[HN Gopher] Varda Capsule Reentry - Five Minutes from LEO to Ear...
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Varda Capsule Reentry - Five Minutes from LEO to Earth [video]
Author : enderfusion
Score : 412 points
Date : 2024-02-28 15:01 UTC (7 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| enderfusion wrote:
| This is what filming hypersonic plasma with a gopro from a
| reentry capsule looks like.
|
| For the true space nerds, here is the 27min uncut version.
| https://www.youtube.com/watch?v=BWxl921rMgM
| kragen wrote:
| this is so awesome, thank you
|
| also, congratulations. space is hard, and what you've done is
| harder than reentry
| bragr wrote:
| Watching this somehow makes the whole MOOSE concept [1] of a
| person falling from orbit seem a lot more reasonable. It
| wouldn't be pleasant obviously
|
| https://en.m.wikipedia.org/wiki/MOOSE
| kragen wrote:
| this is great! i think you could make it as pleasant as a
| typical rush-hour trip on the city bus: louder and more
| dangerous, but with less people, and perhaps roughly as
| comfortable, at least if you have the kind of rush hour where
| you are frequently in danger of fainting from the heat
| lupusreal wrote:
| Eventually Red Bull is going to sponsor somebody to do this.
| IncreasePosts wrote:
| No, it's going to be some old, rich tech nerd! (eg Alan
| Eustace, who broke Felix's balloon record shortly after it
| was set but without anywhere near as mich fanfare)
| myself248 wrote:
| You kidding? I'd pay to try that. Suck it, Baumgartner!
| enderfusion wrote:
| Maaaaaaybe. But we did pull like 20g+ on descent, so that's a
| bit problematic
| enderfusion wrote:
| Grabbed the wrong link, that's the 5min version.
| notso411 wrote:
| Looks identical
| logtempo wrote:
| I find the most crazy thing is not the reentry, but the number of
| objects (satellites) visible at the beginning of the video.
|
| And maybe the most worrying part is that there is more and more
| unidentified objects:
| https://sdup.esoc.esa.int/discosweb/statistics/
|
| Also the number of payload really rised after 2020 (because of
| spaceX I guess).
|
| 1980: less than 1000 objects Today: Almost 10000 objects,
| including approx. 4000 in LEO only.
| causal wrote:
| Pretty sure that's just debris from the separation, most likely
| to end burning up in the atmosphere too.
| enderfusion wrote:
| Yeah, that's some dust from the heat shield
| pfdietz wrote:
| If not, their orbits would rapidly decay due to very low
| ballistic coefficient (mass/area).
| pfdietz wrote:
| Those little white specs moving from lower left toward upper
| right? I think that's just tiny pieces of debris dislodged when
| the RV separated, shining in the sunlight.
| logtempo wrote:
| Make sense...still impressive to have x10 more objects
| floating around in less than half a century.
| teraflop wrote:
| Those specks are almost certainly not distant satellites, but
| very nearby specks of dust and debris caused by the separation
| process.
|
| One dead giveaway is that they don't appear to be moving in
| perfectly straight lines. If they were distant, this would
| imply they were not free-falling but under powered flight, at
| an implausibly high acceleration.
|
| You can see the same phenomenon in e.g. film footage of Apollo
| stage separation: https://youtu.be/9DNnZ82Kg3w
| wkat4242 wrote:
| So we know what dropping from hyperspace looks like? Area 51
| confirmed!!
| isx726552 wrote:
| Was there a jump cut at the end or was the person collecting the
| chute really mere steps away from where it landed?
| enderfusion wrote:
| Jump cut. We helicoptered in, but it took about 20 minutes.
| athenot wrote:
| That is still an impressive aim that y'all achieved.
| Congrats!
| focusedone wrote:
| IDK what your job title is, but 'helicoptered in to collect a
| recently landed spacecraft from the desert' sounds like an
| awesome day at work.
| bombcar wrote:
| Seriously muddy sneakers tho.
| marssaxman wrote:
| I laughed - looks exactly like the "playa stilts" you see
| after rainfall at Burning Man.
| bombcar wrote:
| Reminded me of
| https://www.youtube.com/watch?v=QrxPuk0JefA
| enderfusion wrote:
| I don't really have a job description, I just solve
| problems.
| alias_neo wrote:
| You can tell it was a cut, by the way the person faded into
| view.
| baerrie wrote:
| Can anyone explain the random bright flashes at the apex of its
| velocity?
| enderfusion wrote:
| Tiny pieces of the heatshield debonding from the craft and
| interacting with the plasma.
| danesparza wrote:
| "...and interacting with the plasma"
|
| That sounds like an exciting day at work. ;-)
| rbanffy wrote:
| Rapid unscheduled dismantling happening at the molecular
| level.
|
| In this case, it wasn't really unscheduled.
| BryanLegend wrote:
| That's what a several miles per second wind looks like!
|
| The heat is not from the friction, but from the compression of
| the gasses.
| enderfusion wrote:
| All those little molecules trying to get out of the way.
| rbanffy wrote:
| They are screaming, first in infrared, then red, orange,
| white...
| enderfusion wrote:
| They were not expecting this....
| pfdietz wrote:
| They're so excited, and they just can't hide it.
| pfdietz wrote:
| I often see that claim, but I don't like it.
|
| The implication is that the heating is like when one compresses
| air in a bicycle pump, the increase in temperature that comes
| from adiabatic (reversible, isentropic) compression of a gas.
| And some compression does occur, so there is _some_ necessary
| heating from that source (as required by the second law).
|
| But entry heating is not reversible. It's fundamentally
| irreversible, in fact. The gas is going through a shock. Shocks
| fundamentally cause an increase in entropy as fast gas slams
| into slow gas over a region whose thickness is on the order of
| a mean free path of molecules in the gas. And, in fact, the
| increase in density of gas going through a shock approaches a
| limit (around 4, IIRC, for air) regardless of the Mach number.
| So at sufficiently high speed most of the heating is coming
| from dissipation at the shock (a process akin to friction),
| over and above the heating implied by adiabatic compression.
| rbanffy wrote:
| I prefer to say it's the molecules screaming in agony as they
| are violently compressed and forced to hit each other at
| speeds they are mostly uncomfortable with.
| TeMPOraL wrote:
| A molecular equivalent of a massive, high-gee car pileup on
| a highway.
|
| (Hope that never actually happens.)
| pfdietz wrote:
| Shock wave dynamics are observed in the flow of traffic
| on sufficiently crowded highways.
|
| https://en.wikibooks.org/wiki/Fundamentals_of_Transportat
| ion...
| pixl97 wrote:
| I see you've never seen people drive in Texas when
| there's ice on the road.
| mindfulmark wrote:
| Seems like the gases are getting compressed either way and
| it's just different ways of wording the same effect. As for
| it being reversible or not, is it not just a matter of
| whether the energy was actually transferred somewhere? Like
| you could technically undo the shock the same as you could
| depressurise air in a pump no? I don't really know what I'm
| talking about though, fyi.
| pfdietz wrote:
| Gas is being compressed, but that doesn't mean the heating
| is from compression.
|
| There's a gas heater on the market that works by using
| rapidly moving vanes to induce shock waves in the gas. The
| outflow has the nearly the same pressure as the inflow, but
| the gas has been heated, potentially to a temperature
| higher than could be achieved by resistive heating
| elements. EDIT: I mistated this; see below for link.
|
| Consider also that once the shock heated air around the
| reentry vehicle has expanded back to ambient pressure, it
| will be hotter than it initially was.
| kragen wrote:
| resistive heating elements made of carborundum can heat
| air to 1625deg
| https://www.kanthal.com/en/products/furnace-
| products/electri... and molybdenum disilicide to 1800deg
| https://zircarceramics.com/wp-
| content/uploads/2017/02/Design.... while graphite heating
| elements can go to 2200deg
| https://apps.dtic.mil/sti/tr/pdf/ADA329681.pdf but not in
| air. what are these vanes made of?
| Tuna-Fish wrote:
| The point is that the shock isn't the air hitting the
| vanes, it's the air hitting other air.
|
| Similar to re-entry heating: the specific kinetic energy
| of the returning capsule is many times greater than would
| be required to melt and vaporize any material. So why do
| things survive re-entry? Because most of the energy is
| dissipated in the bow shock, significant distance away
| from from the capsule, where air gets heated to
| temperatures higher than the surface of the sun when
| other air slams into it. The purpose of the heatshield is
| to protect from radiative heating from the bow shock, not
| convective heating. Ablative heatshields do not work
| because ablation consumes energy which removes heat
| (again, there is sufficient energy going around to ablate
| the entire craft), but because they place a shade (made
| of ablated carbon particles) between the bow shock and
| the craft, which shields it from the radiative heating.
| pfdietz wrote:
| > The purpose of the heatshield is to protect from
| radiative heating from the bow shock, not convective
| heating.
|
| In this case the entry regime was such that convective
| heating far outweighed radiative heating.
| kragen wrote:
| i'm interested to hear more about these heaters. do you
| know what they are called or what they are made of?
| pfdietz wrote:
| See link in a comment below.
| kragen wrote:
| got it, thanks!
| https://news.ycombinator.com/item?id=39540283
| https://coolbrook.com/wp-
| content/uploads/2023/06/REPRINT-202...
| kragen wrote:
| hmm, that's a good point; so if you run coolant through
| the vanes they can operate without damage while producing
| temperatures that would vaporize them?
| ballenf wrote:
| Do you have a link or company/product name? Sounds
| fascinating.
| pfdietz wrote:
| https://coolbrook.com/wp-
| content/uploads/2023/06/REPRINT-202...
|
| I mistated slightly: the gas is accelerated to supersonic
| speed then slowed in a diffuser, where shock waves heat
| it.
| kragen wrote:
| thank you, this is great! it sounds like they're only
| targeting 1700deg, though, which is a temperature that
| exotic resistive heating elements can reach. it's too bad
| they didn't include any kind of diagram
| BryanLegend wrote:
| The gasses get so hot they give off a lot of black body
| radiation. Heat shield is mostly beat up with infrared.
|
| When the gases decompress they'll be a lot cooler, just
| like your AC.
| pfdietz wrote:
| I believe for entry from LEO, and particularly for small
| RVs like this one, convective heating is orders of
| magnitude higher than radiative heating.
|
| https://ntrs.nasa.gov/api/citations/20140012475/downloads
| /20... (see slide 7)
| BryanLegend wrote:
| From Slide 7: "Radiation dominates convection at
| ~11.5km/s for 1m radius * Radiation dominates convection
| at ~10km/s for 5m radius"
| pfdietz wrote:
| Since this is reentering from LEO, it's maybe 8km/s (and
| dropping). And the radius of curvature on the nose of
| that shield was maybe 20 cm?
| kragen wrote:
| thank you, this is very illuminating. i'm very weak on
| thermodynamics
| imjonse wrote:
| Is the bright body visible from 0:25 to 0:35 the Sun? It looks
| much brighter already at 4:04.
| enderfusion wrote:
| The moon!
| mholt wrote:
| This footage is amazing. And I love how the microphone just gave
| up as the plasma formed xD
|
| EDIT: As commenters noted, it fades out so it probably was edited
| in post.
| alias_neo wrote:
| I was curious at this point; did the mic actually give up (it
| was working again later), or was it muted because of lots of
| noise?
| enderfusion wrote:
| But it came back later! Frankly we're all surprised and a
| little confused how much audio we got while at 500km altitude
| before reentry.
| mik3y wrote:
| It sounds like it indeed was a GoPro, neat! Were you not
| surprised to get video back, then? What steps were taken? I
| don't know much about Space Stuff but seems like even with
| shielding, you would expect off-the-shelf consumer hardware
| to fail somehow..
| enderfusion wrote:
| Heavily modified. But it's the Gopro sensor and board.
| bohanker wrote:
| How interesting... the anacoustic zone apparently begins at
| about 160km altitude.
| pfdietz wrote:
| What's the maximum voltage in a GoPro? In some ranges of
| air pressure, if the voltage is sufficiently high a
| discharge could occur, perhaps shorting out something
| temporarily.
| kragen wrote:
| maybe a lot of that audio is electromagnetic interference?
| that's what it sounds like, and audio amplifiers can be
| pretty sensitive
|
| also, sometimes audio amplifiers oscillate on their own
| (though i think the single-jfet preamp in an electret mic is
| unconditionally stable); an amplifier that oscillates in
| space in a way that physically vibrates the microphone might
| be damped by air so that you don't notice it when air is
| present
|
| interestingly, microphone amplifiers oscillating and
| producing physical vibrations is not a phenomenon restricted
| to electronic systems:
| https://en.wikipedia.org/wiki/Otoacoustic_emission
|
| pfdietz seems to be suggesting corona discharge encouraged by
| the lowered paschen voltage in low vacuum, and of course the
| negative-resistance characteristic of gas discharges can
| easily set up a parasitic relaxation oscillator; all you need
| is some parallel capacitance or series inductance, plus some
| kind of ballast that quenches the discharge
| http://tinyurl.com/23dt3d5e http://tinyurl.com/2de5uaog https
| ://www.physics.purdue.edu/demos/display_page.php?item=6...
| spdustin wrote:
| The audio (in both videos) sounds like it was ring modulated. And
| later, cut out entirely. Is that an attempt to stretch audio that
| was sampled periodically from another system, or an artifact of
| the GoPro's own audio circuitry?
| enderfusion wrote:
| Entirely from the Gopro internal mic
| ordu wrote:
| Could video camera be damaged by a direct imaging of Sun?
| mnw21cam wrote:
| Just like from the surface of the Earth. The atmosphere doesn't
| really diminish the brightness that much.
|
| So, while you should be careful including the sun in a photo
| from a camera, it really depends on the focal length and
| aperture of the lens used. Lenses with long focal lengths will
| create a larger sun image on the sensor leading to greater
| heating. The camera should automatically shrink the aperture
| when the sun appears in frame to adjust the brightness, but if
| it doesn't and the aperture is sufficiently large then you
| could end up with enough heating on the sensor to damage it.
| With a very wide-angle lens like the one used for this video,
| it's not likely to be a problem.
| kragen wrote:
| for people using non-medieval units of measure, [?](GM/r) is a
| fairly precise approximation to circular orbital speed, and
| units(1) is good at calculating things like this:
| You have: (G earthmass / earthradius)**.5 You want:
| Definition: 7909.7861 m / s
|
| it was amusing when the sound cut out at 2'59" (sumerian units of
| measure). for a while i thought the microphone had been destroyed
| by the sound at that point
| enderfusion wrote:
| I am ashamed, I misread the room.
| enderfusion wrote:
| Everything in mission control is typically m/sec, we're not
| animals :P
| kragen wrote:
| well i am, which is why unit conversion is difficult for me
| pfdietz wrote:
| Statistically, it wouldn't be too surprising if at least
| one of you was a furry. :)
| kragen wrote:
| probably a lot of them; every high-tech field is _full_
| of furries
|
| also though the humans are animals, not stable
| configurations of plasma currents in the chromosphere or
| something
| coder543 wrote:
| Sound came back later in the video, so I'm pretty sure they
| just turned the volume way down. The sound was probably very
| annoying for that period of time, but they actually wanted
| people to be able to enjoy the beauty of that scene.
| kragen wrote:
| thanks for the correction; incorporated
| fnordpiglet wrote:
| I find it interesting people are pretty hardcore that meters is
| a superior measure based on its lack of human foot reference,
| but still hold onto Celsius. Basing a unit on the temperatures
| water phase changes at 1atm is as barbaric and anthropomorphic.
| That's why I only measure with a zero based on actually zero.
| Negative heat?? Wtf.
| hn_throwaway_99 wrote:
| Your argument doesn't make that much sense to me when
| Kelvins, while 0=absolute 0, have the same magnitude as a
| degree Celsius. I.e. they're still based on water phase
| changes at 1 atm.
| fnordpiglet wrote:
| The language defining the Celsius unit originally was: "The
| arbitrary points which coincide on the two scales are 0deg
| and 100deg"
|
| Those distances are arbitrary, and not specifically moored
| on the anchors of 0 and 100. Kelvin units are moored
| however on a fundamental anchor of zero heat energy, with
| arbitrary sized units above. It happens they were later
| calibrated to the Boltzmann constant, which itself is
| anchored on the triple point of water. None of this is
| based on human experience.
| kragen wrote:
| it's water because the humans are mostly made of water.
| rumor has it that on they use the triple point of what
| the humans call 'phosphoric acid' (it's a toasty place)
| and in they use the triple point of the ammonia-methane
| eutectic
| nuancebydefault wrote:
| It's funny that I can't even accomplish an emoticon in
| these comments while some people manage to draw complete
| scenes or algebraic formulas interleaved with the text.
|
| I must admit that, unlike a lot of HN'ers, I'm using a
| virtual keyboard on a heldheld device to type comments; I
| never took the effort of looking up how it is done though
| it must have to do with extended char sets.
| kragen wrote:
| most emoji are banned, as are nonstandard space symbols
| like thin space and some other things. emoticons (things
| like :-) and XD) are allowed. generally alphabetic
| characters and digits are allowed, and some other things,
| but i think unknown unicode is forbidden by default.
| https://news.ycombinator.com/item?id=23440551 has some
| investigation and results which are probably still
| accurate
|
| i do most of my algebraic formulas with the compose key
| and a custom compose map mostly written by mark shoulson
| https://github.com/kragen/xcompose
|
| for the above, after a false start picking random unicode
| characters, i realized that maybe i shouldn't use a
| modern language because someone who actually uses the
| language might feel like i was calling them an
| extraterrestrial, so i switched to googling archaic
| scripts. i pasted part of the old permic table from
| wikipedia >>> s = '''
| ... U+1036x
| ... U+1037x '''
| >>> print(''.join(c for c in s if ord(c) >= 0x10350))
| >>> len(''.join(c for c in s if ord(c) >= 0x10350))
| 38 >>> permic = (''.join(c for c in s if ord(c)
| >= 0x10350)) >>> ''.join(random.choice(permic)
| for i in range(5)) ''
|
| and then i tried out the hieroglyphs range
| >>> print(''.join(chr(i) for i in range(0x13000,
| 0x14000))) ...
|
| but realized that most of them were unassigned, at least
| in my font and probably in the current unicode standard
| (in case someone discovers a new hieroglyph), so i just
| did this >>> hiero = (''.join(chr(i)
| for i in range(0x13000, 0x13100))) >>>
| ''.join(random.choice(hiero) for i in range(4))
| ''
|
| you can do all this in python in termux on your phone too
| (you'll probably have to install it from f-droid) but
| it's a bit clumsier
|
| it's funny how this conversation has swung from the
| extreme of universal constants of the universe to the
| opposite extreme of completely arbitrary and historically
| contingent things like which ideograms (themselves
| completely arbitrary) are prevented from being posted by
| implementation bugs in hacker news
| nuancebydefault wrote:
| Exactly a good reason why I love HN comments so much. The
| off-topic reply is frowned upon.
|
| Thanks so much for this, let's see if copy paste works on
| this unix derived os.
| kragen wrote:
| i'm glad you liked it!
| jtvjan wrote:
| Oh, they were just random hieroglyphs? I thought you made
| a tiny cartoon of a man flipping a table.
| kragen wrote:
| hahaha, that's awesome! i hadn't even noticed that it
| sort of looks like that
| fnordpiglet wrote:
| That's why we picked water, but water exists everywhere.
| Earth, the kings foot, 1atm, are specific to the human
| experience.
| kragen wrote:
| most of the non-dark-matter non-dark-energy mass of the
| universe finds itself in conditions that prevent the
| existence of water: black holes, degenerate-matter stars,
| conventional plasma stars, things like that. almost all
| of the rest is hydrogen and helium, so water exists there
| in the same sense that uranium exists here. but, although
| almost all of the universe is cold enough to freeze
| hydrogen, its vapor pressure is high enough at the cbr
| that most of it is vapor, so basically none of that is
| solid. solid objects do have a substantial amount of
| water in them, although if our solar system is typical,
| many of them don't
|
| but sure, if it turns out that there are electron-
| degenerate-gas vortex intelligences on the surface of
| white-dwarf stars, they could very likely work out some
| way to launch robotic probes out of the star into places
| where water could exist, so that they could measure its
| triple point. and the folks on use trace amounts of
| water in their biology (it's a reasonably powerful base)
| and have isolated it in liquid form in their cryogenic
| laboratories. it's accessible in a way that the artifact
| kilogram and artifact meter and the circumference of the
| earth aren't
| cyberax wrote:
| > triple point of the ammonia-methane eutectic
|
| Which is a shame that the temperature scale is still
| anchored in that arbitrary mix, picked by a lazy
| apprentice. It's also historically base-10, not like the
| modern systematic base-8 units.
|
| (Can ammonia actually alloy with methane? Their
| crystalline lattices don't seem to be compatible, and
| they don't react together.)
| kragen wrote:
| guilty as charged. it gets worse, though: meters are
| originally based on the size of the earth, but humboldt's
| expedition (?) fucked up the measurement and now we're stuck
| with a meter that's significantly too short, nominally
| defined as the distance light travels in 9192631770/299792458
| cycles of the hyperfine transition radiation frequency of
| cesium-133. you probably think this is a goddamned joke but
| it's not
|
| i ask you, what the fuck kind of number is 9192631770? is
| that a hexadecimal encoding of linus torvalds's first child's
| birthdate? no, it's just a random fucking number derived from
| the sumerian base 60 numbering system and the average
| rotational speed of the earth in the 20th century. the kelvin
| has a similarly filthy history; it's when the thermal energy
| changes by 1.380649e-23 joules, because that makes the triple
| point of water come out to 273.16 kelvins. so now we have to
| preserve those numbers for all eternity like they're the
| fucking holy writ of the priestesses at delphi in order to
| interpret scientific papers from the 19th and 20th century.
| (and don't get me started on the motherfucking calendar.
| jesus jumping blue christ.)
|
| you will be pleased to learn about
| https://en.wikipedia.org/wiki/Natural_units (which i used in
| https://dercuano.github.io/notes/2017-sap-allocation.html
| because i'm uncreative) and https://en.wikipedia.org/wiki/Duo
| decimal#Systematic_Dozenal_...
| lupusreal wrote:
| It all gets the job done, no reason to let any of it bother
| you.
| nuancebydefault wrote:
| You probably know all this, but it is fun to write. Units
| are parts of models. Used Models were the best in class, at
| the time they were derived or adopted. Models are wrong and
| get replaced by less wrong models over time.
|
| That said I think meters and Kelvins are doing their job
| just fine even for use with rocket science. I'm glad I
| learned the SI units at school, they reduced the number of
| constants a lot in physical formulas.
| kragen wrote:
| yeah, but there are still a lot of constants even with
| the si units, which is because they predate the
| discoveries of many of the constants. more constants
| generally means more arithmetic operations you can
| accidentally leave out of your program and constants you
| can get wrong. this was a bigger concern in the slide-
| rule era, but the humans are still infallible, so it
| hasn't gone away entirely
|
| i don't think it makes sense to describe miles or meters
| or stoney lengths as 'wrong' or 'right'; you can express
| the fitzgerald contraction or orbital speed or whatever
| equally well with any of the three, but one of them
| simplifies the fitzgerald contraction somewhat
| fnordpiglet wrote:
| I think a key tho in a measurement unit that's desirable
| is its relationship to something consistent everywhere in
| the universe, such that the reference unit is
| reproducible by anyone. This doesn't matter much day to
| day but as a system we should converge to one that anyone
| anywhere can agree how long a distance may be without a
| mutually agreed upon calibration but can calibrate
| without access any specific reference unit. The triple
| point of water is always what it is, and a colony on mars
| without easy access to something locked in a room in
| Paris or whatever can create their own reference
| measurements from whole cloth and they'll be the same as
| the colony at Alpha Centauri now and in 20,000 years.
| kragen wrote:
| yes, even before alpha centauri, a big problem with the
| kilogram artifact locked in a room in paris was that it
| keeps changing its mass and nobody knows why or exactly
| how much or in which direction, although the best
| estimates are that it's a fair fraction of a part per
| million by now
|
| agreeing on distances with a faraway colony is actually a
| considerably easier problem than the kilogram; if we
| transmit them a radio or laser message, they can measure
| its length to within parts per billion, and we can do
| that with 01950s technology, while kibble didn't invent
| the kibble balance (previously known as the watt balance)
| until the 01970s
|
| (you do have to worry about redshift: one part per
| billion of redshift is 300 millimeters per second, so you
| have to know the relative velocity of alpha centauri to
| within meters per second to correct for it--and, while
| that's also the 01950s technology of measuring spectral
| line frequencies to that precision, that same technology
| is what allows you to do without the radio message
| entirely)
|
| transmitting or storing the number "9192631770/299792458"
| can be done with significantly higher exactitude, of
| course, and can be done over twenty millennia more easily
| than transmitting a radio message can
| kragen wrote:
| it wasn't humboldt's expedition https://en.wikipedia.org/wi
| ki/Alexander_von_Humboldt#Spanish... which had nothing to
| do with the decades-earlier meter-measuring expedition http
| s://en.wikipedia.org/wiki/French_Geodesic_Mission_to_the...
| (except for being inspired by it) and the contemporary
| calculations of the paris meridian https://en.wikipedia.org
| /wiki/History_of_the_metre#M%C3%A8tr...
| thfuran wrote:
| https://en.m.wikipedia.org/wiki/Negative_temperature
| fnordpiglet wrote:
| Quantum and their oppositionally defiant exceptions.
| TeMPOraL wrote:
| Beautiful, thank you for posting!
|
| I predict new reentry shaders being made for Kerbal Space Program
| by modders in short order.
| kraig911 wrote:
| The mud on those shoes at the end man. Still impressive footage!
| pfdietz wrote:
| It's been rainy lately out west, I think. Kayaking in Death
| Valley!
|
| They needed it.
| taway789aaa6 wrote:
| I was very confused about the shoes. I was watching on low res
| (bad internet) and I thought it was some sort of weird ghillie
| suit! Thx
| SenHeng wrote:
| I'm surprised it took only around 2-ish minutes from somewhere
| above the clouds to on the ground.
| thejohnconway wrote:
| There's a cut at 5:10, after the parachute opens:
| https://youtu.be/qw4DseiPu7E?si=QZFAnKYfVnQc92TD&t=305
|
| There's another cut earlier when still outside the atmosphere
| as well.
| SiempreViernes wrote:
| Yeah, I think it would have been nicer if they used wipes or
| some other more obvious transition when hey cut out bits. Some
| of the cuts you almost don't notice tricking you into thinking
| things happens much faster than they really did.
| enderfusion wrote:
| Full 27min uncut video here.
| https://youtu.be/BWxl921rMgM?si=q50ewZw4ARRU-hG0
| next_xibalba wrote:
| This is definitely not dropping out of "hyperspace". Title should
| be changed.
|
| Very cool video though.
| elliotbnvl wrote:
| I mean it definitely _looks_ like it.
| bennyp101 wrote:
| That meringue got toasted!
|
| Pretty neat the way it went from crazy hyperspace to a gentle,
| peaceful floating in the air!
| krisoft wrote:
| On the other hand a reentering ICBM warhead (test) looks like
| from the ground as if the gods are angry with you and your
| general vicinity: https://www.youtube.com/watch?v=2a1acYZ93yc
| pfdietz wrote:
| Notice the two that impacted at almost exactly the same spot, a
| few second apart (around 1:00). What precision!
| krisoft wrote:
| Yeah. To understand why this is quite a flex: nearly no
| structure survives when they are directly hit with a nuclear
| weapon. The way hardened structures are designed is that the
| designers guestimate how big of a boom they have to survive
| and at what distance. They do this based on your intelligence
| sources of course.
|
| So let's say your spies are telling you that the enemy can
| deliver 60 kiloton device with 200m circular error probable
| (CEP). Then your engineers can calculate how likely is that
| your bunker/silo will survive that (and can do something like
| a counter attack.)
|
| And you build the number of silos you think you need based on
| that calculation. You put a lot of concrete and lot of work
| literally in the ground based on those numbers. And then
| suddenly your enemy just improves their guidance system and
| they drop (figuratively) such a video on you. That tends to
| cause jitters.
| dylan604 wrote:
| Yeah, that was the first thing that popped into my mind as
| well when I saw that. Horse shoes and hand grenades, and
| atomic weapons was what we always joked about being close
| enough
| ericbarrett wrote:
| Awesome link. Reminds me that one of my biggest gripes with
| movies is that when they show meteors (or whatever) entering
| Earth, it's never at realistic speeds. They're always super
| slow and floaty, hovering in the sky to menacing effect. Great,
| that's the artist's choice. But the real thing is so much
| scarier, like this footage! And it's still a fraction of the
| speed of an interstellar object.
| marcosdumay wrote:
| On movies those are usually very large objects. Very large
| objects do hoover menacingly for a very long time before they
| finally appear to fall for a few seconds.
|
| The larger it is, the longer it will stay hoovering and only
| slowly growing in size.
| ericbarrett wrote:
| Nah, even the big ones are shown sauntering through the
| atmosphere at _maybe_ Mach 3, trailing smoke and flames
| like lit pitch.
|
| A city-sized asteroid wouldn't be more than a bright dot
| until the last seconds before entry, and at interstellar
| speeds it would take about three seconds to go from the
| vacuum of space to ground impact unless it had a very
| shallow vector.
| pfdietz wrote:
| At relativistic speeds it would take about 1 millisecond
| to go from LEO altitude to the ground.
| buildbot wrote:
| A relativistic asteroid would not be a good time for
| earth. Apparently according to gpt4 (so big grain of
| salt), a 1km asteroid going 0.9c is roughly 4.37x10^16
| megatons of TNT worth of energy.
| szundi wrote:
| Or a grain of TNT
| dylan604 wrote:
| that's one of those too big to comprehend type numbers.
| that's fine when talking about number of atoms, or the
| distances to another galaxy. trying to have my brain
| apply that to explosion just immediately goes to BSOD
| buildbot wrote:
| Yeah same haha - for a slightly more relevant number, if
| every nuclear weapon yielded 50MT of TNT, the asteroid
| impact is approx 63 Billion times the entire worlds
| nuclear arsenal in terms of power.
| short_sells_poo wrote:
| And that is still impossible to comprehend, so how about
| this, the Sun's energy output is about 10^10 megatons of
| tnt per second, so this impact would release 1 million
| second's worth of the Sun's output, or about 12 days. In
| other words, it would instantly vaporize the entire
| planet.
| buildbot wrote:
| For the ultimate nerd snipe, how far would the light from
| that explosion be visible?
| dylan604 wrote:
| using what to "see"? naked eye? binocular aided?
| telescopes?
|
| also, seen by who/what? for the only known living things
| that could see it, it would be the last thing they did
| see. so maybe as far away as a couple of inches?
| pineaux wrote:
| This is in the correct ballpark. But 0.9c is crazy fast.
| [Expanse spoiler alert]
|
| I love how they use this mechanic for storytelling in
| "The Expanse". The rebels of the belt threaten earth by
| slinging rocks at it at really high speed. Seems a very
| realistic way of interplanetary war. Why not bend some
| fast moving rocks to your enemy?
| aurelwu wrote:
| I don't know if it's been the first time in fiction where
| that concept was described but in Heinleins "The Moon is
| a harsh Mistress" this was what the Moon Colonists did.
| Terr_ wrote:
| > according to gpt4 (so big grain of salt) [...]
| 4.37x10^16 megatons
|
| I decided to challenge the glorified-autocorrect machine
| with some more-manual napkin math, and I get 5.56x10^13
| megatons, which is smaller by a factor of ~786x.
|
| That discrepancy is too big to explain just in terms of
| asteroid composition: Even an impactor of _pure Osmium_
| would only be ~12x more energetic.
|
| Here's my work, if anyone wants to check for errors:
| Asteroid volume 1 km3
| Asteroid density 1 2 grams / cm3 h
| ttps://en.wikipedia.org/wiki/Standard_asteroid_physical_c
| haracteristics Volume conversion
| 1E+15 cm3 / km3 Asteroid density 2
| 2E+15 grams / km3 Asteroid mass
| 2E+15 grams Asteroid velocity
| 0.9 c Relativistic kinetic energy
| 2.33E+29 joules
| https://www.omnicalculator.com/physics/relativistic-ke
| TNT energy 4.18E+03 joules/gram
| TNT mass equivalent 1 5.56E+25 grams
| Mass conversion 1.00E+12 grams per
| megaton TNT mass equivalent 2
| 5.56E+13 megatons
| sushisource wrote:
| >stay hoovering
|
| Hehe, I too love vacuuming.
| dylan604 wrote:
| No, that's Hoovering. case sensitivity is important /s
|
| Edit: added /s for those unable
| wongarsu wrote:
| I've never seen anyone capitalize googling or
| astroturfing, though my dictionary seems to want to
| capitalize Xeroxing.
| kwhitefoot wrote:
| No one does that. Except perhaps the PR and legal
| departments of the Hoover company.
|
| I suppose you capitalise aspirin as well.
| pfdietz wrote:
| The other problem with movies showing large meteors is how
| dim they are. In reality you would be blinded, even lethally
| burned, before the thing even hit the ground.
| sdflhasjd wrote:
| Hollywood does slow explosions too. Its kind of a funny meta-
| anachronism when CGI uses the slow firey explosions that I
| suppose are inherited from the limitations of practical
| effects using gasoline deflagrations.
|
| YouTube has shown people real big explosions (Beirut,
| Tianjin, etc) and how vicious they are, but you rarely see a
| CGI shock wave.
|
| Rockets too, RPGs are fast but movies have them sauntering
| through the air.
| ajuc wrote:
| I mean just look at laser beams in sci-fi :)
| abecedarius wrote:
| Imagine if _Don 't Look Up_ had tried for a realistic comet
| impact. It could make a much greater _artistic_ impact, the
| contrast to the surrealistic spin games up to that point.
| wutwutwat wrote:
| "Peacekeeper" ICBM... the irony
| krisoft wrote:
| How many did it kill?
| wutwutwat wrote:
| I'm not talking about the test. I'm talking about an entire
| missile system designed to deliver nuclear payloads to
| anywhere in the world being dubbed "Peacekeeper", but you
| already knew that.
| krisoft wrote:
| > I'm talking about an entire missile system designed to
| deliver nuclear payloads to anywhere in the world being
| dubbed "Peacekeeper"
|
| I'm also talking about the LGM-118 Peacekeeper missile
| system. It was in service from 1986 to 2005. Did it ever
| needed to be used in anger or not? During that time did
| any military attack the nation which fielded it?
|
| If not I would say it lived up to its name.
| runjake wrote:
| Seeing as the Peacekeeper hasn't killed anyone, the name
| seems pretty apt.
|
| The US nuclear program is about deterrence after all. Well,
| after 1945, anyway.
| wutwutwat wrote:
| Weapon designed for use in a war or otherwise some sort of
| conflict requiring the use of lethal force, which would be
| the exact opposite of peace, is named peacekeeper
|
| These comments are being obtuse on purpose. Look at the
| name and look at what the name is on. The name peacekeeper
| is on a weapon that will only be used in times of no peace.
| Not a hard thing to see the irony in.
| runjake wrote:
| I'm not being obtuse, I think we just have different
| views on how the world works.
|
| In my view, violence, or hopefully, just the threat of
| violence, maintains order.
|
| There are certain classes of people where diplomacy and
| pacifism just isn't going to work.
|
| Again, the post-1945 US nuclear program is about
| deterrence ("peace through superior firepower"). So, in
| that perspective, the Peacekeeper's threat of violence...
| kept the peace.
|
| The US and the Soviet Union/Russia both do not want to
| use nuclear weapons.
|
| Citation: Self. Was in the nuclear program during the
| latter days of the Cold War and shortly thereafter.
| pasabagi wrote:
| If you look at the rich history of nuclear near-misses
| through the cold war, I don't think there's any reason to
| feel secure in the idea that nuclear deterrence _ensures_
| peace. What it does do, is ensures that the consequences
| of war will be catastrophic, likely civilization-ending.
|
| Which, you know, is the dice we're going to be rolling
| from now on. Maybe we'll survive the next century, then
| maybe the next, but in the long term? Humans just don't
| have that good judgement.
| computerfriend wrote:
| Is it any different to "peacekeepers" being soldiers?
| krisoft wrote:
| > will only be used in times of no peace
|
| It is indeed a deadly weapon system. But it is used every
| second during peacetime too. Every second it is fielded
| it maintains a situation where the preferable choice of
| action is to not attack the one fielding it. In other
| words it is keeping the peace.
| jandrewrogers wrote:
| You are being obtuse to the fact that this missile's
| primary and explicit purpose was to be a compelling and
| credible strategic deterrent. The entire point of
| building it is was so that it would never need to be
| used. This is not a contradiction. Strategic deterrence
| is an effective way of keeping the peace as has been
| demonstrated throughout history.
|
| The name "peacekeeper" is a formal acknowledgement of its
| purpose in the military arsenal. It has no other role.
| Sohcahtoa82 wrote:
| https://en.wikipedia.org/wiki/Si_vis_pacem,_para_bellum
|
| If you want peace, prepare for war.
|
| Or as Roosevelt put it, speak softly and carry a big
| stick.
|
| Building an incredibly powerful weapon and calling it
| "Peacekeeper" is meant to strongly imply that we don't
| plan on using it, but rather, it's symbolic as a
| preemptive threat against any would-be attackers. Peace
| is kept by showing that any attack would be retaliated
| with overwhelming force.
| PKop wrote:
| If you can't conceive of some adversary being aggressive
| if they perceive you as weak, then you don't understand
| geopolitics or history. So yes, credible deterrence by
| means of a powerful destructive weapon can prevent war
| and maintain some level of peace particularly in
| preventing large scale war between large industrial
| powers.
|
| What else _does_ maintain peace besides power?
|
| The strong do what they can, the weak suffer what they
| must. If you want peace prepare for war. Do you think
| these are just famous slogans or they really do reflect
| some hard earned wisdom?
| lupusreal wrote:
| The weapon is used by not being used. It's purpose is to
| be a threat. It has been in continuous use ever since it
| entered service.
| kraquepype wrote:
| I was just thinking about what the alternatives to nuclear
| would have been, had it not been created. (Purely
| hypothetical, as I know it would require a vastly different
| timeline of scientific discovery to avoid nuclear
| entirely.)
|
| Would we still have an equivalent war deterrent today
| without nuclear? What would it look like?
|
| My guess is something biological. My tongue-in-cheek guess
| would be something zoological (laser sharks anyone? pigeon
| pirahna hybrids?)
| runjake wrote:
| My guess is biological, too.
|
| And in the short-term future, I think synthetic biology
| will represent an even greater threat than nuclear.
|
| Why? Lethality, ease of manufacture once figured out,
| mishandling of process or materials, lack of regulation,
| ethnic/DNA targeting, etc.
| qup wrote:
| Hard to pinpoint origin in the case of bad actors...
| wongarsu wrote:
| The only reason nuclear weapons are easy to pinpoint is
| because so few actors are capable of making them. If you
| had one you could load it onto a semi truck, drive into
| the middle of New York or Moscow and detonate it, with
| all evidence conveniently destroyed in the blast.
| runjake wrote:
| Keep in mind that there are nuclear detection sensors
| deployed throughout the US and if you tried to roll a
| nuke-containing semi into New York, there would be a
| heavily-armed team trying to intercept you[1].
|
| Supposedly[2], they are sensitive enough that it's
| untenable to transport enough lead around to shield it.
|
| 1. https://en.wikipedia.org/wiki/National_Nuclear_Securit
| y_Admi...
|
| 2. I have no inside info.
| dylan604 wrote:
| Biological has the advantage of not destroying the
| infrastructure of the place you are attacking nor making
| it inhabitable for thousands of years. So if you're
| wanting to take over the land after you remove the pesky
| opponents currently occupying it, nuclear is a really bad
| choice. Biological and chemical can be cleaned up and or
| inoculated against depending on method used.
| runjake wrote:
| From what I remember, the US's nuclear weapons make a
| place uninhabitable in terms of weeks, not years. But,
| point still noted.
| jandrewrogers wrote:
| A strategic deterrent needs to be targetable and
| scalable. Biological and chemical weapons don't have this
| property. Before nuclear, strategic deterrence meant
| maintaining a massive standing army and navy. This was
| very expensive and also difficult to scale due to the
| logistical footprint, so most countries could not
| maintain it very long. There is also the issue that the
| economic cost of strategic deterrence is relatively much
| higher for smaller countries.
|
| What changed with nuclear is that you could maintain a
| credible and scalable strategic deterrent indefinitely at
| a tiny cost compared to maintaining conventional forces
| at an equivalent level of deterrence effect.
| wongarsu wrote:
| Scalability is a bit of an issue, but a biological weapon
| like weaponized anthrax or chemical weapon like a powder
| that converts to 4highly effective nerve gas could
| conceivably delivered by methods similar to the nuclear
| triad. Strategic bombers could airdrop them over
| population centers, and with enough engineering we could
| probably make ballistic missiles with payloads that
| disperse such agents in an air burst, using a small
| amount of explosives to scatter it over an area the size
| of Manhattan
| lupusreal wrote:
| WW2 showed that strategic deterrence with chemical and
| biological weapons doesn't work. Both sides feared gas
| particularly and therefore didn't use war gas on each
| other (civilians is another matter.) Germany had very
| potent nerve gasses and had reason to believe the allies
| did as well, and didn't dare use them. But the threat of
| these gasses wasn't strong enough to deter the rest of
| the war.
| ryandrake wrote:
| There have been many wars since 1945, and also since the
| development of this so-called "peacekeeper." Its existence
| is not doing a great job of keeping general peace.
|
| The only thing nuclear weapons seem to do is ensure their
| owners are always the aggressors in war and not defenders.
| Nobody wants to attack a country with nuclear weapons, so
| it enables them to pick and choose which wars to start.
| floatrock wrote:
| you'd have to be MAD to have it make sense
| a_gnostic wrote:
| "It keeps the peace, in a dominating, intimidating sort of
| way."
| drno123 wrote:
| Americans call their ICBM "peacekeeper", while renaming
| Russian ICBM to "Satan"
| lupusreal wrote:
| NATO reporting names use common starting letters for
| different categories of weapons. For surface-to-surface
| missiles all begin with the letter S. Most of the names
| chosen wouldn't raise eyebrows: Sapwood, Sasin, Sibling,
| Stone... Some of them seem to have an appreciative "cool
| factor": Skyfall, Saber, Stiletto... But generally there
| isn't a derogatory theme to these code names. For instance,
| codenames for fighter jets include Foxhound, Firebird,
| Fencer, and Felon. Some of these are really cool names that
| could have been given to western jets by marketting while
| others seem derogatory. There's not much of a pattern here.
| jamiek88 wrote:
| I've always thought the worst thing about ICBM's is the
| _hypocrisy_ of the name too!
|
| But seriously these names are pretty much random, sometimes
| 'cool' sometimes not, just sequential NATO designations
| like Falcon, Felon, etc.
| moffkalast wrote:
| Nothing ironic about it, nukes have made their owning
| countries impervious to invasion. Peace through superior
| firepower as they say.
| ajuc wrote:
| It literally kept the peace?
| tomcam wrote:
| TIL the shockwave effect so popular in movies the last 20 years
| is 100% accurate
| Terr_ wrote:
| On the subject of impressive old missile footage, I recommend
| the Nike-X program's Sprint interceptor-missile. Not hot
| glowing plasma on re-entry, but instead _going up_.
|
| As a short-range interceptor, Sprints were slammed up out of
| their silos via an explosively-driven piston, then they would
| ignite and reorient in midair, accelerating at 100g to reach
| Mach 10. The missile itself couldn't see very much, but would
| be remotely guided with strong signals from the launch
| installation.
|
| https://www.youtube.com/watch?v=gSFIkGfbLxs&t=23m37s
|
| https://www.youtube.com/watch?v=6lWDbwmsz9E&t=7m15s
|
| https://www.youtube.com/watch?v=3dl9Ovwmnxw&t=2m44s
| runlevel1 wrote:
| Here's footage of several MIRVs entering the atmosphere at
| night: https://youtu.be/3ZM3y5qpMgY?t=68
|
| On a more scientific note, here's a video from the Space
| Shuttle boosters as they reenter (2005):
| https://youtu.be/527fb3-UZGo?t=70
| Mistletoe wrote:
| https://arstechnica.com/space/2024/02/vardas-drug-cooking-wi...
| tra3 wrote:
| So I have a question about the audio at the beginning of the
| video. How low is LEO and how much atmosphere is there? You know,
| the whole sci-fi movie trope with lasers making noise in space?
| bombcar wrote:
| > This marks the first time a commercial company has landed a
| spacecraft on United States soil.
|
| I'm assuming SpaceX doesn't count somehow? Boosters have landed
| on soil for sure (well, technically on landing pads), but maybe
| they didn't become spacecraft.
| pfdietz wrote:
| Those reentered from suborbital trajectories. If reaching space
| (> 100 km) was necessary, I think even amateur rocket people
| have achieved that.
| davedx wrote:
| Come on LOL.
|
| Falcon 9 is an orbital booster that's landed dozens of times
| on US soil. Suggesting this spacecraft has achieved some kind
| of world first is totally ridiculous and diminishes the
| actual achievement.
| peeters wrote:
| I mean sure, there's ambiguity around the word
| "spacecraft". But Falcon 9's booster isn't orbital, its
| payload is. So it might still be a first for an orbital
| spacecraft.
|
| The gravitational potential energy of a 100kg payload in
| 100km orbit is 98 MJ. The kinetic energy of a 100kg payload
| in 100km orbit is 3042 MJ, over 30x more. So surviving
| reentry from orbit is orders of magnitude more difficult
| than surviving a straight up/down shot.
|
| Now F9 boosters obviously have a horizontal velocity as
| well that they need to cancel out, but suborbital and
| orbital spacecrafts are _very_ different beasts and it 's
| absolutely noteworthy. It's the difference between
| surviving a car crash at 20 mph vs 95 mph. One is trivial,
| the other requires a heck of a lot of engineering.
| davedx wrote:
| F9 landing is not trivial, and despite all the comments
| on this thread trying to back up the claim this is the
| "first commercial spacecraft to land on US soil"
| ludicrous.
| Tuna-Fish wrote:
| I disagree. Falcon 9 is an orbital booster, but only the
| second stage goes to orbit. The hard part is surviving re-
| entry, the first stage only barely requires a heat shield.
|
| Dragon would qualify, except it lands on the ocean, so not
| "US soil".
| ianburrell wrote:
| Falcon 9 boosters are not orbital. The point of first stage
| booster is to get rocket part of the way to orbit and the
| second stage gets it into orbit. The boosters don't have
| the heat shield to return from orbit.
| myself248 wrote:
| Umm, no. It's a booster of an orbital rocket, the booster
| itself is not orbital. Falcon 9 stages super early even
| compared to other rockets, specifically so the booster can
| come back _before_ it gains anywhere near a significant
| fraction of orbital energy.
|
| This is great because it does make it practical to recover
| the booster, but it's only possible by making the second
| stage significantly larger and more powerful than
| comparable rockets that stage later.
|
| If the booster got up to orbital velocity, it would burn up
| just like the Rocket Lab "mothership" host satellite that
| accompanied the Varda capsule. They were coupled together,
| the mothership performed the braking burn to adjust their
| orbit into a reentry trajectory before the two separated.
| Only a minuscule amount of drift separated the two as they
| hit the atmosphere, but while the mothership burned up, the
| capsule survived.
|
| If Falcon's booster achieved orbit, it would burn up just
| the same. The only reason it doesn't, is that it's only
| going a tiny fraction of orbital velocity when it comes
| home.
| davedx wrote:
| How was the spacecraft in this video "more orbital"? Did
| it reach orbit itself?
| dotnet00 wrote:
| It was a capsule sitting in orbit for a few months
| waiting for bureaucratic processes before being allowed
| to come back down.
| wongarsu wrote:
| Then what about Starliner? Here's a video of the landing from
| OFT-2 [1] two years ago, on the way back from the ISS. It was
| in orbit and landed on land in New Mexico. And while they are
| doing this as part of a NASA contract, the spacecraft and
| mission control were both from Boeing. I don't see how they
| don't qualify
|
| https://www.youtube.com/watch?v=gPFS8Bp643o
| presentmonkey wrote:
| This capsule was recovered from orbit, SpaceX boosters are not
| orbital at all and are just falling basically
| moffkalast wrote:
| I guess the Dragon capsule doesn't count because it lands in
| water just slightly offshore, lol
| p_j_w wrote:
| Water is famously not soil.
| sophacles wrote:
| To be fair, orbit is also "just falling, basically".
| dotnet00 wrote:
| The boosters aren't themselves orbital, and while the Dragon
| capsules have re-entered several dozen times now, they
| splashdown in water. I think technically Starliner would better
| fit the case of a commercial company landing a spacecraft on US
| soil.
| phyzome wrote:
| They should definitely also add an "intact" qualifier. ;-)
| chrisjc wrote:
| Others have pointed out why boosters don't count.
|
| But what about Dragon?
| lapetitejort wrote:
| Dragon capsules (as well as all US-based capsules [could be
| wrong]) splash down in water, so not soil. Soyuz capsules
| land on soil.
| lawrenceyan wrote:
| The experiences of awakening astronauts get when they see Earth
| for the first time make sense to me now.
| xeromal wrote:
| This was incredible to me and I'm not even sure why. I was
| enthralled.
| moribvndvs wrote:
| Immediately before touchdown, the camera rolls slightly before we
| hear and see it impact. Why is that?
| enderfusion wrote:
| 27min full uncut version.
| https://youtu.be/BWxl921rMgM?si=9lVkkMBd5pAw2hSv
| j-wags wrote:
| This is the second time Varda's been on my radar in the past
| year. First time was when their engineer Andrew McCalip
| livestreamed his replication attempt for LK-99 (using company
| equipment) just days after the initial announcement [1][2]. I'm
| not even remotely in the right field, but stuff like this makes
| me think Varda would be a cool place to work.
|
| [1] https://news.ycombinator.com/item?id=36997821 [2]
| https://www.tomshardware.com/news/engineer-details-messy-lk-...
| enderfusion wrote:
| Hehe, that was me. The hobbies do occasionally get out of
| control :P
| vertis wrote:
| When the hobbies become indistinguishable from the job.
| Congrats on the reentry.
| diimdeep wrote:
| This is some serious Deep tech [1] technology, not your average
| fully remote SAAS.
|
| https://en.wikipedia.org/wiki/Deep_tech
| davidw wrote:
| Can anyone post a timestamp?
| SushiHippie wrote:
| 2:44
| Centigonal wrote:
| I have a friend who's at Varda. They manufacture space drugs.
| SPACE DRUGS!!
|
| https://www.healio.com/news/infectious-disease/20240222/hiv-...
| clarle wrote:
| Out of curiosity, what's the benefit of pharmaceuticals
| manufacturing in space?
|
| Is there a benefit to manufacturing drugs in low gravity
| environments, or is it more of an experiment to see if it's
| feasible, in a future where more people might be living in
| space?
| ender341341 wrote:
| I believe last I read about it, some drugs are formed as
| crystals, and being in 0g (or free fall if your pedantic)
| meant the formed crystals were much bigger or easier to
| actually form, can't remember which, the specific drug is
| related to HIV medications
| cyberax wrote:
| Perfect crystals. Also, the proof-of-concept drug was
| ritonavir, and it's nearly impossible to consistently grow
| large crystals of it on Earth. All of the labs that work with
| ritonavir are contaminated by a more stable form
| ("polymorph") that rapidly converts any ritonavir crystals
| into a less-useful form.
| avalys wrote:
| What are the "sparklies"? They look like small particles burning
| up but it's not clear why they're only luminous so briefly within
| the frame of the video.
| DonnyV wrote:
| "Landing on the beach Do Do Do Do!"
| brcmthrowaway wrote:
| What ITAR restrictions do you have for employment?
| OldHunter69X wrote:
| Helldiver reporting for duty!
| thebiglebrewski wrote:
| Are the points of light when it first separates Starlink/other
| satellites moving around up there, or stars?
| dylan604 wrote:
| they could be much smaller and much closer from debris from the
| craft itself. perspective at that altitude is tricky
| a_gnostic wrote:
| What version of Reentry Particle Effect did you use for this KSP
| install?
| hasoleju wrote:
| Only a handful of minutes from a position in space where you can
| see the whole earth to a small spot in the desert of Utah. Where
| you see the feet of a human walking towards you.
|
| Amazing what is achievable with the tech of today. Space is not
| that far away after all. Still very odd to see the two scenes
| described above in a short video on YouTube.
|
| Having the human walk towards the camera has a tremendous effect.
| It's something everyone can relate to and it puts a great context
| to all the scenes that are shown in the video before that.
| mastazi wrote:
| Just a heads up that the video linked above has been cut, the
| full length video can be found here:
| https://www.youtube.com/watch?v=BWxl921rMgM
|
| What you said is still valid though, since the full video is
| not much longer.
| enderfusion wrote:
| Yeah sorry, grabbed the wrong link initially.
| whats_a_quasar wrote:
| If you live in San Francisco you're closer to LEO than you are
| to Los Angeles.
|
| Probably also helps that 17,000 mph is really freaking fast.
| aledalgrande wrote:
| Question, that might be obvious to many but not to me: isn't
| space supposed to be empty? How is the mic picking up noise (=
| sound) just after detaching from the other module?
| SushiHippie wrote:
| I'd say vibrations of the capsule which shake the camera, which
| then shakes the diaphragm/membrane of the microphone, and maybe
| electromagnetic inferences
| abeppu wrote:
| I was confused by the fact that it started off with a little
| sound, and then there was a crescendo, and then it cut off to
| silence at about the 3 minute mark ... and then around the 4
| minute mark sound ramps back up. Was that artificially muted
| out because that section would have been too loud?
| klohto wrote:
| I don't know if Andrew is still answering, but how does it work
| with calculations for reentry?
|
| It's basically ballistic downward, how do you make sure you won't
| hit anything on your way down over many layers?
| Plasmoid wrote:
| What I found interesting is the sun is actually white in this
| camera feed instead of the usual yellow we associated with it.
| SushiHippie wrote:
| Yeah, the sun is actually white! It's a big star, after all
|
| https://en.wikipedia.org/wiki/Sun#Sunlight_and_neutrinos
|
| > The Sun emits light across the visible spectrum, so its color
| is white, [...], when viewed from space or when the Sun is high
| in the sky.
|
| > When the Sun is very low in the sky, atmospheric scattering
| renders the Sun yellow, red, orange, or magenta, and in rare
| occasions even green or blue.
|
| > Despite its typical whiteness [...], some cultures mentally
| picture the Sun as yellow and some even red; the reasons for
| this are cultural and exact ones are the subject of debate.
| jasonwatkinspdx wrote:
| It's a GoPro doing automatic white balance.
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