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Varda Capsule Reentry – Five Minutes from LEO to Earth [video] (youtube.com)
493 points by enderfusion 45 days ago | hide | past | favorite | 272 comments

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

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


Maaaaaaybe. But we did pull like 20g+ on descent, so that's a bit problematic

you'd have to decelerate several times slower (four gees to be safe, three gees to be gravitron-style 'comfortable'), but that's feasible in an aerodynamic (plasmadynamic?) fashion, even with a relatively low mass-per-unit-area projectile like a person facing forward

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

Eventually Red Bull is going to sponsor somebody to do this.

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)

The ultimate billionare sport would be basically parachuting from space (MOOSE-style). It would be such a rush. I volunteer Elon for initial testing.

You kidding? I'd pay to try that. Suck it, Baumgartner!

Grabbed the wrong link, that's the 5min version.

this is so awesome, thank you

also, congratulations. space is hard, and what you've done is harder than reentry

Looks identical

I wasn't able to respond to any other comment in your history, because pretty much everything you post is dead. You don't seem to respond to the obvious feedback from that, but somebody needs to recommend that you stop making flippant, dismissive, and generally worthless comments, because I've never seen an account as deeply downvoted on HN as yours.

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.

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.

Yeah sorry, grabbed the wrong link initially.

Yea, that's something we have to explain to folks quite a bit working at/on Varda; space feels further away than it really is because of how inaccessible it has historically been; really due to cost, but also cadence of launch in near equal measures. Now that both of those barriers have fallen with the Falcon 9, and will continue to do so with Starship, that perception of inaccessibility will slowly change...or I hope it does/I'm working really hard (with some decent progress) to make that true.

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.

You can't see the whole earth (most of one hemisphere) from LEO, only a circle about 1000 km in diameter, which is about the size of Texas or twice the width of Utah. That doesn't stop it being amazing though!

There's also a cut before the person appears, so it could have sat waiting much longer than a few minutes.

> 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.

Those reentered from suborbital trajectories. If reaching space (> 100 km) was necessary, I think even amateur rocket people have achieved that.

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


Done under government contract. This was the first time a purely commercial effort did it on their own dime.

Went from founding to shipped flight hardware in 2 years with 45 people. I think the key was the really good coffee machines.

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.

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.

How was the spacecraft in this video "more orbital"? Did it reach orbit itself?

It was a capsule sitting in orbit for a few months waiting for bureaucratic processes before being allowed to come back down.

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.

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".

apparently the hard part is getting the control systems and landing legs simultaneously lightweight enough and reliable enough, if i correctly understand spacex's long history of failing to land rockets (which i may not, since all i know is a small sample of what they've published)

agreed about dragon. those fuckers do orbit!

The hard part for landing a suborbital rocket vertically is that. The hard part of landing anything from orbit is still definitely the re-entry.

oh, sorry, you're right. a few rocks do survive re-entry every day without the benefit of any engineering at all, but they have a very, very low success rate

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.

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.

I wasn't trying to extend the analogy to saying landing F9 is trivial. But F9 surviving re-entry is fairly trivial, which is the important difference between the two. Once you've survived re-entry and slowed down to terminal velocity, there's not a huge difference between landing from orbital and sub-orbital trajectories. I agree that the way it's phrased is fairly meaningless and reeks of baseball commentary cherry-picking, but surviving from orbit is still a very different milestone than surviving from sub-orbit.

Huh? Did you flunk freshman physics?

E=K+U=GmM/2r−GmM/r=−GmME/r. We can see that the total energy is negative, with the same magnitude as the kinetic energy. For circular orbits, the magnitude of the kinetic energy is exactly one-half the magnitude of the potential energy.

Do the calculation over.

You're quoting this article, but you're misunderstanding it:


This is calculating the gravitational potential between two point masses. In other words, the potential energy if both masses were singular points at a distance from each other.

I was quoting the potential energy differential between being 100km over the ground, and on the ground. This is 98 MJ for a 100kg object, and that's what you have to cancel out to land back on Earth. The total gravitational energy of that object to the Earth's centre is more like 6300 MJ, but that's a meaningless number.

You are correct (aside from the s/ME/M/ typo), but the snark isn't needed.

No, they are not correct either.

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.

This capsule was recovered from orbit, SpaceX boosters are not orbital at all and are just falling basically

To be fair, orbit is also "just falling, basically".

I guess the Dragon capsule doesn't count because it lands in water just slightly offshore, lol

Water is famously not soil.

They should definitely also add an "intact" qualifier. ;-)

Others have pointed out why boosters don't count.

But what about Dragon?

Dragon capsules (as well as all US-based capsules [could be wrong]) splash down in water, so not soil. Soyuz capsules land on soil.

I have a friend who's at Varda. They manufacture space drugs. SPACE DRUGS!!


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?

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.

> 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.

The incredible case of the disappearing polymorphs: https://en.wikipedia.org/wiki/Disappearing_polymorphs

It's an actual virulent molecule!

Is it virulence, or surface tension?

You just need a crystallographer with a beard in the lab (https://improbable.com/2011/02/09/legend-of-chrystallographe... https://www.science.org/content/article/pure-stupid-luck https://www.chemistryworld.com/opinion/czochralskis-pulley/3...).

More seriously: this was pretty much solved already through improved techniques. I'm generally of the opinion that if you have to send a molecule to space to crystallize it better, you should probably spend your money on other, more terrestrial approaches. I do credit Varda for doing this automatically, rather than on ISS, because launch costs for autonomous vehicles are much more affordable than human space flight.

It's actually still not solved, you can't grow large ritonavir crystals on Earth.

Ritonavir used as a drug works around the issue. It's produced as dispersed molten droplets inside a matrix of inactive material. Its heated above the melting temperature of ritonavir, so it prevents contamination.

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

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.

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.

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.

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.

resistive heating elements made of carborundum can heat air to 1625° https://www.kanthal.com/en/products/furnace-products/electri... and molybdenum disilicide to 1800° https://zircarceramics.com/wp-content/uploads/2017/02/Design.... while graphite heating elements can go to 2200° https://apps.dtic.mil/sti/tr/pdf/ADA329681.pdf but not in air. what are these vanes made of?

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.

> 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.

i'm interested to hear more about these heaters. do you know what they are called or what they are made of?

See link in a comment below.

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?

Do you have a link or company/product name? Sounds fascinating.


I mistated slightly: the gas is accelerated to supersonic speed then slowed in a diffuser, where shock waves heat it.

thank you, this is great! it sounds like they're only targeting 1700°, though, which is a temperature that exotic resistive heating elements can reach. it's too bad they didn't include any kind of diagram

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.

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)

From Slide 7: "Radiation dominates convection at ~11.5km/s for 1m radius • Radiation dominates convection at ~10km/s for 5m radius"

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?

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.

A molecular equivalent of a massive, high-gee car pileup on a highway.

(Hope that never actually happens.)

Shock wave dynamics are observed in the flow of traffic on sufficiently crowded highways.


I see you've never seen people drive in Texas when there's ice on the road.

thank you, this is very illuminating. i'm very weak on thermodynamics

All those little molecules trying to get out of the way.

They are screaming, first in infrared, then red, orange, white...

They're so excited, and they just can't hide it.

They were not expecting this....

Beautiful, thank you for posting!

I predict new reentry shaders being made for Kerbal Space Program by modders in short order.

What version of Reentry Particle Effect did you use for this KSP install?

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?

Eric here from Varda. Short answer: lots of math. But really, that's the job of lots of folks over here, but primarily comes from our GNC and Hypersonic/Analysis teams. Folks like my colleagues Marat Kulakhmetov

That meringue got toasted!

Pretty neat the way it went from crazy hyperspace to a gentle, peaceful floating in the air!

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

What a strange way to take a dig at non-metric measurements. The "units" command makes it trivial to get whatever you want:

  You have: (G earthmass / earthradius)**.5
  You want: mph
   * 17693.688
   / 5.6517331e-05
  You have: (G earthmass / earthradius)**.5
  You want: furlongs / fortnight
   * 47560632
   / 2.1025793e-08

yes, but why would you want that?

the original title said 'at 17000 mph', and as you can see, that's very significantly low, about 4%:

    You have: (G earthmass / earthradius) ** .5 / 17000mph - 1
    You want: %
            * 4.0805157
so if you, like any rational person, want to know how fast the capsule was entering in meters per second, you're better off using units(1) to calculate it from first principles rather than converting it from a 4% wrong quantity in medieval units

Maybe 17000mph was a bit sloppy of a title on my part. It was a weird orbit, with the burns we were doing.

naw, 4% is fine, i'm half joking

i'm pretty much a raw beginner with orbital dynamics but my vague idea was that you'd have to ellipticize the orbit by hundreds of kilometers to change the orbital speed by more than a fraction of a percent, and that would be expensive enough that you'd only do it if you had a really good reason

but the only satellites i've ever troubleshot had only extremely limited maneuverability (though i'm not totally sure how much more than that i can say)

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.

Nope, all audio was straight from the camera, no gain adjustment or muting. Something odd happened with the diaphragm in the mic I think.

Fascinating, I wouldn’t have expected that!

thanks for the correction; incorporated

I am ashamed, I misread the room.

Everything in mission control is typically m/sec, we're not animals :P

Statistically, it wouldn't be too surprising if at least one of you was a furry. :)

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

well i am, which is why unit conversion is difficult for me

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.

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.

The language defining the Celsius unit originally was: "The arbitrary points which coincide on the two scales are 0° and 100°"

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.

it's water because the humans are mostly made of water. rumor has it that on 𐍨𐍓𐍰𐍚𐍠 they use the triple point of what the humans call 'phosphoric acid' (it's a toasty place) and in 𓃾𓂃𓂌𓀩 they use the triple point of the ammonia-methane eutectic

> 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.)

i don't actually know. however, the same considerations would suggest that methane clathrates in water are impossible, which turns out not to be true. methane freezes at 90 kelvin, so if there's a eutectic, it would be lower than that.

Clathrates are different, they are not eutectics. If you try to freeze them, they separate into methane gas and water ice.

Metals can alloy with each other because the shared electron layer "glues" small imperfections in crystals where different metals meet. Can frozen ammonia behave similarly? Liquid ammonia can solvate free electrons, so perhaps frozen ammonia also can?

It'd be interesting to actually try experiments with frozen ammonia.

that's a fascinating idea! frozen electrides! it's a lot freezier than methane (195 kelvin, a difference large enough to make a methane eutectic much less likely) to the point where you might even be able to freeze it with convenient and safe dry ice rather than liquid nitrogen. and, i don't know, maybe if dry ice by itself won't do the trick, maybe dry ice mixed with liquid ammonia will. trying to buy anhydrous ammonia around here gets you put on a list, though, so i'm gonna opt out of this one

there are a lot of solvated ionic eutectics with atmospheric-pressure water ice, despite the absence of metallic bonding

That’s why we picked water, but water exists everywhere. Earth, the kings foot, 1atm, are specific to the human experience.

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 𐍨𐍓𐍰𐍚𐍠 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

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.

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 = '''𐍐‎    𐍑‎       𐍒‎       𐍓‎       𐍔‎       𐍕‎       𐍖‎       𐍗‎       𐍘‎       𐍙‎       𐍚‎       𐍛‎       𐍜‎       𐍝‎       𐍞‎       𐍟‎
    ... U+1036x     𐍠‎       𐍡‎       𐍢‎       𐍣‎       𐍤‎       𐍥‎       𐍦‎       𐍧‎       𐍨‎       𐍩‎       𐍪‎       𐍫‎       𐍬‎       𐍭‎       𐍮‎       𐍯‎
    ... U+1037x     𐍰‎       𐍱‎       𐍲‎       𐍳‎       𐍴‎       𐍵‎'''
    >>> print(''.join(c for c in s if ord(c) >= 0x10350))
    >>> len(''.join(c for c in s if ord(c) >= 0x10350))
    >>> 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

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. 𓀝𓀞𓀟𓀠𓀡𓀢𓀣𓀤𓀥

i'm glad you liked it!

Oh, they were just random hieroglyphs? I thought you made a tiny cartoon of a man flipping a table.

hahaha, that's awesome! i hadn't even noticed that it sort of looks like that

Quantum and their oppositionally defiant exceptions.

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/Duodecimal#Systematic_Dozenal_...

> 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

Uhm, a kilometer is supposed to be 1/40000-th of the Earth's meridional (i.e. from South to North poles) circumference. The modern value is 40008km, so the official meter is juuuust about 0.02% shorter than it should be.

i think it was a ten thousandth of the distance from the north pole to the equator through paris, disregarding the southern hemisphere, which was more difficult to survey. i've been looking for a precise number for how far that distance actually turned out to be, but i haven't been able to find it; i would be delighted if you could!

whether 0.02% sounds ridiculously good or ridiculously bad depends on your frame of reference

https://en.wikipedia.org/wiki/History_of_the_metre#History_o... says that the original mètre des archives in 01799 was machined to within 50μm, which is 0.005%, four times smaller than the error in delambre and méchain's computation. so even at the time that was a pretty large error. since then the measurement uncertainty of the meter has improved by five more orders of magnitude, to about 0.1 part per billion. 0.02% is 200 parts per million, or 200000 parts per billion, which is a lot more than 0.1

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.

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

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.

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

it wasn't humboldt's expedition https://en.wikipedia.org/wiki/Alexander_von_Humboldt#Spanish... which had nothing to do with the decades-earlier meter-measuring expedition https://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...

It all gets the job done, no reason to let any of it bother you.

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.

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

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.

Make sense...still impressive to have x10 more objects floating around in less than half a century.

Pretty sure that's just debris from the separation, most likely to end burning up in the atmosphere too.

Yeah, that's some dust from the heat shield

If not, their orbits would rapidly decay due to very low ballistic coefficient (mass/area).

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?

I'd say vibrations of the capsule which shake the camera, which then shakes the diaphragm/membrane of the microphone, and maybe electromagnetic inferences

If it's a go pro in an airtight housing, it has that air to make the mic work normally

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?

From OP:

> Nope, all audio was straight from the camera, no gain adjustment or muting. Something odd happened with the diaphragm in the mic I think.


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.

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.

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...

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..

Heavily modified. But it's the Gopro sensor and board.

How interesting... the anacoustic zone apparently begins at about 160km altitude.

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.

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?

What I found interesting is the sun is actually white in this camera feed instead of the usual yellow we associated with it.

Yeah, the sun is actually white! It's a big star, after all


> 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.

That last sentence about the color of the sun being cultural is weird to me.

The sun simply looks very different depending on where you are on earth.

Example (from experience/memory): the sun looks very orange/red during a Norwegian winter sunrise for like an hour or so.

Around the equator the sun is up and white within minutes.

It's a GoPro doing automatic white balance.

Was there a jump cut at the end or was the person collecting the chute really mere steps away from where it landed?

Jump cut. We helicoptered in, but it took about 20 minutes.

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.

I don't really have a job description, I just solve problems.

That sounds worrying. Maybe they shoot you up next.

Awesome video you created! Looks like there is bad weather over half of the planet though.

Seriously muddy sneakers tho.

I laughed - looks exactly like the "playa stilts" you see after rainfall at Burning Man.

That is still an impressive aim that y'all achieved. Congrats!

You can tell it was a cut, by the way the person faded into view.

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?

Entirely from the Gopro internal mic

This is some serious Deep tech [1] technology, not your average fully remote SAAS.


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?

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.

This answer and the following children answers will answer your question: https://news.ycombinator.com/item?id=39539147

I didn't know what to ctrl+f to find my answer, settled with "sparks" and then "flashes".

What ITAR restrictions do you have for employment?

Are the points of light when it first separates Starlink/other satellites moving around up there, or stars?

they could be much smaller and much closer from debris from the craft itself. perspective at that altitude is tricky

The experiences of awakening astronauts get when they see Earth for the first time make sense to me now.

Immediately before touchdown, the camera rolls slightly before we hear and see it impact. Why is that?

I'm surprised it took only around 2-ish minutes from somewhere above the clouds to on the ground.

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.

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.

Is the bright body visible from 0:25 to 0:35 the Sun? It looks much brighter already at 4:04.

The moon!

This was incredible to me and I'm not even sure why. I was enthralled.

Can anyone explain the random bright flashes at the apex of its velocity?

Tiny pieces of the heatshield debonding from the craft and interacting with the plasma.

Compare the heat shield in the pic here (before launch): https://x.com/VardaSpace/status/1671621386065027072?s=20

To here (after reentry): https://x.com/VardaSpace/status/1760726397889466792?s=20

"...and interacting with the plasma"

That sounds like an exciting day at work. ;-)

Rapid unscheduled dismantling happening at the molecular level.

In this case, it wasn't really unscheduled.

The mud on those shoes at the end man. Still impressive footage!

It's been rainy lately out west, I think. Kayaking in Death Valley!

They needed it.

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

Could video camera be damaged by a direct imaging of Sun?

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.

there are definitely video cameras that can, but a gopro (with, as mnw21cam pointed out, a wide-angle lens) probably isn't one of them—even in space with no air to cool the focal plane

Surprising to see another spacecraft at 1:30

Rocketlab Photon?

that's the spacecraft that dropped us off!

oh god I need to change my HN username

Helldiver reporting for duty!

Can anyone post a timestamp?



Nope, not me.

"Landing on the beach Do Do Do Do!"

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

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.

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.

I mean just look at laser beams in sci-fi :)

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.

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.

At relativistic speeds it would take about 1 millisecond to go from LEO altitude to the ground.

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 4.37×10^16 megatons of TNT worth of energy.

> according to gpt4 (so big grain of salt) [...] 4.37×10^16 megatons

I decided to challenge the glorified-autocorrect machine with some more-manual napkin math, and I get 5.56×10^13 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 https://en.wikipedia.org/wiki/Standard_asteroid_physical_characteristics
    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

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?

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.

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

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.

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.

For the ultimate nerd snipe, how far would the light from that explosion be visible?

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?

Or a grain of TNT

>stay hoovering

Hehe, I too love vacuuming.

No, that's Hoovering. case sensitivity is important /s

Edit: added /s for those unable

I've never seen anyone capitalize googling or astroturfing, though my dictionary seems to want to capitalize Xeroxing.

No one does that. Except perhaps the PR and legal departments of the Hoover company.

I suppose you capitalise aspirin as well.

the chelyabinsk meteor was super slow and floaty, hovering in the sky to menacing effect (while glowing much brighter than the rising sun): https://youtu.be/gRrdSwhQhY0

however, that's because its trajectory was nearly horizontal rather than nearly vertical, so most of the people who saw it and were injured by it were tens of kilometers away, and it broke apart (exploded really) at 30 km up. it was initially traveling 19 km per second, 2½ times leo orbital speed. if you're traveling 19 km per second vertically instead of horizontally you only have 5 seconds from the von karman line (100km) until you make a crater or a tunguska

3 seconds from visibility to devastation still might be enough for hollywood dramatic flair


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.

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.

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.




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

Notice the two that impacted at almost exactly the same spot, a few second apart (around 1:00). What precision!

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.

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

TIL the shockwave effect so popular in movies the last 20 years is 100% accurate

"Peacekeeper" ICBM... the irony

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.

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.

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.

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.

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.


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.

> 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.

Is it any different to "peacekeepers" being soldiers?

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?

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.

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?)

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.

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

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.

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.

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.

From what I remember, the US's nuclear weapons make a place uninhabitable in terms of weeks, not years. But, point still noted.

Hard to pinpoint origin in the case of bad actors...

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.

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_Security_Admi...

2. I have no inside info.

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.

Nothing ironic about it, nukes have made their owning countries impervious to invasion. Peace through superior firepower as they say.

you'd have to be MAD to have it make sense

It literally kept the peace?

How many did it kill?

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.

> 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.

"It keeps the peace, in a dominating, intimidating sort of way."

Americans call their ICBM “peacekeeper”, while renaming Russian ICBM to “Satan”

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.

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.

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