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->
⟨kingparity⟩ trying to get to kerbol-kerbin L3 point, all i get is this psychedelic mess that won't even display right 😭
<queqiao->
⟨Damien⟩ ⟪kingparity⟫ trying to get to kerbol-kerbin L3 […] ⮪ why are you in KCKF then?
<queqiao->
⟨Damien⟩ in a kerbin fixed frame, everything else rotates around kerbin
<queqiao->
⟨kingparity⟩ isn't that what you're supposed to do to get to lagrange points easily, set the small body to fixed
<queqiao->
⟨kingparity⟩ +reference frame
<queqiao->
⟨Damien⟩ the small body is mun
<queqiao->
⟨Damien⟩ you've fixed the surface of kerbin
<queqiao->
⟨kingparity⟩ that's what i did for getting to mun lagrange points L4 and L5
<queqiao->
⟨kingparity⟩ im trying to get to kerbol-kerbin L4
<queqiao->
⟨kingparity⟩ not mun
<queqiao->
⟨Damien⟩ oh
<queqiao->
⟨kingparity⟩ yeah xD
<queqiao->
⟨Damien⟩ then you want sun centered kerbin aligned or whatever the frame that fixes sun an kerbin is
<queqiao->
⟨Damien⟩ * and
<queqiao->
⟨Damien⟩ I can never remember the names
<queqiao->
⟨kingparity⟩ kerbin-sun-orbit?
<queqiao->
⟨Damien⟩ yeah maybe. I'm not in game so don't know for sure what it's called
<queqiao->
⟨Damien⟩ the names changed a while back and I still have the old names in my head
<queqiao->
⟨kingparity⟩ ah
<queqiao->
⟨Damien⟩ I've never been to sun-kerbin L3 but I've done L1/L2 a few times
<queqiao->
⟨kingparity⟩ or sorry not L3, L4
<queqiao->
⟨Damien⟩ yeah I get you. I just had to check the numbers myself
<queqiao->
⟨Damien⟩ L3's the useless one on the other side
<queqiao->
⟨kingparity⟩ i have a feeling this is more annoying because im coming from the small body
<queqiao->
⟨Damien⟩ yeah I reckon it'll be an ejection into a solar orbit then phase into the right position then try and capture into L4, or do some kind of low energy transfer from L1 or L2
<queqiao->
⟨Damien⟩ I've done kerbin-mun L3/4 but never sun-kerbin
<queqiao->
⟨Damien⟩ as you say, it's trickier from the small body
<queqiao->
⟨Damien⟩ on the plus side you do have a good testing ground with kerbin-min
<queqiao->
⟨Damien⟩ * kerbin-mun
<queqiao->
⟨Damien⟩ try and go from mun to kerbin-mun L4
<queqiao->
⟨kingparity⟩ truee
<queqiao->
⟨kingparity⟩ ill try that first
<queqiao->
⟨Damien⟩ then you'll know how to do it from kerbin
<queqiao->
⟨Damien⟩ and principia once again turns a fun space game with little green men into an n-body trickshot simulator
<queqiao->
⟨Damien⟩ if you do a search for posts containing images by me in this channel you can see the stuff I've experimented with
<queqiao->
⟨kingparity⟩ oh yes i love it
<queqiao->
⟨Damien⟩ low energy ballistic captures, SSO/molniya/tundra orbits etc
<queqiao->
⟨Damien⟩ yeah it's really fun
<queqiao->
⟨kingparity⟩ strapped a 16t rocket onto a clyesdale is the best
<queqiao->
⟨Damien⟩ hohmann transfer from earth/kerbin to moon/mun? Nope. low energy ballistic capture via sun-kerbin/earth L2
<queqiao->
⟨kingparity⟩ * strapping
<queqiao->
⟨kingparity⟩ yes
<queqiao->
⟨Damien⟩ * L1
<queqiao->
⟨Damien⟩ completely pointless but super fun
<queqiao->
⟨Damien⟩ and you can't get much cooler for an earth sat than a terminator riding SSO
<queqiao->
⟨Al₂Me₆⟩ To be clear, the frame with the _surface_ of either body fixed is never the correct frame for Lagrange points. The truly correct frame is the rotating-pulsating frame fixing the positions of both bodies (whereas the <parent> <child> orbit frame fixes the position of the parent but only the direction of the child), which you might note is currently being worked on.
<queqiao->
⟨Damien⟩ ⟪Al₂Me₆⟫ To be clear, the frame with the […] ⮪ yeah I got excited seeing that
<queqiao->
⟨kingparity⟩ ⟪Al₂Me₆⟫ To be clear, the frame with the […] ⮪ oo that sounds nice
<queqiao->
⟨kingparity⟩ nothing like reaching 9 TWR at 30km 😂
<queqiao->
⟨egg⟩ Yeah I recall you have been interested in this reference frame for a long time—at a time when we had no expectation that we would ever implement it.
<queqiao->
⟨Damien⟩ ⟪egg⟫ Yeah I recall you have been interested […] ⮪ I'm guessing it passed the 'developmentally interesting' test then 🙂
<queqiao->
⟨sichelgaita⟩ ⟪Damien⟫ I'm guessing it passed the […] ⮪ It did. It also passed the "developmentally frigging hard" test. Soon reaching "developmentally mindboggling".
<queqiao->
⟨Damien⟩ ⟪sichelgaita⟫ It did. It also passed the […] ⮪ one for the history books along with the 'physx is crap' debacle I'm assuming
<queqiao->
⟨Damien⟩ I'm mathematically challenged so I have no clue how you guys weave this magic but I'm continuously fascinated by it
<queqiao->
⟨Damien⟩ I had some astrodynamics student on reddit DM me once to ask me for some physics help because I'd answered a question about orbital mechanics once in a space thread. I had to awkwardly let him down by explaining I have no clue how it all works mathematically but I'm just kinda ok at playing KSP
<queqiao->
⟨Damien⟩ -once
<raptop>
lol nice
<queqiao->
⟨kingparity⟩ poor gu
<queqiao->
⟨kingparity⟩ * guy
<queqiao->
⟨Damien⟩ just another example of how games like KSP do an amazing job at teaching a complicated subject intuitively
<queqiao->
⟨Damien⟩ once maths start throwing letters and symbols at me my brain just turns to TV static
<queqiao->
⟨kingparity⟩ yaknow what would be nice would be a thing to show the lagrange points somehow on the map so you don't have to eyeball it
<queqiao->
⟨egg⟩ ⟪kingparity⟫ yaknow what would be nice would be a […] ⮪ yes, which is why we have been working on it for a year or so
<queqiao->
⟨Damien⟩ ⟪kingparity⟫ yaknow what would be nice would be a […] ⮪ from what I understand, that's how it's calculated IRL. just constant trial and error until the trajectory looks right
<queqiao->
⟨kingparity⟩ oh god
<paculino>
Can the stable ones be calculated analytically, or is it all numerical?
<queqiao->
⟨egg⟩ The positions of the points are fairly easy to calculate analytically. Trajectories are computed numerically.
<queqiao->
⟨kingparity⟩ that's how i eyeball it, also i got to kerbin-mun L4 just fine from the mun, dunno why kerbol-kerbin L4 has to be so annoying 😭
<queqiao->
⟨egg⟩ But the points only make sense in the rotating-pulsating reference frame, and for context it would be useful to show the equipotentials around them. Hence https://github.com/mockingbirdnest/Principia/issues/3358.
<paculino>
I would have guessed many elliptical integrals would come along and make analytical calculations finding the points difficult.
<queqiao->
⟨Damien⟩ there goes the TV static again