Wubslin

We should just keep expanding the hypothesized scope of what KSP 2 multiplayer will be until someone stops us or announces details. What's bigger than an MMO?

I have to ask. We're all very fond of waterfall, and I'm sure Chris' joining on has come with a lot of new insight for you guys for how his mod worked - at least from a "getting inside the head of the mod's creator" perspective if not any new technical gleanings. As they say, there are a lot of ways to skin a cat. In terms of technically making the code work, what would you say are the biggest differences in implementing plumes between his solution and your new one? Any particular advantages and disadvantages from each that jump out at you?

Nice! Good to see the team is doing their homework on exhaust plumes and implementing it beautifully. I can't wait to watch nuclear plumes peel away from my spacecraft at a hundred thousand meters per second.

Okay, so this game has been one giant parade of me being made a fool of myself through my own unbelievable idiocy. Did you know that only last night, at the ripe old age of 1,164 hours of playtime on record in steam, did I realize that you can force a timewarp with Alt+. during a burn? I think I need to go to drop by one of those year-round halloween stores and pick up a nice clown wig for myself. Really? Huh. Waterfall has always been pretty intimidating to me in the past, so I'll have to check it out. I know it can't be done in the first game but I hope KSP 2 supports dynamic enough lighting that in certain situations your plume can be seen to be dozens, even hundreds of times longer than your ship. I mean, look what this guy posted on reddit last night after the Inspiration 4 launch: That's a big structure. Vacuum exhaust is nothing short of awe inspiring to me.

Okay wow. That's a lot of Isp, Nert. Just yesterday I flew out to Enceladus using your new engine without one maneuver node and I've expended, what, like 3 percent of my fuel? This thing has like half a million meters of delta-v. Holy smokes, and it looks awesome too. Thing's ridonculous. Also, I hope the KSP 2 devs make reactors that shut down automatically when you're idle for a really long time. Imagine getting all the way out here, and then you do a three year coast only to find you have no power because you forgot to turn the reactor off and it slowly petered out of fuel after all that time. After smashing F9 and having nothing happen, I could almost feel the clown wig descending down onto my head! If only I'd known how dumb 120,000 seconds is I could've dispensed with 95% of the fuel and gotten the mission done via 10 minutes of 5 G burns rather than 100 minutes of 0.5 G burns.

Oh my god, that's amazing! And yeah, if you can direct a completely ionized exhaust via magnetic fields then that would obviously be the best shot at preventing your engines from picking up heat and getting destroyed. I'm not exactly sure where you'd get the current to run those nozzles without an external power supply though. Maybe absorptive surfaces could still be placed near or just downstream of the nozzle such that a traditional Rankine power plant could be run? You would probably want to swap NaK instead of water for miniaturization's sake. There's certainly no making the nozzle from superconductors, considering how hot it gets. Maybe electrical current could somehow be tapped off of moving charged exhaust products? I have no idea, especially considering the exhaust has no net electrical charge. My knowledge of plasma dynamics stops about at the right hand rule. I do agree though that running shield water through the inside-facing walls of the magnetic coil nozzles would be a good idea to prevent overheating and neutron embrittlement like you say. Maybe if you have some extreme pressure of water you can tap off from somewhere then perforations could be added to create a hybrid of the two designs. Who's to say? By the way, have you thought about adding some more expanded, less luminous "cones" of exhaust coming out the back in vacuum to represent where the confinement ends? For such an extreme exhaust I imagine the plasma/gas/reaction mass would still be under an immense amount of pressure as it leaves the nozzle. It would definitely be cool to see that. Maybe even that central exhaust cone could be seen to peel away with its angle of divergence increasing slightly as the gas expands? I don't know how modding works so don't listen to me if I'm not making any sense. Okay, all is well in the world. Don't freak out or anything, but I've had this idea kicking around in my head of a spacecraft that didn't have a single electrical circuit anywhere. Not one blinky light or battery or wire or instance of V=IR or anything. I'm talking life support from Einstein refrigerators that are powered by waste heat from a fission reactor and regulated via an analog computer loop made out of refrigerant in lines. Cockpits with actual accelerator pedals which are mechanical linkages coupled directly to the rotating control rods and LH2 valves in the solid core NTR reactor. Gyroscopic navigation powered by H2 boiloff going into high speed turbines like you might find in a dentist's office. And of course everything needs a brass, steampunk 20,000 leagues under the sea aesthetic. The very first PID controllers to be invented used compressed air to close their control loop. Who's to say that couldn't be done again in three axes to give us SAS authority?

Oh come on. No one? It's obvious. Untitled Surface Colony

Hey, thanks! I'm a HUGE fan of your work, by the way. Seriously, No install of mine ever feels complete to me without the complete near and far future packs. Sometimes I'll spend 10 straight minutes single staging a nuclear salt boat into Low Earth Orbit just so I can admire the plume work and the soft glow of those radiators. Not to mention that without the Heinlein engine, drunkenly tooling around the outer Solar System would have been way harder. The Intercept team is sorely missing out not having you on board.

Actually, on second thought that one's already taken. Back in high school I had come up with an idea for a nuclear powered sniper rifle that was guaranteed not to miss its target when you pulled the trigger. I named it the 'Buster Jangle'.

I dunno, "Chernobyl drive" feels a tiny bit in poor taste to me. Besides, I'd argue it doesn't even do the system justice in terms of power output. If you wanted to do historically inspired names though, U.S. nuclear test cycles always had a nice ring to them. You could call it the 'Ivy King' for the largest pure fission test ever conducted or maybe the 'Buster Jangle' just because that's a super fun name. In keeping with the KSP 1 convention there'll probably be some kind of creature-themed title. What do you call this vacuum ripper of an engine? The only thing that comes to my mind is atomic breath, so my money's on it being called the 'Godzilla'.

Titled Space Craft

Aw man, I was actually in love with the new navball arrangement you guys had set up. I even play KSP 1 with my navball scooched all the way to the left next to my orbital info window, though I do seem to be in the minority on liking it that way. The navball is at least staying on the left side of the screen, right? I'm looking forward to hearing about whatever changes have been made.

Very interesting! Interesting to see the small tweaks that have been done to the flight UI. Looks like the SAS target indicator has been flattened from a 3D shuttle-datum-thing into a simple two dimensional needle. Makes sense to me. Also noted that the devs have abandoned the seven segment display motif. That's a shame, because that was finally starting to grow on me after all. Good to see the roll indicators and semi-transparent backing are still there though.

Thank you! And I don't know how I would take this wrong, considering everything I posted is completely unvalidated and you have simply pointed out this much. Yes, there are a few unsolved questions in the design. For one, it's basically a given that any prompt (aka not kept alive by the decay of daughter products like in modern power reactors) fission reaction is going to be able to propagate through the UBr4 solution far faster than any real turbopump could reasonably move it. This leads to a few things. For one, the reaction will basically climb up as close as it can to the laminar nozzle which will basically be one neutron MFP away. At this distance, the radiative heat transfer to said nozzle will be extreme. One way of solving this problem would be to have the nozzle be ablative and consumable, with a very large length of honeycomb constantly extruding out while the engine is in operation like a thermic lance. Another option would be to take the UBr4 nuclear fuel and mix it with an extreme amount of the dopant responsible for making the normal shield water absorb x-rays. Transport of energy out of the reaction due to x-rays will be inhibited at first, so there's no telling what kind of effect such a design change might have. The third option, which is the option I imagine to be more sensible and one which I didn't write about, is to actually have the stream of nuclear salt water be subcritical on its own and require the addition of more neutrons from an external supply like a gun pointed at the flow. That way the reactivity could be carefully controlled, and also be able to happen further away from the nozzle itself. How you can shoot a beam of neutrons through so much heat and water, I have no idea. Another unsolved problem is the specific details regarding heat transport from the reaction to the shield water flowing through the engine bell. Excuse my language here but to quote the old plumber's adage, "excrements don't flow uphill". Simply put, the highest pressure zone in the entire coolant loop needs to be the exit of the turbopump moving the shield water. In addition, the entirety of the layer of water flowing down through the engine bell needs to be at a higher pressure than the zone lining its inside, so that water will actually exit the pores to receive heat and turn into reaction mass while cooling the rocket. Allowing all of this to happen at the same time as the water turns into basically the stuff that came out the back of the Saturn V and have it constantly be a downward gradient in pressure is difficult, to say the least. Not to mention, the fact that the inner lining of the nozzle needs to have a low enough atomic number and be thin enough that the x-rays skip right over it and absorb into the shield water layer inside means withstanding those conditions will be even harder. The coolant heat injection process is almost like an inside-out nuclear light bulb. Ha, I'm glad it got your attention. By the way, I'm sorry that interview I had with you guys didn't pan out this summer. Suffice it to say, I traveled the other path and now I'm pursuing a master's degree. While doing it I'm actually conducting research for my university that's funded by NASA in support of Orion and Artemis. How cool is that? Anyway, say hi to Shana for me! Edit: My plumber's adage appears to have been autocensored. Shame

Ha, thanks. I think 500,000 seconds might be a bit extreme for these engines. After all, they are in the end thermal rockets that use water as reaction mass. I would imagine these guys have maybe 10,000 or 20,000 seconds of Isp at the very most - the real engine you'd be conducting interstellar flight with would definitely be that Daedalus drive we've been shown. Not that the NSWR engines won't be great for doing flip n' burns between planets in a given solar system, though. Also, AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

Hi all, I've been fairly certain that the unnamed "torch drive" engine that has yet to be announced is in fact Robert Zubrin's own nuclear salt water rocket. For those who aren't aware, the basic concept is that an aqueous solution of an ionic salt of fissile material (usually Uranium) is pumped into a nozzle or reaction chamber where it undergoes a supercritical reaction to create thrust from the water. In short, it's basically an Orion drive except it's a continuous nuclear explosion rather than intermittent pulses. Suffice it to say, there's serious potential for this to be a high thrust and high specific impulse torch drive. That image is via the old game informer interview, by the way. I feel fairly confident this is what these engines are, especially considering there appear to be dozens of little apertures dotting the inside of the engines' nozzles. This "shower head" configuration would agree with what prior to KSP 2 being announced were basically the only two concept sketches in existence for such a rocket engine: Seeing as this is a really cool rocket engine that would deservedly be the brachistochrone-between-planets Expanse drive that we all wish for in KSP 2, I thought I would give some thought as to how I personally would design such an engine. This is my concept for a fully self-propelled nuclear salt water rocket engine. It runs on an aqueous solution of enriched Uranium Bromide, as well as a second aqueous mixture which contains a dopant that is exceedingly good at absorbing X-rays. As opposed to the NSWR engine that appears in Nertea's Far Future Technologies (I love your mod!) and what I expect will show up in KSP 2, this engine requires no external electrical input to run motors. In fact, this engine will actually generate large amounts of electrical current when operating. It 's sort of a cross between the steam Rankine cycle that's likely keeping your lights on this very moment, and the old expander cycle rocket engine. "Now wait a minute", you might ask, "I know a thing or two about the expander cycle! Because of the square cube law, those things can only get so big. And surely a machine that makes a constant nuclear explosion isn't going to be tiny, right?" It is correct that under normal circumstances, at larger scales the expander cycle has insufficient surface area for even normal chemical propellants to be pumped. The key lies in the way heat transport occurs within this engine. Because the fission reaction is hot enough to produce X-rays and the interior of the nozzle is constructed from a material which is relatively transparent to these X-rays, heat transfer actually occurs volumetrically through the thickness of the nozzle channel rather than convectively through only its inner surface. Of course there is no math here but I'm assuming the heat picked up through this process will be enough to expand the shield water into a dry, intense superheated steam. One consequence of the radiative heating is that the inner wall containing the cooling pores must relatively delicate and a balance between the extreme pressures on either side of it are required to avoid collapse. Steam which went into turning the turbine is sent through a bank of radiators - because no spaceship is cool without glowing orange panels on it somewhere. The radiators allow the steam to condense down into a liquid again and be sent back into the shield water pump. One thing I think is worth noting about this concept is that it is very miserly when it comes to dumping material overboard. The shield water which serves to both power the entire engine through turbines and also insulate the engine walls from the furious heat of the X-rays is actually the main reaction mass of the engine. Since the nuclear reaction takes up only a tiny part of the total mass flow rate through this engine, it makes sense for the vast majority of the water in the system to be of the simple inert shielding variety. If we take a closer look at the nozzle itself, you'll see that I've taken a far different approach than what appears in the material we have so far for Kerbal Space Program 2. Rather than support the reaction inside a combustion chamber of some kind or even a more focused nozzle, I feel that the conditions generated by the fission reaction will be too extreme for anything except the slightest deviation from the classic Orion drive pusher plate. You'll also see that, outside of the main laminar flow jacket, shield water is injected normal to the inside of the nozzle rather than parallel to the flow of the nuclear fuel. The intention here is that a sort of "stagnation zone" sets up that ensures shield water does not truly exit the engine until it's hot enough to either repel the steam front developing inside the nozzle walls or else eject out the back at a significant clip. So what do you guys think? I of course am satisfied with the design of the engine as it appears in game now, but I thought this was a fun thought exercise and really got me thinking about the possibilities.

Significant alterations? Like a complete overhaul/rework of the Mohole? I can think of far cooler geology than just a cone shaped divet.

The one fusion drive that we've been shown is the inertial confinement Daedalus drive seen in the original cinematic trailer. If there are others, they haven't been shown. I'm assuming that due to the extremely low acceleration and ridiculous delta-v that this will be the interstellar colony drive of choice. Moving the factories that make the factories, and all that.

I pulled it from a screenshot post on the /r/kerbalspaceprogram discord server, but it's pretty evidently from that year old gameinformer article just judging by the visual communication. The two engines on the right are good ol' UBr4 spittin' continuous nuclear explosion engines complete with reaction mass/shield water spray nozzles lining their engine bells to keep the walls cool and turn hard X-rays into reaction force. Pretty cool, huh?

I can guarantee the original four will be there, and no magnetic sails. Magnetic sails would fail to be effective outside the heliopause and also, are kind of pathetic. How about two different flavors of screaming nuclear salt water rocket?

That would seem to be based on an overdramatic, worst case assumption of a December 31, 2022 release.

Haha, thanks lol. I know fans of giant SSTOs like Stratzenblitz75 will appreciate that

Uh oh, campers! Is that some slightly raised, hilly terrain just downrange of the KSC runway? I sure hope all your future spaceplane designs will in fact have the lift to peel off the runway before it ends. Looks like it might not be so easy to fall off the end and take flight using a miniature dipsy doodle maneuver any more.

Looking good, damn.

Right and now it might not need electric pumps, assuming low flow rates compared to chemical engines the expander cycle may suffice.