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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<_whitenotifier-4f63> [Skopos] ekstasis commented on issue #39: Map view, clicking "Show network", rotates the whole map view - https://github.com/mockingbirdnest/Skopos/issues/39#issuecomment-2816998007
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<_whitenotifier-4f63> [Principia] pleroy closed pull request #4204: Don't draw the same equipotential multiple times. - https://github.com/mockingbirdnest/Principia/pull/4204
<_whitenotifier-4f63> [Principia] pleroy opened pull request #4205: A safety mechanism to avoid looping if delineation fails - https://github.com/mockingbirdnest/Principia/pull/4205
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<queqiao--> <T​iv​ec​> i have two contracts that require eccentric orbits, how do i deal with those without crashing back to earth? both of those are going to need orbits that are quite dangerous when it comes to the moon interfering https://media.discordapp.net/attachments/480397772248580098/1363523468817207426/image.png?ex=680657b0&is=68050630&hm=c9b2980835a6e69398d6f2b9f601a6e2fd364c5666773479cce4f5395a366d51&
<queqiao--> <e​zs​na​ck​> also if your argpe is at high latitude the moon doesnt affect your orbit almost at all
<queqiao--> <T​iv​ec​> i launch at the equator, so...
<queqiao--> <T​iv​ec​> well kourou
<queqiao--> <N​az​fi​b> Just make sure you do not launch into the same plane as the Moon. Use Principia's orbit analyzer to check the lowest altitude you'll reach over the next year or so (try it in a sim).
<queqiao--> <T​iv​ec​> isn't the moon plane shifting around?
<queqiao--> <N​az​fi​b> A little bit, yeah. The inclination varies between 18° and 28°.
<queqiao--> <T​iv​ec​> Okay. I’ll light up the sim and try a few different orbits
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<queqiao--> <K​ir​k ​(H​e/​Hi​m)​> 4 cats
<queqiao--> <T​iv​ec​> with the orbit analyser, is there a way to figure out when reentry will happen?
<queqiao--> <e​zs​na​ck​> reduce the analyzer prediction till the lowest point is not the same anymore
<queqiao--> <e​zs​na​ck​> but yea it should be included in the UI smhw :v
<queqiao--> <T​iv​ec​> absolutely, yeah...
<queqiao--> <C​la​ye​l> make an issue!
<queqiao--> <T​iv​ec​> i can do that, sure. it's probably not trivial (i checked the code)
<_whitenotifier-4f63> [Principia] tivec opened issue #4206: Request: Add orbit when reentry happens to orbit analyser - https://github.com/mockingbirdnest/Principia/issues/4206
<queqiao--> <T​iv​ec​> done
<queqiao--> <e​zs​na​ck​> launching into plane is always more costly than due east unless you are at the same latitude as the moons inclination
<queqiao--> <T​iv​ec​> yes but.. that's the issue being at 5 degrees
<queqiao--> <T​iv​ec​> since i have the moon touching my orbits way too often 😄
<queqiao--> <e​zs​na​ck​> aaaah you mean the opposite lol i didnt realize, how to avoid the moon
<queqiao--> <T​iv​ec​> i want to avoid the moon 😄
<queqiao--> <e​zs​na​ck​> play with the orbit altitude and coast time and see what the orbit preview in map view looks like
<queqiao--> <e​zs​na​ck​> worse case scenario you use a kick from circular?
<queqiao--> <T​iv​ec​> thing is, the orbit is so close to earth i don't quite understand why i reenter.. possibly because of eccentricity?
<queqiao--> <e​zs​na​ck​> is your PE over one of the poles?
<queqiao--> <T​iv​ec​> i'm at 5 degrees, can't be over any poles
<queqiao--> <e​zs​na​ck​> you can launch polar :V
<queqiao--> <T​iv​ec​> i probably couldn't 😄 but i can give it a try
<queqiao--> <T​iv​ec​> nope, this orbit is reentry after 180 days. let's try a polar
<queqiao--> <T​iv​ec​> i guess my PE should be over a pole then? so i can't launch to orbit, but have to kick from orbit
<queqiao--> <e​zs​na​ck​> i mean 180 days is plenty to do what you need to do no? if you aim higher PE you gain more time
<queqiao--> <T​iv​ec​> i could try a higher PE, but i'm a little starved for dV 😛
<queqiao--> <e​zs​na​ck​> you can also launch into a slightly higher ap and raise pe at ap
<queqiao--> <e​zs​na​ck​> so add a kick and launch to lower pe to begin with to gain mroe dv
<queqiao--> <T​iv​ec​> let me try a higher pe orbit to gain some time
<queqiao--> <e​zs​na​ck​> the last thing i suggested is a more efficient way to achieve it
<queqiao--> <T​iv​ec​> kick to the higher orbit?
<queqiao--> <T​iv​ec​> well, i can launch to 350x45000 i think, which is still within parameters
<queqiao--> <e​zs​na​ck​> but its better to 150x45000 and kick
<queqiao--> <T​iv​ec​> yes, but how much is the kick going to be? I have 600m/s pointing the wrong way 😛 i can of course lower the fuel in that kick
<queqiao--> <T​iv​ec​> 700 days at least, which is more than enough
<queqiao--> <T​iv​ec​> the mean altitude does change a lot in that period though.
<queqiao--> Reply to "T​iv​ec​: yes, but how much is the kick going to be? I have 600m/s pointing the wrong way 😛 i can ..."
<queqiao--> <e​zs​na​ck​> /calculator
<queqiao--> <e​zs​na​ck​> if i were to guess like 40ms
<queqiao--> <T​iv​ec​> yeah at that altitude i need very little to kick up to 300 or so. and i'm certain i can do like 150x55000 if i want to
<queqiao--> <T​iv​ec​> anyway, thanks for the help. i think the issue with reentry here is not as much the moon but rather the orbit being elliptical
<queqiao--> <T​iv​ec​> and it seems to be 15m/s if i want to kick from 150x55000 to 350x55000. heh. i can do that.
<queqiao--> <T​iv​ec​> oh wait, it can do high orbit science too, nevermind me
<_whitenotifier-4f63> [Principia] pleroy commented on issue #4206: Request: Add orbit when reentry happens to orbit analyser - https://github.com/mockingbirdnest/Principia/issues/4206#issuecomment-2817349915
<queqiao--> <K​ag​a> Im curious, if the earth has a sun synchronous orbit, does the moon also have one? For constant sunlight
<_whitenotifier-4f63> [Principia] pleroy closed pull request #4205: A safety mechanism to avoid looping if delineation fails - https://github.com/mockingbirdnest/Principia/pull/4205
<_whitenotifier-4f63> [Principia] Clayell commented on issue #4206: Request: Add orbit when reentry happens to orbit analyser - https://github.com/mockingbirdnest/Principia/issues/4206#issuecomment-2817369922
<queqiao--> Reply to "K​ag​a: Im curious, if the earth has a sun synchronous orbit, does the moon also have one? For co..."
<queqiao--> <C​la​ye​l> hm, id imagine not, but looking on almighty google gives no answers
<queqiao--> <C​la​ye​l> low orbits around the moon are very unstable, and the tidal bulge of the moon is pretty big, so i think such an orbit would have to be out of the moon's soi to work
<queqiao--> Reply to "C​la​ye​l: hm, id imagine not, but looking on almighty google gives no answers low orbits around the..."
<queqiao--> <K​ag​a> Yeah, i checked google before answering since im hoping some experts here know
<raptop> I'm pretty sure you end up wanting something like L4, L5, NHRO, etc. (For reasons related to why in patched conic land, there's no synchronous orbit around the Moon)
<queqiao--> <K​ag​a> But how would i get low moon science for long term but with a solar panel only facing one side?
<queqiao--> <e​zs​na​ck​> by giving it enough battery to survive the dark side and a big enough panel so that it rechares them fully before its dark again?
<queqiao--> <K​ag​a> Thats true but my current LV might not have the sufficient lifting power if said probe had bigger panels or more battery
<queqiao--> <N​az​fi​b> Most sun-synchronous orbits (around Earth) don't have constant sunlight. The closest are dawn-dusk sun-synchronous orbits, which have their ascending/descending nodes on the terminator (the line between the day and night side). However, even those experience eclipses around either the summer or the winter solstice, depending on whether the AN is at 18:00 or 6:00 local solar time. The exception are dawn-dusk SSO's at altitudes
<queqiao--> between 1392 and 3327 km — those are the only SSO's that don't experience eclipses at all, and therefore are in constant sunlight year-round.That said, for the Moon: a rough estimation using only the J2 effect (ignoring the influence of most of the Moon's irregular gravitational field, as well as the influence of the Earth — this is a very inaccurate calculation) says that a lunar sun-synchronous orbit might exist at 50 km and 138°
<queqiao--> inclination. Of course, at such a high inclination, the orbit will still pass through the Moon's shadow on every orbit. A constant sunlight low lunar orbit does not exist.
<queqiao--> <K​ag​a> Ah bollocks, guess i dont have a choice
<queqiao--> Reply to "N​az​fi​b: Most sun-synchronous orbits (around Earth) don't have constant sunlight. The closest are ..."
<queqiao--> <C​la​ye​l> why do those specific SSO's not experience eclipses?
<queqiao--> <N​az​fi​b> Most sun-synchronous orbits (around Earth) don't have constant sunlight. The closest are dawn-dusk sun-synchronous orbits, which have their ascending/descending nodes on the terminator (the line between the day and night side). However, even those experience eclipses around either the summer or the winter solstice, depending on whether the AN is at 18:00 or 6:00 local solar time. The exception are dawn-dusk SSO's at altitudes
<queqiao--> between 1392 and 3327 km — those are the only SSO's that don't experience eclipses at all, and therefore are in constant sunlight year-round.That said, for the Moon: a rough estimation using only the J2 effect (ignoring the influence of most of the Moon's irregular gravitational field, as well as the influence of the Earth — this is a very inaccurate calculation) says that a lunar sun-synchronous orbit might exist at 50 km and 138°
<queqiao--> inclination. Of course, at such a high inclination, the orbit will still pass through the Moon's shadow on every orbit. A constant sunlight low lunar orbit does not exist.
<queqiao--> <N​az​fi​b> The required inclination for a sun-synchronous orbit depends on the orbital altitude, with higher orbits requiring a larger (i.e. more retrograde) inclination. Only in that range are the inclination and altitude such, that the whole orbit is outside the Earth's shadow even during the solstice.I don't have any good pictures to help you visualise, but if you want the full details: