raptop changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Galois. We currently target 1.8.1, and 1.9.1. <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… | <egg> also 4e16 m * 2^-52 is uncomfortably large
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[Principia] rnlahaye forked the repository - https://git.io/JUavI
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[Principia] eggrobin opened pull request #2733: Much ado about nothing - https://git.io/JUawe
<discord->
Calvin_Maclure. — Trying to plan a simple reentry maneuver and figure out the optimal place to do the burn, but when I enter my -295m/s tangent value, Principia forces me to have a node prediction of 774 days. Just... why??
<discord->
egg. — > Principia forces me to have a node prediction of 774 days
<discord->
egg. — I have no idea what this means.
<discord->
Calvin_Maclure. — Plan Length
<discord->
Calvin_Maclure. — It takes on a value of 774 days which I cannot reduce.
<discord->
Calvin_Maclure. — I'm trying to return from LEO, I just need 2 hrs at most
<discord->
egg. — can you take a screenshot?
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[Principia] eggrobin closed pull request #2733: Much ado about nothing - https://git.io/JUawe
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[Principia] eggrobin pushed 11 commits to master [+0/-0/±22] https://git.io/JUaiv
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[Principia] eggrobin fbe489d - test a non-arithmetic comparator with golden section search
<discord->
lpg. — I should find the commit that fixed "solids can throttle" and revert it, one of these days. Before that was fixed, it was possible to have solids active but not yet burning (by leaving throttle at 0), and it made principia happy
<discord->
egg. — ooooh that is a very clever behaviour
<discord->
egg. — (also it means you can light the boosters by pushing the throttle which sounds satisfying :-p)
<discord->
badgermasher. — I think that's from ThrottleLocked = True
<discord->
egg. — though to be honest SRBs should really be special-cased by Principia, since they have fixed Δv (and thus only direction should be left to sliders)
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<discord->
Kitten Dispenser. — my save files are getting really huge
<discord->
Kitten Dispenser. — most recent one is 112MB
<kmath>
<eggleroy> Ryan P. Russel and Martín Lara (2006), Repeat Ground Track Lunar Orbits in the Full-Potential Plus Third-Body Probl… https://t.co/9lt46X9ssR
<kmath>
<eggleroy> Michel Capderou (2012), Satellites : de Kepler au GPS. https://t.co/vAqW1Adq8Z
<discord->
Serina. — in other words, buy books on orbital mechanics?
<discord->
Damien. — @Serina for actual humans who don't read astrodynamics books, use the orbit analyser
<discord->
Serina. — ❤️
<discord->
Serina. — is that a built in function?
<discord->
Damien. — The downside is that's for verifying orbits you're already in
<discord->
Damien. — Yed
<discord->
Serina. — kewl
<discord->
Damien. — Yes (edited)
<discord->
Damien. — For actual orbit planning, get the books out
<discord->
Serina. — mhn
<discord->
egg. — and the cats
<discord->
Damien. — Yup
<discord->
egg. — (since apparently the actual humans do not read the books)
<discord->
lpg. — as far as rp-1 is concerned, it's largely a non-issue
<discord->
Serina. — Say I want to put a space station into a 300 x 300 km orbit
<discord->
Serina. — would that just, work?
<discord->
Damien. — Sure
<discord->
lpg. — it won't stay in that precise 300x300, but it'll stay close enough
<discord->
lpg. — likewise your GEO sats may not stay in their perfect pretty orbit forever, but won't drift in any way that matters
<discord->
egg. — what won’t work so well is, say, having a GEO sat over Africa
<discord->
Damien. — Orbit stability re: orbit failure is only really an issue at the moon and in lagrange point
<discord->
egg. — GEO sats drift in longitude except at two stable longitudes
<discord->
Damien. — Drift is the main issue on regular orbits
<discord->
Damien. — Orbit stability re: orbit failure is only really an issue at the moon and in lagrange points (edited)
<discord->
lpg. — On the other hand, don't plan on orbiting deimos for any significant amount of time
<discord->
egg. — yeah @Damien summarizes it well
<discord->
egg. — note that you can still find stable orbits about the Moon, just like you can find non-drifting (for some purposes) orbit about the Earth
<discord->
egg. — note that you can still find non-crashing orbits about the Moon, just like you can find non-drifting (for some purposes) orbit about the Earth (edited)
<discord->
egg. — but here you start having to do a little bit of homework
<discord->
egg. — note that you can still find non-crashing orbits about the Moon, just like you can find non-drifting (for some purposes) orbits about the Earth (edited)
<discord->
Serina. — *nodnod*
<discord->
Damien. — @Serina instability is opportunity though. Drift can be exploited for useful purposes
<discord->
Serina. — so orbital pertibuation should be difficult
<discord->
Serina. — buuut
<discord->
Serina. — everything sub 100 days is doable on the moon without too much stress
<discord->
Damien. — If an orbit precesses around the earth at the same rate the earth moves around the sun, that orbit is sun-synchronous
<discord->
Damien. — Gross simplification of one example but yeah, your loss in simple orbits is your gain in interesting ones
<discord->
lpg. — your first moon orbiter will stand a good chance of getting eaten in short order, since you're unlikely to have much control over its shape. past that point, the only trickiness you're likely to run into is trying to harvest low-in-space moon science (staying below 150km but safely high)
<discord->
Serina. — *nodnod*
<discord->
siimav. — I'm curious - what would happen with a vessel in orbit of Moon if Hack gravity were turned on and then timewarped for a few months.
<discord->
Damien. — It'd go back to patched conics and be unchanging I imagine
<discord->
siimav. — I'd be really surprised if it's as easy as that
<discord->
egg. — not sure if the hack gravity exemption works in timewarp
<discord->
smartdummies. — My main problem with lunar orbit are the eccentricity requirements Kerbalism puts on some experiments. The Moon's low requirement fir space high makes staying in a non circular orbit, maintaining the eccentricity, and keeping a decent chunk of the orbit in space low rather fun
<discord->
Serina. — that's where the fancy orbital mechanics books come from
<discord->
Serina. — that book on orbital motion is insanely pricey
<discord->
badgermasher. — It's a textbook, unfortunately it's not ubiquitous enough to have cheap international versions floating around.
<raptop>
Capderou is on libgen, but apparently the book is only in French?
<raptop>
(Also, do I need to speak feline to ask ANBOcat for advice?)
<discord->
egg. — The book has an English translation
<discord->
egg. — Handbook of satellite orbits: from Kepler to GPS
<discord->
egg. — There is also an earlier edition called satellites: orbits and missions iirc
<discord->
egg. — @Damien was able to find them iirc
<discord->
n9gaming. — I've noticed craft placed on the lunar plane in a 10Mm above Earth don't stay in that plane for very long - reckon this would be true for craft in much lower orbits as well?
<discord->
n9gaming. — I've noticed craft placed on the lunar plane in a 10Mm orbit above Earth don't stay in that plane for very long - reckon this would be true for craft in much lower orbits as well? (edited)
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[Principia] eggrobin labeled pull request #2734: Reduce heap usage in Poisson series - https://git.io/JUadz