mikeman7918

When dealing with speeds this high, it hardly matters what you measure it relative to. My current thinking if I make this mod is that I'll just use speed relative to world coordinates, which I believe Kerbin and possibly all stars will be stationary with respect to. Time dilation, that's what the Lorentz factor would be for. It wouldn't be a full Lorentz transformation. Since I'd only simulate a single frame of reference, what would happen is that the ship would experience less time than Kerbin due to the time dilation it experienced on the way out, and on the way back there'd be no time dilation. No correction is needed because in the way this gets simulated there is never a paradox. And this result would be the same as what you'd expect in real life, give or take a small margin of error. The idea would be to communicate to players why the engines seem to be getting weaker and less efficient, that it's due to time dilation. If players look at this and ask why the crew can travel light years in arbitrarily short amounts of time from their perspective, they can look it up and learn that from the crew's perspective length contraction will physically shorten the journey. But I see no reason to portray that given how much effort it would take to program, nor do I see how you'd even do that from a technical point of view. If you really want a lore explanation, there is a clean one. In KSP you aren't playing as the Kerbals on the ship, you are playing as the space program director back on Kerbin. That is true, but personally I don't see that as a big issue. You'd have to try really hard to even prove that two ships can fly past each other with a relative speed of nearly twice the speed of light. Anyone trying that hard to test the limits of the game's simulation of special relativity probably already understands special relativity. 99.9% of players would never run into a situation where that matters. And from a stationary frame of reference, it's not even a wrong prediction. The main gameplay advantage is that the speed of light would be enforced as a hard speed limit even if the player had arbitrarily efficient engines, doing it in a way that can help players understand why it's impossible. It would lack length contraction, but players would have no easy way of noticing that anyway. It would have only one frame of reference, but that's enough to get the measurable results right. This would make special relativity work in every way that is relevant to a player flying a starship at relativistic speeds between the stars. They aren't driving relativistic trains into barns or comparing clocks as they fly past another ship here, for our purposes just having time dilation applied to all time-dependent aspects of the ship would do the job quite well.

I did acknowledge that in my original post. Applying math to the spiciest confirmed interstellar-class engines implies that you need utterly impossible fuel ratios to reach relativistic speeds. But this might only be the case because the devs deemed relativistic physics too hard to add, so they are relying on the tyranny of the rocket equation to keep us slower than light. There are plenty of theoretical engines that are efficient enough to achieve relativistic speeds though, and it would be cool if the devs could add some. The KSP2 devs themselves probably think so too, I know that Nertea has previously modded in an antimatter torch drive with a specific impulse that approaches the theoretical limit of 30 million seconds which could get to relativistic speeds easily, and he’s one of KSP2’s main concept designers. If this ends up in fact being purely the domain of mods, I do hope to be the modder who keeps these hubristic Kerbals below the universal speed limit. Once the interstellar update releases, I’ll get right on developing that. That’s probably true. Still, it’s a lot of work for a feature that will only be noticed by very few people.

Not really, no. One convenient thing about relativity is that all reference frames will agree on all measurable results, so you only actually need to calculate out one of them. Slowing down universal time doesn't actually make much sense in practice. This is because it won't matter that time on Kerbin is running slower from the ship's point of view, in order to know that time is running slower on Kerbin the crew of the starship will need to turn around and in the process of accelerating they will Lorentz transform Kerbin into the past from their frame of reference such that by the time they return they will find that more time passed on Kerbin than passed on the starship. Simply slowing down time for the moving starship as I suggest would have an identical outcome. Same with any light speed signal sent from Kerbin containing the time, the signal travel time is different in different reference frames due to lightspeed frame invariance and length contraction such that both reference frames agree on what the clock of the starship will be once it gets the message from Kerbin. There is no point in calculating both reference frames, especially for the effort that it would take to overhaul the physics engine to such a major extent. I do like the idea of changing sim speed to match the Lorentz factor of the active ship, but that might add some more complications both in theory and in implementation. The definition of meters and seconds is different in different reference frames, so which one does the navball show as your speed? I do really like the idea of burning an engine for ages and watching as your speed gets closer and closer to 299,792,458 meters per second without ever reaching it, which would be measured from an external reference frame. But then from the ship's perspective that speed would be a lie, if you don't simulate length contraction you would see the distance to a distant star ticking down faster than what your speed says. If you do simulate length contraction it will seem like distant stars spontaneously get closer as you accelerate towards them, and then the distance would tick down slower than what your speed would suggest once you stop accelerating. That's the tradeoff you'd have to make. I think it would just be so much cleaner to have the player camera always operate in the "stationary" frame of reference. Ships at relativistic speeds would just have their clocks slowed down. Length contraction of the ship itself doesn't matter in the context of the game, good luck trying to stage an actual Barn Paradox scenario to prove that it's not being simulated. If I end up modding this into the game myself, this is how I will do it. --- My current thinking is that I will wait until interstellar is released, and if that update does not include any kind of special relativity approximation I will immediately get to work on a mod to add it. I don't know if I'll be able to pull it off, but I'll give it my all and see what comes of it. My ultimate goal is to show that it's possible, and maybe I can convince the developers to implement it. If not, at least there will (hopefully) be a mod for it. Albert E Kerman shall be proven right!

I am obviously not fully in the know about the technical side of KSP2 development, but I have reason to believe that a good enough approximation of special relativity is relatively doable (no pun intended). Doable enough that I want to try to mod it in if the devs don't implement it. It's entirely possible that traveling fast enough to experience relativistic effects may not be possible with the engines we will be getting in the future of KSP2. In the KSP tutorial stream done recently, the example number for the specific impulse of the Crucible was 100,000 seconds. At that efficiency, assuming that number is to be trusted, you'd need an utterly impossible fuel ratio to get near light speed. It may very well be that the tyranny of the rocket equation will be the thing that keeps us below light speed, just as it did in KSP1. But the theoretical limit on specific impulse is 30,570,000 seconds (corresponding to an effective exhaust velocity of the speed of light), and even if the devs don't provide engines which get anywhere near that point the modders certainly will. An ideal photon rocket like that would be able to get to light speed with a fuel ratio of barely over 60%. Plus, it would be a waste to have a whole game where you have realistic interstellar travel between multi light year stars where you don't take the chance to show players why the speed of light is the hard speed limit of the universe. KSP2 would be improved if it showed people what it feels like to hit up against that speed limit. That would be super cool. My proposal is to have a different on-rails model for trajectories that you switch to when a ship goes above some threshold speed, perhaps 10% the speed of light. Below that speed, everything works as it does now. In this high-speed model, trajectories are approximated as straight lines (with gravity being ignored entirely) and time dilation takes effect. The time dilation itself could be modeled in a very simplistic way where the vessel's speed is used to calculate a lorentz factor, and that lorentz factor is used to scale every time-dependent variable on the ship. Engine thrust, fuel consumption, RTG lifetime, electrical power production, electrical power consumption, the speed of converter parts, the rate at which heat builds up and dissipates, all that stuff. Slow the ship down in time relative to the rest of the game. This would have the effect of making engines weaker and less efficient asymptotically as you approach light speed, making it take infinite delta-v to get to light speed just like how it works in the real world. It seems pretty straightforward to me. Which of course in software development means that it will be horrendously complicated at best. But it's worth a shot.

KSP1’s lander can cockpits all had the window facing “down” relative to the control orientation. As strange as this may seem at first, it makes a lot of sense in practice. When I’m coming in to land my craft is coming in engine-first and upside down, this makes the controls the most intuitive to me, since from this orientation the lander’s engine turns to point in the direction of the key I press, and the direction of the window in that orientation matches that of the real life Apollo lunar lander. Another benefit of a downward-facing lander can window is that it makes lander cans work as cockpits for rovers in the way you would expect, which those cockpits are fantastic for. in KSP2, the windows on the lander cans face “up” from their control orientation. Two of them do at least, the new large sized lander can is oriented the same as the lander cans in KSP1 with a down-facing window. There is a certain logic to upwards-facing windows on lander cans since they allow the things to be used as airplane cockpits while looking sensible, but that’s not really their purpose. It would be one thing if KSP2 reversed the direction of lander cans across the board, but it’s inconsistent which leads me to believe that it’s a mistake. The game does have the ability to change control orientations on command pods, but for lander cans none of them allow you to give lander cans a KSP1 style control orientation. If you want that you need to control the craft from a probe core or a docking port, which is a little clunky. In my opinion the lander can control orientations should include the downward-facing window as the default option, an option to make the window face forward for use on rovers, and the current up-facing window as an option for use in planes.

I tend to quicksave a lot. In my current game, I've done it exactly 994 times. I know because the game has kept all of them. Loading the list of quicksaves for my world now hangs the game for multiple seconds, and my game's file is multiple gigabytes. As I continue using the save, these problems will just get worse. At least until now, when I decided to just clear out my quicksaves manually. But the game really shouldn't make you do that. There is certainly an argument to be made that it's both useful and fun to be able to time travel around to any point in your save's past, but I think KSP1 had a better way of doing this in the form of named saves. And though keeping multiple quicksaves is nice, I don't think I need a thousand of them. My proposed solution is to add a setting for how many quicksaves the game will keep, and when the limit is reached the oldest quicksave is deleted to make room. Similar to how the game already handles autosaves. The default number of retained quicksaves could be a large but reasonable number like 100, with the setting to keep all of them or to change the number. Named saves could be retained indefinitely.

In KSP2 some experiments take time to perform and they come with certain piloting challenges like requiring you to stay in a biome or in flight for a certain period of time. Automating that would cause a lot of problems, and generally limit how interesting and gameplay-relevant experiments could be.

I don't know how feasible this even is from a technical perspective. In KSP2, maneuver nodes account for the time it takes you to accelerate. This means accounting for not just your current thrust to weight ratio but also how it changes over time as you burn fuel and get lighter. The behavior of maneuver nodes is different depending on what engine you have and how its fuel consumption impacts your craft's mass. If you think about it, it's not really clear what the intended behavior of this system should be if you have no fuel. The system in place right now where you can't plan maneuvers over the amount of fuel you have makes sense, I would argue.

I found this on Pol during my very eventful Jol-5 mission. Rover for scale. Though you have to squint a bit to see it. This was a fun mission. I ended up falling short on delta-v returning to Kerbin, but with gravity assists I was just barely able to get a very fast Kerbin encounter with less than 100 meters per second of delta-v left. Jebediah Kerman promised he'd bring the crew home, he did not specify at what velocity. I had to launch another ship from Kerbin to intercept the incoming vessel and bring them a landing pod. I also visited the Bop skeleton, the Laythe skeleton, and the Tylo monument in this same mission. Though I assembled the craft in orbit in 9 launches, so I don't think it counts.

Some of the pre-alpha footage from dev diaries have shown larger RCS blocks. It seems they are already in the works. (Look at the left side of the screenshot) I imagine they are not in the game yet mostly because they appear to be the size of a MK1 command pod, and that makes them a bit excessive for anything we can build in the game right now. They do have the massive radial monopropellant tanks in the game already though despite them also being super excessive for anything that exists right now, which is a little confusing. Though some more mid-range RCS thrusters would be nice too.

To be even more pedantic: the KSP2 devs have said that Minimus is not an icy world, but a glassy world. A ceramic planet. They could not justify putting an ice moon that close to the sun. So why do the biomes still call it ice?

I imagine that this will remain the realm of mods. But it would be cool to have a mod for that. Though I seriously doubt this will happen if only for technical and tonal consistency reasons. The first major technical problem is the question of what size to make the Sol system. Is it Kerbal scale, or real scale? Because Kerbal planets are pretty small. The second major technical problem is having a star system with another space faring civilization. How would that look in-game? Humans have spacecraft, so would there be an AI controlling that? Kerbals meeting modern or near-future humans would be some serious scope creep to the game. You could also have the solar system be from the distant past or future, where humans haven't developed space travel yet or humans have destroyed themselves. But the KSP2 devs have a very specific tone in mind for the game, and anything like that would break from it. I don't see how humans would fit the tone at all. The whole reason of using Kerbals instead of humans in KSP is because it makes the tone less serious. Crashing Jeb into the Mun at 2 kilometers per second becomes funny and not a tragedy. Leaving a Kerbal alone in a tiny capsule for a decade is something they don't seem bothered by, but we know that if you did that to a human it would be torture. The KSP2 devs have described the tone of KSP2 as a funny man straight man comedic duo, except that the funny man is the Kerbals and the straight man is the world they find themselves in. The universe is realistic, beautiful, vast, and full of wonders a billion times larger than you; and the Kerbals fall up the stairs into it with the power of pure obsessive perseverance. I don't know how you would add humans into that without breaking that tone and that dynamic.

This screenshot from this old animation from KSP1 is a great example of what I'm talking about: In KSP2 I've done reentries that come in real hot and I've sometimes been a little overzealous with the boosters. The little goobers in the cockpit are sometimes subjected to so many G forces that I've joked that they were compressed into puddles of green goo before reconstituting into Kerbals. But in the actual game they're just vibin'. Maybe panicking a little. Or a lot. But they are not really reacting to the G forces being as high as they are, and that's some untapped comedy potential right there. The Kerbals of KSP2 are fantastic, and the way that they already do react to the direction of G forces is impressive and very fun to watch. Clearly the tech is there to make Kerbals react in more funny ways to extreme acceleration. And it would be very funny if the faces of the Kerbals got all stretched back in silly ways when they are being absolutely yeeted in what is hopefully the general direction of space on a rocket that has about a hundred too many boosters.

I know that this thread is a bit dread at this point, but I had a dream last night that I couldn't not share on this forum. In the dream, there was a rocket that was about to launch and for some reason I thought it was a good idea to sneak up close to it (which I don't regret). I replicated the rocket in Space Agency (a cool IOS game), it looked something like this: The rocket's mission was to launch a rather prestigious mission to put up an interplanetary communication satellite, and it was evidently a manned mission. When I got close to the launchpad, I saw a strange wooden tower about 6-7 meters high and less then 40 meters from the launch pad. There was a ladder on the side which I used to climb on top of the structure to watch the launch. The rocket looked much bigger from up close, looming above me like a skyscraper. Before long the countdown started, and in one glorious bang the engines roared to life. Just the sound alone almost knocked me off my feet. Do you know how you can sometimes feel sound if it's low and loud enough? That happened to me on an extreme scale. The sound was incredibly loud. I could really feel the incredible power of the rocket, and it was AWESOME! As the rocket flew into the distance, I thought to myself "YES! I have finally seen a rocket launch in a dream, I want to do that again in a lucid dream. I will have one interesting story to tell when I wake up. ... Wait a minute, this is a dream isn't it..." At that point I fell backwards to try to stabilize the dream. Everything dissolved around me leaving me in an empty void, I tried accelerating forward to stabilize the dream but it wasn't enough. I woke up and did a reality check confirming that the dream did in fact end.

"Are you telling me that it was not a seismology experiment?" I send a manned mission to Gilly.