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->
⟨Benji⟩ Is vessel.orbit.ApA and vessel.orbit.timeToAp different than what principia calculates?
<queqiao->
Or asked the other way round...do I get the principia values when I catch these numbers?
<queqiao->
⟨Butcher⟩ Pretty sure you get the patched conics.
<queqiao->
⟨Benji⟩ And those are different from what principia handles/shows?
<queqiao->
⟨lpg⟩ principia doesn't even _have_ singular Ap/Pe values
<queqiao->
⟨Benji⟩ Hmmmm, interesting/complicated(?)....but it's probably sufficient (for my purposes) to use the patched conics values....they can't be soooo much off?
<queqiao->
My very crude understanding of principia was, that it calculates stuff on its own and forces its values onto the "stock-system-thing-however-things-are-done".
<queqiao->
⟨Al₂Me₆⟩ Yes. Point being the resultant KSP orbital elements are the osculating elements. The more perturbed your orbit is the more useless those elements become.
<queqiao->
⟨Benji⟩ Not english native hear....what's a perturbed orbit.
<queqiao->
Not knowing this makes me perturbed.
<queqiao->
⟨Benji⟩ * this,
<queqiao->
⟨Benji⟩ * here....what's
<queqiao->
⟨Al₂Me₆⟩ As in, an orbit that deviates from Keplerian due to n-body effects.
<queqiao->
My use of them happens around circularizing after a launch. So the patched conics should still be usable enough in my case.
<queqiao->
Almost no n-bodies involved.
<queqiao->
⟨Benji⟩ +Save to use it with principia running the higher maths.
<queqiao->
⟨sichelgaita⟩ Note that, while we all think of Principia as doing _n_-body gravity, it also does extended body gravity (e.g., lumpy Moon) and those effects may be more important/visible in practice. Not sure if it's relevant to the discussion at hand, though.
<queqiao->
⟨Benji⟩ No, probably not, but thanks.
<queqiao->
I ran some tests, it's within cm accuracy, for what I'm doing.
<queqiao->
⟨test_account⟩ Osculating elements definitely affect LEO orbits, despite the lack of any serious n-body perturbations. It's possible to launch a craft to something like 315x700 orbit, but not complete "first solar-powered satellite" mission because the osculating periapsis keeps falling below 300km (mission requirement is 300km and it's checked continuously for 14 days).
<queqiao->
⟨itsRyan⟩ <pedant> That's not exactly orbital oscillation, that's the ground getting closer and farther away due to the oblateness of the Earth. </pedant>
<queqiao->
⟨test_account⟩ that would mean that periapsis reported by the game is altitude above the surface, and not something that is determined from orbital parameters and earth radius alone 🤔
<queqiao->
⟨Benji⟩ There's ApA/PeA - sealevel
<queqiao->
and ApR/PeR - groundlevel
<queqiao->
⟨Vee (She/Her)⟩ Do folks have any tips for maintaining orbits? I'm thinking of building a communication constellation in medium earth orbit (I considered GSO but I think the moon does a lot of out of plane perturbations there?)
<queqiao->
⟨Cirelion⟩ Is there any good way to set a alarm for when I'm near an enconter interplanetary? Like you can without principia by clicking on the line usually? If not, how can I see how many days away a specific point in my predicted trajectory is?
<queqiao->
⟨Cirelion⟩ * encounter
<queqiao->
⟨test_account⟩ Add a maneuver with 0 dv
<queqiao->
⟨test_account⟩ Open kac and there will be an option to add alarm at maneuver node
<queqiao->
⟨test_account⟩ ⟪Vee (She/Her)⟫ Do folks have any tips for maintaining […] ⮪ I think the only relay network worth building is a couple of satellites in the two stable GEO points. Everything else is difficult and dubious. Pr maybe i just know how to do it, but why, GEO works.
<queqiao->
⟨test_account⟩ * Or maybe i just dont
<queqiao->
⟨Vee (She/Her)⟩ Hmm gotcha. I was thinking of a constellation of in medium orbit at like 60-70 degrees inclination, I guess I can launch fewer satellites to GEO with some fuel for corrections
<queqiao->
⟨test_account⟩ The only advantage of lower orbits would be smaller client antennas. Geo will most likely need tl2 client antennas.
<queqiao->
⟨Cirelion⟩ ⟪test_account⟫ Open kac and there will be an option to […] ⮪ Feels kinda clunky but I guess that works, thanks!
<queqiao->
⟨Vee (She/Her)⟩ My thought was more I could maybe get it done with less delta v, do one launch to 60 degrees inclination, then at set intervals go to higher orbit, using low orbit LAN shift to shift where the target orbit is
<queqiao->
⟨test_account⟩ Yes, it less dv, but how to keep these satellites in low orbits from wandering and having uneven coverage
<queqiao->
⟨test_account⟩ It might work if you launch all of them on one rocket and use phasing orbits to insert in the same orbit at equal intervals but even then im mot sure it will be stable
<queqiao->
⟨test_account⟩ * not
<queqiao->
⟨test_account⟩ And it needs more satellites to have good coverage, and also you dont complete the geo contracts when launching them, and geo contracts pay decent money.
<queqiao->
⟨Vee (She/Her)⟩ Oh I'm swimming in money atm, I'm playing a lower stakes game this time around
<queqiao->
⟨Vee (She/Her)⟩ Yeah plan was launch like 5 at a time
<queqiao->
⟨Cirelion⟩ Is there a way to not have precise node open with principia? I never use it and that's quite annoying considering I can only close it with a hotkey