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…
<queqiao-->
<Maxsimal> If be feral too if I was dealing with that
<queqiao-->
<Tivec> why are retrograde orbits so hard to get "even"? been trying to get a retrograde orbit around the moon but it has +- so much on the inclination, and i can't lower that
<queqiao-->
<Tivec> the orbit goes to 178 +- 1 degree, and no matter what i do it seems to "wobble" on the orbit over time. is it because it is retrograde?
<queqiao-->
<kuzinat0r> Interesting. I'd guess it's because rather high.
<queqiao-->
<Tivec> maybe, it doesn't feel very stable at all 😄
<queqiao-->
<Tivec> my next little experiment is figuring out how to deal with multiple satellites in the same geo orbit.. like, i would like them to have their apogees at opposite "times". it has a bit of inclination (around 53) and i need to get better uptime over the atlantic
<queqiao-->
<Tivec> i guess i need to change the LAN so it's opposite to the other satellite? does that even work on stationary sats
<queqiao-->
<kuzinat0r> I think it's better to use orbits designed for high latitude areas
<queqiao-->
<kuzinat0r> Geo is no good
<queqiao-->
<Tivec> right, so molniya or similar?
<queqiao-->
<kuzinat0r> Molniya 😍
<queqiao-->
<Tivec> so 63.4 degrees and uh.. half a sidereal day?
<queqiao-->
<Tivec> and then launch to the same plane with the second, use phasing to get them to the opposite orbits?
<queqiao-->
<Tivec> 270 degree argpe too of course
<queqiao-->
<kuzinat0r> Don't worry much about the numbers. Start from 500x500 circular, burn to about the right altitude and then fine tune it so it doesn't drift
<queqiao-->
Reply to "Tivec: and then launch to the same plane with the second, use phasing to get them to the opposit..."
<queqiao-->
<kuzinat0r> 4 satellites with 90° LAN spread will cover both US and Russia
<queqiao-->
<Tivec> right, and the LAN spread is easiest done by launching into plane, and then using a phasing orbit?
<queqiao-->
<kuzinat0r> No, don't launch into plane. I find my satellites having drifted a bit after the final insertion. Just launch straight into lan.
<queqiao-->
<Tivec> so this satellite assembly is definitely up for the task, just have to get four launched. should be doable with not too much delay, though i have to use the big pad for it.
<queqiao-->
Reply to "kuzinat0r: 4 satellites with 90° LAN spread will cover both US and Russia"
<queqiao-->
<Tivec> what kind of orbits do i aim for to cover the south pacific and indian ocean, if you know? maybe this is more for the skopos channel though, since it's the skopos challenges..
<queqiao-->
Reply to "Tivec: because they have this orbit, and the coverage isn't what i want"
<queqiao-->
<Vlood> You could also just use a Tundra orbit if you can put stuff on a GSO
<queqiao-->
<Tivec> what's the difference between tundra and molniya?
<queqiao-->
<Vlood> Tundra is geosynchronous
<queqiao-->
<Vlood> It also requires fewer satellites for full coverage
<queqiao-->
<Tivec> ah, i can do that. the launcher i have places stuff in GSO without problem
<queqiao-->
Reply to "Tivec: what kind of orbits do i aim for to cover the south pacific and indian ocean, if you know..."
<queqiao-->
<Butcher> If this wasn't for skopos I would suggest a couple of sats in GEO. :p
<queqiao-->
Reply to "Tivec: what kind of orbits do i aim for to cover the south pacific and indian ocean, if you know..."
<queqiao-->
<kuzinat0r> Probably)
<queqiao-->
<Tivec> yeah, that's the thing, skopos is a bit of a nuisance 😛 i'll just set up 4 molniya for the sake of it
<queqiao-->
<Vlood> Also, there's no rule in the book saying that Molniya and Tundra orbit have to dwell over the northern hemisphere, there's just more stuff there at higher latitudes
<queqiao-->
<Tivec> right but are those orbits stable if launched with a north hemisphere periapsis?
<queqiao-->
Reply to "Vlood: It also requires fewer satellites for full coverage"
<queqiao-->
<kuzinat0r> But it doesn't look like a swing👎
<queqiao-->
Reply to "Tivec: right but are those orbits stable if launched with a north hemisphere periapsis?"
<queqiao-->
<Vlood> Why wouldn't they be?
<queqiao-->
<Tivec> because that would solve things brute force - 8 satellites should be good enough?
<queqiao-->
<Tivec> well, i guess there is no reason they wouldn't
<queqiao-->
<Butcher> Earth doesn't have lumpy enough gravity to throw things off duie to north / soluth hemisphere variance.
<queqiao-->
<Vlood> Yeah, there is some variation, but J2 influence dominates if i'm not mistaken
<queqiao-->
<Vlood> Also, you're playing with the tool that allows you to analyze long term orbit stability
<queqiao-->
<Tivec> true
_whitelogger has joined #principia
<queqiao-->
<mako> so is anyone else having problems with the Lagny release?
<queqiao-->
<Clayel> you might wanna elaborate lol
<queqiao-->
<egg> The status code changed in Lagny, and the code that picks the error message was not updated accordingly.
<queqiao-->
<egg> The correct error message would be something like The integrator reached the maximum number of steps after [some time]; try increasing 'Max. steps per segment' or avoiding collisions with a celestial.
<queqiao-->
<JD> I think I should try principia clueless
<queqiao-->
<Tivec> Principia is awesome
raptop has quit [Ping timeout: 190 seconds]
<queqiao-->
<mako> Note, it means you can’t use mechjeb maneuver planner anymore, so you have to learn how to do orbital maneuvers accounting for orbital perturbations
<queqiao-->
<mako> Transfers to other bodies are relatively easy now that there’s the optimizer
<queqiao-->
<mako> For rendezvous in orbit you need to account for the LAN of a lower orbit moving west faster than the higher orbit, so even if you launch to the same plane you’re not going to be in the exact same plane after a few orbits
<queqiao-->
<mako> Mechjeb ascent guidance is not going to be fully accurate so avoid low periapsis, I tend to use 180km for most thing
<queqiao-->
<mako> Usually if I target 180km circular I end up with something more like 170x190km
<queqiao-->
<mako> Improving mechjeb guidance to account for Principia when present is left as an exercise to the reader
<queqiao-->
<mako> In general with Principia I focus way more on the orbital period than the altitude especially for constellations
<queqiao-->
<walmart> is there a way to install principia and load an already existing save in rp1
<queqiao-->
<mako> Absolutely
<queqiao-->
<mako> Install and load
<queqiao-->
<mako> If you have interplanetary transfers going on those are likely going to be messed up
<queqiao-->
<mako> Otherwise it’s just plug and play
<queqiao-->
Reply to "mako: Install and load"
<queqiao-->
<walmart> oh it actually works?
<queqiao-->
<mako> Yup!
<queqiao-->
<walmart> saw a comment about how it breaks craft in orbit
<queqiao-->
<mako> Not for me
<queqiao-->
<mako> But crafts in transit will no liger hit their target and you have to correct
<queqiao-->
<mako> Other tips: try to terminate spacecraft asap because the history eats up savegame space
<queqiao-->
<mako> It also acts as a motivator to eliminate orbital debris which is fun!
<queqiao-->
<walmart> thats awesome I need to figure out why it keeps crashing first then
<queqiao-->
Reply to "mako: Other tips: try to terminate spacecraft asap because the history eats up savegame space"
<queqiao-->
<walmart> I have plenty of space thats fine
<queqiao-->
<mako> Other things to note: if you have solid rockets that are activated, the thrust of those active engines will be in the maneuver planning calculation
<queqiao-->
<mako> I.e add decouples for all your separation motors or ullage rockets to get rid of them as needed
<queqiao-->
Reply to "mako: I.e add decouples for all your separation motors or ullage rockets to get rid of them as..."
<queqiao-->
<mako> Likewise for probes or satellites you may want to use a solid rockets kick stage and then use RCS after that
<queqiao-->
Reply to "walmart: otherwise they'll affect maneuver planning?"
<queqiao-->
<mako> Correct, the burn will be way too short
<queqiao-->
<walmart> ah ok thanks
<queqiao-->
<walmart> good to know
<queqiao-->
<mako> Unguided transfers are way harder to nail
<queqiao-->
<mako> There are good news though! You’ll never have to suffer with the glitchy patched conics ever again
<queqiao-->
<mako> There’s no concept of an SOI so you won’t accidentally warp past an SOI or anything like that. Once you have done your maneuver, what you see is what you get
<queqiao-->
Reply to "mako: There are good news though! You’ll never have to suffer with the glitchy patched conics e..."
<queqiao-->
<walmart> 🙏 I love when the patched conics dont show me entering an SOI until after I already enter it
<queqiao-->
<mako> Basically, guided burns are way easier, unguided burns are way harder, and your initial orbital insertion via ascent guidance is less accurate
<queqiao-->
<mako> It makes spacecraft design more realistic since you need to have the spacecraft do more to get the exact orbit you desire
<queqiao-->
<mako> Mechjeb rendezvous autopilot will no longer work, but the docking autopilot does
<queqiao-->
<mako> Also ballistic transfers are sooooo much fun!
<queqiao-->
Reply to "mako: Mechjeb rendezvous autopilot will no longer work, but the docking autopilot does"
<queqiao-->
<walmart> I see
<queqiao-->
<walmart> have to figure out why its crashing first
<queqiao-->
<mako> For rendezvous it took me a while to learn to read the target EO reference frame, but once I got it I could use official documents to plan orbital rendezvous maneuvers
<queqiao-->
<walmart> official documents for orbital rendezvous?
<queqiao-->
<mako> I linked something in #research-notes
<queqiao-->
<mako> Ping me when you get to that point
<queqiao-->
<mako> The lunar environment is very different
<queqiao-->
<mako> The frozen inclinations are the only stable ones, you will have to do stationkeeping for any others
<queqiao-->
<mako> Also geostationary orbits will drift like they do IRL, so you have to do station keeping every few months. The stable and unstable longitudes matter.
<queqiao-->
<walmart> not an issue I dont send satellites into geostationary orbits anyways
<queqiao-->
<mako> Well you have to for some missions
<queqiao-->
Reply to "mako: The frozen inclinations are the only stable ones, you will have to do stationkeeping for ..."
<queqiao-->
<walmart> does principia let you know when one vessel needs stationkeeping/gets too low
<queqiao-->
<mako> Plotting maneuvers in Principia is more difficult than IRL because you can’t do reverse integration
<queqiao-->
<walmart> or do you just have to manually check in the tracking station
<queqiao-->
Reply to "walmart: does principia let you know when one vessel needs stationkeeping/gets too low"
<queqiao-->
<mako> Yes in the sense that you can plot the route as far into the future as you desire and you can see when it drifts with your eyes. Or the final orbit window.
<queqiao-->
<mako> No in that there’s no pinging
<queqiao-->
Reply to "mako: Yes in the sense that you can plot the route as far into the future as you desire and you..."
<queqiao-->
<walmart> ah ok
<queqiao-->
<mako> So if I have a satellite orbiting the lunar L2 point, it’ll be quasi-stable for a while and then I can see it yeet off into heliocentric orbit. I can then plot a maneuver to correct it and set a maneuver alarm. Often like 50 days or so.
<queqiao-->
<mako> The main perturbations you’ll notice is the LAN twisting west (which you can use to your advantage if you want to, SSOs are a thing etc) and with eccentric orbits the argument of periapsis will twist around and the periapsis will usually fall down.
<queqiao-->
<mako> So if you have a marginal capture for a Venus orbiter, it’ll eventually drop down and crash into venus. That’s cool!
<queqiao-->
Reply to "mako: So if you have a marginal (highly elliptic) capture for a Venus orbiter, it’ll eventually..."
<queqiao-->
<walmart> noooo my orbiter 💔
<queqiao-->
<walmart> is that just because of orbital pertubations (no clue how to spell it) or because of the elliptic orbit
<queqiao-->
<mako> Orbital perturbations yes
<queqiao-->
<mako> Basically, they don’t matter for the basic stuff in the game, but they matter if you want precision
<queqiao-->
<mako> You want precision if you want constellations to keep their relative angles, basically
<queqiao-->
<mako> If you just place the geocentric satellites into a triangle they will slowly drift over into the two stable longitudes
<queqiao-->
<mako> I have to say that the transfer maneuver optimizer is very very nice to use. I played with Principia before it existed and plotting an accurate interplanetary transfer took quite a bit of work!
<queqiao-->
<Tivec> I need to get a group of sats in tundra orbit. Spaced out. Not sure how to do this with the EO frame
<queqiao-->
Reply to "Tivec: I need to get a group of sats in tundra orbit. Spaced out. Not sure how to do this with t..."
<queqiao-->
<mako> Launch to 0, 120 and 240 lan (for instance)
<queqiao-->
<mako> If you do the apogee raise burn at the first pass, they will end up in the same orbit evenly spaced
<queqiao-->
<mako> Ditto with Mikita
<queqiao-->
<Tivec> First pass being as soon as possible?
<queqiao-->
<mako> Tgt EO frame isn’t needed
<queqiao-->
<mako> Yes
<queqiao-->
<mako> If you want to launch multiple tundra sats at once you’re going to have to use the J2 perturbation to your advantage (twisting LAN east). Raise your apoapsis on the first pass, then let the satellite drift until you are at your desired LAN, and raise your perigee
<queqiao-->
<Tivec> I don’t launch on the same but this could also be used to drift sats into correct orbits no?
<queqiao-->
<mako> Yup!
<queqiao-->
<mako> Especially launching to geocentric
<queqiao-->
<mako> There’s a reason why IRL geocentric launches take a long time to reach their target longitude
<queqiao-->
<Tivec> At some point I need to understand how LAN affects my orbit. I understand what it is, it’s where I pass through the equator on my way toward apogee but..
<queqiao-->
<mako> This btw is also what Starlink launches do
<queqiao-->
<mako> Correct.
<queqiao-->
<Tivec> Oh so that’s why starlink can launch everything from the same place
<queqiao-->
<Tivec> They just drift into orbit
<queqiao-->
<mako> Yup!
<queqiao-->
<mako> Hence why they are launched to a lower orbit than the final one
<queqiao-->
<mako> As a pro tip for GTO launches you want to have the apogee beyond geocentric so the satellite does less work
<queqiao-->
<mako> Earth-centered, Earth-fixed is basically ground track view (but in 3d instead)
<queqiao-->
<Tivec> Yea. I wish we could see the ground track on the planet
<queqiao-->
<Tivec> I also wish I could turn off all ground stations and other craft…
<queqiao-->
<mako> Would be cool.
<queqiao-->
<mako> You kinda can
<queqiao-->
<Tivec> I can hide crafts
<queqiao-->
<haysox> Quick question regarding manœuvers. If principia is not recognizing an active engine (it’s been staged but not throttled up. So it’s at 0 throttle but when I right click on it the engine is activated) how should I go about plotting a manœuver to ensure dev mechjeb can execute it properly?
<queqiao-->
Reply to "haysox: Quick question regarding manœuvers. If principia is not recognizing an active engine (it’..."
<queqiao-->
<mako> If it’s active but not throttled, Principia does the right thing
<queqiao-->
<mako> I don’t know why that is. However, the one thing I can point out is that the maneuver node editor mod is not gonna work with Principia so you may want to uninstall that
<queqiao-->
<Tivec> Try clicking ”active engine” again for the manoeuvre
<queqiao-->
Reply to "mako: I don’t know why that is. However, the one thing I can point out is that the maneuver nod..."
<queqiao-->
<haysox> I can do that, I haven’t been using it but it makes sense that it might screw with things
<queqiao-->
Reply to "Tivec: Try clicking ”active engine” again for the manoeuvre"
<queqiao-->
<haysox> I have tried that
<queqiao-->
<mako> Oh you need to do that after staging yeah!
<queqiao-->
<mako> If you staged, rebase and (if necessary) hit active engine
<queqiao-->
<haysox> I staged before starting the flight plan but I can try rebasing as well
<queqiao-->
<egg> You have added celestial bodies to your game since you created that save.
<queqiao->
⟨kingparity⟩ Does principia handle ground bases well? Particularly ones that are anchored to the ground with part mods that have that feature
<queqiao->
⟨kingparity⟩ Like USI MKS has parts that have a ground teacher option
_whitelogger_ has joined #principia
<queqiao-->
Reply to "egg: You have added celestial bodies to your game since you created that save."
<queqiao-->
<walmart> tried a completely new save and still crashed
<queqiao-->
<walmart> should I resend logs with new save
<queqiao-->
<walmart> using rss
<queqiao-->
Reply to "haysox: Still having the same issue…"
<queqiao-->
<haysox> The issue persists… maybe I should update principia
<queqiao-->
<Ernos> hey I've just installed RO/RSS with Principia on Fedora, and I'm getting this error from Principia. I went and installed libcxx as that provides both libraries, however I'm still getting this same error after relaunching KSP
<queqiao-->
<Ernos> Prolly not such a passive aggressive wording that demonstrates a seeming lack of knowledge of Linux
<queqiao-->
<Clayel> the note at the top? i dont think its too passive aggressive
<queqiao-->
<Ernos> it sure reads as such to me
<queqiao-->
<Ernos> You don't need the "not 50 operating systems (the same plus 47 weird distros of Linux)". Just provide the packages needed (including specifying llvm-libunwind), most will be able to sort it out from there
<queqiao-->
<Nazfib> You need the library named "libunwind.so" (the LLVM version, not the other one), version 17 or later; which package provides this library depends on which distribution of Linux you run. I just happened to know which package has it on Fedora, since that's what I run.
<queqiao-->
<Ernos> is that directed towards me or Clayel?
<queqiao-->
<Ernos> If i was writing that section Clayel screenshotted, I'd do it as> Note to Linux users: we support three operating systems (Windows, macOS, and Ubuntu). If you are using a distro other than Ubuntu, the information below might be useful to you.You need libc++1, libc++abi1, and LLVM's libunwind version 17 or laterAlso, your working directory needs to be <KSP directory>, otherwise principia.so will not be found
<queqiao-->
<Ernos> Maybe a different wording of specifying LLVM libunwind
<queqiao-->
<Ernos> my only two issues are that passive aggressive line and that I think LLVM libunwind should be specified
<queqiao-->
<Ernos> but I'm not sure the best wording for that second part so I'm not too keen on touching it rn
<queqiao-->
<Nazfib> The Principia devs cannot support all Linux distributions that exist, and they have decided that the only Linux distribution they will officially support is Ubuntu. The rest of the text is just a note that, if you're using an unsupported distro, it may still work; or it may not, at which point they will not promise to investigate the issue for you, you'll have to do that yourself (or ask other users for help).
<queqiao-->
<Nazfib> It is specified that you need libunwind version 17 or later; the other libunwind package only has versions up to 1.8, so it cannot be the right one. As far as I can tell, the package on Ubuntu is just called libunwind-<version>
<queqiao-->
Reply to "egg: You have added celestial bodies to your game since you created that save."
<queqiao-->
<walmart> have any idea what it could be? still occurs on new saves