UmbralRaptop changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Fuchs. We currently target 1.5.1, 1.6.1, 1.7.x, 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
<discord-> e​gg. — well, RA integration is probably critical to doing something sane about SAR and microwave imaging in KC anyway
<discord-> D​RVeyl. — The drawing code for it is at <https://github.com/DRVeyl/RealAntennas/blob/master/src/RealAntennasProject/MapUI/RACommNetUI.cs>. Uh, no warranty on the readability or comments.
<discord-> e​gg. — hm, my KSP froze
<discord-> e​gg. — ... engines heat up at full throttle even if they have no fuel
<discord-> e​gg. — free energy I suppose
<discord-> D​RVeyl. — KSP runs on optimism, and so do your engines, apparently!
<discord-> e​gg. — looks like most of my engines have 0 max thrust; I am good at installing this
<discord-> e​gg. — ah yes perhaps I should have installed RO itself
<discord-> e​gg. — always a good idea
<raptop> conda install ro
Wetmelon has joined #principia
egg|anbo|egg has joined #principia
egg|anbo|egg__ has joined #principia
egg|anbo|egg___ has joined #principia
egg|anbo|egg has quit [Ping timeout: 190 seconds]
egg|anbo|egg_ has quit [Ping timeout: 189 seconds]
egg|anbo|egg___ has quit [Remote host closed the connection]
Wetmelon has quit [Ping timeout: 189 seconds]
<discord-> S​tandecco. — and you haven't even seen ion engines heat up to 3000K when running
<discord-> S​tandecco. — in a couple of seconds too
<discord-> S​tandecco. — for a 7 kW input, that's free energy even when running with fuel
<discord-> C​onventia. — This is surprisingly useful for geosat positioning.
<discord-> C​onventia. — The more I use principia, the more I ❤️ principia.
<discord-> M​ikicat. — this is both confusing and beautifull at the same time
<discord-> M​ikicat. — actually, when you use principia, gravity assists should work completly different, right?
<discord-> S​tandecco. — unless you use lagrange points when doing assists, they shouldn't
<discord-> M​ikicat. — but shouldn't it be like... to accelerate planet pulls you? so to accelerate you must escape SOI in retrograde to planets movement?
<discord-> S​tandecco. — the concept as I've always heard it explained ~~and never went through the proper math to understand it because I didn't have the tools yet~~ is that you keep the same velocity relative to the planet at approach and departure, but the planet has moved and so you're in a different place with the same velocity
<discord-> S​tandecco. — the energy conservation part is that you steal some of the orbital energy
<discord-> S​tandecco. — the energy conservation part is that you steal some of the orbital energy of the planet (edited)
<discord-> M​ikicat. — well, time to read things again
<discord-> S​tandecco. — the planet pulls you towards itself at all times, and it does it in a conservative manner (meaning that at a given distance the pull is exactly the same, and all paths trough 2 points at the same altitude will have zero velocity or energy gain); the difference is that, while the velocity is the same, its direction isn't, and the planet has effectively curved your trajectory
<discord-> S​tandecco. — which changes your speed relative to the sun
<discord-> M​yshiko. — @Mikicat I recommend first reading https://en.m.wikipedia.org/wiki/Elastic_collision
<discord-> M​yshiko. — When viewed form the sufficiently far-far away, the interaction of probe with planet is essentially an elastic collision.
<discord-> M​yshiko. — When viewed from the sufficiently far-far away, the interaction of probe with planet is essentially an elastic collision. (edited)
<discord-> M​yshiko. — And you can see, that elastic collision with much heavier object provides disproportionate increase in the speed of the lighter object.
<discord-> S​tandecco. — the maximum impulse is still 2mv
<discord-> S​tandecco. — cannot get higher than that
<discord-> M​yshiko. — https://en.m.wikipedia.org/wiki/Gravity_assist 🙂
<discord-> M​yshiko. — With skill and lucky planetary positions, gravity assists work very well.
raptop has quit [Ping timeout: 190 seconds]
<discord-> C​onventia. — Is the curve of the path caused by the gravity of venus increasing as the probe gets closer?
<discord-> D​amien. — VCI only really makes sense when you're close to it or in orbit of it
<discord-> D​amien. — what does your trajectory look like in SCI or VCSA?
<discord-> C​onventia. — It looks 'normal'.
<discord-> C​onventia. — I included the reference frame specifically cause I was curious about the way it looks in this one. 😛
<discord-> S​tandecco. — the trajectory displayed is just a reference frame change, if it looks weird there is probably some significant relative motion
Iskierka has quit [*.net *.split]
Rokker has quit [*.net *.split]
mofh_ has quit [*.net *.split]
discord- has quit [*.net *.split]
egg has quit [*.net *.split]
VITAS has quit [*.net *.split]
acc has quit [*.net *.split]
Rokker has joined #principia
Iskierka has joined #principia
mofh_ has joined #principia
discord- has joined #principia
acc has joined #principia
VITAS has joined #principia
egg has joined #principia
<discord-> D​amien. — it's got mascons yes
<discord-> D​amien. — also it's oval shaped from the side, and also from above
<discord-> D​amien. — geostationary sats are hard
<discord-> D​amien. — also the moon tugs you up and down
<discord-> D​amien. — unstable longitude
<discord-> D​amien. — stable longitude
<discord-> D​amien. — not much you can do about the vertical oscillation
<discord-> C​onventia. — Interesting
<discord-> D​amien. — when looking down on the earth from above, you have the minor and major axis (it being wider along the major axis). Satellites get pulled around by the offset mass if they're not positioned on a point in between both the bulges
<discord-> D​amien. — placing satellites on the minor axis puts the two bulges on either side and balances it
<discord-> B​utcher. — Ugh, I'd forgotten how painful building principia from source is.
egg|anbo|egg__ has quit [Ping timeout: 204 seconds]
<discord-> C​onventia. — Why build from source?
<discord-> B​utcher. — Fed up the RCS planner being terrible.
<discord-> C​onventia. — Hmm... never tried.
<discord-> P​rofiremu23. — > The perfectionist in me is pleased... though apparently, stationkeeping is a thing. 😛
<discord-> P​rofiremu23. — @Conventia Wait, that is illegal
<discord-> C​onventia. — What's illegal?
<discord-> P​rofiremu23. — > My speed in ECEF is 0.2 m/s
<discord-> P​rofiremu23. — @Conventia the 0.2 m/s speed on Earth orbit
<discord-> D​amien. — 0.2m/s relative to the surface 😛
<discord-> P​rofiremu23. — Oh, i am a dumbass
<discord-> P​rofiremu23. — My brain is thinked about 0.2 m/s on orbital speed
raptop has joined #principia
egg|anbo|egg has joined #principia
egg|anbo|egg has quit [Read error: Connection reset by peer]
egg|anbo|egg has joined #principia
<discord-> e​gg. — @Butcher ah yes I should look into your RCS bug
<discord-> l​amont. — egg would that awful angular momentum reentry-affecting bug you fixed awhile back cause rockets to wobble on takeoff?
<discord-> l​amont. — (like literally right on releasing the launch clamps)
<discord-> l​amont. — or is that too low of an altitude for principia to ever care?
<egg|cell|egg> Hm
<egg|cell|egg> Principia has no altitude threshold
<discord-> l​amont. — i should probably just upgrade and find out
<egg|cell|egg> Maybe the second iteration of the but
<egg|cell|egg> Bug
<egg|cell|egg> Which version are you on
<discord-> B​utcher. — I assume it's not just the sketchy launch clamp collision @lamont?
<discord-> l​amont. — i'm on an old version, its whining about how it wants to be upgraded, so i should probably just do that
<discord-> B​utcher. — Principia is needy.
<discord-> l​amont. — and i don't think its launch clamp collision
<discord-> S​tandecco. — does a differential equation solver exist somewhere?
<discord-> S​tandecco. — simple stuff
<discord-> B​utcher. — mmm dirty.
<discord-> e​gg. — What is the name of the version
<discord-> e​gg. — Lamont
<discord-> l​amont. — lots of differential equation solvers
<discord-> S​tandecco. — I just have a y'' + b/my' = g thing
<discord-> S​tandecco. — I can solve it by hand, but what I'm finding is different than what the supposed solution is
<discord-> S​tandecco. — so I just need the dumbest solver imaginable to do this
<discord-> S​tandecco. — but I don't know any
<discord-> l​amont. — % egrep -rl Fubini .
<discord-> l​amont. — ./x64/principia.dll
<discord-> l​amont. — ./MacOS64/principia.so
<discord-> l​amont. — ./Linux64/principia.so
<discord-> l​amont. — oh symbolic ODE solver?
<discord-> S​tandecco. — yeah it's a 2nd order ODE
<discord-> S​tandecco. — don't need nothing fancy, just something that someone has implemented in a website 20 years ago will suffice
<discord-> l​amont. — yeah i've never even played around with that in matlab's symbolic toolbox
<discord-> e​gg. — Fubini had the nastiest version of the bug yes
<discord-> S​tandecco. — time to play with the help command in matlab
<discord-> l​amont. — if it does it, you'd need to buy the symbolic toolbox
<discord-> S​tandecco. — isn't it a free addon?
<discord-> l​amont. — no
<discord-> l​amont. — everything in matlab nickle and dimes you
<discord-> l​amont. — well, $50 and $100 you
<discord-> l​amont. — everything in matlab nickel and dimes you (edited)
* raptop throws an octave of sneks at matlab
egg|anbo|egg_ has joined #principia
<discord-> S​tandecco. — <https://it.mathworks.com/help/symbolic/solve-a-single-differential-equation.html> hey, maybe this'll work
<discord-> S​tandecco. — it took a good second to just create the symbolic function
<discord-> s​cimas. — Sympy is another choice
<discord-> S​tandecco. — ok it's giving me yet another solution
<discord-> S​tandecco. — I probably wrote it incorrectly
<discord-> S​tandecco. — ok, works now
<discord-> S​tandecco. — ... and it's my own solution
<discord-> S​tonesmile. — Wait, your first step wasn't Wolfram Alpha?
<discord-> S​tandecco. — right, it exists
<discord-> S​tandecco. — and does exactly this in the easiest way imaginable
<discord-> S​tonesmile. — Remote exams with "all tools allowed" was interesting
<discord-> S​tandecco. — that is new
<discord-> A​udaxxx. — tufx
<discord-> S​tandecco. — we have to have like 15 cameras pointed at us and the program locks your entire desktop
<discord-> S​tandecco. — (fun fact, you can actually alt+tab out of it and you only get a warning - the first time)
<discord-> S​tonesmile. — That seems like a bodge...
raptop_ has joined #principia
<discord-> s​cimas. — I mean, obviously there is only one computer in the whole world...
raptop has quit [Ping timeout: 189 seconds]
<discord-> S​tandecco. — that's what the 3 different cameras should prevent
<discord-> S​tandecco. — we couldn't even use matlab (we would've had to remote desktop our way to the university's computers, but that wasn't a viable option for 5k simultaneous users) so they had to change the exam to have only syntax and theory questions
<discord-> S​tonesmile. — Yeah, i think my Uni's thought was that some people will figure out a way to cheat no matter the regulations, so they allowed all tools for everyone and accounted for that in the questions
<discord-> S​tandecco. — that's very reasonable, actuall
<discord-> S​tandecco. — that's very reasonable, actually (edited)
egg|anbo|egg has quit [Ping timeout: 190 seconds]
egg|cell|egg has quit [Read error: Connection reset by peer]
<discord-> S​tandecco. — you can have wolfram alpha, but if the question was specifically made to make it useless, it's not worth much
<discord-> S​tandecco. — the even funnier fact is that while we do have various cameras, there is no way for the professor to check them all at once, so the program gives warnings when it doesn't see your face for 0.1 ns, which is literally all the time if you're trying to write things down
<discord-> S​tonesmile. — That just seems over engineered, without actually accomplishing anything
<discord-> S​tandecco. — must use all that sweet state money in some way
<discord-> S​tandecco. — we're one of the only 2 universities that gets some money, so better than nothing I guess
<discord-> S​tonesmile. — I assume you are in the US, so which uiversities get government money?
<discord-> S​tonesmile. — I assume you are in the US, so which universities get government money? (edited)
<discord-> S​tandecco. — nope, I'm in italy
<discord-> S​tonesmile. — Oh, thought all were funded there
<discord-> S​tandecco. — they are, but the amount of funding isn't fixed
egg|cell|egg has joined #principia
<discord-> S​tandecco. — it really shows in the quality of the infrastructure
<discord-> S​tandecco. — so if I stayed back home at my local uni, I would've gotten a much worse experience in general
<discord-> S​tandecco. — if this whole pandemic didn't happen, I would've gotten to visit CERN around april (for free!)
<discord-> S​tandecco. — while here, if this whole pandemic didn't happen, I would've gotten to visit CERN around april (for free!) (edited)
<discord-> S​tonesmile. — Is the trip re-scheduled or canceled?
<discord-> S​tandecco. — canceled, afaik
<discord-> S​tonesmile. — Ouch
<discord-> S​tandecco. — yeah I know
<discord-> S​tandecco. — I hope we get something next year
<discord-> S​tandecco. — but chances are slim until a vaccine is found and the situation is fully back to normal
<discord-> l​amont. — once i got past like sophomore physics all the tests were open book / open notes
<discord-> S​tandecco. — so you're not supposed to remember those enormous equations in advanced physics
<discord-> S​tandecco. — very good
egg|anbo|egg_ has quit [Remote host closed the connection]
egg|anbo|egg has joined #principia
<discord-> T​ransparent_Elemental. — I'm trying to use KSPTOT to plan my missions with principia, but right now the problem is that i need to figure out the initial orbit requirements. I'm kinda confused as to how can i know which inclination to use (I'm at Baikonur) or which argument of periapsis considering that orbits change over time, is there a way to tell or any other methods to plan interplanetary departures?
<discord-> T​ransparent_Elemental. — And i'm still getting some wacky results if i try to import my orbital parameters directly from ksp like this one
raptop_ has quit [Read error: Connection reset by peer]
raptop has joined #principia
<discord-> C​onventia. — You'll want to do polar, which makes things slightly simpler. I found polar to be easier with principia even when launching from kourou.
<discord-> C​onventia. — If you do a circular parking orbit, your Arg of Peri doesn't matter.
<discord-> C​onventia. — Only your LAN does. I'm not sure if that's what RAAN is, cause I don't know what RAAN stands for.
<discord-> s​cimas. — Right Ascension of Ascending Node, basically the same thing I think.
<discord-> e​gg. — yes, "longitude" is more generic but also more ambiguous
<discord-> e​gg. — "right ascension" tells you that you are measuring things along the celestial equator, and not, for instance, along the ecliptic
<discord-> e​gg. — (or even on the surface: the longitude of the node is relevant if you want your ground track to be in a specific place)
<discord-> e​gg. — (or even on the surface: the terrestrial longitude of the node is relevant if you want your ground track to be in a specific place) (edited)
Jesin has quit [Quit: Leaving]
<discord-> T​ransparent_Elemental. — @Conventia thanks
<discord-> B​utcher. — Hmm, my lunar oribter disappeared. The mascons claim another victim.
<discord-> B​utcher. — Hmm, my lunar orbiter disappeared. The mascons claim another victim. (edited)
Jesin has joined #principia
<discord-> e​gg. — 🌘
<discord-> C​onventia. — One of my orbiters got masconed, the other 2 didn't.
egg|cell|egg has quit [Ping timeout: 204 seconds]
egg|anbo|egg_ has joined #principia
egg|anbo|egg_ has quit [Ping timeout: 204 seconds]
<discord-> B​utcher. — It was in a fairly low orbit, 87x450 km on insertion.
<discord-> e​gg. — what were the inclination, eccentricity, and argument of periselene?
<discord-> B​utcher. — No idea off hand.
<discord-> B​utcher. — Inclination maybe 50°
<discord-> e​gg. — Hm
<discord-> e​gg. — that orbit does not sound all that low
<discord-> e​gg. — (from from Martín Lara, 2011, *Design of long-lifetime lunar orbits: A hybrid approach*)
<discord-> e​gg. — 50° should be stable if your orbit is circular
<discord-> e​gg. — but it was not, what with 87<450
<discord-> e​gg. — (also if your periselene is not over one of the poles things will not be stable)
egg|cell|egg has joined #principia