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->
⟨jfinizolas⟩ hello principia people can y'all do my homework?
<queqiao->
⟨jfinizolas⟩ its making me sleepy
<queqiao->
⟨jfinizolas⟩ +💤
<queqiao->
⟨lpg4999⟩ > If you can manually fly better than PVG then the settings must be way offthat's overstating it. it's not very hard for a well flown manual ascent to be more _efficient_ than a somewhat sloppy pvg ascent
<queqiao->
⟨lpg4999⟩ (more _precise_ is a different kettle of fish)
<queqiao->
⟨jfinizolas⟩ ⟪raptop⟫ Hm, looks more like a Griffiths problem […] ⮪ i wonder why....
<raptop>
heh
<queqiao->
⟨.auer⟩ ⟪Marsh⟫ You should be using ascent guidance […] ⮪ okay, after a laborious and millimetric fine tuning, I got a difference of +402 DV with respect of the original predicted by TWP...should I consider this as acceptable?
<queqiao->
⟨_itsryan⟩ That seems a bit high, but if it works for your craft, then it works. I rarely see over 100m/s extra with a reasonable TWR on the ejection stage. I've had it come out slightly _under_ TWPs prediction several times. Does your parking orbit exactly match the ejection LAN and inclination TWP is calling for? Is your ejection burn purely tangential?
<queqiao->
⟨Kirk (He/Him)⟩ ⟪.auer⟫ okay, after a laborious and millimetric […] ⮪ Matching inclination and LAN? That is a bit high
<queqiao->
⟨.auer⟩ yes, yes
<queqiao->
⟨.auer⟩ using pvg and etc
<queqiao->
⟨.auer⟩ well , I was hitting over 1k Dv before....I can keep trying
<queqiao->
⟨lpg4999⟩ my experience has been fairly consistent results below 100m/s off
<queqiao->
⟨.auer⟩ then there must be something I´m doing wrong...double-checking
<queqiao->
⟨jfinizolas⟩ ummm maybe you are using the wrong frame of reference on flight plan?
<queqiao->
⟨jfinizolas⟩ thus making it more inefficient
<queqiao->
⟨jfinizolas⟩ i think TWP just considers an ECI prograde maneuver? (?)
<queqiao->
⟨jfinizolas⟩ or at least something similar to it
<queqiao->
⟨.auer⟩ found a slight difference between the orbit inclination made by PVG and the orbit inclination suggested by TWP (I use the "show parking orbit in map view" in TWP)
<queqiao->
⟨.auer⟩ ⟪jfinizolas⟫ ummm maybe you are using the wrong […] ⮪ it is a mars transfer, I´m using MCI as reference
<queqiao->
⟨jfinizolas⟩ yes but for making the maneuver you need to use ECI you dont care about whats your prograde in relation to mars, you care about the prograde with relation to earth
<queqiao->
⟨jfinizolas⟩ theres the plot reference plane the maneuver reference plane
<queqiao->
⟨jfinizolas⟩ +map
<queqiao->
⟨jfinizolas⟩ +and
<queqiao->
⟨.auer⟩ ⟪jfinizolas⟫ theres the map plot reference plane and […] ⮪ well, I always start with earth reference plane, when I got the dotted line going out I check the time slider for to get as close as possible to the target, then, I switch to the target reference plane and start the fine tuning.
<queqiao->
⟨jfinizolas⟩ show your flight plan window and the main principia window
<queqiao->
⟨jfinizolas⟩ or menu ig
<queqiao->
⟨lpg4999⟩ you don't seem to have understood the distinction between plotting frame and maneuver frame
<queqiao->
⟨.auer⟩ ⟪lpg4999⟫ you don't seem to have understood the […] ⮪ I think your statement is correct
<queqiao->
⟨lpg4999⟩ your _mistake_, as was guessed, is the maneuver frame
<queqiao->
⟨lpg4999⟩ (well, _one_ mistake)
<queqiao->
⟨.auer⟩ ahm are there more?
<queqiao->
⟨lpg4999⟩ 🤷
<queqiao->
⟨lpg4999⟩ 2 days to ignition certainly isn't a good sign
<queqiao->
⟨_itsryan⟩ Step 2 would be to get as close as you can only tweaking your tangential velocity and your start time.
<queqiao->
⟨_itsryan⟩ Oof, oh yeah, you probalby want to just go within one orbit.
<queqiao->
⟨lpg4999⟩ there's not a lot of diagnisis possible without information about _either_ twp's request or the actual orbit
<queqiao->
⟨.auer⟩ yiah I push the orbits trying to getcloser
<queqiao->
⟨lpg4999⟩ * diagnosis
<queqiao->
⟨_itsryan⟩ 90% of my interplanetary burns have 0 radial or binormal.
<queqiao->
⟨Al₂Me₆⟩ ⟪_itsryan⟫ Oof, oh yeah, you probalby want to just […] ⮪ (Beware nodal precession. In two days your parking orbit will be no good.)
<queqiao->
⟨.auer⟩ okay, will delet this one and do it again with the corrections
<queqiao->
⟨.auer⟩ Better? got a difference now of +55 Dv
<queqiao->
⟨lpg4999⟩ much better
<queqiao->
⟨lpg4999⟩ though if you're actually planning to split that burn between 2 stages, I hope you've anticipated the need for a large post-burn correction
<queqiao->
⟨Quadrupole🇵🇸🇸🇾🇨🇺⟩ Why so many engines btw?
<queqiao->
⟨.auer⟩ ⟪lpg4999⟫ though if you're actually planning to […] ⮪ yeah, actually one stage is for the ejection, and the insertion is splited between what is left on the ejection stage (around 1.3 K Dv) and the next stage, what is left on the next stage will be used for to assist the landing (chutes+engines)
<queqiao->
⟨.auer⟩ ⟪Quadrupole🇵🇸🇸🇾🇨🇺⟫ Why so many engines btw? ⮪ it is a rover, needs to go down safely
<queqiao->
⟨Kirk (He/Him)⟩ What engines are you even using?
<queqiao->
⟨Kirk (He/Him)⟩ The answer better not be RD-0110 verniers
<queqiao->
⟨.auer⟩ lol, nah they re RL-10
<paculino>
Are you using every variant at once or something?
<queqiao->
⟨Al₂Me₆⟩ ...exactly how big is your rover to warrant that many RL-10s??
<queqiao->
⟨.auer⟩ LOL no no, whay you are seen on the pic are no the RL-1os that was the last stage of the behemoth I use for to put the thin in orbit
<queqiao->
⟨.auer⟩ * what you are seen on the pic are not the RL-10s
<queqiao->
⟨Al₂Me₆⟩ I am not sure if that is more or less terrifying.
<queqiao->
⟨.auer⟩ * thing
<queqiao->
⟨Kirk (He/Him)⟩ What is the last stage?
<queqiao->
⟨Al₂Me₆⟩ +(Recall that even the S-IV only used six...)
<queqiao->
⟨.auer⟩ ⟪Al₂Me₆⟫ I am not sure if that is more or less […] ⮪ that´s why I call it a Behemoth
<queqiao->
⟨.auer⟩ ⟪Kirk (He/Him)⟫ What is the last stage? ⮪ the last stage is finishing the insertion maneuver and landing that´s were the RL-10 are
<queqiao->
⟨lpg4999⟩ so you clearly realize this given the earlier conversation, but planning the ejection burn while the last to-orbit stage is still active is not a good plan
<queqiao->
⟨.auer⟩ ⟪lpg4999⟫ so you clearly realize this given the […] ⮪ I think your statement is very correct
<queqiao->
⟨.auer⟩ I forgot to stage it
<queqiao->
⟨.auer⟩ so now i have to do the maneuver all over again...lol
<queqiao->
⟨.auer⟩ anyways many thaks for your help guys, now I´m more confident on to use TWP
<queqiao->
⟨.auer⟩ * thanks
<queqiao->
⟨.auer⟩ still have a last question, when should I not use ECI on the maneuver frame?
<queqiao->
⟨Al₂Me₆⟩ The manœuvre frame should be whatever one makes sense at the location of the burn. Generally that will be the inertial frame of the parent body, unless you're messing with more exotic n-body trajectories.
<queqiao->
⟨Al₂Me₆⟩ +current
<queqiao->
⟨Al₂Me₆⟩ * body of origin,
<queqiao->
⟨.auer⟩ ⟪Al₂Me₆⟫ The manœuvre frame should be whatever […] ⮪ so in this case using ECI is a convenience because of how TWP predict a transfer?
<queqiao->
⟨.auer⟩ * predicts
<queqiao->
⟨Al₂Me₆⟩ No; because you perform the burn while in LEO.
<queqiao->
⟨.auer⟩ ⟪Al₂Me₆⟫ No; because you perform the burn while […] ⮪ understood, thanks
<queqiao->
⟨.auer⟩ somebody told me time ago that the two frames should be the same, I think that´s were my confusion comes
<queqiao->
⟨.auer⟩ ⟪Al₂Me₆⟫ I am not sure if that is more or less […] ⮪ the Behemoth....
<paculino>
I keep thinking you are a bot telling about the arch user repository on my lug's channel when I see the irc notification. Is there any connection with the name?
<queqiao->
⟨Al₂Me₆⟩ That seems exceedingly unlikely.
<paculino>
Well, arch users are proud of using it. I've seen usernames proudly indicating distro before.
<queqiao->
⟨Al₂Me₆⟩ ...holy cow Discord did not like that gif
<queqiao->
⟨test_account9540⟩ Dragging with mouse is not good for any precision maneuver tbh
<queqiao->
⟨vlood⟩ ⟪Al₂Me₆⟫ ...holy cow Discord did not like that […] ⮪ didn't realise they backported KSP to the Amiga
<queqiao->
⟨Al₂Me₆⟩ ⟪test_account9540⟫ Dragging with mouse is not good for any […] ⮪ Nor is that the intended use-case. Say you want a burn to be roughly at some position along the orbit. It's probably faster to drag it there and then fine-adjust as usual with the burn editor.
<queqiao->
⟨test_account9540⟩ Yes, should work as the first step when setting up the maneuver
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<queqiao->
⟨kerbmario⟩ does principia change anything with atmospheric flight?
<queqiao->
⟨November (she/her)⟩ I'm pretty sure it shouldn't, but FAR changes things quite a bit compared to stock KSP
<queqiao->
⟨kerbmario⟩ ⟪vlood⟫ didn't realise they backported KSP to […] ⮪ To be fair, it looks like EGA graphics with a higher resolution
<queqiao->
⟨kerbmario⟩ ⟪November (she/her)⟫ I'm pretty sure it shouldn't, but FAR […] ⮪ I have FAR already
<queqiao->
⟨Kirk (He/Him)⟩ Stock KSP does angular momentum calculations wrong on purpose (for complicated reasons). Principia will do them correctly
<queqiao->
⟨drveyl⟩ ⟪Kirk (He/Him)⟫ Like, three oranges are chemists (or […] ⮪ Makes sense, I guess, that folks into rocket engines might be into chemistry.
<queqiao->
Now how do we go find a civil or mechanical engineer? That'd be a good skill set to address wobbly rockets and more importantly mechanical strength/stress at various points in the rocket. (Need more wall thickness at the bottom of the rocket with all the weight on it?)
<queqiao->
⟨drveyl⟩ Clearly those folks must be sane enough to know not to get involved here, right? 😛
<raptop>
The problem is that what makes rockets wobbly in KSP 1/2 is different from what does so in real life (well, partially)
<queqiao->
⟨drveyl⟩ Yep. Of course, flex within a part itself is probably not a friendly thing to do (live manipulation of the meshes?!) so you're somewhat limited to part boundaries. Of course, which boundaries and why/how is a different matter.
<queqiao->
⟨drveyl⟩ All boundaries and the joint system (applied at 1 central point?)probably not the best solution.
<queqiao->
⟨marmellata⟩ sorry to bother, but im gonna ask... there is a way to have the mechjeb planner work in principia?
<queqiao->
⟨drveyl⟩ You would use the principia planning.
<queqiao->
You could use MJ or TWP to give you a starting point if you have no idea how to do the interplanetary transfer I suppose.
<queqiao->
⟨marmellata⟩ yeah but for something like venus, how do tou plan without the target?
<queqiao->
⟨nazfib⟩ ⟪marmellata⟫ yeah but for something like venus, how […] ⮪ If you mean the Earth escape burn to get to Venus: start with TWP's values (that should get you decently close); then adjust prograde Δv (no more than +/- 100 m/s should be necessary I believe) and burn start time to fine-tune your approach
<queqiao->
⟨kwat⟩ i think i asked this a while ago but asking again. is there a way to see a targets orbit while being landed? would help to make less tedious to plan rendevouz launches (avoid switching to tracking station and launch 😅)
<queqiao->
⟨lpg4999⟩ no
<queqiao->
⟨.auer⟩ is there someway for to put a Dv map into Kspedia?
<queqiao->
⟨Marsh⟩ ⟪marmellata⟫ yeah but for something like venus, how […] ⮪ If you’re in the proper orbit, with the proper reference frames, when you type the numbers in it should already be pretty close to an encounter
<queqiao->
⟨Al₂Me₆⟩ ⟪.auer⟫ is there someway for to put a Dv map […] ⮪ Yes; such mods even exist for stock. It probably requires using PartTools to make though...
<queqiao->
⟨.auer⟩ ⟪Al₂Me₆⟫ Yes; such mods even exist for stock. It […] ⮪ 🤟