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About Three_Pounds

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    Pedlar of Space Nuts

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  1. Thanks for the tip. I have used the solver in the past for other purposes and found that it had problems converging but since this is a much simpler task maybe it can stand up to it. I'll give it a another go. This going a bit OT but do you know if there is an equivalent to the atan2 function from the script above? I wasn't able to find it. EDIT: Never mind. I am using a non English version of Excel and they gave it a really stupid name. So behold, it's actually working. The solver can even handle negative numbers, which I didn't expect. Yellow are the input fields. To convert M to ν, I let the solver find the value for E and it spits out the true anomaly.
  2. Yes. By editing the safe file. You have to look into one of the bottom most scenarios called FLIGHTSTATE{} and find the craft in question. It's best if you replace the entire vehicle definition with one from a modified craft you just launch for that very purpose. Alternatively, you can do the second thing you described and put the vessel you want to dock onto the launch pad and then replace the orbital information in the save file with the orbital information from the first craft changing just the mean anomaly. They'll be in the same orbit after you load the file, just separated by the number of degrees you chose.
  3. Oh, that's the easy part. Try doing the reverse and you'll quickly see that there isn't a closed-form solution. After I realized that I would have to build some sort of iterative root-finder into the beloved excel spreadsheet that does the usual heavy lifting, I gave up and decided to pray to the Kerbal god of celestial mechanics coliqually known as @wile1411 to expose a function he's most likely already built into the tool to the user interface.
  4. There is an astronomy focused stack exchange? Oh well, there goes the rest of my free time. Thanks for the link. Your wording wasn't harsh at all. I was just afraid you meant that "NASA does what it does and that's why it just works. No need to question it." After all, they also put their pants on one leg at a time. They might have the better tools, experience and better understanding of the maths behind it but at the end of the day, trajectory design isn't magic. It's just very, very complicated around Saturn because of the unbelievably complex orbital perturbations.
  5. I normally don't do feature requests, but there really is something I absolutely want. Can you include a panel in the astrodynamics calculator that takes the one of the different anomalies (true, mean and eccentric) and spits out the other ones? I tried implementing my own but it's actually non trivial and I don't want to rely on a random web based tool.
  6. No actually, that's brilliant. I want to highlight this: That can't be a coincidence. The first sentence is actually new info. Thanks a lot. I think that even solved my question.
  7. I see it this way. If someone tells you something you don't know anything about, it normally just flies over your head and you learn nothing from it. If someone says something you're very familiar with and it makes sense, fine. But if someone tells you something that should in theory make sense, but as you try to comprehend it, it makes less and less sense, you become intrigued. This is normally where you learn the most. As I try to understand the finer points of celestial mechanics and see the masterpiece the trajectory designers have created for the Cassini-Huygens mission, the visualization of which they affectionately call the yarn ball, my heart jumped. As KSP doesn't model anything beyond the very basics of orbital mechanics, I'm struggling to get an intuitive understanding for these kinds of things. I am looking at principia again as a learning tool.
  8. Personally, I'd prefer if they were following stock conventions. If I ever need to attach something in a wild way, I can always use Editor Extensions Redux to make this happen. Normally, when modded parts try to break the mold with attachment rules, they usually become buggy and clunky to use. Not that would ever be a problem with your parts, but a few examples from other mod comes to mind.
  9. I'm starting to think this might have something to do with Titan. The trajectory designers used it extensively for plane changes in the several hundred flybys they've made over the years. Maybe you are right, @YNM and they use the precession actively to track Titan in it's orbit. So if they were in a higher inclination, the precession would slow or even stop and an encounter would somehow cause the periapsis to shift into the rings. I guess that's what the trajectory designers told the scientist, who obviously were asking for a higher inclination and this statement has come out as a result. The only explanation I can see at this point.
  10. The rings are rotationally symmetric, aren't they? So how would a changed argument of periapsis put the space craft into a collision orbit. Links are never annoying, even though I know of that perticular document already. What exactly is it that you want me to read again? This is closer to the answer I expected, thanks for the input. But again, I don't see how Dr. Spilkers remark is related to that. As am amazing scientist as she is, her job is not trajectory design and I am starting to think what she said there might have been a bit imprecise and makes my head spin as a result.
  11. I always thought that apside precession essentially changes the argument of periapsis, not the periapsis itself. But I guess it has something to do specifically with Saturn.
  12. I just posted this to reddit, but I figured you guys are even smarter so I expect to get even better answers here. So here it goes. The title sounds awfully specific and rightfully so. I was watching an awe-inspiring talk about the cassini probe and it's mission around Saturn. One of the statements made by the awesome Dr. Linda Spilker confused me a little bit as I lack the proper understanding of advanced orbital mechanics to appreciate it fully. I was hoping someone out there smarter than me can shine some light on this issue and point me to the right direction. Here is what she said. Source: (at 56:37) The first thing I am unfamiliar with is the relationship between inclination and apsis precession. Secondly, what does she mean by "putting us into the rings"? Does she talk about the orbital plane or the perichron? And how does precessing fit into any of this - I always thought it's just the argument of periapsis that changes. Can someone explain?
  13. No, there isn't.
  14. I am not sure why you don't just balance them yourself. If you feel the engine is underpowered, just make it more powerful by all means. You even have an engine you think closely resembles what you want. Just model the stats after it. You can even turn this into a MM patch that you then share with all of us. It would be a hell of a lot more productive than arguing with blackheart612 over something they clearly think differently about.