raptop changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer. | We can haz pdf
<mofh>
egg|laptop|egg: sorry, tried to redo it b/c I was missing a bunch of files, gave up after ENSG failed at giving me a directory listing with an HOUR timeout.
<mofh>
this mirror is unusable, I don't know why you'd care about it.
<egg|laptop|egg>
O_o
<egg|laptop|egg>
mostly because they list it
<egg|laptop|egg>
also wat
<egg|laptop|egg>
mofh: I get a listing from ftp://igs.ensg.eu/pub/igs/products/mgex/1692/ in seconds
<egg|laptop|egg>
are you using IPv6 or something
<mofh>
Huh, let me retry that, it might be the case.
<mofh>
anyway I'm pretty sure it'll be missing comXXXXXXXXXXXXXXXXXXXXX.bla.Z for those dirs and *likely* not much else?
<egg|laptop|egg>
yeah so it seems to be missing early CODE files (com*)
<mofh>
CODE?
<galois>
CODE: Centre for Orbit Determination in Europe
<mofh>
Ahh.
<egg|laptop|egg>
a couple of SHAO files
<mofh>
Like it seems to track IGN closely, which kinda makes sense.
<egg|laptop|egg>
however it has 3 WHU files which IGN does not have in recent weeks
<egg|laptop|egg>
these 3 WHU files are pretty much the eggstent of the < diff
<mofh>
That seems to be a point in favour of the whole "things are uploaded independently"
<mofh>
And yeah
<egg|laptop|egg>
yeah, the IGN/CDDIS wrong week situation also points to that
<egg|laptop|egg>
uploaded to current week at different times, or timezone-adjusted GPS week or whatever
<mofh>
btw I have a local copy of IGN now, clearly we need to start serving IGS.ANBO now,
<egg|laptop|egg>
I don't really have a server
<mofh>
I do but not one that has the bandwidth for a MGEX mirror (or any reason to set one up, for that matter).
<egg|laptop|egg>
well, not eggsternal at least
<egg|laptop|egg>
bandwidth for a MGEX mirror << what is your estimate of the required bandwidth though
<egg|laptop|egg>
I don't expect thousands of queries per second on that,
<mofh>
I... actually that is a good question, how used *are* these mirrors?
* egg|laptop|egg
headache
<mofh>
b/win 20
<egg|laptop|egg>
20-bit windows
<egg|laptop|egg>
cursed
<egg|laptop|egg>
!wpn mofh
* galois
gives mofh a krypton cannon
<mofh>
!wpn egg|laptop|egg
* galois
gives egg|laptop|egg a potato with a axe attachment
<mofh>
look I've used (okay, admittedly only in an emulator) a system with CHAR_BIT being 9 and only word-addressable addresses.
<mofh>
(UNIVAC 494)
<egg|laptop|egg>
mofh: i am infinitely annoyed at C's conflation of the addressable unit and the character type
<egg|laptop|egg>
mofh: what if you have a machine with addressable bits
<egg|laptop|egg>
(and 67-bit pointers accordingly, yes, that's a thing)
<egg|laptop|egg>
"The horizontally-microprogrammedR1000 provided two independent 64-bit data paths, permitting simultaneous computationand type checking."
<mofh>
feh, seems to be business mainframes that were made for only 9 years
<mofh>
A) I doubt that hobbyists would even have access to them, B) If you do, dear gods why would you want to run *C* on them?
<egg|laptop|egg>
mofh: B obviously not, they're designed for Ada
<mofh>
Eggsactly.
<egg|laptop|egg>
A I think there's a card from one of those in the basement here
<egg|laptop|egg>
(but I don't think anybody has had a working one for a long time)
<egg|laptop|egg>
business mainframes << well, Ada, so aerospace stuff mostly
<egg|laptop|egg>
iirc Eurocopter had a few?
<mofh>
Airbus, as well?
<egg|laptop|egg>
possibly
<egg|laptop|egg>
Eurocopter is Airbus now anyway :-p
<mofh>
well Aérospatiale and/or MATRA at the time,
<egg|laptop|egg>
yeah
<B787_300>
MATRA?
<egg|laptop|egg>
also i should tell you about the "dual processor" one someday
<galois>
[WIKIPEDIA] Matra (entreprise) | "Matra (acronyme de Mécanique Aviation Traction) est une entreprise fondée en 1937. Historiquement, elle couvre une large palette d'activités dans l'aéronautique, l'aérospatiale, l'automobile, le sport automobile, le transport, les télécommunications et la défense. Elle s'est progressivement orientée..."
<egg|laptop|egg>
and two network connections,,,
<mofh>
ooh, that sounds interesting and/or amusing.
<galois>
[WIKIPEDIA] Matra R550 Magic | "Le Matra R550 Magic (Missile Auto-Guidé Interception et Combat) est un missile air-air à courte portée de conception française. Il travaille grâce à un auto-directeur infrarouge bande I...."
<mofh>
ROFL
<B787_300>
interesting
<egg|laptop|egg>
!acr -add:Magic Missile Auto-Guidé Interception et Combat
<galois>
[WIKIPEDIA] Soviet space dogs#/media/File:БелкаСтрелка VizuIMG 3703.JPG | "During the 1950s and 1960s the Soviet space program used dogs for sub-orbital and orbital space flights to determine whether human spaceflight were feasible. In this period, the Soviet Union launched missions with passenger slots for at least 57 dogs. The number of dogs in space is smaller, as some dogs..."
<mofh>
egg: yeah, updating the diffs file atm
<mofh>
egg: there seems to be more < diffs, interestingly
<egg>
Ꙩ_ꙩ
<mofh>
I "like" how none of these mirrors even resemble subsets of each other
<egg>
meanwhile adding cheesy solar radiation pressure improves the GNSS residuals, but not enough
<mofh>
By how much, out of curiosity?
<mofh>
Also wait, why wasn't solar radiation pressure already in principia?
<egg>
it's nonconservative
<egg>
so it can't be easily added to the symplectically integgrated stuff
<egg>
mofh: improves residuals by ~half, but they were double what they should have been to start with
<egg>
well not quit half
<egg>
500-600 m on a GPS sat after 24 h became 300-400, 1100 m on a Galileo sat became ~700 m
<egg|laptop|egg>
whitequark: strangely i seem to have followers than are way less dog than average
<egg|laptop|egg>
only 93 %, and dogs is not first on the list
<egg|laptop|egg>
mofh: hm the residuals are essentially the same for E01 and E02
<mofh>
egg: not bad, that's a pretty decent improvement (which makes a lot of sense)
<egg|laptop|egg>
yes but all of that is too high
<egg|laptop|egg>
I should be getting 220 m errors on a day from solar radiation from solar radiation pressure
<egg|laptop|egg>
and the rest of the unmodelled forces amount to at most a handful of metres on a day
<mofh>
egg|laptop|egg: okay, 1777 onwards the diffs are almost eggsclusively >
<mofh>
egg|laptop|egg: also file updated with all of them
<egg|laptop|egg>
fewer > than CDDIS though
<egg|laptop|egg>
mostly a tonne of CODE files between 1777 and 1824
<egg|laptop|egg>
E01 and E02 having the same residuals is interesting
<egg|laptop|egg>
G01 and G02 more difference in residuals
<egg|laptop|egg>
E01 and E02 are in A02 and A06 respectively
<galois>
[WIKIPEDIA] List of Galileo satellites | "This is a list of past and present satellites of the Galileo navigation system. As of February 2019, 22 satellites are declared operational, 2 satellites placed in non-nominal orbit are declared in testing, and 2 satellites are currently not usable. The two GIOVE prototype vehicles were retired in 2012..."
<egg|laptop|egg>
G01 is D2, G02 is B3
<egg|laptop|egg>
s/B3/D1/
<galois>
egg|laptop|egg meant to say: G01 is D2, G02 is D1
<egg|laptop|egg>
but block IIR vs. IIF
<egg|laptop|egg>
R01 and R02 have very similar residuals as well
<mofh>
egg|laptop|egg: [MGEX] ahh, I SEE
<mofh>
egg|laptop|egg: so those .mirror.cddisprodmgex and .mirror.depotsmdprodmgex files are useful
<mofh>
turns out that IGN syncs from CDDIS and "vm-igsdepot.ign.fr/pub/igs/products/"
<egg|laptop|egg>
assuming R01 is the slot number, R01 and R02 are both Ms in plane I
<mofh>
presumably the latter accounts for the majority of the missing files
<egg|laptop|egg>
ah, vm-igsdepot.ign.fr/pub/igs/products/, which is documented nowhere,
<mofh>
yes, it seems to be internal
<mofh>
13:24:22 < egg|laptop|egg> E01 and E02 having the same residuals is interesting
<mofh>
I mean based on their orbits that seems like it would make sense?
<egg|laptop|egg>
well time-dependent residuals
<egg|laptop|egg>
that's a bit odd, because they're not on the same place on their orbit
<_whitenotifier-3d18>
[Principia] eggrobin labeled pull request #2133: Use the warning style if the initial time of a manoeuvre is too large - https://git.io/fjmkj
<egg|laptop|egg>
OK it's by plane, not satellite kind
<egg|laptop|egg>
E01 = E02 /= E03
<egg|laptop|egg>
G01 ~ G02 /= G03
<egg|laptop|egg>
R01 = R02
<egg|laptop|egg>
C11 ~ C12 /= C14
<egg|laptop|egg>
hm.
<egg|laptop|egg>
okay so there is a perturbation that depends on the plane, but not on where on said plane the satellite is
<_whitenotifier-3d18>
[Principia] pleroy synchronize pull request #2133: Use the warning style if the initial time of a manoeuvre is too large - https://git.io/fjmkj
<_whitenotifier-3d18>
[Principia] pleroy commented on issue #2128: Engine thrust offset with maneuver planning (feature request) - https://git.io/fjmcn
<_whitenotifier-3d18>
[Principia] pleroy commented on issue #1565: Switching between vessels does not update maneuver node. - https://git.io/fjmlL
<_whitenotifier-3d18>
[Principia] pleroy unassigned issue #1565: Switching between vessels does not update maneuver node. - https://git.io/v5FCe
<_whitenotifier-3d18>
[Principia] pleroy assigned issue #1565: Switching between vessels does not update maneuver node. - https://git.io/v5FCe
<_whitenotifier-3d18>
[Principia] pleroy assigned issue #2107: Journal replaying is no longer deterministic - https://git.io/fjJyD
<mofh>
egg|laptop|egg: G_{sc} ~ 1361W/m^2, divide by c to get a pressure, then calculate the force based on angle between spacecraft and sun?
<egg|laptop|egg>
mofh: what shape is the cow in this model
<egg|laptop|egg>
radiation pressure models are a right mess
<mofh>
egg|laptop|egg: that should get you most of the correction right there (obviously modelling anisotropic absorption/emission via Yarkovsy etc is harder)
<mofh>
egg|laptop|egg: the flat (or at least cuboid) cow is the easiest to consider here
<egg|laptop|egg>
based on angle between spacecraft and sun? << *handwaving intensifies*
<mofh>
since you then get G_{sc}/c * A * cos(\theta) for an area A
<mofh>
I mean it's a perturbative correction, of course hands will be waved vigorously,
<egg|laptop|egg>
even in box-with-wings models, you have the orientation of the solar panels and that of the spacecraft
<egg|laptop|egg>
mofh: tbh I'm tempted to just say "constant force away from ☉" and simulated anneal that to fit a 1-day SP3 file
<egg|laptop|egg>
(β doesn't meaningfully change over a day)
<egg|laptop|egg>
mofh: that way I see whether the residual can be eggsplained by SRP, and I punt on modeling it in game because that's an entirely different can of worms
<mofh>
egg|laptop|egg: I mean that sounds more complicated than the boxy-cow-with-wings approach, but it *would* work nicelt
<mofh>
nicely*
<egg|laptop|egg>
dunno, boxy-cow-with-wings sounds like it has a lot of fudge factors that you have to optimize
<egg|laptop|egg>
I'd rather optimize just one fudge factor and not have to write code to model a cow :-p
<mofh>
touché :P
<_whitenotifier-3d18>
[Principia] pleroy closed pull request #2133: Use the warning style if the initial time of a manoeuvre is too large - https://git.io/fjmkj
<_whitenotifier-3d18>
[Principia] pleroy pushed 5 commits to master [+1/-0/±15] https://git.io/fjmlc
<_whitenotifier-3d18>
[Principia] pleroy cfd6a07 - An attempt that doesn't work.