Jump to content


  • Posts

  • Joined

  • Last visited

Everything posted by Terwin

  1. CKAN can be kind of Jankey, it is recommended to manually install. As RoverDude no longer supports CKAN, it is possible that whoever made the latest changes left out something important(like USItools or firespitter) and so CKAN is seeing a missing dependency.
  2. I think that if there were known technologies that could make a useful SSTO, we would have one by now. Generally speaking you will not find a plausible engine that can give you the dv to get to orbit with a useful cargo fraction in one stage and still have enough thrust to get off the ground. Staging is a way to 'cheat' the rocket equation posted above, by discarding dry-mass that is no longer needed, letting you have multiple stages that each have a high fuel fraction. Each stage you add, just adds another chunk of dv to the existing rocket when you add it to the bottom. The trade-off is that each additional stage counts all later stages as part of it's dry-mass, but a SSTO would need to be much larger than any multi-stage rocket for the same task, so even with huge early stages, staging still makes an over-all smaller rocket.
  3. Looking in GameData\UmbraSpaceIndustries\MKS\ResourceConfigs\water.cfg I see entries like: PLANETARY_RESOURCE { ResourceName = Water ResourceType = 0 PlanetName = Kerbin Distribution { PresenceChance = 100 MinAbundance = 1 MaxAbundance = 50 Variance = 20 Dispersal = 3 } } So if you just duplicated this entry and changed the planet name from Kerbin to Iota (or however it is named in the other config files) then it seems like that should add water to iota with an abundance similar to what you find on the land parts of Kerbin. Be sure to check for a similar config entry in the Galileo planet pack however, as if there are two, I would expect the last one loaded to over-write the previous one, and as the default water is not zero, I am pretty sure the iota water config already exists somewhere.
  4. You need to start with the depot, but aside from that you only need to add enough modules in a chunk to not have any deficiencies. Improving a depot/biome in stages is the intended usage as far as I am aware.
  5. That is only the heat that is deliberately generated by the repulsors, there is generally also waste heat generated by pushing a current through a wire, friction from moving parts, etc (like how computer processor chips need a heat-sink because they produce a lot of waste heat) Unless you are using an open-circuit cooling process, you are probably not ejecting it as part of your thrust pulses. Also, if you are only heating up the air outside of any sort of containment, how are you keeping that heated air from rushing back over your limbs as it expands? How are you getting thrust from the expansion of an external bubble of gas unless it pushes against you(and thus conducts the heat to your suit)?
  6. The problem with this is the price of entry: Self-driving car: someone needs to pay for a bunch of hardware and software development, total cost: similar to the expenditures of a mid-sized business Profit: could be similar to the cost of a full-time driver per-vehicle and still save the customer money(less the cost of hardware) For each car/truck on the road Reformatting urban infrastructure: cost of all existing urban infrastructure to be reformatted+ costs of demolition + costs of construction, total cost: more than the GDP of the entire US for a large town/small city Profit: value of the re-formatted infrastructure - a hefty percentage because the layout is new and the specific property values are unproven For that one urban area. One of these can be afforded by a single medium to large business(or even a focused start-up) with a potentially huge profit margin once it is working. The other is outside of the fiscal capabilities of any individual, small group, or even the US government for each re-formatted urban area, and most of the projects will likely end up having a loss of total value, at least in the short-term. And that is without the on-going costs of public transportation or the problems of 'nail houses/properties'(where the owner refuses to sell or move out)
  7. This is less a suit and more a small pod with arm and leg waldos. Not sure if you can pull your legs into the pod, but clearly you can pull your arms into the pod for operating controls or the like.
  8. For a chemical rocket, the larger the better. The fuel mas increases based on volume, and tank mass only increases based on area, giving a higher fuel fraction the larger you go. While available thrust is also limited based on area, you can always go with a wider diameter to mitigate this. Side-mounted boosters are also a good way to increase thrust-area, even if they may not have as much of a benefit as increasing the diameter. (Falcon heavy shows a good example of this) I am pretty sure that the only reason to have a first stage the burns out within a few hundred feet of the launchpad is if you are limited to pre-existing rocket parts assembled in a lego fashion(like KSP) and your vessel is on a much larger scale than the parts. While w have not yet figured out how to make engines larger than a specific size(thus limiting per-engine output), SpaceX is a good example of using lots of reliable engines in tandem for huge thrust. There may come a point where engine reliability limits your ability to increase the TWR of the engine section of a given stage, but increasing engine reliability can push that point out to ridiculous extremes. No, if you want a pulsed fusion powered engine, you want to make every pulse relatively small(as in grams of TNT equivalent per pulse per engine), so that you can have chamber walls of a reasonable thickness and thus a reasonable twr.
  9. In the release version, you need to have specific transport containers to count for vessel transport capacity.
  10. Compared to a pure-fusion Orion as advocated by that article, a fission Orion is likely a better choice, as it is much simpler. On the other hand, the article was advocating for a deep-space fusion Orion because it could refuel from ice or any other hydrogen source. Should the technical hurdles be over-come, there is the argument to be made that a pure-fusion Orion would be superior to a fission Orion with regards to ISRU. On the other hand, compared to a more realistic use of fusion for propulsion(mini-mag, fusion torch, micro-pulses, etc.) any form of Orion is the lesser choice. A 50g fusion pellet will not have the same out-put as a 100lb fission bomb. Then again, a 100lb fission bomb weighs more than 900 50g pellets, so even if the pellet has two orders of magnitude less impulse, it may still have a higher isp. To the best of my understanding, we have not yet successfully demonstrated a sustained reaction in a tokamak style reactor, but we have demonstrated fusion pulses(NIF). While it would be an awful design, we could theoretically put a NIF style ignition, powered by an on-board fission reactor, to super-heat the reaction mass for a deep space(low-thrust, high ISP) vessel. This would not require anything we cannot do today, so I would argue that a fusion micro-pulse propelled spacecraft is possible with today's technology, but a continuous fusion torch is not yet in our grasp.
  11. Sort of replacing the combustion of a chemical rocket with little bits of fusion? If you have sufficiently rapid small-scale fusion events, that sounds a bit like a fuel-rich fusion torch set-up when running. When using an actively cooled chamber/nozzle, I do not think that the heat is the greatest problem, but the pressure-wave caused by the fusion blast would very much be a limiting factor, as the stronger the blast, the thicker everything needs to be to contain it without popping like an over-filled balloon. Ablative cooling works, so long as you have ablative left, but it does not help much against pressure waves. I think pressure waves would be a bigger issue than straight-up heating.
  12. Fission does not scale down below critical mass, while fusion can scale all the way down to 17.6 MeV (2.8 x 10^-12 joules). The only reason to use a pusher-plate is if you have no materials that can contain/redirect the blast out of a nozzle. As a thin layer of balsa-wood is plenty strong enough to contain the 'blast' from a single pair of hydrogens fusing into a helium, you would need some serious handwavium going on for a fusion powered pusher-plate vessel to make any sense. Because anything less than 42 gigajoules(10 tons of TNT, aka smallest fission bomb yield and roughly 2x10^13 times the size of the smallest workable fusion yield) will attract the giant space-beavers that will eat your crew-cabin, then use the rest of the rocket to build their space-dams.
  13. Why? This gives you all the complexity of pure fusion(which can scale down to single fusion events) with the scaling problems of fission(minimum impulse size limited by critical mass). Instead of a single large impulse every X seconds, do 100 impulses of 1% of the large impulse at a rate of 100 per x seconds. This lets you reduce the strength of just about everything involved by at least two orders of magnitude, greatly reducing engine weight and improving TWR. Take this to the logical extreme and you have a drive that is either continuous or has very small discrete fuel 'pellets' igniting many times per second. Also, with fusion, you do not need pre-packaged pure-fusion bombs, but can instead use the same ignition source and just pump in the hydrogen you want to ignite(possibly in a magnetic bottle or some such). Why would this form of engine create mushroom clouds when other engines that also shoot out super-hot gas do not? There is no huge fireball to ascend into the sky and provide that mushroom shape(unless something goes very wrong, and at that point your ship is no longer reusable). With fusion, you do not want discrete bombs, you have a single reusable means of igniting the fusion that you use either continuously for a torch drive, or for small discrete packages of fuel for a pulse drive. Ideally, your fuel is a large tank of hydrogen that you can refuel anywhere with easily accessible hydrogen.
  14. Also, all of that extra detail is something that should only even exist if it will be a significant plot point. With science fiction, the needs of the story drive everything else. Everyone needs air to live, but how often does a story mention a character breathing? Only when it illustrates or extends something directly important for the story, the rest of the time, it is a useless side-bar that usually detracts from the story as a whole. If pusher-plates come up as a critical dramatic point in the story, then you have pusher-plates, even if they make no technical sense. If they do not serve as a critical dramatic point, then the reader should be completely ignorant of those drive details. If the story requires that an apollo stack can get to alpha centari in less than 5 years, then it can. If the story does not come first, then nothing else matters because no one will read it.
  15. Orion only works in atmosphere if you are ok with melting the whole thing and irradiating your cargo while you do so. (Atmosphere can reflect both heat and radiation, space not so much. This is not even considering the atmospheric shock-waves) All of the hardest parts of fusion rocketry are also required for a pure fusion orion. If anything they are made harder by having more space and an extended pusher-plate between the ignition sources and the ignition target. Fission is generally safer then fission, yes, but you may still have more radiation because your nuclear reaction is not inside of any sort of containment vessel.
  16. I was referring to liftoff, but an atmospheric retro-burn would likely be at least as bad, especially once you get sub-sonic.
  17. And this is why you cannot launch using ORION: anything strong enough to get it off the ground will melt your ship to slag. A pusher-plate will *not* shield you from atmospheric heating.
  18. They are in the save file. But it does not save modules, just the effects of the modules. So you will need to manually reverse the effect of any modules you want to 'remove'
  19. 5th percentile female is 4'11" 95th percentile male is 6'2" Just another place that being a statistical outlier is annoying (6'6")
  20. General relativity says that there is no absolute frame of reference. Everything is only relative to a specific point of observation. I had a physics professor that claimed he would define his house as the center of the universe. It may make some of the math more complicated, but it all works out. It is also just as technically valid as any other possible 'center-point'. That is also how you define an immovable object: that object is your reference point, so no matter if it is closer to Earth or Jupiter, it is still your origin point, and thus, by definition it has not moved.(but the math on the rest of the universe may get a bit complicated if a force is being applied to your immovable object...)
  21. Due to expansion, this would allow multiple objects that are at 'absolute rest' even though they are traveling at close to C relative to each other if they are far enough apart.
  22. You propose a definition of absolute rest to be going at a speed that is the average of your observable universe? Wouldn't that mean (possibly rapid) acceleration every time something left your observable universe? I think I would have difficulty agreeing that a state is 'absolute rest' if I can be pulled out of that state due solely to a very distant object moving beyond my detection range.
  23. To be fair, there may be 100x as many people working on tesla mass energy storage(Tesla wall?) as there are working on Starship, and I cannot see it mentioned in the news, especially here. There was also mention of converting atmospheric co2 into methane for Starship. If we are launching 1000 fully fueled starships towards mars every 26 months, that sounds like a lot of carbon that will be not only long-term stored, but physically removed from earth(some will come back, but I expect that most of it will not once out of earth orbit). I could even see the efforts towards buying twitter as an effort towards trying to prevent/limit civil warfare, especially around his research/production areas.(Assuming he could make discourse more civil on a large social platform that thrives on conflict(conflict increases engagement which in turn increases revenue))
  24. For an observer, they can seem to be moving faster than 300,000km/s, but that is only because as you approach c, the amount of time it takes for your subjective seconds to pass gets longer and longer. If you are going 290,000 m/s, each of your subjective seconds takes 3.9448 seconds for someone at your origin point, giving you a subjective speed of ~3.8c If you are going 295,000 m/s, each of your subjective seconds takes 5.615 seconds for an observer at your origin point, giving you a subjective speed of ~5.5c So you *feel* like you are going faster and faster as you approach c, but only because time is slowing down for you. Of course trying to figure out how this works when your origin point is traveling close to c compared to a reference point then you accelerate to bring your velocity close to that of this reference point, is beyond my simplistic understanding.
  25. Nothing can go faster than c (speed of light in a vacuum = 300 Mm/sec) Cherenkov radiation is due to particles going faster than light in a medium(usually water which is 225 Mm/s). So any particle that is shot though water at a speed higher than 225Mm/s will give off Cherenkov radiation. No need to go faster than c for this.
  • Create New...