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->
⟨Dost Thou Even Shred⟩ Ok so I dont know really know where to ask this but Im trying for the moon with principia and I was just wondering is it the same delta v and how do you do it exactly. I also asked in #rp1-career-help but I feel like it might be more appropriate here
<queqiao->
⟨Dost Thou Even Shred⟩ One thing is getting in a good enough inclination with the moon from the cape cause I know it wont be perfect but Im not sure how to get it close
<queqiao->
⟨Dost Thou Even Shred⟩ Its hard to find tutorials cause most of them are stock where youre automatically inline with the mun
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ See the top two.pinned messages.
<queqiao->
⟨TheSquirrelPatrol⟩ There are about a dozen different ways people use, with the "best" being a kos script. There is also a nasa/jpl spreadsheet somewhere with all the launch windows
<queqiao->
⟨Dost Thou Even Shred⟩ So dont launch from the cape essentially
<queqiao->
⟨Dost Thou Even Shred⟩ cause thats the second pinned comment
<queqiao->
⟨Dost Thou Even Shred⟩ But I dont have a pad anywhere else
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ Or launch due east and do it off plane
<queqiao->
⟨Dost Thou Even Shred⟩ Isnt that a normal launch
<queqiao->
⟨Dost Thou Even Shred⟩ Or is that retrograde orbit
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ Launch normally, without a dogleg or anything, into a low circular orbit
<queqiao->
⟨Dost Thou Even Shred⟩ Ok its nice that I dont need to dogleg cause I mainly use mechjeb so I dont think you can do that
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ Burn at either the an or dn when doing so will put the ap in the right spot. Play around with the time slider to do this part
<queqiao->
⟨Dost Thou Even Shred⟩ Ok thanks Ill try that out
<queqiao->
⟨Dost Thou Even Shred⟩ Will it still only be around 3000 ms for a flyby
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ Unless you try ballistic capture
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ Nevermind, that wouldn't be a flyby for long
<queqiao->
⟨Dost Thou Even Shred⟩ No I see historically how well it went
<queqiao->
⟨Dost Thou Even Shred⟩ aka not wwell
<queqiao->
⟨Dost Thou Even Shred⟩ * well
<queqiao->
⟨Paculino (ŝi/ri/she/they)⟩ * long, and won't get close enough for the contract probably
<queqiao->
⟨Dost Thou Even Shred⟩ What frame of reference do you use for moon transfers
<queqiao->
⟨Quadrupole⟩ Just MCI or EMO (earth-moon-orbit, can't recall the exact name)
<queqiao->
⟨Quadrupole⟩ Also ballistic capture is really for bailing out. It requires a DCM near earth-sun L1, where TL1 can't reach, and the delta v saving is only around 150 m/s
<queqiao->
⟨Dost Thou Even Shred⟩ Ok well Im gonna be honest I dont know what all these circles mean
<queqiao->
⟨Quadrupole⟩ What circles?
<queqiao->
⟨Quadrupole⟩ Did you read the principia wiki?
<queqiao->
⟨Starcatcher⟩ I just read a whole bunch of diagrams in order to understand ballistic capture
<queqiao->
and still dont get anything
<queqiao->
⟨Dost Thou Even Shred⟩ And I tried but most of it was vanilla ksp and its hard to transfer to realism overhaul
<queqiao->
⟨Quadrupole⟩ ⟪Starcatcher⟫ I just read a whole bunch of diagrams […] ⮪ Given you are 13, I recommend read some physics first.
<queqiao->
⟨Quadrupole⟩ ⟪Dost Thou Even Shred⟫ These circles ⮪ Those circles just mean the earth is moving wrt the moon, so your probe is orbiting a moving earth.
<queqiao->
⟨Dost Thou Even Shred⟩ But no matter how much prograde I add it doesnt get any closer it seems
<queqiao->
⟨Starcatcher⟩ this is like the only pic I can understand
<queqiao->
others just look like spaghetti paths produced by n-body physics
<queqiao->
⟨Dost Thou Even Shred⟩ Well how do I get it to look like that
<queqiao->
⟨Dost Thou Even Shred⟩ Like I know thats how it should look but I dont know how to get it to look like that
<queqiao->
⟨Quadrupole⟩ Look like what? You want a normal transfer or ballistic one?
<queqiao->
⟨Dost Thou Even Shred⟩ Probably a normal
<queqiao->
⟨Starcatcher⟩ it look like a simple ballistic capture like above can be done even with stock physics
<queqiao->
⟨Dost Thou Even Shred⟩ Cause Im just trying to understand and dont want anything too advanced just yet
<queqiao->
⟨Quadrupole⟩ Did you read the wiki
<queqiao->
⟨Dost Thou Even Shred⟩ Yeah but I dont understand it
<queqiao->
⟨Dost Thou Even Shred⟩ Ive tried all the reference frames and none of them work
<queqiao->
⟨TheSquirrelPatrol⟩ Looking at your screenshot above, one thing that stands out to me is the 3d limit on plotting your trajectory. Expand that out to 5 or 7 days
<queqiao->
⟨Dost Thou Even Shred⟩ plus it seems outdated
<queqiao->
⟨Dost Thou Even Shred⟩ Cause some of the references arent options
<queqiao->
⟨Transparent_Elemental⟩ the reference frame description says this
<queqiao->
⟨TheSquirrelPatrol⟩ Yeah, I'm trying not to say too much, as my last principia career was before all the references got renamed, and I haven't gotten that far in the career I'm doing now
<queqiao->
⟨Transparent_Elemental⟩ if you're in LEO and you choose a moon's center as a reference, then your orbit is drawn relative to that centre
<queqiao->
⟨Transparent_Elemental⟩ moon is moving, so you see these circles because it's your orbit around earth that's changing position
<queqiao->
⟨Transparent_Elemental⟩ (because moon is fixed)
<queqiao->
⟨Dost Thou Even Shred⟩ Well when I add more to the acceleration it just goes away from the moon
<queqiao->
⟨Quadrupole⟩ Then you are burning at the wrong place.
<queqiao->
⟨Starcatcher⟩ wheres the principia wiki please
<queqiao->
⟨Dost Thou Even Shred⟩ None of it really applies to RP1 cause it assumes you are in line with almost all planets
<queqiao->
⟨pEdro⟩ yeah, but your launch site isnt
<queqiao->
⟨Dost Thou Even Shred⟩ Thats what Im saying]
<queqiao->
⟨Dost Thou Even Shred⟩ You cant use a wiki that assumes you are in line like stock
<queqiao->
⟨Dost Thou Even Shred⟩ Cause it isnt realistic
<queqiao->
⟨Transparent_Elemental⟩ have you tried ECI frame?
<queqiao->
⟨Quadrupole⟩ The wiki tells you wht the reference frames mean. That is transferable.
<queqiao->
⟨Quadrupole⟩ The way to understand an moon transfer is that, you first burn into a highly elliptical orbit that intercept the lunar orbit at _some_ point, then you tune the transfer time so that, when you arrive at moon's orbit height, the moon arrives at your probe's position too.
<queqiao->
⟨Quadrupole⟩ See the pinned message.
<queqiao->
⟨Dost Thou Even Shred⟩ But it never gets close
<queqiao->
⟨Dost Thou Even Shred⟩ I change transfer time and everything but nothing happens
<queqiao->
⟨Dost Thou Even Shred⟩ How do I know the right LAN
<queqiao->
⟨pEdro⟩ kOS, or that JPL/NASA spreadsheet
<queqiao->
⟨zephyr⟩ Also you can just burn like 20m/s more dv at your an/dn if you don't care about flight time
<queqiao->
⟨Dost Thou Even Shred⟩ ⟪pEdro⟫ kOS, or that JPL/NASA spreadsheet ⮪ What JPL/NASA spreadsheet
<queqiao->
⟨zephyr⟩ And completely ignore launch windows
<queqiao->
⟨Dost Thou Even Shred⟩ Ok well give me a minute to relaunch and whatever. Im just doing sims till I get it down but still
<queqiao->
⟨Quadrupole⟩ The fourth slider. t initial
<queqiao->
⟨pEdro⟩ for now, select ECI as uour maneuver frame
<queqiao->
⟨Transparent_Elemental⟩ also it's nice to have an option to make small correction with RCS after TLI using same stage
<queqiao->
⟨zephyr⟩ Ah makes sense then, what did your tli dv end up as in the end?
<queqiao->
⟨Transparent_Elemental⟩ about the same you'd expect, like 3150-3200 depending on exact launch
<queqiao->
⟨Quadrupole⟩ Well, if you don't want windows, you can always launch polar
<queqiao->
⟨Transparent_Elemental⟩ yeah that works too, though you need practice to learn to eyeball it
<queqiao->
⟨zephyr⟩ Wait what? You corrected a 7 degree inclination difference with <100m/s
<queqiao->
⟨Dost Thou Even Shred⟩ Ok so the best way I could get the delta v I have to use SRBs not liquid fuel so 1) is it still active engines 2) Is there a way to compensate for residuals
<queqiao->
⟨Quadrupole⟩ ⟪zephyr⟫ Wait what? You corrected a 7 degree […] ⮪ He probably meant DCM
<queqiao->
⟨Quadrupole⟩ Like how we went to Minmus from equatorial Kerbin orbit
<queqiao->
⟨zephyr⟩ But they said there was no correction out after tli
<queqiao->
⟨Quadrupole⟩ Like how we went to Minmus from equatorial Kerbin orbit
<queqiao->
⟨Transparent_Elemental⟩ ⟪zephyr⟫ Wait what? You corrected a 7 degree […] ⮪ no, I just said you don't correct the 7 degree difference - you live with it
<queqiao->
⟨Dost Thou Even Shred⟩ Uhm so SRBs are they still active engines?
<queqiao->
⟨Transparent_Elemental⟩ though 7 degrees is _the worst_ case, usually it's about 2-4 degrees or so
<queqiao->
⟨Quadrupole⟩ I have an excel spreadsheet that calculates due-east launches on this channel
<queqiao->
⟨Transparent_Elemental⟩ ⟪Dost Thou Even Shred⟫ Uhm so SRBs are they still active […] ⮪ for SRBs you should click instant impulse
<queqiao->
⟨Dost Thou Even Shred⟩ Ok
<queqiao->
⟨Quadrupole⟩ I have an excel spreadsheet that […] ⮪ Gives you 4-day launch windows every day
<queqiao->
⟨Dost Thou Even Shred⟩ And also mechjeb shows worse case with delta v right
<queqiao->
⟨Transparent_Elemental⟩ 🤷♂️ I never had to do that in any of my moon launches with principia
<queqiao->
⟨Transparent_Elemental⟩ I might as well just record a video to make it like a tutorial or something
<queqiao->
⟨Dost Thou Even Shred⟩ Ok so with 3200 m/s it means it can burn for longer
<queqiao->
⟨Dost Thou Even Shred⟩ so therefore I want to make it as far out as possible