chaos_forge

To go back to the topic of axial tilt . . . I'm 99% sure Kerbin will have zero axial tilt, for the same reason that the orbits of Kerbin and the Mun both have 0 eccentricity and 0 inclination. As the starter planet, Kerbin is supposed to be especially easy to go from/get to. In fact, I would be surprised if the Mun doesn't also have 0 axial tilt. So new players probably won't encounter axial tilt until they go interplanetary, at which case the should be more than capable of handling it. And I imagine we won't encounter really crazy amounts of axial tilt until we go interstellar.

Thank you so much for the translation, @nikokespprfan! It seems like the most interesting new news it has is that there will be some sort of life support system added to the game. I'd guess it'll be more similar to something like the Snacks! mod than to a more complicated system like TAC.

I suppose. I'll believe it when I see it.

I mean, you can certainly try, but it's not really feasible. Celestial bodies are REALLY heavy. See this Scott Manley video for reference:

All you need to define a physical system is an initial position and velocity for each object. Since the system is 3-dimensional, that gives us 6 numbers total: a position and velocity for each axis. The orbital parameters (which you'll notice are also 6 numbers) are just a fancy way to write the same information, just in a way that makes it easier to do certain calculations (like evolving the "on rails" orbit of a planet). So you can define the system however you want in Cartesian coordinates, and then just convert to orbital parameter coordinates, and you're good to go. It's just a coordinate change, nothing else. Heck, you could even define Kerbin as orbiting the Mun for all it matters; as long as you have the right numbers to set up the appropriate initial conditions, it'll all still work out once you start the simulation. Yes, this is how it already works in Principia. The bodies aren't on rails, they just affect each other as determined by the law of Newtonian gravitation. There's no need to have the planets be "locked" in their orbits. They're massive enough (and in stable enough orbits) that the player can't do anything to push them out of place.

Automated supply missions would be pretty great. Designing a fuel station is fun, and designing resupply ships for it is fun, but flying the same mission over and over is definitely not fun. Honestly, I wouldn't super mind if the ships weren't actually flown and the system was completely abstracted: Maybe you have to fly the actual mission once as a proof of concept, but then after that you can regularly schedule (maybe with some awareness of launch windows if necessary) automatic supply "missions" that are actually just the game automatically deducting X amount of funds from your bank and adding Y amount of supplies to your station.

https://www.videogameschronicle.com/features/interviews/an-in-depth-conversation-with-the-creator-of-ksp2/

Orbits around a barycentre are an emergent property of n-body dynamics. Rask is exerting gravity on Rusk, and rusk is exerting gravity on Rask. The combined effect of that is that they rotate around their combined center of mass (just like any unconstrained system). "Barycentre" is just a fancy word for the center of mass of the system. For another example, we can look to the fact that objects in space always rotate around their center of mass. When you build a rocket out of parts, the devs don't have to create a special "center of mass" object for the rocket to rotate around. They just set up the parts to follow the laws of physics and have certain predefined interactions with each other, and it works out that the rocket always ends up rotating around its center of mass. Because, well, that's physics. If you set up a simulation of objects that follow the laws of physics, you get the results that are predicted by those laws.

I have to agree I'm not so sure about metallic hydrogen. I understand, for a gameplay perspective, the dev's desire to have a engine that's a middle ground between chemical rockets and torchship drives like the Daedalus or Orion engines, but those engines are at least based on well-understood physical phenomena, while the material properties of metallic hydrogen are totally unknown.

Technically, the L4 and L5 points are only stable if one of the bodies is approximately 25 times (or more) more massive than the other body. But yes, the L4 and L5 points have the capacity to be stable.

Check out A Slower Speed of Light

Kerbals don't die of old age, they die of rocket crashes. Their drive to pilot incredibly dangerous contraptions is how the population is kept in check.

AFAIK, the most massive part in stock KSP is the Kerbodyne S3-14400 tank, which masses 81 tons when full. If we had a ship made of 1,000 of these tanks, the gravitational acceleration it would exert on a ship only 100 meters away from it would be approximately 0.0000005 m/s^2, or 5*10^-8 g. Simulating the gravitational effect that ships have on each other would not be fun, it would be incredibly boring.

Sure, it's not perfectly accurate, but it's fine enough as a back-of-the-envelope estimate. We're not writing our dissertations here. Yes, and the ice found out and about in the solar system (including in Saturn's rings) is far less pure than the tap water that goes out of your faucet and into your ice cube tray. I know. What you don't seem be aware of however is that Rayleigh scattering is emphatically not the process via which planetary rings are rendered visible. The rings are visible because they reflect sunlight. Every photon hitting your eyes (or camera in this case) was emitted by a solid particle in the rings, not scattered by atoms in a gas cloud. Scattering can only happen when a photon interacts with a free particle of a similar or smaller size than the wavelength of the photon, which the particles in Saturn's rings most certainly are not. If you want to get extremely technical, every object is visible only because it scatters light, since scattering is just defined as just the absorption and re-emission of photons by particles. However, when we use the term "scattering" in a colloquial setting, what we typically mean is elastic scattering, which only happens when photons interact with free particles of a similar or smaller size than the wavelength of a photon. When photons are scattered by particles larger than 10 times the photon's wavelength, the processes can be, for the most part, accurately modeled by the laws of ray optics that we all (hopefully) learned in high school or undergrad. Ray optic phenomena are not comparable to the scattering phenomena that give atmospheres their color. For example, ray optics make certain predictions that the theory of scattering does not, such as "if you see an object, it's because a photon hit it and bounced off." Yes, the rings are somewhat translucent. So is a piece of paper. If you hold a piece of paper up to your face and look up at the sun, you will still see some light shining through it, because paper is not perfectly opaque. However, if you hold that very same piece of paper up to your face when you look at the night sky, you'll notice you don't see the stars, because the capacity to transmit (attenuated) light is not the same as the capacity to transmit distinct shapes, and starlight is several orders of magnitude less intense than sunlight. If you so desire, you may also continue to hold that piece of paper in front of your face when you look at your computer screen, and so save me from this inane debate. Honestly, I'm flabbergasted this argument is still going on. "Planetary rings block the stars behind them" shouldn't be a controversial claim.

3-body is not sufficient for plenty of situations. If you're transferring from Mun to Minmus for example, the gravity of Kerbin, Mun, and Minmus all matter quite a bit. Or if you're flying among the moons of the Jool system, it's quite easy to get into a situation where your orbit is resonant with both Laythe and Vall, or both Vall and Tylo, at the same time. If we go by SOIs, we should consider at least the parent body and every child body: If you're in orbit around Kerbin, you consider the influence of Kerbin and all its moons; if you're in orbit around Jool, you consider the influence of Jool and all its moons; if you're in orbit around the sun, you consider the influence of the sun and all its planets; and so on. But even then, I'm not sure if I find that 100% convincing. The L1 and L2 points are both fairly close to the planet, so I could see a situation where you're in Kerbin's L1 and your orbit should be being affected by Mun, but isn't because of SOIs. On a different note, I've found this page from the Principia Github page that claims that putting celestial bodies on rails wouldn't be that big of an improvement for performance, with the caveat that adding a larger number of celestial bodies or using a different Hamiltonian or numerical integrator might change that situation.

oh my bad, I confused this discussion with the one in the n-body thread

At the risk of moving even further away from the topic, this post on the Principia github claims that putting celestial bodies on rails isn't as big of a performance increase as it would seem.

Low orbits in n-body are already extremely stable, on the order of thousands if not millions of years. There's really no need to mess about with patched conics, unless it's super important to you that a craft maintain an extremely specific orbit down to the exact meter (in which case I'd argue that automated station-keeping is a better solution to the problem than some sort of weird hybrid SOI system). That's already the standard proposal for n-body. Ships have infinitesimal mass compared to planets or moons. No sane person would propose trying to calculate the gravitational effect ships have on each other (or on planets) Another thing is just the simple fact that (as hopefully has been established by now) the SOI approximation simply can't handle the case of two objects of similar size orbiting around their common barycenter. If you want to have that in your game (as it seems the devs do), then n-body is basically your only option.

Yep, that's exactly the case. The rocket equation tells us that the delta-v of a rocket is equal to its exhaust velocity times the logarithm of the ratio of wet to dry mass. Since fuel tanks have mass, the mass ratio of a ship can only ever be at best equal to the mass ratio of the fuel tanks. So, given an engine with a certain ISP and fuel tanks with a certain mass ratio, there is a set maximum delta-v we can achieve. Asparagus staging can help somewhat, but you hit diminishing returns pretty quick.

GR is a generalization of SR, but the case of a ship traveling through interstellar space is perfectly encapsulated by SR, so there's no need to make things more complicated. Quantum mechanics is a generalization of Newtonian mechanics, but that doesn't mean I start bringing up wave functions every time I wanna talk about parabolic motion. It's not that having them closer together would reduce the speed, it's that engines in KSP tend to be less powerful than their IRL counterparts, because things are closer together. So if anything, I'd expect the engine in KSP to be less powerful than the Daedalus engine, not more powerful. Would that expectation not already be established by the simple fact that stars are way father away from each other than planets are?

One more thing: Generally, KSP reduces travel times by making things smaller and closer together, not by making parts more powerful. Engines in KSP actually tend to be less powerful than their real-life counterparts (apart from the ion drive, but that's because you can't accelerate during time warp). So if anything, I'd expect the max achievable speed to be lower than .1c, not higher.

I think the reason people might be getting confused that you're talking about special relativity, not general relativity. Special relativity says that the speed of light is constant and nothing can go faster than it. General relativity says gravity isn't a force but rather the bending of spacetime. As far as implementing SR goes, relativistic effects only really start becoming noticeable at above .5c IIRC. So I don't think adding relativistic effects is necessary, but I also wouldn't complain if they do decide to add them.

Because I bought and paid for a program, so why should I have to ask permission from some company to run a program I bought on my own computer? Just because companies promise to be nice and always let me play it doesn't mean I'm interested in giving up my right to control the software I own, any more than I would be interested in giving up my right to free speech if the government promised to always be nice and let me say what I want. I shouldn't need a reason to not have my rights infringed. Also, most DRM schemes depend on support from the company that created them. Once the company decides it's more profitable to shut down the servers than keep them running, poof you lose your ability to play that game forever. This happens all the time with older games: https://www.vice.com/en_us/article/bjbped/nintendos-offensive-tragic-and-totally-legal-erasure-of-rom-sites Or, for a more contemporary example, what if a game studio suddenly decides their already released game is gonna be on the Epic store now? If the game has DRM, they have the ability to make it so that you can't run a game that you bought and paid for on a different platform without installing the Epic game store client (which sells your data to third parties, in case you didn't know). I wouldn't be surprised if something like this has already happened, and if not I'd be willing to bet it's going to happen soon.

Scott Manley also reacted to the Gamescom interview on Twitter, saying he was surprised they kept the wet noodle physics for rockets in the sequel: There's also the FAQ on the KSP dev blog: https://kerbaldevteam.tumblr.com/post/187123836334/kerbal-space-program-2-coming-in-2020 And finally, PC gamer also interviewed the KSP2 devs: https://www.pcgamer.com/kerbal-space-program-2-interview/

Yes, it does. Generally, the performance depends on how far into the future you're trying to predict your trajectories. If you try to predict too much, things can slow down because the system is essentially having to calculate months' or years' worth of trajectory every second. But generally, you can predict far enough along to execute any reasonable maneuver without taking a noticeable performance hit. Also, solar system bodies in Principia aren't on rails, so in order to make a prediction the system doesn't just have to integrate your ship's trajectory, but that of every massive body in the solar system. Having the planets be "on rails" as they are in stock KSP would, for example, be an easy way to dramatically increase performance (taking the calculation from O(n2) to O(n)) without (at least IMO) having a huge impact on realism, if performance is still something you're worried about.