egg changed the topic of #principia to: Logs: https://esper.irclog.whitequark.org/principia | <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/ | <egg> calculating the influence of lamont on Pluto is a bit silly…
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<discord-> l​pg. — hm, I think I'm now encountering pleroy's version of #2957 (game hangs when deleting flight plan). hurry up new moon
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<discord-> l​eudaimon. — Yeah, I'm getting that as well
<discord-> T​heSquirrelPatrol. — Not sure if this is a Principia issue or Mechjeb. I set up a flight plan and manuever in Principia, then go to the Mechjeb Manuever Planner and "execute next principia node" So far so good, but I notice two things: 1: it really wants to warp, stop, reorient to node, warp again, stop, reorient, warp again... Is there some way to stop that? And more importantly, its displaying the node tim
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<discord-> M​arsu. — That’s expected. Principia don’t know the spoolup time for the engine to ignite. So it assume you will burn full thrust immediately. You have to fine tune after the burn.
<discord-> M​arsu. — And for the rotation it’s normal too I think it has to do with how Principia managed the rotation of the craft in space
<discord-> T​heSquirrelPatrol. — Well the problem is, often the vessel loses node tracking with hundreds of dV left and starts letting the course go wherever, and suddenly I've got a huge problem to fix
<discord-> M​arsu. — I usually kill rot seconds before the end of the burn time to stay in line and fine tune
<discord-> C​risti. — I also start the RCS manually for ullage 2 seconds before node execution
<discord-> B​utcher. — Ideally you want to start the burn slightly before the principia start time - 2.5s for pumped or 0.9s for pressure fed seems about right for me.
<discord-> B​utcher. — Also I start ullage 8 seconds before hand as sometimes it takes a while if you have weak RCS.
<discord-> T​heSquirrelPatrol. — Is there some way to tell mechjeb to do that? Or are you just back to doing it by hand?
<discord-> T​heSquirrelPatrol. — My main point here is that there seems to be principia-mechjeb integration, but it doesnt work very well
<discord-> B​utcher. — I do it by kos scripting.
<discord-> l​eudaimon. — Yeah, unfortunately the mj node execution doesn't work great...
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<discord-> e​gg. — node time = burn start time with Principia.
<discord-> e​gg. — It works poorly with RO, because it’s all open-loop. Solving this will probably take @XKdiver a few years.
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<discord-> S​tonesmile. — Just starting the burn the correct time before the node time gives you a very accurate result
<discord-> e​gg. — yeah; MechJeb not knowing about spool-up is the main source of the problem here; the lack of closed-loop guidance just means it cannot compensate for the things it does not model
<discord-> l​eudaimon. — Yeah, even if it got the timing wrong, things would be fine if it went for total impulse instead of the times given
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<discord-> S​tonesmile. — @Butcher IIRC you use a fixed spool up time for PF and HP engines? I think I have figured out a good calculation for the time; `~0.414*ln(sqrt(massOfEngine*maxThrust^2))`
<discord-> S​tonesmile. — @Butcher IIRC you use a fixed spool up time for PF and HP engines? I think I have figured out a good calculation for the time for PF; `~0.414*ln(sqrt(massOfEngine*maxThrust^2))` (edited)
<discord-> s​cimas. — That magic number 0.414 is suspiciously close to `1 - sqrt(2)`...
<discord-> B​utcher. — @Stonesmile Yes I use a fixed time, because iirc so does RF. 😉
<discord-> S​tonesmile. — I thought so too, but I tested some times today, and they all had different times; seems like that has been fixed in a RF version I use
<discord-> B​utcher. — It was empirically determined for a number of engines such that starting N seconds before the principia burn gave the correct results, I didn't notice a significant difference between engines.
<discord-> S​tonesmile. — Yeah, I came to the same conclusion, but when I re-ran those tests today, I got different numbers 🤔
<discord-> B​utcher. — I mean there is this, `responseRate = (float)(RFSettings.Instance.throttlingRate / Math.Log(Math.Max(RFSettings.Instance.throttlingClamp, Math.Sqrt(part.mass * maxThrust * maxThrust))));` which correlates with your calcs.
<discord-> B​utcher. — Possibly everything was hitting the throttling clamp and it's changed recently.
<discord-> S​tonesmile. — Yeah, I think that might be the case
<discord-> B​utcher. — throttlingRate is 3 for RO, and clamp is 1.1
<discord-> B​utcher. — mass will be in Mg and thrust in kN I assume, so that gives for instance 3/3.32 for an RL10 and 3/10 for an F-1. That would mean the RL-10 spools in about a second which is definitely not what I was seeing.
<discord-> S​tonesmile. — The number we are interested in is time that results in '100% at t-0', not sure how that relates to those numbers
<discord-> S​tonesmile. — The number we are interested in is time that results in 'as if 100% at t-0', not sure how that relates to those numbers (edited)
<discord-> B​utcher. — I modelled that as half the area under the curve during spool up. Seemed to work.
<discord-> e​gg. — OK, let’s try this.
<discord-> e​gg. — Some here may remember discussions with SirMortimer *et al.* about the idea of having the player do orbit and mission design (instead of « put this sat on that orbit » career and « activate this device between this and that altitude over a forest » science, something closer to real-life requirements like « give us images of this area at that resolution in this wavelength, and do so this ofte
<discord-> e​gg. — Below is a prototype. It is not a career mode mod, it not really playable (it is more like early-days Principia ; things are not even persisted in the save file), but it should allow for some toying with mission design, which so far has not really been part of KSP (even with RP-n).
<discord-> e​gg. — Consider this as a sort of « mission design exercise/problem set » rather than something self-standing.
<discord-> e​gg. — **IMPORTANT** : make a separate install for it. In that install, you should NOT have Kerbalism (the download includes a dev build of Kerbalism 4) or ROKerbalism (which is not Kerbalism 4-compatible). Play on sandbox, NOT career. You may play with or without RSS/RO, with or without Principia (obviously I mostly have RO+Principia in mind, *e.g.* some of the informations given by the orbit analyser are
<discord-> e​gg. — Feel free to cheat your satellites into their orbits (or launch if you enjoy launching; but this is not really the point of the exercise).
<discord-> e​gg. — Performance is likely to be abysmal at high time warp. In any case, time warping over 100’000× will mess with things; avoid that (if the imaging map gets silly, you can press the « Reset » button to clear it).
<discord-> e​gg. — I am NOT looking for bug reports, merely for interesting solutions that you may come up with.
<discord-> e​gg. — When you start the game, you should find an Imaging window with a map of the home planet (it cannot be closed; I did mention this was a barely-usable prototype). You will find in the Science parts something called VIIRS (it may be marked non RO; disregard that). It is an imager in 1 μm infrared with a power consumption of 240 W. It needs to be turned on in the part action window before it starts imag
<discord-> e​gg. — The map will then show the areas that have been imaged with a 10 km resolution, with freshness: currently imaged, within the last 3 hours, within the last 6 hours.
<discord-> e​gg. — The goal is to get sustained full-earth coverage with 6 hour freshness (this is the sort of thing you need to feed a weather model).
<discord-> e​gg. — This will require multiple satellites. You will see, for instance, that a GEO sat will happily image most of a hemisphere, but it will never cover the polar regions: its resolution is too low there. An LEO sat on the other hand will have a smaller field of view, and will be in the shade for most of its orbit (unless it is in a crepuscular orbit; but you cannot get 6 hour freshness just with crepuscula
<discord-> e​gg. — Bonus question: how do you get down to 3 hour freshness?
<discord-> e​gg. —
<discord-> e​gg. — Please post your solutions here.
<discord-> D​amien. — @egg does the dev version of kerbalism need any specific KSP version?
<discord-> e​gg. — I believe this should work on 1.8 through 1.10; I have been using it on 1.8.
<discord-> D​amien. — cool. I think I'm still on 1.8 because I've not played for a long while but this has piqued my interest
<discord-> e​gg. — (Also note: downlink is not modeled at the moment. This would obviously be a design constraint in a more fleshed-out version of the mod; Suomi NPP has a 300 Mbps downlink for instance—but that would also require changes on the RealAntennæ side.)
<discord-> e​gg. — (This being thermal IR, solar illumination is irrelevant; future exercises may incorporate it, as well as sunglint, etc.; but I am starting with something easy both to implement and think about here.)
<discord-> v​evladdd. — RealAntennæ🤔 hmm I like this
<raptop> egg takes his solutions to the Чебышёв problem very seriously
<discord-> D​amien. — Ah, solar illumination not being required helps a lot
<discord-> l​pg. — I missed the "infrared" part at first reading; I was wondering how 6 hour freshness was going to work 😛
<discord-> S​tonesmile. — I tried putting my cat to work on Eggs bonus question; he got tired
<raptop> caaat
<discord-> M​arsu. — Which version of Harmony should I let ?
<discord-> S​tonesmile. — If it needs an independent version of Harmony, then it should be Harmony 2 I think (what other options exist? 🤔)
<discord-> M​arsu. — The 1 is bundle with egg’s package
<discord-> M​arsu. — Trying with it 🙂
<discord-> S​tonesmile. — @egg I got this message when starting up KSP with your zip; is it expected or should I re-install?
<discord-> e​gg. — Hm, weird
<discord-> e​gg. — I have no idea
<discord-> M​arsu. — Same here
<discord-> e​gg. — Do you have some RP-0 stuff installed maybe? On my machine it appeared to work...
<discord-> S​tonesmile. — I did copy an existing install and ripped out 'what didn't seem necessary', going to try a more clean install process
<discord-> e​gg. — @Stonesmile did that message pop up during save creation or on the main menu
<discord-> S​tonesmile. — Once I loaded a new save (created a new one)
<discord-> e​gg. — OK, will try that; hold off on doing more work on your end, I probably messed something up while trying to reduce the amount of Kerbalism clutter I brought it…
<_whitenotifier-edb> [Principia] eggrobin opened issue #2975: [Grassmanian branch] Crash when loading a pre-existing save - https://git.io/J3SXY
<_whitenotifier-edb> [Principia] eggrobin labeled issue #2975: [Grassmanian branch] Crash when loading a pre-existing save - https://git.io/J3SXY
<_whitenotifier-edb> [Principia] eggrobin assigned issue #2975: [Grassmanian branch] Crash when loading a pre-existing save - https://git.io/J3SXY
<discord-> e​gg. — re. the Чебышёв problem, the cube root documentation (in review) also addresses the 𒋛𒄥𒊏𒌅 problem
<raptop> If requested, will documentation be available on clay tablets?
<discord-> e​gg. — Hm, I am not running into this issue even when creating a new save. I have a fairly minimal RO install, and definitely no RP-n nor ROKerbalism stuf though, so maybe that is the issue?
<discord-> P​aculino (ŝi/ri/she/they). — What is the 𒋛𒄥𒊏𒌅 problem?
<discord-> P​aculino (ŝi/ri/she/they). — I got no search results
<discord-> K​irk (He/Him). — No, Google apparently doesn't understand cuneiform
<discord-> e​gg. — « the Чебышёв problem » is a reference to the problem of transliterating that name ; there are countless transiterations, Chebyshev, Tschebyschoff, etc. etc.
<raptop> The only letter consistent between the 100s (yes, hundreds) of transliterations is the 'b'
<discord-> P​aculino (ŝi/ri/she/they). — So, you transliterated Cyrillic to cuneiform?
<discord-> e​gg. — 𒋛𒄥𒊏𒌅 is *si-qur-ra-tu*, a middle assyrian spelling of *ziqqurratu*, ziggurat
<discord-> S​umguy. — Is this loss?
<discord-> K​irk (He/Him). — can't have people complaining about mistranslations if you translate it to a language no one can understand
<discord-> e​gg. — (googling the transcription "si-qur-ra-tu" will give you results for relevant things, including on oracc)
<discord-> P​aculino (ŝi/ri/she/they). — lɛts ɔl ʤʌst swɪʧ tu ˈjuzɪŋ ði ˌɪntərˈnæʃənəl fəˈnɛtɪk ˈælfəˌbɛt fɔr ˈɛvriˌθɪŋ.
<discord-> P​aculino (ŝi/ri/she/they). — ðæt weɪ, ˈtrʌbəl ˌʌndərˈstændɪŋ ˈdɪfərənt ˈæksɛnts ænd ˈdaɪəˌlɛkts wɪl əˈplaɪ ˈivɪn ɪn tɛkst!
<discord-> e​gg. — zis iz definitli œ gud ajdi ɛnd nɔlt œ tɛʁibœl wan
<discord-> e​gg. — zis iz definitli œ gud ajdi ɛnd nɔt œ tɛʁibœl wan (edited)
<discord-> e​gg. — (googling the transliteration "si-qur-ra-tu" will give you results for relevant things, including on oracc) (edited)
<discord-> e​gg. — Hm, I am not running into this issue even when creating a new save. I have a fairly minimal RO install, and definitely no RP-n nor ROKerbalism stuff though, so maybe that is the issue? (edited)
<discord-> e​gg. — OK so while I did not run into your issue (I suspect it is due to things in your install clashing with Kerbalism), I trying to add it to a stockish install did bring up the fact that Kerbalism depends on B9PartSwitch and CommunityResourcePack (but it will complain if these are missing) and KC depends on ContractConfigurator (and it will *not* complain about these, it will simply do nothing)
<discord-> v​evladdd. — Ноу, юз зе рашн алфабет инстед
<discord-> D​amien. — @egg I've just thrown it into my 1.10.1 JNSQ install and no errors
<discord-> e​gg. — Nice! but unless you have ContractConfigurator you will also not get the Imaging window
<discord-> e​gg. — … window which looks to be broken when I start a new save ? what have I done
<discord-> e​gg. — not sure what I did, but I am able to get the imaging window to show a map of Earth but not a map of Kerbin. Will keep digging.
<discord-> e​gg. — If someone manages to get an imaging window to show up with a map of *something* do keep me posted.
<discord-> S​tonesmile. — I noticed the same, got an install working without Kebalism complaining, but with no map of Kerbin; will try installing RSS now
<discord-> e​gg. — Note that you need ContractConfigurator to get anything running (I have some code from SirMortimer code that depends on that for no good reason given the scope of the exercise)
<discord-> S​tonesmile. — I did however get a Earth map with the broken install, so seems to work with RSS
<discord-> D​amien. — TIL that the imager doesn't work from sun-kerbin L1
<discord-> D​amien. — and my god it was laggy
<discord-> K​irk (He/Him). — Ooh proper yeah proper earth observation contracts would be cool
<discord-> D​amien. — fast time warp in JNSQ scale
<discord-> K​irk (He/Him). — Better than the current RP-1 contract of "trust me putting a barometer in LEO helps us predict weather"
<discord-> D​amien. — @egg is there an ideal altitude range for this experiment?
<discord-> D​amien. — RIP engine failure from kerbalism
<discord-> D​amien. — 250ish days and then it'll be in some random heliocentric orbit
<discord-> e​gg. — @Damien It is 10 km resolution at a wavelength of 1 μm; back of the envelope says anything about 1.5 million kilometres will be too far to see anything.
<discord-> e​gg. — @Damien It is 10 km resolution at a wavelength of 1 μm, with an aperture of 19.1 cm; back of the envelope says anything about 1.5 million kilometres will be too far to see anything. (edited)
<discord-> e​gg. — @Damien also, looking at my code, it will probably utterly fail if you are outside Kerbin’s SoI, so I guess L1 is out
<discord-> J​ustMozzie. — how do i make mechjeb execute principia nodes, and stop at the correct time?
<discord-> D​amien. — I just relaunched with a standard polar 300km orbit and got 20% coverage so I suppose the pedestrian option is a constellation of those
<discord-> D​amien. — I'm off to work now though so I'll have a play later
<discord-> e​gg. — yup, that is one option indeed.
<discord-> D​amien. — I was originally hoping for L1 and L2 sats to cover it, possibly with some highly eccentric polar orbits for the poles
<discord-> e​gg. — stationary satellites + a polar orbit or two should work. Lagrange points are probably stretching it a bit, at least on Earth (but also this silly implementation limitation comes into play at the moment).
<discord-> e​gg. — @Damien It is 10 km resolution at a wavelength of 1 μm, with an aperture of 19.1 cm; back of the envelope says anything above about 1.5 million kilometres will be too far to see anything. (edited)
<discord-> S​tonesmile. — You don't; RO gives engines spool up time, which MJ doesn't account for, so it gets it wrong. kOS can do it better
<discord-> J​ustMozzie. — is there a tutorial on how to write kOS scripts to get it just right?
<discord-> S​tonesmile. — A good start would likely be the kOS wiki, google for it. If you are not comfortable using kOS, then manually is the next best option
<discord-> J​ustMozzie. — i mean it probably would be a good thing to learn kOS
<discord-> J​ustMozzie. — so ill start there
<discord-> e​gg. — manually, starting when Principia tells you to, and stopping when it looks right in map view (or when Principia tells you to, but looking at map view is likely going to be more accurate) is a good way to do things without going into a rabbit hole
<discord-> J​ustMozzie. — is engine spool up the same for every single engine or no?
<discord-> K​irk (He/Him). — no
<discord-> J​ustMozzie. — is there an easy way to determine spool up time then for each engine?
<discord-> J​ustMozzie. — is it in the config or something like that?
<discord-> K​irk (He/Him). — ```~0.414*ln(sqrt(massOfEngine*maxThrust^2))```
<discord-> J​ustMozzie. — got it
* raptop stares at the sqrt(2)-1 magic number
<discord-> J​ustMozzie. — what is this bot for..?
<discord-> A​l2Me6. — It's also not far from `log10(e)`...
<discord-> A​l2Me6. — Lets people on IRC talk to Discord
<egg|anbo|egg_> it’s a good bot
<discord-> J​ustMozzie. — irc? whats that
<raptop> ...
<discord-> J​ustMozzie. — ohhh okay
<discord-> S​tonesmile. — I have *no idea* where that 0.414 comes from, it isn't even the total spool up time; just what gives you the correct time before a node that you need to ignite
<discord-> e​gg. — Correction; it looks like it works on 1.8 but not 1.10. Not going to look into why right now, just use 1.8; those who are here probably have 1.8 installs lying around that they can copy anyway
<discord-> e​gg. — **IMPORTANT** : make a separate install for it. In that install, you should NOT have Kerbalism (the download includes a dev build of Kerbalism 4) or ROKerbalism (which is not Kerbalism 4-compatible). Play on sandbox, NOT career. You may play with or without RSS/RO, with or without Principia (obviously I mostly have RO+Principia in mind, *e.g.* some of the informations given by the orbit analyser are
<discord-> e​gg. — B9PartSwitch, CommunityResourcePack, and ContractConfigurator are required dependencies (Kerbalism will complain about the first two, KerbalismContracts will not complain about the third but will not work without—even though it is irrelevant for the problem at hand). Use KSP 1.8.
<discord-> e​gg. — Feel free to cheat your satellites into their orbits (or launch if you enjoy launching; but this is not really the point of the exercise).
<discord-> e​gg. — Performance is likely to be abysmal at high time warp. In any case, time warping over 100’000× will mess with things; avoid that (if the imaging map gets silly, you can press the « Reset » button to clear it).
<discord-> e​gg. — I am NOT looking for bug reports, merely for interesting solutions that you may come up with. (edited)
<discord-> e​gg. — updated the **IMPORTANT** message above to list the required mods and the version. Apologies for the confusion.
<discord-> J​ustMozzie. — hey sorry one last thing for kOS which one should i select?
<discord-> S​tonesmile. — CommNet
<discord-> S​tonesmile. — If you want help specific to kOS, then there exists a discord server for kOS, they are probably better at providing help regarding kOS
<discord-> J​ustMozzie. — i def will join that
<discord-> A​shnoom. — Someone was not born between 1980 and 1990 :p
<discord-> J​ustMozzie. — nope,,,
<discord-> e​gg. — Also for the sake of showing that 1. it can work 2. there is a solution, here is a (somewhat boring) 2-satellite solution to the 6-hour coverage problem. Note that fewer sats isn’t necessarily better, e.g. a GEO satellite could also do telecoms while doing that, which may be better than having a dedicated weather sat; so I am definitely interested in solutions with more satellites than two (and you
<discord-> e​gg. — (and for the next exercise I should definitely cut into the codebase to remove the CC dep; I am ages away from turning any of this into actual contracts at this point)
<discord-> S​tonesmile. — *Oh my 'whatever thing you believe in'*... The error was caused by the KSP DLCs... 😫
<discord-> e​gg. — hah
<discord-> e​gg. — well, good to know; that is not getting fixed anytime soon, because it was the Kerbalism 4 dev build complaining about that, and that is going to take quite a while to move I think
<discord-> S​tonesmile. — Yeah; might be worth adding to your long message though
<discord-> e​gg. — yeah
<discord-> e​gg. — **IMPORTANT** : make a separate install for it. In that install, you should NOT have Kerbalism (the download includes a dev build of Kerbalism 4) or ROKerbalism (which is not Kerbalism 4-compatible). It should NOT have the KSP DLCs (they are weirdly incompatible with that Kerbalism 4 dev build). Play on sandbox, NOT career. You may play with or without RSS/RO, with or without Principia (obviously I m
<discord-> e​gg. — B9PartSwitch, CommunityResourcePack, and ContractConfigurator are required dependencies (Kerbalism will complain about the first two, KerbalismContracts will not complain about the third but will not work without—even though it is irrelevant for the problem at hand). Use KSP 1.8.
<discord-> e​gg. — Feel free to cheat your satellites into their orbits (or launch if you enjoy launching; but this is not really the point of the exercise).
<discord-> e​gg. — Performance is likely to be abysmal at high time warp. In any case, time warping over 100’000× will mess with things; avoid that (if the imaging map gets silly, you can press the « Reset » button to clear it).
<discord-> e​gg. — I am NOT looking for bug reports, merely for interesting solutions that you may come up with. (edited)
<discord-> S​tonesmile. — *Wohoo*, that only took a couple of hours 😅
<discord-> e​gg. — \o/
<discord-> e​gg. — (and yeah, because of the way I initialized things, it believes that the entire world was imaged at the start of the game, hence 100% coverage initially; warp a bit and that will go back down :-p)
<discord-> J​ustMozzie. — for the max thrust here is it in kN or N or what?
<discord-> e​gg. — KSP uses mts, so forces are in kilonewtons, masses are in tonnes.
<discord-> J​ustMozzie. — got it!
<discord-> (​ᴇxᴘᴇʀɪᴍᴇɴᴛᴀʟshells). — why do you have to do this to us ksp
<discord-> (​ᴇxᴘᴇʀɪᴍᴇɴᴛᴀʟshells). — it's not that hard to just use SI
<discord-> K​irk (He/Him). — It is SI
<discord-> K​irk (He/Him). — Just not mks
<raptop> I want to say that it's metric, but not SI (as well as not being MKS)
<discord-> e​gg. — it’s units compatible with the SI, to use terminology from the SI brochure
<raptop> yeah, that