Setting Jam: Hyperbolic Trajectory

[PTTG]

I've been really hankering for a hard-ish science fiction setting. What I mean by that is that it avoids the obvious pitfalls of softer sci-fi, and adopts the aesthetics of real diamond-hard "speculative engineering," but is ok making assumptions where convenient to allow the story to proceed. The Expanse is a great example, as is much of The Andy Weir ouvre. For visualization, see SAVAGES, The Lunar War, and Mare Ignis. Transhuman space is cool, but we're going back to the drawing board and taking a fresh look at everything, and probably looking at an earlier time period.

If you have the same craving, please join in! Ask and answer questions, and please quote. We're going by SCP rules: there's no canon but try to yes-and previous ideas.

Some non-binding general thoughts before we begin: in keeping with the themes, there's no FTL, artificial gravity, force fields, or handheld laser pistols. More recently discredited tropes are hyper-performance rockets (no acceleration above 2G is likely), hyper intelligent AI (intelligence explosion takes time and has limits), and magical nanotech (waste heat and energy storage). Any exceptions should have some rationalization, and ideally point to major adventure seeds. And finally, I would like to avoid individual modern nations having an identity in the game. Ideological factions is great, but nations should exist in the background to avoid casting any players as the bad guys.

Ok, that all done, here's some starting questions:

Where and when is this set? What are the borders of the known?
What's an important group in the game?
What's a good character background?
Why might 2-5 people find themselves in control of a spacecraft?
What's a rumor someone might hear?
What's something common now that's rare in-universe?
What's the solution to the Fermi Paradox, or is it as mysterious as it is now?
Who is a powerful individual NPC?

[whswhs]

I don't feel that I can take full part in this discussion—I find collective design an alien idea—but I'll talk about some of my thoughts for my recently proposed GURPS campaign, Trucking (though that was set in a further future). Specifically, I was thinking of it as a safetech future, especially with regard to biotech, so much so that they look back at 20th century pharma and are appalled.

* No use of oral contraceptives, on three grounds: they're excreted into the water and mess up fertility in many animal species, they alter mate selection preferences in humans, and they're historically associated with a fertility crash that caused massive economic disruption and evoked fears of human extinction

* Minimal use of psychopharmaceuticals, which characteristically have unpleasant side effects and which are seen as only palliative (the brain resets itself to compensate for them)

* General avoidance of medical treatments that prolong the final days or months of life when a person is disabled and in chronic pain

Taking this as a bioethical outlook produces some interesting cultural differences. I wasn't going to focus on it primarily, but I anticipated thinking of other implications over time, had I ended up running that campaign.

[PTTG]

Totally sounds like a faction that could be pretty widespread. How do they feel about cybernetics, particularly neuroprosthesis? (I'm skeptical of brain enhancement, but direct neural control of limbs and senses seem like a sure thing eventually.)

[Anthony]

Originally Posted by PTTG

More recently discredited tropes are hyper-performance rockets (no acceleration above 2G is likely)

I would point out that acceleration above 2G is not hyper performance, it's routinely exceeded by missiles. What we lack are solutions that are both high thrust and high specific impulse, despite various theories, we're still using LOX/RP-1, which is about a seventy year old fuel mix.

[PTTG]

Good point. Large spacecraft with crew are not likely to have greater than 2G, but projectiles certainly can.

[Outlaw]

Originally Posted by Anthony

I would point out that acceleration above 2G is not hyper performance, it's routinely exceeded by missiles. What we lack are solutions that are both high thrust and high specific impulse, despite various theories, we're still using LOX/RP-1, which is about a seventy year old fuel mix.

True, but keep in mind that, in space, there is no aerodynamic control so all course corrections require ejecting mass, so much more mass is required (or much less use of available mass). Of course, this does not preclude very high accelerations but they would have to be over shorter intervals to manage fuel consumption and allow course corrections all the way to impact. Granted that, in the short range encounter it would be less problematic but see below for other issues related to range.

Without energy weapons, combat in space is not practical. Just look at the PDCs in Expanse. I imagine them comparable to modern day Vulcans and/or GAU-8s spitting out 4,000-6,000 RPM of 20mm-30mm rounds that will not stop going until they hit something. 0-infinity years in the future the rounds designed for penetration will still be cruising around the universe at near muzzle velocity.

And don't forget all the debris from weapon impacts. Nothing is stationary in space as everything is in orbit around something and, thus, must follow the physics of orbit. Potentially every hit on a target could require a course correction on the firer's part to avoid the debris. Close range combat is probably near suicidal for all combatants. Think of the movie "Gravity" as a reference.

Additionally, any weapon discharge that ejects mass will require the expenditure of fuel to remain in the same orientation and/or velocity pre-firing. It would have been really cool in the Expanse if, every time they launched something the external shots would have shown the RCS jets going off all over the ship.

--Outlaw.

[Outlaw]

Originally Posted by PTTG

Good point. Large spacecraft with crew are not likely to have greater than 2G, but projectiles certainly can.

If you're talking about humans, 2G is absolutely crushing for anything but relatively short intervals. You certainly could not function/perform tasks under that acceleration for very long.


--Outlaw.

[ericthered]

I mean, you're letting me decide an awful lot, but I suppose we have to start somewhere.

Where and when is this set? What are the borders of the known?

In the solar system, with a focus on "extended earth orbit": The moon, the L5 and L4 points for the moon earth system, the L5 and L4 points in the earth sun system, and earth's orbit in general.

The time period is 2525, 500 years from now. Probes have been sent to all the reasonably close stars and sent data back, and a number of colonies have been sent out to nearby stars... maybe a few of them even made it there.

Adding a question:
How do people get stuff off of earth into space?

[Comrade Ishmael]

Originally Posted by PTTG

Mare Ignis

Another Mare Ignis enjoyer? Literally dozens of us now!

If you have the same craving, please join in! Ask and answer questions, and please quote. We're going by SCP rules: there's no canon but try to yes-and previous ideas.

What's the solution to the Fermi Paradox, or is it as mysterious as it is now?

Unless the setting is edging heavily into horror, like Eclipse Phase, I generally like the solution just being "intelligent spacefaring species only come along once in a supercluster".

[Anthony]

The solution to the Fermi paradox, given the prior assumptions, is "type-II and type-III civilizations are impossible, and our detection range for type-I civilizations is really short".