scale - though #s 2-3 with too much technobabble can get annoying.

Frankly though - I can't think of any TTRPGs harder about a 3 on the scale which are truly sci-fi.

I disagree with the definitions. If the only science you're going to allow is what is known today - it's not science fiction, it's science fact.

Other than that, I've read William Gibson loyally, and he's been moving over the decades ever closer to 'only science found today'. Which is sort of cool, because he's so excellent a story teller that he (and I) don't need anything more speculative.

He's the only one, though. I read hard facts in news papers, and speculative fiction in books.

[Anonymouswizard]

Looking at the SF RPGs that I own.

Rocket Age: ~2. There's actually some decent things in there, especially if you go by the fluff rather than the rules (rocketships seem to be fission torch rockets and while the rules give them set speeds the fluff just has them accelerating for the entire journey). Sure, a lot of the science is wrong, but it's consistent in it's wrongness, both with itself and with it's inspirations.

Traveller: ~3. While you can use the rules for many settings, both the rules and default setting assume a universe harder than Star Trek but with several bits of applied handwavium.

Eclipse Phase: 3.5-4. It'll depend on the exact game being run, as there are some harder and some softer elements, but most of the apparently soft elements are justified leaving mainly wormholes, Asyncs, and the Exurgent Virus (and all three can be absent from a game very easily). In general the more the EV shows up the closer to 3 it edges.

GURPS Space: It flits all over the place, but due to being GURPS it's happeist at a sort of 3-5 level. It expects most groups to eventually give up and just slap reactionless engines on spaceships so that they don't have to deal with delta-v reserves, but still provides decent rules for dealing with reaction engines and how much delta-v you'll need to get into and leave orbit from a planet. There's also a lot of unrealistic technology you can slap onto ships and characters in a softer setting, generally noted by a ^ for superscience, but everything is assumed to work like reality unless otherwise noted.

Transhuman Space: a specific setting for GURPS, and as the page says probably about a 5 or 5.5. Probably one of my favourite tabletop SF setting because of how realistic it feels while still fitting in a few more outlandish concepts.

Shadowrun: with the fantasy elements, 6. Without them it's closer to a 4 or 5, it's just overly optimistic about certain developments.

Eldritch Skies: unclear. The technology isn't gone into in much detail, but it's certainly at least a 4 due to everything seeming to work in a consistent way. There's a lot of out there things, including magic, but there's the implication of it all being related to hyperspace and the energy and intelligences within.


FWIW my favourites are GURPS set to a level of about 4-5 (no shields, ships use reaction drives and non superscience weapons, but there's a lot of stuff like nanofabrication, rejuvenation, and braintaping, and FTL drive exists) and Rocket Age at the complete other end of the spectrum. I also have a massive soft spot for Eldritch Skies, but I use it as more of a level 4 GURPS setting than with either of the actual systems it was published under.

Note that I do require dodging spaceships to spend delta-v reserves, and have things act as close to reality as possible. Because I spent several years playing with fellow engineers and a couple of scientists, and we all found breaking the game to discuss how was really fun, even in a fantasy game (I once asked the GM how the elf's teleport spells worked, he responded that the in-universe theory was basically swapping information between two points).

[Pleh]

I disagree with the definitions. If the only science you're going to allow is what is known today - it's not science fiction, it's science fact.

Nah. Read The Martian by Andy Weir (or watch the Ridley Scott adaptation) and get back to me on that. Colonizing Mars is still a fiction rather than fact, and the entire story was an exploration of established science rather than speculation. The only fiction really was assuming best-case response to a worst case scenario.

[CharonsHelper]

I disagree with the definitions. If the only science you're going to allow is what is known today - it's not science fiction, it's science fact.

Nah. Read The Martian by Andy Weir (or watch the Ridley Scott adaptation) and get back to me on that. Colonizing Mars is still a fiction rather than fact, and the entire story was an exploration of established science rather than speculation. The only fiction really was assuming best-case response to a worst case scenario.

In addition - I figure that it's there partially as a baseline.

[LordCdrMilitant]

Looking at the SF RPGs that I own.

Rocket Age: ~2. There's actually some decent things in there, especially if you go by the fluff rather than the rules (rocketships seem to be fission torch rockets and while the rules give them set speeds the fluff just has them accelerating for the entire journey). Sure, a lot of the science is wrong, but it's consistent in it's wrongness, both with itself and with it's inspirations.

Traveller: ~3. While you can use the rules for many settings, both the rules and default setting assume a universe harder than Star Trek but with several bits of applied handwavium.

Eclipse Phase: 3.5-4. It'll depend on the exact game being run, as there are some harder and some softer elements, but most of the apparently soft elements are justified leaving mainly wormholes, Asyncs, and the Exurgent Virus (and all three can be absent from a game very easily). In general the more the EV shows up the closer to 3 it edges.

GURPS Space: It flits all over the place, but due to being GURPS it's happeist at a sort of 3-5 level. It expects most groups to eventually give up and just slap reactionless engines on spaceships so that they don't have to deal with delta-v reserves, but still provides decent rules for dealing with reaction engines and how much delta-v you'll need to get into and leave orbit from a planet. There's also a lot of unrealistic technology you can slap onto ships and characters in a softer setting, generally noted by a ^ for superscience, but everything is assumed to work like reality unless otherwise noted.

Transhuman Space: a specific setting for GURPS, and as the page says probably about a 5 or 5.5. Probably one of my favourite tabletop SF setting because of how realistic it feels while still fitting in a few more outlandish concepts.

Shadowrun: with the fantasy elements, 6. Without them it's closer to a 4 or 5, it's just overly optimistic about certain developments.

Eldritch Skies: unclear. The technology isn't gone into in much detail, but it's certainly at least a 4 due to everything seeming to work in a consistent way. There's a lot of out there things, including magic, but there's the implication of it all being related to hyperspace and the energy and intelligences within.


FWIW my favourites are GURPS set to a level of about 4-5 (no shields, ships use reaction drives and non superscience weapons, but there's a lot of stuff like nanofabrication, rejuvenation, and braintaping, and FTL drive exists) and Rocket Age at the complete other end of the spectrum. I also have a massive soft spot for Eldritch Skies, but I use it as more of a level 4 GURPS setting than with either of the actual systems it was published under.

Note that I do require dodging spaceships to spend delta-v reserves, and have things act as close to reality as possible. Because I spent several years playing with fellow engineers and a couple of scientists, and we all found breaking the game to discuss how was really fun, even in a fantasy game (I once asked the GM how the elf's teleport spells worked, he responded that the in-universe theory was basically swapping information between two points).

I think the assumption that you cannot neglect the fuel mass budget of your spacecraft is unrealistic. It relies on two of three assumptions: that the maximum delta-v of the spacecraft is very high [which is unrealistic], the range is very short [which is unrealistic], and the weapons are very slow [which is unrealistic].

Also, I don't think spacecraft can dodge. Again, the assumptions under which this would be relevant would be highly unrealistic.

[CharonsHelper]

Also, I don't think spacecraft can dodge. Again, the assumptions under which this would be relevant would be highly unrealistic.

It probably depends upon what's being shot at them. What's the effective range?

And even if you're talking lasers/particle weapons, you could still set up a strafing pattern to be a harder target to hit if the range of the weaponry is far enough that you can be someplace else by the time the laser crosses the distance between you. (Technically x2 that speed since you may already be somewhere else by the time they fire unless they have a faster way of tracking you than looking.)

[Anonymouswizard]

I think the assumption that you cannot neglect the fuel mass budget of your spacecraft is unrealistic. It relies on two of three assumptions: that the maximum delta-v of the spacecraft is very high [which is unrealistic], the range is very short [which is unrealistic], and the weapons are very slow [which is unrealistic].

Also, I don't think spacecraft can dodge. Again, the assumptions under which this would be relevant would be highly unrealistic.

I'm a bit confused as to what the first paragraph means. You talk about neglecting the fuel mass being more realistic (), then give three reasons that have to come together as to why you might be able to ignore remass constraints. Do you care to explain further.

Also, dodging spaceships refers to ships making (pseudo-)random changes in their vector so that aimed beam and dumbfire weapons will be targeting a different place. It is, of course, harder to dodge a missile unless you can get it to exhaust it's delta-v reserve, and as in space the difference between 'missile' and 'ship' is entirely the payload section that might be impossible without exhausting your own (in which case you're now a sitting duck). So preactively dodging, not reactively, evasive maneuvers if you will.

[LordCdrMilitant]

It probably depends upon what's being shot at them. What's the effective range?

And even if you're talking lasers/particle weapons, you could still set up a strafing pattern to be a harder target to hit if the range of the weaponry is far enough that you can be someplace else by the time the laser crosses the distance between you. (Technically x2 that speed since you may already be somewhere else by the time they fire unless they have a faster way of tracking you than looking.)

I guess you could, though I'd hypothesize that that's the factor governing effective range.

Also, a "dodge" is 3-4 discrete maneuvers, so if I was tracking fuel mass I definitely would not allow a dodge action.

[LordCdrMilitant]

I'm a bit confused as to what the first paragraph means. You talk about neglecting the fuel mass being more realistic (), then give three reasons that have to come together as to why you might be able to ignore remass constraints. Do you care to explain further.

Those are the three assumptions that have to come together to create a scenario where you cannot ignore mass.



I may not have worded it well:
The assumption that the specific impulse of the engine is very high is not unrealistic. There are quite a few motors in development, some tested and flight proven, with specific impulses that are quite high, and theorized possibilities that are extremely high. It is by no means hard to assume that in the future we have more efficient rocket motors.

[Anonymouswizard]

Those are the three assumptions that have to come together to create a scenario where you cannot ignore mass.

Huh? It's the other way around, if two of the assumptions are true you can ignore delta-v.

that the maximum delta-v of the spacecraft is very high [which is unrealistic]

If we assume that our delta-v is high enough to, for example, blast off from Earth, accelerate all the way to Jupiter, drop to one mile within Jupiter's atmosphere, leave Jupiter's atmosphere, break out of Jupiter's gravity well, accelerate all the way to Pluto at the furthest point of it's orbit from the sun, have a cuppa tea, and then accelerate all the way back to Earth, then our delta-v budget is probably so big that any individual action won't make a dent in it.

the range is very short [which is unrealistic]

Of course, at short ranges changing your vector enough to make attacks miss is highly improbable, so we can likely ignore delta-v as thrusting will have little affect (barring, of course, attempts by one craft to move closer to or further away from another craft).

and the weapons are very slow [which is unrealistic].

Depends on the weapon as to realism, but to go with slow weapons suddenly delta-v becomes more important because they're easier to dodge, but you only have remass supplies.


So, according to you, you cannot ignore remass when a) the ship has a very high delta-v reserve, b) the range is close, and c) weapons are very slow.

I still don't follow.

[Honest Tiefling]

1-2. I am not a scientist, but I'd like to contribute, please. If a DM somehow could make a harder setting appeal to non-scientists and allow them to contribute to group victory, I'd be impressed and pleasantly surprised.

That and I have a soft spot for zany weird Sci-Fi. Less applied applied phlebotinum and more applied crazy.

[Kaptin Keen]

Nah. Read The Martian by Andy Weir (or watch the Ridley Scott adaptation) and get back to me on that. Colonizing Mars is still a fiction rather than fact, and the entire story was an exploration of established science rather than speculation. The only fiction really was assuming best-case response to a worst case scenario.

I wouldn't say that The Martian isn't sci-fi. But then again, it really isn't.

Allow me to explain: It's essentially science fiction about something that we could do today. It's existing science, it's something that's on the table, something we can - and almost certainly will - do.

In other words, none of the science is really fiction, except that we haven't done it yet. We can, if we so chose. Could have, if the will had been there.

So it's actually more like comtemporary fiction that happens to take place in space.

Now, fictional science can take two forms: Stuff that we can sort of assume will become available - and stuff that's just magic by another name. Or, well, most likely magic by another name.

Lots of typical sci-fi elements - cybernetics, genetics, AI (well, maybe, I don't believe in AI), some weapon tech's, and so on, are things we can see the outline of already.

Others, such as replicators, personal force fields, certain types of energy weapons and so on, are unlikely to ever become real.

FTL takes a special place - to me. It seems a lot of scientists have kinda-sorta potentially viable ideas for how to get there. I dunno. I'm just a salesguy.

[Pleh]

I wouldn't say that The Martian isn't sci-fi. But then again, it really isn't.

Allow me to explain: It's essentially science fiction about something that we could do today. It's existing science, it's something that's on the table, something we can - and almost certainly will - do.

In other words, none of the science is really fiction, except that we haven't done it yet. We can, if we so chose. Could have, if the will had been there.

So it's actually more like comtemporary fiction that happens to take place in space.

Now, fictional science can take two forms: Stuff that we can sort of assume will become available - and stuff that's just magic by another name. Or, well, most likely magic by another name.

Lots of typical sci-fi elements - cybernetics, genetics, AI (well, maybe, I don't believe in AI), some weapon tech's, and so on, are things we can see the outline of already.

Others, such as replicators, personal force fields, certain types of energy weapons and so on, are unlikely to ever become real.

FTL takes a special place - to me. It seems a lot of scientists have kinda-sorta potentially viable ideas for how to get there. I dunno. I'm just a salesguy.

I'm a big defender of the importance of arguing semantics, but in this instance, I don't think the distinction here is particularly meaningful.

[LibraryOgre]

Over-medium.

Using that scale, I tend to be most comfortable about 3... mostly plausible, but with certain concessions to whatever I want to tell.

[Mr Beer]

In fiction I prefer 3.5 to 5.

In games I don't care, I mean I don't like Star Wars particularly but I don't morally object to flying space wizards if we're all having fun.

[LordCdrMilitant]

Pardon me, I phrased it very poorly, let me start over.

The rocket equation states that the change in velocity is equal to the product of the specific impulse of the motor, g₀ [9.80665m/s²], and the natural log of the mass ratio [m_t=0/m_t=1]

deltaV = I_sp*g₀*ln(m_t=0/m_t=1)


I_sp, the specific impulse, is the value of importance. I believe that future spaceships will almost certainly be using high-specific impulse low-thrust motors. In 2017, Ad Astra Rocket Company tested the VASIMR VX-200SS motor, which output 3N of thrust with 4000s I_sp. Ion thrusters can achieve 10000s, and a hypothetical ideal photonic rocket, according to Wikipedia, could get as much as 30000000s. These experimental motors aren't very good for getting to orbit, since they have really low thrust, but they're very good for going between planets. I'm going to go with 5000s _Isp for the following computations.


Let's list off a couple of ship sizes:
Imperial Ultima Battle Barge: 10000m
Imperial Imperial I Star Destroyer: 1500m
United States Nimitz Aircraft Carrier: 330m
Systems Alliance Normandy Frigate: 150m
ISS: 100m

Here's a few potential ranges. I'm listing ranges in seconds, because the speed of the projectile can be from 1km/s to the speed of light, and what's more of interest is how long the ship has to react.
1s
100s
10000s

The percentage of the mass burned as fuel will be equal to the 1-.99998^delta-v. Delta-v can be computed using kinematics as the length of the ship [twice half it's length, which would be the distance it must displace itself] divided by the flight time of the shell.

We can assume that the ship begins stationary, because only the displacement from it's original trajectory is relevant, since the shot can be led.

Therefore, the complete equation for the percentage of the ship's mass burned for such a maneuver is 1-.99998^(l/t), where l is the length of the ship and t is the flight time in seconds.

1s
Ultima: 18.1271%
ISD: 2.9555%
Nimitz: 0.6578%
Normandy: 0.2996%
ISS: 0.1998%

For some of these vessels, this is an extreme maneuver that it would be impossible to make. The stresses involved would destroy them. For those which might actually be able to conduct this maneuver, you'll notice that the mass fraction is incredibly tiny. If you have enough fuel to travel interplanetary distances, this maneuver is essentially negligible.

100s
Ultima: 0.1998%
ISD: 0.03%
Nimitz: 0.0066%
Normandy: 0.003%
ISS: 0.002%

Now, even for the big ships we've basically hit the point where they basically don't care about the mass loss. Sure, the Battle Barge is probably burning yoctotons of fuel, but that's not really a relevant problem.

10000s
Ultima: 0.002%
ISD: 0.0003%
Nimitz: 0.000066%
Normandy: 0.00003%
ISS: 0.00002%

This is really only relevant for the science fantasy ships, because at this point you've also had hours to move to evade the shot.



As demonstrated, the mass loss from a small maneuver is essentially negligible. While you could argue that very little of the ship is fuel, that's a rather unreasonable argument, considering the ship can travel at the speed of plot between planets whenever it wants, which will take a lot more propellant than any small maneuver in combat time.

In addition, I fully expect rocket motors to improve in specific impulse in the future, which will further lower the mass loss required.



By definition, if the I_sp is large then the mass loss is 0. However, given the above computations with near-future motors, is by no means unreasonable to assume that I_sp is large enough to treat mass loss a 0 in a science fiction game regardless of hardness.

[PhoenixPhyre]

As with any game system, playability is more important to me than rigor. "Real" sci-fi does nothing for me in particular--I like fantastic settings in particular, and am willing to give up a lot of physical rigor for that. Even though I can do the vector calculus, I'd rather not have to.

In addition, the "harder" something claims to be, the less I can suspend my disbelief, and so the harder I take any departures from "reality." But that's a personal issue.

[LordCdrMilitant]

As with any game system, playability is more important to me than rigor. "Real" sci-fi does nothing for me in particular--I like fantastic settings in particular, and am willing to give up a lot of physical rigor for that. Even though I can do the vector calculus, I'd rather not have to.

In addition, the "harder" something claims to be, the less I can suspend my disbelief, and so the harder I take any departures from "reality." But that's a personal issue.

I agree entirely.

"The space cathredal flies through hell, and if the Gellar Field fails then everyone gets eaten by daemons," is something that I can nod my head to and go "yeah, that's cool, makes sense." "The Nuclear Damper projects a field of nodes and antinodes that cancels out the nuclear strong force and renders nuclear devices inert," is something that makes my mind and attention to the story and setting come to a screeching halt as I go, "Wait, what? What does that even mean?" Some things are better left unexplained.



The one thing that gets me is when spaceships keep their engines on at full burn to maintain speed, though.

[PhoenixPhyre]

I agree entirely.

"The space cathredal flies through hell, and if the Gellar Field fails then everyone gets eaten by daemons," is something that I can nod my head to and go "yeah, that's cool, makes sense." "The Nuclear Damper projects a field of nodes and antinodes that cancels out the nuclear strong force and renders nuclear devices inert," is something that makes my mind and attention to the story and setting come to a screeching halt as I go, "Wait, what? What does that even mean?" Some things are better left unexplained.



The one thing that gets me is when spaceships keep their engines on at full burn to maintain speed, though.

Yes, especially the bold part. Oh, and the additional part is a WTF all by its own, unless we've repealed (through technobabble, maybe) Newton's First Law (in which case...wow).

[LordCdrMilitant]

Yes, especially the bold part. Oh, and the additional part is a WTF all by its own, unless we've repealed (through technobabble, maybe) Newton's First Law (in which case...wow).

I mean, every sci-fi I've played, read, and watched does that. They could be using a continuous-burn-transfer, I guess.

It's because of naval tradition, and that way captains can ask for things like "flank speed!" It's also a visual cue to viewers that the ship is moving, since the engines are glowing.


It's also the same reason that starfighters roll over when they dive like SBD Dauntlesses, and bombs fall from the underside [or arc downwards towards their target] during bombing runs. In general, for big things Space is an Ocean and they behave exactly like a navy ship, and for small this Space is Air and they behave like a plane from a WWII movie.

[PhoenixPhyre]

I mean, every sci-fi I've played, read, and watched does that. They could be using a continuous-burn-transfer, I guess.

Yeah, "Inertial dampeners" are a necessary part of any but the slowest space-oriented sci-fi. Space is just too stinking big otherwise, at human-accessible accelerations. I'm fine with it, as long as it's waved away and the rest of the setting isn't too obnoxious about realism otherwise.

If they're using continuous-burn-transfer orbits, then they must have reaction mass to burn (or be using something like an ion engine, which poses its own set of issues).

[LordCdrMilitant]

Yeah, "Inertial dampeners" are a necessary part of any but the slowest space-oriented sci-fi. Space is just too stinking big otherwise, at human-accessible accelerations. I'm fine with it, as long as it's waved away and the rest of the setting isn't too obnoxious about realism otherwise.

If they're using continuous-burn-transfer orbits, then they must have reaction mass to burn (or be using something like an ion engine, which poses its own set of issues).

I don't think inertial dampeners has anything to do with it or anything. I think it's just technobabble that one author used one time and everyone latched onto, I'm not even sure what they're supposed to do.

I was talking about that earlier. I actually think it would be more reasonable to assume they're using an ion engine or than a conventional engine.

[CharonsHelper]

I mean, every sci-fi I've played, read, and watched does that. They could be using a continuous-burn-transfer, I guess.

The Kris Longknife novel series doesn't.

Well - technically they do continuous burn, but at the halfway point they flip ship to start to slow down.

No inertial dampeners or artifical gravity - the in-ship gravity is due to the constant acceleration/deceleration. They make a point of the smaller warships being crewed entirely by younger crews who can take being banged around at 3gs while dodging incoming fire.