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
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<kmath> <cosmos4u> Sorry, no #occultation of #Sirius by a small #asteroid for the U.S.: "The path of the event for the Sirius A (mag -… https://t.co/Cqy9GIixeg
<B787_300> anyone know how hot you have to heat lunar regolith to vitirify it?
<B787_300> i want to know how big of a orbiting parabolic mirror you need to vitrify a nice landing pad
<B787_300> or if it would be doable with a nice large laser
<bofh> B787_300: so let's use standard sand as a baseline, since I'm pretty sure lunar regolith is to first order silicates
<bofh> I'm fairly certain vitriying sand via laser is nontrivial, at least at scale.
<bofh> But I could be wrong.
<B787_300> http://adsabs.harvard.edu/full/1973Moon....8..346N this paper says they needed 400 W/cm^2
<B787_300> and that was with a solar furnace of 3.2 m
<B787_300> s/3.2/3.0 m in dia
<galois> B787_300 meant to say: and that was with a solar furnace of 3.0 m in dia m
<B787_300> but they had spallation which might defeat the purpose
<bofh> Wait, why would that defeat the purpose?
<B787_300> when landing on the moon there is no noticable atmo to slow down debris kicked up by the landing
<bofh> Okay, true.
<B787_300> which could fly around the moon and destroy shit at or near the antipode of landing or things in low lunar orbit
<B787_300> now the solution is reasonably trivial... make a permanent landing pad
<B787_300> but the question is HOW to do it with out kicking up all the dust trying to land stuff
<B787_300> an orbiting mirror was a though i had to vitirfy the landing zone
<B787_300> s/though/thought
<galois> B787_300 meant to say: an orbiting mirror was a thought i had to vitirfy the landing zone
<B787_300> but if you need 400 W/cm^2 that is really hard to do while still being accurate with the pointing
<B787_300> (also talk about a nice weapon if you want to destroy other peoples shit)
<bofh> Do you still need a high degree of pointing accuracy?
<B787_300> i would think so as you are trying to only glass a small portion of the moon
<bofh> I mean your beamwidth isn't going to be *that* big
<B787_300> another thing you need is a slight dish or bowl effect in the LZ to deflect all the exhaust gas up. if it gets shot out to the sidethen you will dig out the regolith to the sides of the pads (and possibly shoot stuff at your hab
<B787_300> )
<B787_300> or a lip on the LZ
<B787_300> ironically this is one thing that trying to land on mars is much easier
<B787_300> i guess you could always land a smaller light rover first and use it to bind regolith into a LZ
<B787_300> as the amount kicked up is proportional to the weight of the lander
<bofh> I mean aerobraking on Mars is still, like, not really a thing.
<bofh> cf. Six Minutes of Terror
<B787_300> yeah it is... MAVEN and most of the other Oribiters aerobraked
<B787_300> aerobraking to a landing is a different thing that HIAD should solve
<B787_300> or super/hupersonic retro propulsion which SpaceX has been messing around with for the last 3-4 years
<B787_300> but really i was just talking about the dust kicked up on landing issue not the getting to that point
<bofh> I mean okay, yes, that's what I meant, oops.
<B787_300> actually is there an epoxy that can withstand the temp of a rocket engine?
<B787_300> becuase most epoxies dont need air to set
<B787_300> plus with an epoxy route and a specialized drill you could make essentially foundation piles under the landing pad to help it support even more weight
<B787_300> and it would be easier to shape the pad the way you wanted in 3d profile
<bofh> 03:15:01 <@B787_300> actually is there an epoxy that can withstand the temp of a rocket engine?
<bofh> I'm tempted to say "no" but I've run into some frighteningly temperature-resistant phenolic epoxies
<whitequark> is that like ablative
<UmbralRaptop> Troll answer: well, GEM SRBs are a thing, right?
<whitequark> it sounds ablative fundamentally
<whitequark> maybe with expansion
<B787_300> well we are talking moon landing so the expansion ratios would be like 100-200
<B787_300> brb running some CEA
<B787_300> huh, using a RL10 (with the 280 area ratio) the exit temp is only 721 K or ~850 F which is cool https://usercontent.irccloud-cdn.com/file/sx4HShJY/image.png
<B787_300> ugh all the epoxies i am finding for that temp range need water to activate and have a pretty strict cure schedule
<B787_300> and while it would be possible to use a essentially a large sunshade with various optical densities to regulate the temp it would be a pain
<B787_300> and that is before moving all that water to surface to mix with the epoxy
<B787_300> and if i am going to have a sunshade why not be like a kid and use a large magnifying glass
<bofh> SC21AF... huh.
<bofh> Okay that's the CRS Command Word opcode, so not *too* helpful w/o knowledge of what it's actually being changed from and to. Still, I *really* want a damn copy of 618-505.
<egg> meow
<egg> bofh: so have you found anything re. these covariances
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<_whitenotifier> [Principia] pleroy opened pull request #2077: Fix the version script: just say no to CP850 - https://git.io/fh5CW
<_whitenotifier> [Principia] Pending. Build queued… - 
<_whitenotifier> [Principia] Pending. Building… - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3448/
<_whitenotifier> [Principia] pleroy opened pull request #2078: Fix bugs in DiscreteTrajectory and friends - https://git.io/fh5Ca
<_whitenotifier> [Principia] Pending. Build queued… - 
* bofh 32
<egg|zzz|egg> bofh: 32?
<_whitenotifier> [Principia] eggrobin labeled pull request #2077: Fix the version script: just say no to CP850 - https://git.io/fh5CW
<_whitenotifier> [Principia] eggrobin labeled pull request #2078: Fix bugs in DiscreteTrajectory and friends - https://git.io/fh5Ca
<_whitenotifier> [Principia] Success. Build finished. - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3448/
<_whitenotifier> [Principia] Pending. Building… - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3449/
<_whitenotifier> [Principia] pleroy closed pull request #2077: Fix the version script: just say no to CP850 - https://git.io/fh5CW
<_whitenotifier> [Principia] pleroy pushed 2 commits to master [+0/-0/±2] https://git.io/fh5WO
<_whitenotifier> [Principia] pleroy 1a49bd2 - Fix the version script: just say no to CP850.
<_whitenotifier> [Principia] pleroy 2f32c56 - Merge pull request #2077 from pleroy/UTF8 Fix the version script: just say no to CP850
<_whitenotifier> [Principia] Success. Build finished. - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3449/
<egg> bofh: meow
<egg> bofh: covariances
<bofh> egg: one moment
<egg> bofh: you mean six months?
<bofh> egg: no I mean like, 2 hours.
<bofh> of irl wallclock time
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<_whitenotifier> [Principia] pleroy closed pull request #2078: Fix bugs in DiscreteTrajectory and friends - https://git.io/fh5Ca
<_whitenotifier> [Principia] pleroy pushed 3 commits to master [+0/-0/±8] https://git.io/fh5lr
<_whitenotifier> [Principia] pleroy 93c80c6 - Fix a bug in ForgetBefore when the trajectory is left empty.
<_whitenotifier> [Principia] pleroy 8084b56 - Fix a bug when attaching a fork to an empty fork.
<_whitenotifier> [Principia] pleroy cfb60a6 - Merge pull request #2078 from pleroy/TrajectoryBugs Fix bugs in DiscreteTrajectory and friends
<egg> bofh: in what reference system
<egg> <bofh> egg: no I mean like, 2 hours. <<< 2 hours later (TT)
<_whitenotifier> [Principia] Sinderion29 closed issue #2063: Principia DLL failed to load - https://git.io/fhZtt
<egg|zzz|egg> B787_300: bofh: do you know whether the positions in an SP3 file are TT-compatible or TCG compatible
<B787_300> i have no idea what TT ot TCG is
<B787_300> also i have never had the (mis)fortune to deal with a SP3 file
<egg|zzz|egg> hm
<egg|zzz|egg> "Most ITRS realizations are given in TT-compatible coordinates (except ITRF94, 96 and 97)"
<egg|zzz|egg> B787_300: SP3 files are decently well specified and fairly nice to work with, all things considered
<egg|zzz|egg> B787_300: TT and TCG are two TCG-based timescales
<egg|zzz|egg> TT?
<galois> TT: Temps Terrestre
<egg|zzz|egg> TCG?
<galois> TCG: Temps-Coordonnée Géocentrique
<egg|zzz|egg> B787_300: TCG is the time coordinate of the GCRS
<egg|zzz|egg> B787_300: whereas TCB is the time coordinate of the BCRS
<egg|zzz|egg> and TDB is a scaling of TCB so it looks a bit like TT
<bofh> egg|zzz|egg: hrm. that of proper time of a clock moving away from a co-moving barycentric solar system reference frame at around 0.95c?
<egg|zzz|egg> >_>
<bofh> (i.e. I got distracted but I found the references I was looking for, so maybe another hour TT?)
* egg|zzz|egg slaps bofh with a relativistic flyswatter
<egg|zzz|egg> bofh: also I resoldered the finder reticle illuminator
<SnoopJeDi> superluminal newspaper
<bofh> egg|zzz|egg: ooh excellent. I take it after that + battery replacement it is working better?
<egg|zzz|egg> yeah
<egg|zzz|egg> SnoopJeDi: nah I have a dedicated flyswatting instrument for bofh
<bofh> It's very useful.
<egg|zzz|egg> !acr -add:GSSC GNSS Science Support Centre
<galois> Definition added!
<egg|zzz|egg> bofh: has your advisor tried flyswatter btw
<egg|zzz|egg> !acr -add:ENSG École Nationale des Sciences Géographiques
<galois> Definition added!
<egg|zzz|egg> !acr -add:CDDIS Crustal Dynamics Data Information System
<galois> Definition added!
<egg|zzz|egg> bofh: hey you can into GNSS right?
<egg|zzz|egg> bofh: does the numbering of the directories in ftp://igs.ensg.ign.fr/pub/igs/products/ have any obvious meanng
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<bofh> egg: yeah, GPS week
<kmath> <LiaSae> To be fair this WAS a bit of an experiment into how much cheese you can put in a bread before it stops being struct… https://t.co/ocn8FwYbDc
<SnoopJeDi> art is alive and well
<SnoopJeDi> !wpn bofh, egg, et al.
* galois gives bofh, egg, et al. a RPN soufflé
<SnoopJeDi> !wpn -add:wpn eigenvector
<galois> Added wpn 'eigenvector'
<SnoopJeDi> !wpn -add:adj pathological
<galois> Added adj 'pathological'
<SnoopJeDi> probably broken but it's a thing ¯\_(ツ)_/¯
<bofh> SnoopJeDi: now I'm imagining a soufflé containing an HP-15C inside
* bofh is now reminded of that one galette des rois where the relevant item in it was a random power N-channel MOSFET we had lying around, lol.
<SnoopJeDi> To be fair, that WAS a bit of an experiment into how much computer science you can put in a bread before it stops being structurally sound.
<SnoopJeDi> s/bread/puff/
<galois> SnoopJeDi meant to say: To be fair, that WAS a bit of an experiment into how much computer science you can put in a puff before it stops being structurally sound.
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<SnoopJeDi> bofh, I think that the mail may have eaten your postcard if you've already sent it btw :/
<bofh> SnoopJeDi: argh. like I sent it very late in the year, so I'd give it another week or two
<SnoopJeDi> mkay!
<SnoopJeDi> so, that notion I had to make a Telemachus-aware KSP mapview-alike in Three.js has turned into a phone call next week with a startup that makes a satellite OS and mission control software o.O
<SnoopJeDi> one of the devs at the company found the concept said "hey wanna interview with us?" basically
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<egg> !wpn whitequark
* galois gives whitequark a Hermitian morphism
<egg> !wpn bofh
* galois gives bofh a divergent adjoint trout with a plotter attachment
<egg> UmbralRaptop: phl: it is commonly said that there are only two forms of life on Kerbin, grass and Kerbals; but there's a third one, the birds you hear in the space centre view
<UmbralRaptop> egg: kerbin's trees are no longer eggstinct~
<egg> hm
<egg> UmbralRaptop: but still, birbs
<egg> !wpn UmbralRaptop
* galois gives UmbralRaptop a plotter
<egg> !wpn SnoopJeDi
* galois gives SnoopJeDi a logarithmic graph
<egg> !wpn -add:wpn botfly
<galois> Added wpn 'botfly'
<UmbralRaptop> !wpn egg
* galois gives egg a discrete isomorphic rubber chicken
<SnoopJeDi> I pre-seeded it with a bunch of garbage, but it understands -del:wpn and -del:adj too fwiw
<egg|zzz|egg> bofh: are the R01 through R26 ГЛОНАСС satellites and the G01 through G32 GPS satellites?
* egg|zzz|egg stares at the SP3 file
<egg|zzz|egg> oh no, there are only P records, no V records, this is unusable
<kmath> <profanegeometry> oh: "The instrument is mounted on a trolley and is quite mobile when powered by one or more research students."
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<B787_300> UmbralRaptop: Army definition of Portable: if it has Handle(s) it is portable
<UmbralRaptop> So if you attach handles to a W-53…
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<egg> bofh: UmbralRaptop: whitequark: TIL ⏨
<egg> !u ⏨
<galois> [WIKIPEDIA] Six-bit character code#GOST 6-bit code | "A six-bit character code is a character encoding designed for use on computers with word lengths a multiple of 6. Six bits can only encode 64 distinct characters, so these codes generally include only the upper-case letters, the numerals, some punctuation characters, and sometimes control characters..."
<galois> ⏨: U+23e8 DECIMAL EXPONENT SYMBOL
<egg> this seems like a good idea
<egg> this 6-bit encoding seems really nice tbh
<egg> matched quotes \o/