UmbralRaptop changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is 🐇. We currently target 1.5.1, 1.6.1, and 1.7.x. <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…
UmbralRaptop has quit [Remote host closed the connection]
UmbralRaptop has joined #principia
egg|zzz|egg has quit [Remote host closed the connection]
<discord->
Damien. — @egg yeah I thought so too. I was looking for information on manipulating/stabilising L-point orbits (my attempts to do things like change inclination of a halo orbit have been hamfisted at best) and came across it.
<discord->
egg. — The problem with these Lagrange things is that in practice you live in the ER3BP, not the CR3BP; and we don't have a rotating-pulsating reference frame (that's a weird frame, which fixes both bodies and therefore wherein things that actually stay the same size look like they grow and shrink over time)
<discord->
egg. — so you don't have a frame where you can see the Lagrange points
<discord->
Damien. — And the NRHOs proposed for LOP-G are apparently easy to maneuver between (L1/L2 north/south) but I haven't seen any information on *how*
<discord->
Damien. — Yeah I was going to ask about a frame centered on the L point but want sure if the earth- moon live for example was the same thing
<discord->
Damien. — Yeah I was going to ask about a frame centered on the L point but wasn't sure if the earth- moon live for example was the same thing (edited)
<discord->
Damien. — Yeah I was going to ask about a frame centered on the L point but wasn't sure if the earth- moon line for example was the same thing (edited)
<discord->
Damien. — Could anything be done to the bodies file before importing to fix the inclination ksptot sees from whatever principia does?
sdrodge has joined #principia
<discord->
Damien. — Or any other workaround you can think of
<discord->
egg. — @Damien I don't know how KSPTOT works
<discord->
egg. — @Damien ultimately this seems to be a KSPTOT bug
<discord->
egg. — to quote myself, these are just ICRS axes; it's very weird that KSPTOT needs some special reference frame https://forum.kerbalspaceprogram.com/index.php?/topic/33568-winmaclinux-ksp-trajectory-optimization-tool-v164-new-vehicle-sizing-tool/page/120/&tab=comments#comment-3441940
<discord->
egg. — and as Arrowstar replies, the bug here is that he doesn't support tilt
<discord->
Sir Mortimer. — I'm poaching other mods for parts. I need communication dishes to put on a satellite that provide some form of communication infrastructure, and cameras for surface observations. Luckily, Bluedog_DB uses a very permissive license
<discord->
Sir Mortimer. — Next step in the contracts thing will be a mission to provde uninterrupted service coverage over a random location on kerbin for a year or so 🙂
<discord->
egg. — @Sir Mortimer should that be a two-point thing?
<discord->
egg. — i.e. the satellite must be in view of the broadcasting station and of the random receiver
<discord->
egg. — or do we assume that they are virtually in the same place
<discord->
Sir Mortimer. — actually that's a nice consideration. didn't think about that
<discord->
egg. — (assuming we're going for TV sat here)
<discord->
egg. — (but telecom is kinda similar)
<UmbralRaptop>
random longitude, or also latitude?
<discord->
egg. — well, varied latitudes mean varied solutions
<discord->
egg. — I'm bad at keyboards
<discord->
egg. — молния̀ ετχ͂
<discord->
Sir Mortimer. — If that works, I'll add further constraints
<discord->
egg. — low latitudes make GEO viable
<UmbralRaptop>
yeah, those
<discord->
Sir Mortimer. — maybe that will be for an advanced contract, later. right now my goal is to find a way to work with contract configurator so that it can do that with more than one satellite. I'm not sure that this is within it's capabilities atm.
<discord->
egg. — молния
<discord->
egg. — υμ
<discord->
egg. — here
<discord->
egg. — higher ones are more interesting
<discord->
Sir Mortimer. — @UmbralRaptop totally random. might even be over an ocean (think naval telecommunication)
<discord->
egg. — @Sir Mortimer yeah as a prototype one-point should have most of the technical issues
<discord->
egg. — and then once I get back to that design doc we can think of something more realistic
<UmbralRaptop>
kerbal SSBNs
<discord->
Sir Mortimer. — I could vary the location constraints based on difficulty level. Easiest would be a geostationary, but I could really mess with the player using different latitudes
<discord->
egg. — why is that diagram in dutch
<discord->
egg. — though tbh I guess in a lot of cases the receiver and emitter are close
<discord->
Sir Mortimer. — but anyway, baby steps. first have to find out if/how to nudge contract configurator into doing what I want it to do.
<discord->
egg. — > An event called sun outage occurs when the sun lines up directly behind the satellite in the field of view of the receiving satellite dish.[27] This happens for about a 10-minute period daily around midday, twice every year for a two-week period in the spring and fall around the equinox. During this period, the sun is within the main lobe of the dish's reception pattern, so the strong microwave noise
<discord->
egg. — this sounds fun to simulate :D
<discord->
egg. — also yeah, the article mentions GEO and Молния, so this would be a good test contract with multiple different and exciting solutions
<discord->
Sir Mortimer. — wait, they use Молния for satellite tv? do they have tracking antennas up there?
<discord->
egg. — cc @bofh453 / mofh
<discord->
egg. — hm, unsure
<discord->
egg. — (stock can use any inclination for high-eccentricity constellations, Principia players need Молния)
<discord->
Sir Mortimer. — or are they just more tolerant to the transmitter being slightly off center of the dish?
<discord->
Damien. — Thanks @egg. I was under the impression it was an issue only with principia, not RSS
<discord->
egg. — well, it's even more of an issue with Principia because Principia actually has tilt, RSS is kinda fudging it; but ultimately it's a KSPTOT issue rather than an RSS or Principia one
<discord->
Damien. — Fair enough
sdrodge has quit [Ping timeout: 378 seconds]
<discord->
Sir Mortimer. — what does a tv satellite look like?
<discord->
Sir Mortimer. — all i can find are illustrations
<discord->
Sir Mortimer. — i'd like to see an image of an actual tv satellite
<discord->
egg. — > Primarily used for satellite communications, for full-time satellite TV networks or raw satellite feeds. Commonly used in areas that are subject to tropical rainfall, since it is less susceptible to rainfade than Ku band (the original Telstar satellite had a transponder operating in this band, used to relay the first live transatlantic TV signal in 1962).
<discord->
egg. — @Sir Mortimer so if you want to get fancy, which instrumentation you put on your TV satellite will depend on the kind of climate you have where you want to broadcast
<discord->
Sir Mortimer. — @egg that would be fancy, yes... but a) I couldn't make parts to save my life, and b) I'd like to avoid adding too many different parts
<discord->
egg. — I mean, this is largely a technology demonstrator anyway; given how RO works with configs + existing mods the shortage of parts shouldn't be a problem there
<discord->
egg. — but it's interesting that just the question of "plain old TV or comsat" allows us to have quite a bit of interesting complexity to work with
sdrodge has joined #principia
<discord->
Sir Mortimer. — yep 🙂
<discord->
Sir Mortimer. — maybe by making the required parts very expensive?
<discord->
egg. — yeah, the reason why you don't do that in practice is that satellites and launches are expensive
<discord->
Sir Mortimer. — just thinking about something else... people could just spam the sky with satellites so that they don't have to think about the orbits. do we want to stop them from doing that?
<discord->
egg. — you need a reasonably chonk bus to broadcast TV from GEO, and you need to lob it all the way there
<discord->
Sir Mortimer. — launches in KSP are quite cheap. so are parts. I never run out of money in a hard career game
<discord->
Sir Mortimer. — maybe put a hefty price tag on the transmitter parts, and pay for one or two transmitters with the advance granted by the contract?
<discord->
Space Dwarf. — If people want to trade fps for signal coverage by starlinking the sky I say let em
<discord->
Sir Mortimer. — it could be an additional requirement on the contract: provide service without using more than x satellites
<discord->
egg. — as @Space Dwarf says, I don't think we really need that kind of requirement
<discord->
egg. — you can brute force it, but you'll also spend quite a bit of time launching all those things
<discord->
egg. — I think the player's time is a better incentive than hardwired limits
<discord->
egg. — I'm trying to find some price tags on those GEO sats
<discord->
Sir Mortimer. — I tend to agree. anyway, the people who really are behind it will always strive to make the most out of as few as possible satellites
<discord->
egg. — > Apstar 7B, commandé le 30 avril 2010, un contrat de 112,3 millions d'euros (148,7 millions de dollars américains) comprenant aussi le centre de contrôle du satellite37, renommé en Chinasat 12, lancé le 27 novembre 201238.
<discord->
Sir Mortimer. — how much of that was for the payload?
<discord->
Damien. — @Sir Mortimer yeah RP1 players aren't the issue. We can't afford the launches
<discord->
Sir Mortimer. — Typical launch price for launching a satellite into GEO is ~ $10-12K per pound
<discord->
egg. — > Apstar 7B will carry 28 C-band and 23 Ku-band transponders on Thales Alenia Space’s Spacebus 4000 C2 platform and is expected to weigh about 4,000 kilograms at launch. The satellite will resemble the Apstar 7 satellite — but with five fewer Ku-band transponders — that Thales Alenia Space is building under a September 2009 contract valued at 128.5 million euros.
<discord->
Sir Mortimer. — so, if I read this correctly: 128 millions for the payload, and about 50 millions to launch it
<discord->
egg. — I suppose
<discord->
egg. — > contracted with Thales Alenia Space of France and Italy to build Apstar 7B in a deal valued at 112.3 million euros
<discord->
egg. — 7B is cheaper than 7
<discord->
Sir Mortimer. — ok, so a probe should cost 2-3 times as much as the launch vehicle.
<discord->
egg. — if the price difference were just the price of the 5 fewer Ku transponders, that puts the price tag on one of them at 3,24 million euros
<discord->
egg. — > Unweighted global average annual lease price for a C-band transponder is $1.96 million; for a Ku-band transponder the global average is $3.98 million.
<discord->
egg. — @Sir Mortimer so that's the order of magnitude for the price of the actual bit that does the TV (the satellite bus is more the "probe core + RCS etc." part; the transponders are the actual contract-fulfilling bit)
<discord->
egg. — and then you put dozens of those on each sat
<discord->
Sir Mortimer. — ok. it's going to be an expensive part, then.
<discord->
egg. — @Sir Mortimer yeah on second thought it's hard to get a breakdown of which bits of the satellite are costly between the bus and the various instruments; but definitely the payloads aren't cheap
egg|zzz|egg has quit [Remote host closed the connection]
egg|zzz|egg has joined #principia
<discord->
egg. — @Sir Mortimer though I would guess the payload price would be different in LEO, where you could live with lower-power transmitters
<discord->
egg. — apparently an Iridium sat was about 15 million USD apiece
<discord->
egg. — (but then you need a whole constellation of them if you want coverage; more sensible for whole-world telecommunications than regional TV)
<discord->
Sir Mortimer. — no wonder they went bankrupt.
egg|zzz|egg has quit [Remote host closed the connection]
egg|zzz|egg has joined #principia
egg|zzz|egg has quit [Remote host closed the connection]
egg|zzz|egg has joined #principia
<discord->
Damien. — getting really fed up with trying to type 'principal' at work and typing 'principia'
<discord->
Damien. — just in that sentence I started to type principial and had to correct it
egg|zzz|egg has quit [Remote host closed the connection]
<discord->
DRVeyl. — Sure, cubesat platforms don't have to survive as long, so you get reduced reliability costs. But probably not 1000x.
<discord->
DRVeyl. — Sure, they won't stay in space as long, so you get lower reliability requirements, but you also get a price point per equipment.
<discord->
DRVeyl. — Don't need to solve a multi point problem, so much as also require the sat providing service to a ground point also just meets "is connected to home" -- and if you want, also "provides x rate to home"
<discord->
DRVeyl. — Of interest to me anyway, RA does model noise from celestial bodies incl sun being in the antenna pattern and affecting reception ;)
<discord->
Damien. — seems like the stars are aligning (pun unintended) for these highly detailed satellite contracts
<discord->
Damien. — can't wait
egg|work|egg has joined #principia
egg|cell|egg has quit [Ping timeout: 204 seconds]
egg|cell|egg has joined #principia
<discord->
egg. — @DRVeyl RA?
<discord->
DRVeyl. — RealAntennas, my CommNet mod.
egg|cell|egg has quit [Read error: Connection reset by peer]
egg|cell|egg has joined #principia
egg|cell|egg has quit [Ping timeout: 204 seconds]
<discord->
egg. — ah
<discord->
egg. — I don't know whether @Sir Mortimer's comsat efforts will be RA-based, but that's good to know
egg|cell|egg has joined #principia
<discord->
user1453. — Real antennas works really well with kerbalism
<discord->
Sir Mortimer. — since RA has authority over data rates, it will at least affect data transmissions
<discord->
Sir Mortimer. — note to self: contract paramter for minimum transmission speed
egg|cell|egg has quit [Ping timeout: 206 seconds]
<discord->
Sir Mortimer. — (not sure if possible to implement atm)
egg|cell|egg has joined #principia
<discord->
egg. — @DRVeyl but then does RA distinguish between C and Ku band, and does it model the different data rates to ground based on pluviometry between those :-p
<discord->
egg. — (that's a concern in this particular context, see backlog)
<discord->
Damien. — it definitely has UHF/VHF/X/S bands, I know that much
<discord->
DRVeyl. — For the DSN, yes, it does.
<discord->
DRVeyl. — There is a lot of recorded data on that.
<discord->
Damien. — damn neph's on a roll with all these wiki pages
<discord->
DRVeyl. — I use averages for a singular value, but...
<discord->
egg. — wait, you take pluviometry into account? how
<discord->
egg. — do you have rainfall models?
<discord->
DRVeyl. — Published rain fade specs in the DSN handbook
<discord->
DRVeyl. — It's been measured for the 3 DSN stations
<discord->
egg. — ah
<discord->
egg. — so I guess here it would have to be expanded planetwide
<discord->
egg. — RA does sound nice, I'll have to poke at it someday
<discord->
DRVeyl. — ;)
<discord->
egg. — @DRVeyl random fun thing that may be of interest to you: the plume of Vega launches interferes with telemetry, so they had to add a flanking station
<discord->
egg. — unsure if that's within the realm of things you can model
<discord->
DRVeyl. — I only have S, X, K(ish) specs, C isn't in the DSN now, though other ground stations will have it.
<discord->
user1453. — Vega is hydrolox?
<discord->
egg. — no, solids
<discord->
DRVeyl. — Neat. No, I avoided vessel and antenna part physical orientation, and naively let the player say where the antenna should point and believe it can.
<discord->
egg. — yeah, dealing with that would have to wait for proper persistent rotation
<discord->
egg. — we're working on it but elliptic integrals are hard
<discord->
user1453. — And an arm you can tell point this at earth
<discord->
Sir Mortimer. — (PersistentRotation doesn't persist rotation at all, it just applies the persisted values when the vessel goes off rails)
<discord->
egg. — yeah
<discord->
egg. — but things that freely rotate do very funky things on their own
<discord->
Sir Mortimer. — (which is why there's a workaround in kerbalism)
<discord->
user1453. — Is there any way to keep a probe auto pointed at the sun and expend rcs fuel as required?
<discord->
Damien. — having to physically point antenna at bodies would be a pain I can imagine
<discord->
egg. — @DRVeyl the context here was TV satellites, so the idea would be to look at the data rate (C or Ku) to receivers in pretty much arbitrary locations
<discord->
DRVeyl. — Yep, I read the chat history.
<discord->
Sir Mortimer. — physically pointing antennas would be overkill since the game doesn't have a way to deal with physics of vessels on rails. or for automation. just imagine a deep space probe with a dish pointed at earth that needs to adjust orientation for a burn -> you're offline and have no way to regain comms.
<discord->
egg. — yeah.
<discord->
egg. — The flanking thing is a bit different since that's during launch, where you're never on rails, but in space it's a right mess.
<discord->
Damien. — @Sir Mortimer also, see every space telescope mod. it's impossible to stay pointing directly at a target
<discord->
Sir Mortimer. — even changing unloaded vessel resources is a mess in KSP. the amount of code duplication in kerbalism for that alone is... painful.
<discord->
egg. — yeah I'm not sure how we'll deal with that when we add rotation to Principia
<discord->
egg. — On the Principia side we'll know how things are oriented
<discord->
egg. — but I'm not sure whether it's worth changing the KSP side until it reloads
<discord->
Sir Mortimer. — you'd have to do the same what PR does: apply values whenever a vessel goes off rails. or change the persisted state of the protoVessel, which i'm not sure is necessary.
<discord->
DRVeyl. — I did shortcut many atmospheric effects if not linking to a ground station, but calculating data rate between two antennas at arbitrary locations is a thing I do ;)
<discord->
egg. — @Sir Mortimer yeah, I think it's not worth poking at the protovessel (unless you care about it?)
<discord->
Sir Mortimer. — you could, however, provide some API function that would return the vessels orientation at the current point
<discord->
Damien. — as a clueless user, I can say that just having it snap to the correct orientation when coming off rails would be fine
<discord->
egg. — @Sir Mortimer yeah that I can do too
<discord->
Damien. — anything to save my pioneer missions
<discord->
Damien. — it's been so long
<discord->
Sir Mortimer. — @egg kerbalism did that, but now we just assume a constant sun relative orientation for the solar panels.
<discord->
Damien. — I need to finish it
<discord->
egg. — yeah so I guess just doing the PR thing
<kmath>
YouTube - про эффект Джанибекова -- (ОБЯЗАТЕЛЬНО загляните в описание под видео !!)
<discord->
Sir Mortimer. — just thinking... for the case of a rotating craft with panels that don't track the sun... determining a correct solar panel output will be messy.
<discord->
egg. — yeah, because determining orientation is messy to start with :D
<discord->
Sir Mortimer. — why does it do that??
<discord->
egg. — :D :D :D
<discord->
Sir Mortimer. — that unstable rotation
<discord->
Sir Mortimer. — why?
<discord->
egg. — I'm not sure I can adequately explain that without waving my hands at a piece of paper or a blackboard
<discord->
Sir Mortimer. — interesting. never noticed that effect
<discord->
Space Dwarf. — probbably cause tend not to give uncontrolled spin to things around their intermediate axis?
<discord->
DRVeyl. — @egg Principia doesn't like HyperEdit because... It tries to set Orbit information and Principia laughs at that? If instead (or in addition) it directly set the Vessel position and world velocity, would this work? (ie Principia would accept the new position / velocity and carry forward from there? History might get confused...)
<discord->
DRVeyl. — Oops ;)
<discord->
egg. — nope, we are the source of truth
<discord->
egg. — anything done on the KSP side will get laughed at except engines burning
<discord->
DRVeyl. — Intent is not to create an orbit. Understand orbit params don't make sense. Intent is to set an initial vessel condition and then apply from there.
<discord->
DRVeyl. — Ok.
<discord->
DRVeyl. — Can I ask principia via API to discontinuously move something?
<discord->
Damien. — I'm pretty sure you're asking egg if you can have a satellite IRL be magically teleported to another position
<discord->
Damien. — it's equally as likely
<discord->
egg. — @DRVeyl we have no such API at this time, though we could imagine adding something someday. What are you trying to do by setting your vessel degrees of freedom?
<discord->
egg. — @DRVeyl also technically we do allow hyperedit/orbit editing if you hack gravity (if you hack gravity, Principia will ignore loaded vessels, so KSP is free to move them)
<discord->
DRVeyl. — Play around with a vessel without having to fly there, obviously. ;). Practice re-entry. Watch the stability of a network of satellites around Jupiter.
<discord->
egg. — @DRVeyl okay so if it's just for manual testing, hack gravity
<discord->
Damien. — @DRVeyl you're supposed to go there the long way on a new RP-1 career
<discord->
Damien. — starting with sounding rockets
<discord->
egg. — hack gravity, put your things in place via stock means, unhack gravity
<discord->
Damien. — does hacking gravity affect anything regarding bodies, or crafts already in orbit?
<discord->
egg. — nothing can touch bodies
<discord->
egg. — this only affects loaded vessels
<discord->
Damien. — (except egg)
<discord->
Damien. — ok cool
<discord->
Damien. — good to know
<discord->
Sir Mortimer. — hack gravity as in use the cheat menu and tick a checkbox?
<discord->
egg. — yup
<discord->
Damien. — all this time
<discord->
Damien. — and we find out now
<discord->
egg. — Hm, how is there a separate reaction with 🌩️ and one with 🌩
<discord->
egg. — oh, differ by a VS-16
<discord->
DRVeyl. — Gotta be willing to ask the right question and accept the right restrictions. ;). (Don't introduce or move new gravitational sources, batch)
<discord->
Sir Mortimer. — how is that separate?
<discord->
DRVeyl. — Thanks.
<discord->
egg. — @Sir Mortimer in @DRVeyl's question above
<discord->
egg. — there are reactions with egg, and two separate reactions with cloud with lightning
<discord->
DRVeyl. — It's so you can have lots of thunderclouds in the same response, ofc!
<discord->
Sir Mortimer. — ⛈️
<UmbralRaptop>
both look the same over here
<discord->
egg. — yeah they just differ by a VS-16
<discord->
Sir Mortimer. — 🌩️ ☁️ 🌧️ 🌨️ ⛈️ 🌪️
<discord->
Damien. — do 🥚s come from 🍆s?
<discord->
DRVeyl. — They're differently shaded thunderclouds in my view, neat. But not in the line egg typed.
<discord->
Sir Mortimer. — it's like a weather forecast
<discord->
neph. — read the backlog v. exciting
<discord->
DRVeyl. — Gotta be willing to ask the right question and accept the right restrictions. ;). (Don't introduce or move new gravitational sources, natch) (edited)
<discord->
neph. — Re: properly aiming at targets, am I reading it wrong that making that work unloaded is the same problem as station keeping?
<discord->
Damien. — we need custom emoticons
<discord->
Damien. — even if only in the ~~shitposting~~ principia channel
<discord->
Sir Mortimer. — @neph i think properly aiming at targets is not at all practical in KSP.
<discord->
neph. — Basically the requirement is to trade RCS propellent for orientation/linear impulse while the vehicle is unloaded?
<discord->
Damien. — doing it realistically would probably be a nightmare
<discord->
Damien. — hacking it with an <x> over time approximation, doable maybe
<discord->
Damien. — (not a dev)
<discord->
neph. — Yes
<discord->
Damien. — for orientation anyway
<discord->
Damien. — fixing it for stationkeeping could require egg's kindly provided gravity stop, reposition, gravity fix hack
<discord->
Damien. — it's hacks all the way down
<discord->
egg. — that hack is not for programmatic use, it's clumsy on purpose
<discord->
Damien. — ~~hack~~ feature
<discord->
neph. — I suppose station keeping is almost the same problem as atmospheric decay...?
<discord->
egg. — nah, not really
<discord->
Sir Mortimer. — well, adding something that slowly eats up all the monoprop or whatever poisonous liquid it is that you use in RO wouldn't be hard. problem would be determining the rate at which it happens. and of course it would do nothing in regards to craft orientation. and then tell PR or whatever mod to randomly orient your craft once the monoprop is up. not sure if that is something people crave for.
<discord->
Damien. — in terms of the main thing preventing a lot of people taking up principia (apart from 'hard') is stationkeeping requirements
<discord->
egg. — stationkeeping requires expressing a great deal of intent, which is tricky
<discord->
Damien. — in terms of the main thing preventing a lot of people taking up principia (apart from 'hard') it's stationkeeping requirements (edited)
<discord->
Damien. — that's the complaint I see most
<discord->
egg. — (is that complaint justified though)
<discord->
egg. — that is, you require stationkeeping to fulfill impossible contracts
<discord->
Damien. — on my last experimentation safe, I was stationkeeping 5 sats manually
<discord->
Damien. — it started to be a pain
<discord->
egg. — but that's the fault of the contract, not a necessity
<discord->
Damien. — on my last experimentation save, I was stationkeeping 5 sats manually (edited)
<discord->
Damien. — granted they were in lagrange points
<discord->
egg. — you could fulfill a sane contract with stable orbits
<discord->
neph. — I can see other reasons potentially
<discord->
neph. — Trying to maintain something in very llo for a week for exampld
<discord->
neph. — Trying to maintain something in very llo for a week for example (edited)
<discord->
Damien. — L1/2/3 sats, geosats
<discord->
neph. — Or anything around L1-3
<discord->
Damien. — llo sats
<discord->
Damien. — yeah
<discord->
egg. — to the contrary, stationkeeping being hard incentivizes using molnyia orbits over random eccentric orbits
<discord->
DRVeyl. — I don't think it is contract, I think it is more around a stable communication network that has good coverage and stays that way rather than refreshing anything
<discord->
egg. — @DRVeyl that doesn't require stationkeeping per se
<discord->
egg. — you can construct that with stable orbits
<discord->
siimav. — I've seen people also struggling real hard at keeping a probe inside the SOI of Phobos or Deimos.
<discord->
egg. — if you choose orbits that are high-maintenance, that's a choice you're making
<discord->
DRVeyl. — Don't disagree.
<discord->
Damien. — to be fair I agree with that
<discord->
Damien. — stationkeepign I'm ok with
<discord->
egg. — the SOI is a silly concept in Principia, but yeah; in the vicinity of tiny rocks you're going to have a weird time
<discord->
Damien. — stationkeeping I'm ok with (edited)
<discord->
Damien. — rotation is the main issue
<discord->
Damien. — my pioneers 😢
<discord->
egg. — but anyway; in order to have stationkeeping, you would have to be able to express what you want
<discord->
egg. — that's hard
<discord->
neph. — yes
<discord->
Damien. — next release then 🥚?
<discord->
Damien. — inb4 trout
<discord->
Sir Mortimer. — how would you even begin to formulate what you want in any language that both you and principia are able to understand?
<discord->
neph. — Under educated and poorly mathed
<discord->
Damien. — come here and egg starts dropping knowledge on you in 3 different languages
<discord->
neph. — Serious how many keyboards do you have installed
<discord->
Damien. — meanwhile I'm trying to understand libration point orbits while not understanding basic geometry
<discord->
neph. — So a triangle usually has three sides, right?
<discord->
Damien. — define 'triangle'
<discord->
Sir Mortimer. — @Damien don't worry, I've still not wrapped my head around J2 😉
<discord->
Damien. — J2 = 🥚
<discord->
Damien. — ezpz
<discord->
neph. — Funnily enough, J2-n make good sense to me
<discord->
Sir Mortimer. — yeah. but *why* does it change an orbit?
<discord->
Damien. — more mass make spinny thing move
<discord->
Sir Mortimer. — so you're effectively move faster while over the equator?
<discord->
neph. — issa term of the approximation describing how the bumpy masses exert force on your orbiting body
<discord->
Damien. — @Sir Mortimer my mind got blown when egg explained to me that the earth is egg shaped in two dimensions
<discord->
Sir Mortimer. — or is the driving factor that the resulting gravity vector doesn't always point at the center of the body?
<discord->
Damien. — and that's why my geosat position was hard
<discord->
Damien. — and that's why my geosat positioning was hard (edited)
<discord->
neph. — You're being dragged towards the equator at all times, that perpendicular component of that acceleration vector wrt your orbit causes an inclination change
<discord->
Damien. — 🥚 from the side, 🥚 from above
<discord->
Sir Mortimer. — so, earth basically is an egg shaped egg is what you're saying?
<discord->
Damien. — yeah
<discord->
Damien. — 🥚 squared
<discord->
neph. — It's eggs all the way down
<discord->
egg. — @Sir Mortimer there's a cursory explanation of the effect it has in Capderou
<discord->
egg. — not sure whether it is extremely satisfying (it's a lot of Poisson brackets and then a perturbation pops out)
<discord->
neph. — @Damien the earth is super duper complex in mass distribution, you can describe it as an infinite sum of ??spherical harmonics??
<discord->
egg. — J n is (n, 0)
<discord->
Damien. — this convo, this is why #principia is the best channel
<discord->
neph. — Each term is a J0?-N
<discord->
egg. — @neph Cnm, or Jn (which is Cn0 by any other name)
<discord->
neph. — Ah I see
<discord->
egg. — (and Snm)
<discord->
Damien. — o_O
<discord->
neph. — My cursory glance at Wikipedia proved incomplete in comprehension
<discord->
neph. — I need to take an orbital mech class in grad
<discord->
egg. — @Sir Mortimer look at the m=0, n=3 cell in that animated gif above
<discord->
egg. — you can see what I mean by "top-heavy" (or bottom-heavy)
<discord->
egg. — The m=0, n=2 cell is oblateness (or prolateness)
<discord->
neph. — So J-notation only describes those harmonics that are symmetrical to the equatorial plane?
<discord->
egg. — no, those that are symmetrical by rotation around the axis
<discord->
Sir Mortimer. — @egg ok, then I understood correctly 🙂
<discord->
egg. — J (even number) are symmetrical along the equator
<discord->
egg. — oblateness is actually all the J (even), but J2 most of them
<discord->
Sir Mortimer. — are J(>2) really that relevant?
<discord->
egg. — less so, but they can be; depends what you're doing
<discord->
egg. — on the Moon, you have to go to pretty high n (and m)
<discord->
egg. — we go to n=30 for the Moon
<discord->
egg. — we found that this was necessary to properly replicate the behaviour of low lunar orbits
<discord->
Sir Mortimer. — could that be applied to the stock system as well?
<discord->
egg. — sure
<discord->
Sir Mortimer. — i assume its configs
<discord->
egg. — yeah
<discord->
egg. — has to be added at the beginning of the game, you can't change the gravity models once it's started
<discord->
egg. — also computing fun & sensible values for those numbers may be tricky
<discord->
Sir Mortimer. — I'd just like to avoid RSS if possible because 1. Kopernicus doesn't work on 1.8 yet, and 2. my computer doesn't have that much memory
<discord->
Sir Mortimer. — ah i see. the values you have now work for a RSS scale system, just copy+pasting them onto the stock system would be... bad?
<discord->
Damien. — @Sir Mortimer there's a way to fix that - donations for a new rig 😄
<discord->
Sir Mortimer. — @Damien the computer works just fine, it was never my intention to run games on it 🙂
<discord->
Sir Mortimer. — which was pretty stupid in hindsight, I'll admit
<discord->
Damien. — what computer? or is it one of those mac abominations?
<discord->
neph. — @egg would it be those symmetrical wrt both the rotational axis and the equatorial plane?
<discord->
egg. — > the values you have now work for a RSS scale system, just copy+pasting them onto the stock system would be... bad?
<discord->
egg. — they come with a reference radius, so they will scale if you scale the reference radius (and we default that radius to the stock one, see the doc)
<discord->
Damien. — I spend half my time spreading the gospel of principia to the unwashed masses on the ksp discord
<discord->
Damien. — anything to make it easier to blow their minds is a good thing
<discord->
Damien. — square orbit is losing its effectiveness
<discord->
egg. — @Sir Mortimer you can also add tilt if you feel like it
<discord->
Sir Mortimer. — @Damien I've travelled to that godforsaken realm twice. and left soon thereafter, making sure to wipe my shoes on their doormat before I left.
<_whitenotifier-a3da>
[Principia] eggrobin labeled pull request #2379: Get the inertia tensor of the body and push it to the plugin - https://git.io/JePtG
<_whitenotifier-a3da>
[Principia] pleroy synchronize pull request #2379: Get the inertia tensor of the body and push it to the plugin - https://git.io/JePtG
egg|zzz|egg has quit [Ping timeout: 206 seconds]
UmbralRaptop has joined #principia
<discord->
egg. — Argh, FlightCamera.frameOfReference is private
<_whitenotifier-a3da>
[Principia] pleroy closed pull request #2379: Get the inertia tensor of the body and push it to the plugin - https://git.io/JePtG
<_whitenotifier-a3da>
[Principia] pleroy pushed 6 commits to master [+0/-0/±33] https://git.io/Je1UL
<_whitenotifier-a3da>
[Principia] pleroy 60969e8 - New parameters passed through the interface.
<_whitenotifier-a3da>
[Principia] pleroy 9a60537 - Compute the inertia tensor and pass it to the plugin.
<discord->
Sir Mortimer. — stare at code. raise eyebrow. browse other mods code. raise another eyebrow. get an idea. raise both eyebrows. go back to that file you've been in 10 minutes ago... where is it... ah, yes. change one line. compile. start KSP. pray.
<discord->
Sir Mortimer. — rinse and repeat
<discord->
TheRealWiwaxia. — How does that square orbit even work
<discord->
Sir Mortimer. — HA! HEUREKA!
<discord->
Sir Mortimer. — grmpf. back to square 1.
<discord->
DRVeyl. — Know the feeling, @Sir Mortimer. Except I'm also starting not to trust how other mods do it !)
<discord->
DRVeyl. — Know the feeling, @Sir Mortimer. Except I'm also starting not to trust how other mods do it ;) (edited)
<discord->
egg. — depends on the other mods; but in any case, don't trust how KSP does it
<discord->
DRVeyl. — Hah. Fair.
* discord-
egg. — hides behind custom physics libraries to guard against the KSP madness_
<discord->
egg. — (also helps with catching ordinary bugs, but a lot of it was designed specifically to cope with inconsistent units, reference frames, and handednesses from KSP)
UmbralRaptop has quit [Remote host closed the connection]
<discord->
egg. — @Damien can you run the orbit analyser over many revolutions (at least 10, more if you feel patient)?
<discord->
egg. — @Damien also with respect to the Moon as well
<discord->
egg. — might be more interesting with respect to the moon, I don't think there's an Earth ground track cycle but there is a moon one with the tidal locking
<discord->
egg. — (otoh maybe it just NaNs away)
<discord->
Damien. — @egg sure, it won't let me to it on the moon though because it says I'm not under the influence
<discord->
egg. — ah yeah it NaNs away
<discord->
Damien. — @egg sure, it won't let me do it on the moon though because it says I'm not under the influence (edited)