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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<queqiao->
⟨Quadrupole⟩ You mean around Lagrange points or around the moon? For the latter, see the pinned message
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<queqiao->
⟨Serina⟩ Like general rules on where you can kind of expect to find stable orbits
<queqiao->
⟨Stonesmile⟩ It is still a very broad question, around what body?
<queqiao->
⟨Serina⟩ That's the thing. Is there no general these kinds of orbits tend to be stable kind of deals?
<queqiao->
⟨Serina⟩ Or at leadt tend towards stability. I've noticed that higher inclination orbits tend to be more stable in what i've read about both the moon and earth
<queqiao->
⟨Stonesmile⟩ All orbita around Earth are stable, only a few around the moon are
<queqiao->
⟨Stonesmile⟩ All orbits around Earth are stable, only a few around the moon are (edited)
<queqiao->
⟨egg⟩ Orbits are stable by default unless you have something to perturb them into no longer being an orbit
<queqiao->
⟨Serina⟩ Yah but the catch there is that everything is out to modify your orbit in n-body phyisics.
<queqiao->
⟨Serina⟩
<queqiao->
⟨Serina⟩ Can't something in geo end up being yeeted out of geo given enough time due to the moon?
<queqiao->
⟨egg⟩ also due to the inhomogeneity of the earth; but it will remain in a somewhat similar orbit
<queqiao->
⟨egg⟩ the question here is largely what you mean by « stable »
<queqiao->
⟨Serina⟩ It won't get yeeted off into oblivion
<queqiao->
⟨Serina⟩ essentially, can I just leave this thing here and expect the science experiments to complete and not for it to either crash or get yeeted and deleted
<queqiao->
⟨egg⟩ yes (except on the moon), but anyway you don’t have to ask *we give you a tool to answer that question*
<queqiao->
⟨Serina⟩ oh? doesn't that only work if you're already in the orbit?
<queqiao->
⟨egg⟩ yes, but it works for any length of time
<queqiao->
⟨egg⟩ The orbit analyser will tell you how your orbit varies over whatever duration you need
<queqiao->
⟨Serina⟩ True, but I was mostly asking so I know generally what kind of inclinations or eccentricities to aim for so I have a ballpark estimate of what my initial orbit should be.
<queqiao->
⟨egg⟩ anything
<queqiao->
⟨egg⟩ nothing will magically run into the earth, and the moon is a challenge but see the pinned tweet
<queqiao->
⟨Serina⟩ *nod* How about gas giant moons and such?
<queqiao->
⟨egg⟩ I don’t know, try it and tell me ?
<queqiao->
⟨Serina⟩ xD
<queqiao->
⟨Serina⟩ Sure I'll try to figure it out
<queqiao->
⟨egg⟩ we don’t model the inhomogeneities of those, so only perturbations by other bodies (essentially the primary) would matter there, so I suspect they are very easy
<queqiao->
⟨egg⟩ but anyway, perturbations generally *do not* throw you thing into the ground
<queqiao->
⟨egg⟩ that’s just not what they do
<queqiao->
⟨Serina⟩ So I only need to take into account jupiter perturbating the orbit *nodnod*
<queqiao->
⟨egg⟩ but the best way to have an intuition of what those perturbations actually do (and perhaps more importantly what they don’t do) is to actually try seeing what happens to things in various orbits
<queqiao->
⟨Serina⟩ Yeh, Thanks for the tips
<queqiao->
⟨Serina⟩ oh and for the moon document in the pinned messages, I guess it doesn't perturb at the points where the lines cross the 0.00 line?
<queqiao->
⟨egg⟩ at those points, circular orbits are frozen ; but you don’t have to use circular orbits, the y axis is eccentricity (and the sign tells you which pole the periapsis should be over)
<queqiao->
⟨Serina⟩ sign?
<queqiao->
⟨Serina⟩ also what's the a = x km thing about?
<queqiao->
⟨Quadrupole⟩ plus means the perilune is in northern hemisphere and vice versa
<queqiao->
⟨Quadrupole⟩ a is semi-major axis. Radius of the moon is taken as 1738 km
<queqiao->
⟨Serina⟩ Ah
<queqiao->
⟨Serina⟩ so positive eccentricity is perilune is north and opposite for negative eccentricity? gotcha
<queqiao->
⟨Quadrupole⟩ Note that the y-axis is in e *times* sinω, so an orbit having eccentricity of 0.04 and argument of perilune of 90° (i.e. the perilune is at the north-most point) will have the same stability as another orbit with e=0.08 and ω=30°
<queqiao->
⟨Quadrupole⟩ Eccentricity is always positive, but argument of perilune (ω) ranges from -180° to 180°
<queqiao->
⟨egg⟩ that’s not how you should read that graph though, here ω is either -180° or 180°, nothing in betwen
<queqiao->
⟨egg⟩ that’s not how you should read that graph though, here ω is either -180° or 180°, nothing in between (edited)
<queqiao->
⟨egg⟩ (and thus its sine is -1 or 1)
<queqiao->
⟨egg⟩ that’s not how you should read that graph though, here ω is either -90° or 90°, nothing in between (edited)
<queqiao->
⟨Serina⟩ so the arguement of periaspis is always the highest or lowest point lattitude wise in the orbit?
<queqiao->
⟨Serina⟩ depending on what side you go on?
<queqiao->
⟨egg⟩ the argument of periapsis in an orbital element, it’s not a point. The periapsis is as you say.
<queqiao->
⟨Serina⟩ i see
<_whitenotifier>
[Principia] eggrobin labeled pull request #3100: A few improvements to journal replaying - https://git.io/J0mxg
<queqiao->
⟨*ਜੰਗਲੀ ਆਦਮੀ*⟩ yo can anyone tell me how to launch to the plane of the moon, manually or using mechjeb. I've tried mechjeb and it's not working. I'm launching from the cape.
<queqiao->
⟨egg⟩ It is not possible to launch into the plane of the Moon from the Cape (except once every eighteen years).
<queqiao->
⟨egg⟩ Move to a launch site further south (Kourou or Sriharikota should always work) if you want to do that, or intercept the moon in a non-coplanar way.
<_whitenotifier>
[Principia] pleroy commented on issue #3038: Crash after loading screen with ksp 1.10 - https://git.io/J0zlG
<_whitenotifier>
[Principia] pleroy closed issue #3038: Crash after loading screen with ksp 1.10 - https://git.io/JnyRd
<_whitenotifier>
[Principia] pleroy commented on issue #2903: Crash doing flightplanning w Principia - https://git.io/J0z8Q
<queqiao->
⟨JJ⟩ It is my understanding that principia simulates the rotation of vessels, even when in timewarp. Is it still possible to have a vessel keep its solar panels pointed towards the sun without active control input?
<queqiao->
⟨JJ⟩ It is my understanding that principia simulates the rotation of vessels, even when in timewarp or not selected (?). Is it still possible to have a vessel keep its solar panels pointed towards the sun without active control input? (edited)
<queqiao->
⟨Damien⟩ kerbalism currently treats sun illumination on rails as fixed at the last position it was while off rails. this is independent of the true orientation of the craft
<queqiao->
⟨Damien⟩ as for physically keeping the panels oriented, it's being discussed
<queqiao->
⟨JJ⟩ But obstruction from planets still matters, yes?
<queqiao->
⟨Damien⟩ I believe so yes
<queqiao->
⟨JJ⟩ Okay that works for me, thanks!
<queqiao->
⟨Neiehl Space Research Facility⟩ hey all
<queqiao->
⟨Neiehl Space Research Facility⟩ i made a manever
<queqiao->
⟨Neiehl Space Research Facility⟩ but idk where to point my ship and when to start burning
<queqiao->
⟨Neiehl Space Research Facility⟩ how do i know that?
<queqiao->
⟨Damien⟩ there should be an add node to navball checkbox
<queqiao->
⟨Serina⟩ The wiki does help tell you what mode to use and its intuitive i think. Very swirrly but it shows very well how your orbital position will change relative to the target
<queqiao->
⟨SpaceXenthusiast⟩ Thanks.
<queqiao->
⟨Neiehl Space Research Facility⟩ is there a way to knwo the height of my perigee