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
<kmath>
whitequark: Wolfram couldn't understand your gibberish
<whitequark>
well fuck you too
<_whitenotifier-5dfc>
[Principia] pleroy pushed 2 commits to master [+0/-0/±6] https://git.io/fjuwj
<_whitenotifier-5dfc>
[Principia] pleroy 64e24e4 - It now works.
<_whitenotifier-5dfc>
[Principia] pleroy 09426af - Merge pull request #2195 from pleroy/Base32768 Base32768 now works
<_whitenotifier-5dfc>
[Principia] pleroy closed pull request #2195: Base32768 now works - https://git.io/fjEj7
<_whitenotifier-5dfc>
[Principia] pleroy synchronize pull request #2187: Use the new flight plan API in the C# code - https://git.io/fj0P0
<egg>
UmbralRaptor: B787_300: are there satellite navigation systems other than TRANSIT and 北斗一号 that aren't based on the usual principle of onboard clocks & ranging
<egg>
whitequark: is the difference between brazing & soldering just temperature?
<whitequark>
yes
<whitequark>
artificial cutoff
<egg>
whitequark: this is eggstremely confusing coming from french because: 1. souder = to weld (braser = to braze or to solder), 2. souder is often used by extension for brazing as well, so the usual term for soldering iron is fer à souder, even though fer à braser is more correggt
<kmath>
<shipilev> @whitequark Oh yeah. Still, I counter that with googling something LaTeX-related. Preferably with image search enab… https://t.co/lf5DHvjZs3
* Iskierka
reads up, sees satellite navigation question
<Iskierka>
I wonder if you could set up a satellite navigation system using a method similar to the Vive lighthouses with swept beams
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<egg|work|egg>
how does that work
<B787_300>
egg|work|egg: some people have tried using unlocked GPS units for navigation in space
<egg|work|egg>
B787_300: yeah a bunch of sats have GPS antennae (sometimes to stare at the atmosphere too), but that's still GPS
<egg|work|egg>
so if you use it for positioning you still just get timing signals and pseudoranges
<egg|work|egg>
I'm wondering about things operating with a different principle
<B787_300>
egg|work|egg: it is just one layer of abstraction between SLRs and timings
<egg|work|egg>
e.g. the TRANSIT one-satellite-pass doppler
<egg|work|egg>
or the BeiDou-1 two-satellite round-trip to central station that does the computation and intersects with known topography
<egg|work|egg>
(BeiDou-1 is weird)
<B787_300>
If your star map in your star tracker was high enough fidelity couldn't you use that?
<B787_300>
Or would the positional errors be on the scale of the earth
<egg|work|egg>
B787_300: wait there might be some confusion here, by "satellite navigation systems" I mean things that use satellites to navigate on earth, not to navigate satellites
<Iskierka>
the way the Vive works is the lighthouses sweep an IR beam across the room at a very controlled interval (30 Hz IIRC) and the differential timing of sensors on the headset, as well as *which* sensors can even see it, is used to get sub-mm and sub-degree position and rotation precision. I wouldn't expect that from a setup intended for larger than a room but I wonder if similar could still work anyway
<B787_300>
Ah yes... I was thinking the latter
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<Iskierka>
trying to think how a lighthouse system could be used in satellites and probably the biggest problem would just be the receiver. Need multiple receive points and not sure how widely spaced they'd have to be for precision in reading signals from orbit. Would probably also need a carrier signal for the satellite position (vive lighthouses don't, they're just a light pulse)
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<UmbralRaptor>
Iskierka: congratulations!
<egg|work|egg>
also yes, that ^
<egg|work|egg>
Iskierka: not only do you not get banned, you get congratulated :-p
<egg|work|egg>
Iskierka: with a single-satellite system I'd be surprised if you got anything better than TRANSIT in terms of accuracy
<UmbralRaptor>
With sufficiently high pressures and low temperatures, does *everything* become a superconductor?
* UmbralRaptor
just learned that you can make pure oxygen a superconductor
<whitequark>
most things, definitely
<egg|work|egg>
umbralraptor: whitequark: I'm always confused that it's super- in English where it's supra- in French or German
* egg|work|egg
stares at Russian
<egg|work|egg>
is сверх more like supra or super
* UmbralRaptor
thought supra was Japanese for celica
<mofh>
egg|work|egg: I mean RF doppler ranging is fairly standard procedure for deep space stuff, not sure why it's not used for earth sats (likely b/c it's not worth the compleggsity there?)
<egg>
mofh: range = distance, pseudorange = distance + error of receiver clock
<egg>
mofh: that's why you need 4 sats and not 3 for Navstar/ГЛОНАСС/Galileo/北斗二号
<egg>
you are solving for 3d position & receiver clock bias
<egg>
mofh: whereas a *round-trip* time doesn't involve any clocks other than that of the central station, so there's no bias to solve for
<SnoopJeDi>
"Then the whole thing justseemed to fall apart, and our dream disintegrated. What had happened? For one thing there were unexpected and unknown obstructions in the donut."
<SnoopJeDi>
TIL the FNAL main ring vacuum chamber was conventionally known as "the donut"
<egg>
donot obstruct the donut
<SnoopJeDi>
They tried to unobstruct the donut by inserting a ferret.
<SnoopJeDi>
(but she was too scared of it?)
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<egg>
mofh: meow
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<_whitenotifier-5dfc>
[Principia] pleroy closed pull request #2187: Use the new flight plan API in the C# code - https://git.io/fj0P0
<_whitenotifier-5dfc>
[Principia] pleroy pushed 23 commits to master [+5/-2/±88] https://git.io/fju71
<_whitenotifier-5dfc>
[Principia] pleroy 16da601 - Propagate Status through the interface.
<_whitenotifier-5dfc>
[Principia] pleroy 4ce6967 - Status convenience functions.
<egg>
mofh: but not just round-trip from the unit to the satellites, instead round-trip through the satellites to a central station
<egg>
well through the satellites and through the unit
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<egg>
"Firstly, the central control station sends inquiry signals to the users via two satellites. When the user terminal received the signal from one satellite, it sends responding signal back to both satellites. The central station receives the responding signals sent by the user from two satellites"
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<egg>
mofh: meow
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<UmbralRaptor>
!wpn ferram4
* galois
gives ferram4 a wolfram recursion
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<SnoopJeDi>
!wpn UmbralRaptor
* galois
gives UmbralRaptor a bomb
<SnoopJeDi>
:o
<SnoopJeDi>
!wpn -add:wpn cyclotron
<galois>
Added wpn 'cyclotron'
<SnoopJeDi>
!wpn -add:wpn synchrotron
<galois>
Added wpn 'synchrotron'
<SnoopJeDi>
!wpn -add:wpn free electron laser
<galois>
Added wpn 'free electron laser'
<UmbralRaptor>
!wpn -add:adj pumped
<galois>
Added adj 'pumped'
<SnoopJeDi>
!wpn -add:adj resonant
<galois>
Added adj 'resonant'
<UmbralRaptor>
!wpn -add:adj locked
<galois>
Added adj 'locked'
<UmbralRaptor>
!wpn -add:adj switched
<galois>
Added adj 'switched'
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<egg|zzz|egg>
hm i managed to make a 1-kerbal aircraft that cruises at Mach 6 but making a 24-passenger plane with the same cruising speed is proving trickier
<egg|zzz|egg>
!wpn ferram4
* galois
gives ferram4 a divergent tellurium ocelot
<UmbralRaptor>
!wpn SnoopJeDi
* galois
gives SnoopJeDi a xenon bayonette
<UmbralRaptor>
!wpn egg|zzz|egg
* galois
gives egg|zzz|egg a cubic grenade
<UmbralRaptor>
galois?
<egg|zzz|egg>
ferram4: what shape should a Mach 6 passenger aircraft have
<egg|zzz|egg>
hm, I wonder whether J58s would get a single ramjet to high enough speeds that it then sustains flight on its own or whether I really need two ramjets
<ferram4>
It should be shaped like probably a giant highly-swept wing thing
<egg|zzz|egg>
ferram4: ah so my double-delta thingy probably isn't the right way to go then?
<ferram4>
Or maybe?
<ferram4>
I dunno, hypersonics is a weird place
<ferram4>
And I'm pretty sure FAR doesn't simulate it all that properly
<egg|zzz|egg>
ferram4: arguably my problem is rather getting to hypersonics, since the turbojets tend to melt before the ramjet deploys enough thrust to sustain flight
<egg|zzz|egg>
I probably need two ramjets
<ferram4>
Alternatively, use the turbojets to zoom climb and use the dive to pick up speed to light the ramjets
<egg|zzz|egg>
I like this perfectly viable passenger flight profile :D
<egg|zzz|egg>
I tried diving from 20 km to 10 to make things go beyond Mach 3.3 on just the ramjet (turbojets are rated for 2.8, somehow they can be pushed til 3.3) but I ended up eggsceeding the flight envelope