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Finding the B-21's hangar location from the stars in its press image (twitter.com/johnmcelhone8)
809 points by johnmcelhone on Dec 8, 2022 | hide | past | favorite | 216 comments



There's a few highly suspect details in the way the author got the 34-35 degree estimate. Maybe he was just really lucky and the errors cancelled out, but don't count on using his method to produce similar results.

Polaris is about .8 degrees away from the celestial North pole, so using it alone can give a reading off by .8 degrees, and the orientation in the photo is actually nearing the worst case.

The horizon doesn't appear in the photo. I have done celestial navigation strictly as a hobby for fun, and using a sextant without a visible horizon results in a few degrees of error at best. And that's with the benefit of the sensation of gravity helping you estimate. It is theoretically possible to estimate the horizon using the man made parallel horizontal lines in the image, but the author doesn't give any indication he did that.

Additionally, the author used the angle measurement tool in Stellarium to measure the distance to another ambiguous horizon. This is incredibly odd, as just clicking on Polaris in Stellarium will tell you its elevation. But even more odd, is he would have had to explicitly set his latitude in the app in order to get that screenshot.


I'm sure you're correct, as the whole thing reads like "look how smart I am".

1. Extraneous details about satellites not being overhead at night -- as if government spy satellites operate on the same schedule with the same priorities as publicly known satellites.

2. Mentions things like them not scrubbing the EXIF data was a "mistake". How could it be a mistake if this was public information?

3. Says at the end "(this data is all public now)". Making it sound like he made the data public through his top notch sleuthing. It should read "this data was all public a week prior to my analysis".


> as if government spy satellites operate on the same schedule with the same priorities as publicly known satellites.

This bit, at least, is more or less the case. Even if you spend some fuel to alter your orbit and throw people off for a bit, you can't do anything major over the course of a few hours without sci-fi engines.


> as if government spy satellites operate on the same schedule with the same priorities as publicly known satellites.

It's basically impossible to hide things in orbit. Hobbyists have been able to track the Misty spy satellite that has an inflatable cone to mask its optical signature. The major powers all operate space tracking radars that can spot anything up there bigger than about a baseball.

Also nearly all optical imaging sats are in sun synchronous orbits because it maximizes power generation vs solar panel size as well allows comparison of multiple days images with the same shadow angles.

> How could it be a mistake if this was public information?

Well they scrubbed the data from the website so that's a pretty clear indication it was a mistake. You're oversimplifying this into a binary thing, whereas a lot of security is more of the form "this isn't foolproof but there's no need for us to make it this easy."


>How could it be a mistake if this was public information?

Not to pile on, but the government releases info by mistake all the time. Even simple things like doing a crappy job redacting court filings. It's just people doing this stuff, and people make mistakes all.the.time.


> I'm sure you're correct, as the whole thing reads like "look how smart I am".

It's been that way for a long time. The whole "UFO movement" had it's flames fanned by agents of foreign power who literally salivate at how many useful idiots will do the work their analysts would have done.

Some officer in the Russian equivalent of the NRO is probably gonna take that post and run with it.


> 1. Extraneous details about satellites not being overhead at night -- as if government spy satellites operate on the same schedule with the same priorities as publicly known satellites.

You can bet that the US, China and Russia know about at least the orbital data of all satellites that the other nations put up.

> 2. Mentions things like them not scrubbing the EXIF data was a "mistake". How could it be a mistake if this was public information?

Because even what otherwise should be public domain under US copyright rules can still be censored for national security reasons - precisely to avoid OSINT research like this. What some random Twitter hobby astronomy researcher can do in their free time with basic tools, Russian and Chinese secret services can do as well.

Another fine example just how important attention to detail is with maintaining operational security.


> You can bet that the US, China and Russia know about at least the orbital data of all satellites that the other nations put up.

Of course, but I think they would refrain from publishing that information? Unless they want to make sure that "they know that we know"...


We will never learn of satellite war.... we will never hear about attack sat drones that take out other sats but it happens regularly... think of the plane that was in orbit as 3 years, which was the Jimmy Carter of space (I hope you know that ref) ((if you dont, then you dont know shit))


That's paranoid nonsense. Attack drones don't regularly take out other countries' satellites. There is no way to hide such activity in orbit and it would be obvious to everyone, including amateur civilian observed.

Here's the real situation. All of the superpowers have some level of kinetic anti-satellite weapons capability and have conducted a few isolated tests against their own satellites. The X-37B drone spaceplane may have some anti-satellite role but has never been used operationally in that capacity.


1. What orbit sphere level do spy sats sit at?

(I worked with many sat engs from Loral and another quiet facility called Lokheed (Also you shouls look into BALL ((the actual Mason Jar company - and see how many spy sats they make)))

-

Anyway, I think that DEFCON needs to break this shit open....

Read all the lines, then read all the ones in-betweeen....

Serious.


If I were a betting man I would assume he started this exercise with the final assumed location in mind, and worked backwards from there to show how it could have been done.


That's actually what he was implying in his last tweet:

> The press conference to reveal the aircraft was held here last week so we can confirm the location. A guess likely would have landed someone in the same location but fun anyway to star match. I'm sure this entire process could be done with just stars and no google maps as well


Aka, “parallel reconstruction”


I extended many of the assumed parallel lines in the photo, and they all tend to converge just below and to the right of the nose of the plane. And using the known distance between two of the stars to estimate the degrees per pixel, I get a margin of error of about 4 degrees vertically estimating where the horizon is.


For what it's worth, I measured the pixels between Kochab and Pherkad and got .0161 degress per pixel. Then measured from Polaris to my visual guestimate of where the horizon should be and got 34.14 deg, about half a degree off of the real location.

I'd be interested to see what others get. For those not familiar with the stars, Polaris is just a few pixels from the top edge, nearly dead center (it's close enough to the top that you can just use the top edge of the photo as a reference). If you start with a photo the same size I did (4096x2731), you can just crop the photo from top down to where you think the horizon is, then look at the size of the resulting image, multiply the vertical pixels by .0161, and post the answer below.


Wide angle lens distortion?


I thought lens distortion would be a problem too, but there's really not much distortion. The lines on the buildings and runway are all pretty straight, even near the corners of the photo where distortion would be at it's maximum. I'm willing to bet the photographer has a lot of experience photographic large planes and knew what steps to take to avoid it coming out all contorted.


Interesting. So do you think the author had inside information on the location?


The fact that the b21 is being built at plant 42 in Palmdale has been public info for literal years.


And they had the press release there lmao


It was publicly accessible, or so I've read at least


I'm not going to speculate on what someone did or didn't know, let's give him the benefit of the doubt and just say he was really lucky. My main point was just don't expect similar results if you try it yourself.


Yeah, but when did he know it?

(god i hope you get this joke)


What’s more, there’s an 18-minute gap on the tape!


The author notes in the writeup that an educated guess could be made with public details about who the manufacturer was.


Edward’s is a classic and would be a top hit to re-visit on maps with any kind of buildings visible for a quick confirmation.


With the casual change from "34-35 degrees" to "lets draw a line at 34 degrees" followed by the "and this is where the press release was" I got the vibe that this was parallel construction. Still some good sleuthing, don't get me wrong, but still.


You're right, it wasn't too difficult to guess the location without the stars. The base did happen to be right in-between the 34 and 35 degree lines (34.6 lat), and you can estimate pretty well with only one line


Little Rock AFB is a few tens of km north (34.9 deg lat) for what it's worth. There may be some others as well. The chances of getting a picture of the stars that clear in Arkansas is way lower than in the Mojave however...


Considering Little Rock is a C130 airlift base it's pretty easy to rule that out without looking at stars.


"let's draw a line at 34 degrees" makes for a nice display, but presumably the actual filtering for matching bases spanned 34–35 degrees.


You're right. Vandenberg, Kirtland, Canon, Altus, and Little Rock are all matches for the latitude and there is no text explaining them away. Even the "it must be California because Northrup" is both (a) debatable and (b) doesn't exclude Vandenberg.


Also goes to show you the danger of tunnel vision.

If they flew one to some air base outside DC for the roll out the author would be shooting from the hip and who knows what facility he'd have zero'd in on. Sure it might have been the same one because "the same facility as the B2" is an easy just-so story but you don't really know with any certainty.


It doesn’t fly yet, so that narrows it down a bit.


Do they’re trying to scare Russian with an airplane that can only be taxied around?

I wonder if it’s made out of proper material and not just some clay concept


Russia military is a pitiful shell of the former Soviet glory. Putin’s actions in Ukraine have effectively demilitarized them. They squandered their inheritance of Soviet equipment like an 18 year old in Vegas. Their nuclear force is a giant question mark. Their three legs of the nuclear triad are quite shaky. In the event of a MAD exchange; Their boomers won’t get a missile off due to the fast attacks that keep them targeted at all times. Their bombers and cruise missiles have been depleted and their facilities are so insecure Ukraine is able to hit them with drones from the 70s. Maybe their ICBMs work, but given their culture of graft and corruption even that is doubtful. They are a joke.


You're mostly correct, but Russian SSBNs spend much of their time in their own territorial waters. NATO SSNs seldom venture in there as it's just too risky. The boomers can even launch SLBMs when tied up at the pier in Severomorsk if they have to. And they are conducting successful test launches again.

https://www.reuters.com/world/europe/new-russian-submarine-s...

Even if only 10% of Russia's strategic nuclear weapons work correctly that can still make for a really bad day.


Speaking of ICBM's, I'm sure they use more sophisticated targeting now, but in the early days they'd astrogate for any necessary mid-course corrections.

(Cannot remember if I saw this procedure on a film narrated by von Braun himself, but I doubt it; I think I saw him in a Disney)


ICBMs still use a mix of stellar and inertial navigation. They can't rely on satellite navigation because in a major conflict those may be destroyed or jammed.

Some modern ICBMs might also have some limited terminal guidance capacity but there's not much public information on that subject.


With SLBMs, GPS (and the predecessors to GPS e.g. NAVSAT) are/were used to determine where exactly they were being launched from. The ballistic missile submarine would determine its precise location before launch using these satellite geolocating systems and use that position to calculate the flight path which inertial guidance in the missile would follow.

This was useful because inertial navigation in the submarines was imperfect, but having a precise location fix for the submarine was important if you wanted to shoot at things precisely. Of course with ICBMs launched from fixed silos, the origin point was precisely known from the onset.


Believing a satnav constellation will still be up by launch time sounds awfully like an implicit first strike philosophy?


>Russia military is a pitiful shell of the former Soviet glory. Putin’s actions in Ukraine have effectively demilitarized them.

And yet the war is ~8 months long and counting. "The other guy's military is trash." propaganda happens in every war, and on both sides, if you've studied even a few. We just cleared the sale of 116 Abrams tanks to Poland: https://www.defensenews.com/land/2022/12/07/us-state-dept-cl...

From the article:

>Polish defense officials have said the acquisition will enable the country’s military to counter Russia’s flagship T-14 Armata tank. The procurement will also allow Warsaw to replace its outdated Soviet-designed T-72 and PT-91 tanks with a new tracked vehicle platform.

The people on the ground conducting the war don't seem to think they've been "effectively demilitarized".


The US has retired planes decades ago that are superior to the best Russia has today, so no I doubt we really care about Russia's thoughts. China maybe.


Aren't things getting to the point where drones are a global commodity and indigenous manufacturing capability is mostly moot?


> Aren't things getting to the point where drones are a global commodity and indigenous manufacturing capability is mostly moot?

“Drones” covers a wide range of things, from a Tu-141 to a Shahed-136 to a improvised grenade-dropping quadcopter to the MQ-1/9/20 Predator/Reaper/Avenger series to tbe X-47B and the (maybe soon) unmanned operation capacity of the B-21.

Some capability sets are widely enough available to be seen as commodities, some are available on the export market, but from a narrow range of suppliers who provide them very selectively, and some represent unique capacities.


No. There are no drones which can reliably penetrate a modern integrated air defense system and strike a hardened target with large bunker buster bombs. The B-21 is supposed to be able to operate as a drone (optionally manned) but in a conflict with a near-peer adversary which can degrade the satellite communications necessary for remote piloting there will need to be humans in the cockpit.


>and strike a hardened target

!!!

That's the point! There are a hell of a lot of "unhardened" targets and using a full scale aircraft as a drone is missing the point about cost. I mean, there's not just the news from Ukraine, but also this:

https://www.cnn.com/2022/12/08/us/power-outage-moore-county-...

...and it looks like a classic case of "disruptive technology" syndrome, where the incumbents dismiss the upstart as inadequate for their sophisticated customers - justifiably as far as it goes - until all of a sudden the tsunami arrives because the new tech has been iterating until it can address the high end.

I read the original book defining the phenomenon in my university library around the time it came out, and it's interesting how describing the problem manifestly hasn't created a solution:

https://en.wikipedia.org/wiki/The_Innovator%27s_Dilemma


I don't know if I entirely buy the line on "34-35 degrees off the horizon." Unless we knew the focal length of the lens it was taken with, and which camera it was taken from, you don't actually know that. A wide-angle lens is going to have a much larger field of view than, say, a 100mm macro. And different camera systems have different angle of view for the same focal length.


You don't actually need the focal length, it doesn't help accuracy that much but can help you line up the sky to the photo a bit quicker. Anyway, if we did, all that info was in the metadata anyway:

Camera: Nikon D5 F-stop: f/2.8 Exposure time: 5 sec. Focal length: 28mm Max aperture: 3


You know what the angle between the stars in the constellation are, you don't need to know the field of view of the camera.


I think what you're suggesting is that because we know the angle between a pair of stars, we can use that to infer the angle to the horizon by measuring the distance between each in pixels.

I don't think it's a safe assumption that there is a linear relationship between the angles. Like, two pairs of objects in the image, in which the angles subtended by each pair relative to the viewer are the same in real life, may not be separated by the same number of pixels in image space depending on the lens used.

Furthermore, this could be thrown off by even a small hill or mountain obscuring the astronomical horizon.


If you were doing this professionally you would, because lenses introduce distortions of various kinds - typically barrel or pincushion depending on the focal length and/or the lens.

So any view of the sky is an approximation, and will introduce subtle errors that make it harder to pin down an exact location.

They probably won't be huge areas, but this would be a harder problem if the time and longitude had to be exact with no existing guesses.


both the focal length and the field of view are irrelevant, you know the angles between the stars so you can infer everything.


Wow, it's cool to see astrometry.net get put to use! I worked on astrometry.net back in undergrad and grad school. If you have questions about how it works, I can answer them.

How does it work? astrometry.net uses 4-star combinations to define codes, then indexes the codes on the celestial sphere. The particulars of each of these phases matter, but that's the basic idea.


I remember my jaw dropping while sitting in a colloquium hearing about astrometry.net from David Hogg back in ...2007?

Fast forwarding a few years, we started using it at SOFIA Observatory to help speed up telescope acquisitions.


is A,B,C,D in the database the same as D,C,B,A? Or does order infer orientation?


It uses a hash which is scale and orientation independent. A lot of the details are described in this paper:

https://arxiv.org/abs/0910.2233


Order cannot infer anything. Only people, animals, and some programs can infer. Inanimate facts can at most imply.


I used to be in astronomy and I always thought astrometry.net was one of the coolest tools in the field. It feels about as close to magic as you can get.


Astrometry.net is damn handy. I don't use it too much these days for myself except for annotating images, but I do have some friends just getting into astronomy and it's blind solve is amazing to help them.

Plus when I show them plate solving their minds are blown. Hugely useful tool.


Northrop Grumman announced in September that they would unveil the B-21 at Palmdale this week [0]. The location was not a secret.

0. https://www.globenewswire.com/news-release/2022/09/20/251965...


Twitter thread said the same thing, or am I missing something?


It said it at the end after tacitly implying otherwise.


I feel like the entire thread should have led off with "This is in fact a publicly known hangar in Palmdale and this was known as public information as soon as the unveiling event occurred, and thus this is just an exercise to show how locating the spot could have been possible from just this photo as a technical demonstration."

Because I guarantee there are going to be a hundred clickbait articles by various 'news' sites now in the next few days about the MASSIVE SECURITY BREACH of the USAF and how US SECRETS have been EXPOSED so and and so forth. When nothing about this is actually the case.


People have been doing photo analysis for a long long time, and have gotten quite good at doing geolocation based on details in the background that the average viewer ignores. Spy agencies are especially good at it. There's many a spy movie that offers glimpses into this, but The Good Shepard comes to mind.

Even as a joking kind of thing, the opposite has been done. There's a famous exchange between Neil DeGrasse Tyson and James Cameron about how the sky in the movie Titanic was wrong. Cameron accepted the challenge, and on a remastered version had the sky replaced to be historically accurate.

It's a game to some people. It's a challenge. It's self rewarding in this case, sometimes there might be actual rewards of sorts. Hell, I've spent more hours than I'd like to admit on Nasa's website where you use the images taken by the astronauts on the space station and align them on the globe. I got nothing out of it other than being entertained by the challenge, learned about some new places on the globe when I would try to find out why that place was interesting to the astronaut to snap that particular image, etc.


> There's a famous exchange between Neil DeGrasse Tyson and James Cameron about how the sky in the Titanic was wrong. Cameron accepted the challenge, and on a remastered version had the sky replaced to be historically accurate.

Very interesting! https://www.youtube.com/watch?v=8B6jSfRuptY&t=110s

(Interesting comment for a number of reasons. Thanks!)


> It's a game to some people. It's a challenge.

And for some, it crosses all lines of ethics and morals, like the stalker that deduced the location of a pop idol by looking at the reflection of a building in her eyes [1]. That's utterly crazy.

[1] https://sea.mashable.com/article/6776/a-stalker-found-a-japa...


> It's a game to some people. It's a challenge.

GeoWizard on youtube has a whole series where he tries to pinpoint the exact locations of pictures sent to him by fans. Pretty fun to watch:

https://youtube.com/playlist?list=PL_japiE6QKWqMVC3JbyONau_0...


There was an xkcd comic set in the future with the exact date calculated from the stars. https://xkcd-time.fandom.com/wiki/Astronomy


It's pretty clearly an exercise in astronavigation.

The livestream event itself mentioned it was taking place at the Northrop facility in Palmdale.

This author is not responsible for what clickbait farms do.

Aside: I'm not even sure this plane will end up doing flight testing somewhere secret in Nevada. They may just do it out of Edwards South Base, which is an "interesting" location not many in the public know about.


> It's pretty clearly an exercise in astronavigation.

Off topic, but it would be really cool if someone build a hobbyist astronavigationsystem using a something like a Raspberry Pi and a camera with a fisheye lens. Sort of an amateur https://timeandnavigation.si.edu/multimedia-asset/nortronics....


I hadn’t realized that much of the public doesn’t know Edwards. Then again, I’m a SoCal native with a father who was an aerospace engineer…


Edwards AFB was pretty well-known when the Space Shuttle was an active program.

But ... it's been 11 years, kids these days, etc.

Auxiliary Base South is probably less known.


Also all they do is cut it down to a wide band that covers 12 or so states, then compare against known bases (not shown) to narrow it down


I did mention this later in the thread - was just a fun experiment to see if locating it was possible if we didn't know


Sure, but the reason you didn't lead with that, and also the reason you did this for a secretive aircraft and not a new campervan is clicks, no?


To be fair, a secretive aircraft would trigger thoughts about security in a hacker's mind. A camper van does not trigger any such thoughts. It may not be just clicks, with a camper van the whole thread might not even exist. I am not the original poster, so this is just my thought


Even if he did do this for the clicks, so what?


So it's manipulative. Like a sensational headline that buries the mundanity at the end. Lead with "this is already publicly known" so people can make an informed choice about where to direct their attention.


If the point of the article/twitter thread was to reveal the location of the hanger, as if that was previously a secret, then yes perhaps the title is misleading.

But that's not the point of the article. The point of the article was to reveal the location of the hanger using the stars and other metadata, and to explain how that was done. The journey was the story, not the destination.


"as if that was previously a secret"

And that's where the disagreement is. It implied a secret by the nature of the object, enough so that the fact it wasn't needed to be clarified - but at the end. You only publicly reveal something once, and this already had been.

But then, those aren't his words and it's implicit so this is a grey area and not a huge deal. But I still think leaving the clarification to the end was deliberate.


Right. It should be my responsibility to guard everything I say or write from lazy morons.


This trick happened for real with the HWNDU stunt back in 2017. 4channers found the flag based on the stars in the livestream, along with matching aircraft contrails to flight radar maps.

https://youtu.be/vw9zyxm860Q


remember when 4chan figured out the location of a terrorist training camp from one of their PR photos and called in a literal airstrike? I like how 4chan is sometimes described as weaponized autism.

https://imgur.com/N7DwWP1?r


Remember when imgur was marketed as an imagehost that doesn't suck? Now i can't read 2/3 of the text because it's just a blurry mess if I'm not manually changing url parameters. I'm using Firefox on Android and I can't find another method to get the full image. Am I missing some button to show the full res image?


For imgur on Android, I use ImgurViewer[1], which can display images using apis from a bunch of different sites (imgur, Reddit, gfycat, etc) as well as anything that ends with a common image extension. It's a far superior interface, and ability to swipe it away makes it more seamless, like it's just part of the app you opened it from.

For the browsing in Firefox, there's multiple extensions you can use to add the referrer and get the image directly instead of a redirect (see [2], though I'm not sure if it works on mobile)

Alternatively, use Rimgo[3], an alternative frontend to imgur. This page also lists several ways to automate redirects from imgur domains.

[1] https://github.com/SpartanJ/ImgurViewer [2] https://addons.mozilla.org/en-US/firefox/addon/referercontro... [3] https://codeberg.org/video-prize-ranch/rimgo


Same exact boat as you. FF Focus on Android and I can't read anything on that post. If you long click the image you see some url parameters, but when I tried to play with them they only made the image smaller and lower quality lol. What ever happened to imgur linking directly to the full size image?


Add a 0 to maxwidth (6400) and you can read it.


- Open imgur page

- Desktop mode

- Change the TLD back to ".com"

- tap image with finger

Sounds simple, but I figured it out only after running into 3 or 4 other dead ends. For example, desktop mode needs to be in place for forcing the TLD to stick on my phone.

Fantastic.


I feel like when you diss journalists, it should generally be for something they actually did wrong, not preemptively based on your imagination.

If they are so terrible, there should be no need to invent stuff.

When people read something like this post, and they are predisposed to the idea, it’ll reinforce their skepticism of „the mainstream media“. If you want to test yourself, make a bet of how many media outlets will run with the story in the manner outlined above, then check in a few days. My prediction: you won’t see it in the NYT, WSJ, BBC, or on CNN.


I put 'news' in quotes for this reason. I wasn't as much implying that this would be actual news, but instead would be used in clickbait articles on lesser publications. I admit I am being hypothetical, but this does reflect observation on how these kinds of discussions has been get picked up and spread and thus has made me want to avoid such writing style.


I'm not so sure.

It is very interesting--and newsworthy--how difficult it is to be anonymous on the internet. Any person, place, or thing can be "doxxed" by seemingly innocuous background details.


It's worth noting that stars can be seen even in daylight with the right software.

That's because, while no individual star is visible, the exact angles between all stars is fixed, so you can do a brute force search of all possible orientations of the sky to find a matching one. In a 6 megapixel image of half blue sky, you effectively get an oversampling ratio of 3 million:1, so even with very bright sunlight obscuring the stars to the naked eye, your algorithm will pick them out.


Very interesting! Any links for further reading?


Nope - years ago I accidentally discovered this while trying to align star images for stacking. Some of my images were taken in daylight, and I was surprised to find my rudimentary image aligner still worked just fine. Never wrote it up into a blog post.


Do you mind expanding a bit more ? Because I don't understand. Even if you have oversampling, as you say, it would be after you know the locations of the stars, and also, how can you brute force every possible right ascension/declination/rotation ? Without a calibrated camera how do you account for the distortions ? Thanks


In my case, I had nighttime images from the same camera, so all the calibration was already done... I was just looking for a rotated version of the nighttime image in the daytime image.

But even in the general case, smallish image patches don't have enough distortion to matter, while still having plenty of oversampling, and only have 3 unknowns. You can probably do some kind of fft trickery to reduce it to 1 unknown. And you can probably use some kind of hill-climbing to further reduce the search effort.


What does an optimization algorithm have to do with a brute force search?

Even if your image patch is small, without previous images to compare, you need to brute force the entire sky?

And how can "fft trickery" reduce the attitude state to 1 unknown ? 1 unknown with what units ?

Sorry but I suspect you are making all these up.


The claims from pifm_guy are reasonable.

This is a scenario with extremely high coding gain[1]. The DC value of the sky can be removed by high pass filtering. Finding the rigid transform (rotation+translation) between two images captured by the same camera, assuming no distortion[2], assuming the image pair has substantial intersection, doesn't require calibration.

Dropping the "same camera" and "substantial intersection" assumptions requires searching the entire sky and also finding an unknown scaling factor. It all comes down to the images having low enough noise and high enough resolution, relative to the search space. The math is sound.

You're not entitled to a tutorial in signal processing, though.

[1] https://en.wikipedia.org/wiki/Coding_gain

[2] Astronomy lenses have very small FOV and very small distortion.


I’m not trying to call you guys out. Just curious for more information. I would say I have enough knowledge about signal processing to be dangerous, as it’s quite adjacent to my job. But this isn’t clicking with me. Assuming we’re not including cameras outside the visible light spectrum, are there cameras that actually have enough dynamic range to capture a recoverable amount of information about stars against a bright sky? Beyond that, the original commenter takes about oversampling, but oversampling of what exactly? Intuition says that even with a high resolution sensor (like a modern iPhone) the visual size of a star would still be less than a single pixel. If my intuition there is correct, aren’t we spatially under sampling? The shutter is open for some period of time, so I guess you could say we’re temporally oversampling, but then we’re applying the same gain both to the stars and the sky, so that doesn’t seem to helpful. I feel like taking a high pass filter of a daylight sky would leave you with next to nothing save some of the sensor’s inherent noise. Are you discussing exquisite sensors or optics here? Genuinely curious. I tried some basic google searches on the matter of recovering stats in daytime images but didn’t get much back.


About planets and stars in daytime: https://www.skysurfer.eu/daystars.php

The concept here is processing gain, which is algorithmic. It's what enables the miracle of GPS, even though satellites are 20000km far away, there may be clouds, rain, etc and your phone doesn't come with a satellite dish. Also used in CDMA radio for civilian and military communications, it allows reliable transmission at negative SNR by spreading the message over a huge space. In the case of GPS/radio, the space is frequency. Here, the message is coordinates of a rectangular crop of the sky, encoded in the (huge) space of few million pixels. On a per-pixel basis, the SNR can be negative -- looking at a single pixel I can't tell you with confidence if it contains a star, because the shade of blue is just too close to average. But correlating the entire image against the correct "code" (a clean star field), tells me whether I got the location of the sky correctly. Intuitively: accumulated over the entire image, the noise statistics are such that the noise stays bounded, and the tiny amount of signal adds up.

Appropriate optics will increase the SNR so that bright stars can actually become visible. Per the link above, mag 2-3 stars are visible with a 10cm telescope (looking through the eyepiece; no filters or digital sensors needed). So if the conditions are right and the optics are good, you may actually see a few stars reliably, and the scenario reduces to the B-21 hangar scenario.

Finally, it's worth noting that even a consumer grade CMOS sensor will sample at 12 bits per pixel (4096 linear levels) with low noise. The human eye cannot discriminate a luminance difference of 1/4096 relative to full scale, not even close. Using the naked eye for intuition here is misleading, because this is a scenario where a sensor is far better at registering the small additive contribution of a star under daylight, and this is the key to enabling the processing gain through math.


> oversampling, but oversampling of what exactly?

If you have 3 million pixels of sky, and 3 variables to find, then you have oversampled by 1 million times.

In the ideal noise-free world with no other unknowns, any 3 of those pixels would be enough to solve the problem perfectly.


If the "DC value of the sky" could be removed with a simple high pass filter, then there would be no need of doing anything else. The positions of the stars in the sky would be known, and techniques like the one in the article would apply.

I have been working fine so far in startrackers for spacecraft without your tutorial in signal processing, but thanks for the offer


> If the "DC value of the sky" could be removed with a simple high pass filter, then there would be no need of doing anything else. The positions of the stars in the sky would be known, and techniques like the one in the article would apply.

This doesn't make any sense. Even if one could estimate ground truth DC, removing it would leave noise at every other frequency bin.

But this is beside the point. Your questioning isn't coming from a place of curiosity.

I direct you to the HN guidelines: "Be kind. Don't be snarky. Have curious conversation; don't cross-examine."


you were the one suggesting "removing the DC value of the sky with high pass filtering". anyway I'm done. have a nice day.


It might be helpful if you read about what platesolving is: https://en.wikipedia.org/wiki/Astrometric_solving

It's a well defined problem of taking star positions and pinpointing its celestial coordinates. There's even a term for being able to do that without knowing anything about the camera, telescope or distortion, it's called blind solving. Plenty of tools to do it are available online and they're an essential part of an astrophotographers tools.

Fun fact, most of our ICBMs rely on plate solving to navigate so they can hit their targets even when GPS signals are disrupted.


I don't understand what they are saying but it's definitely true if you are careful, you can take images of the locations of the top magnitude stars, point your camera at that, take a long exposure (~15 seconds, so you need a way to keep the moving star at exactly the same pixel over the whole exposure), do some contrast scaling, and you will see point pixels lit up in the right locations.

If you don't already know a star location, I'm sure you could construct a very sensitive camera and some noise reduction and do this with short exposures without any rotation.


GPS works like that too, the GPS signal is so weak it's below the thermal noise floor when it arrives at the receiver, but you know each satellite's special signal pattern, so you just search all satellites at all positions in the noise and see if you get some correlation (a fix).


How long does this take? Could this be run on, say, a smartphone to calculate its rough position from a photo of the sky?


I've never considered that but it makes perfect sense. Might try to code something up given some freetime.


This has only been bested by the 4chan takedown of the Shia LaBeouf's anti-trump flag, which was put up in a random location with a live stream.

"On March 8, the artists, abandoning the idea of a public webcam, raised a white flag, emblazoned with the words “He Will Not Divide Us,” in an “unknown location.” The livestream showed only the flag and the expanse of sky behind it. 4Chan and 8Chan (the forum where discussions that are banned from 4Chan go) snapped into action.... They used the star patterns visible behind the flag at night and the paths of planes flying overhead to confirm the location. A troll who lived nearby drove around honking until the noise was audible on the livestream. On the night of March 10, a group raided the site, took down the flag, and replaced it with a Pepe the Frog T-shirt and a “Make America Great Again” hat. The stream soon went dark again."


Agreed. Here are the full details: https://youtu.be/vw9zyxm860Q?t=15


This is very cool sleuthing. Really enjoyed the walkthrough.

Though, if you would have asked me, I would have guessed Lancaster/Palmdale, because I know (a) That's where the unveiling was (b) I have seen B-1's fly over me while driving in Palmdale and (c) I know Edwards and a bunch of other spacey stuff is there. I feel like Captain Kirk looking for whales and saying "I think we'll find what we're looking for at the Cetacean Institute in Sausalito" - a far less methodical or impressive approach.


Do you mean B-1 or B-2? I thought the B-21 was intended as a successor to the B-2, only cheaper. Also, they look the same to me.


I'm sorry, yes... I meant the B-2, not the Rockwell B-1 Lancer. You are correct. We were driving through Palmdale and I saw one of the B-2 flying wings cruise over the freeway on approach. Was very very cool to see.... But thank you for the correction. B-2, not B-1.


Ahem, not to be that person… but I think you mean Admiral Kirk :) Either way, it’s a perfect reference.


You sir, are correct. Thank you for the correction! Please be that person. Btw, my wife and I were able to visit the Monterrey Bay aquarium for the first time this past November -- and I would just not shut up with the references. My wife loved them, but also was a bit over them by the end.


Haha, that’s awesome. The first time I visited there with my wife, I started on about how the “Cetacean Institute” sign was missing (gasp!) and before I could even finish whatever joke I was leading up to, my wife simply gave me a look that registered somewhere between, “I’m going to pretend I don’t know you” and “you will wait in the car if this continues.” No further references or colorful metaphors were communicated that visit. Years later I took my kids there for an overnighter and they became the captive audience for all the references and terrible jokes. Luckily i think there were too young to really remember. Along those lines, I re-watched ST:IV with my kids a few months back and they loved it. Of all the lines, my youngest was rolling in laughter when the old lady in the hospital is chanting “the dr gave me a pill and i grew a new kidney!”


It's "hangar", not "hanger", dammit!


I thought the article was going to tell us about a secret clothes closet aboard the new bomber.


Jeff Attwood replied exactly that.


The investigation breaks down halfway when you have to pull up a public list of airbase locations and google where certain jets are made.


Note to self: Always, always, ALWAYS strip exif data.


Couldn't the same conclusion be reached, without? That plane flying overhead, center, would probably make things much easier.


I would like to know what else is embedded in digital pictures, similar to the printer yellow dots, except it will be undetectable.


Sensor noise has been used to successfully identify the camera used to take a picture. No embedded features just the physical characteristics of sensors being individual enough to identify.


Always, always, ALWAYS black out the sky.


Plot twist: they replaced the sky with a different starry background.


You’ve confused the data with the metadata.


Exif data is the metadata of the image.


Exactly, whereas stars shown in the image are just data, you don't need the exif data to see them.


But the time the photo was taken was extracted from the exif which is what OP was referring to stripping


If you can see stars, satellites and planets you can figure out the time. It makes the problem a little harder (you've got to locate a point in 2+1 dimensional space rather than on the 2 dimensional surface of the Earth), but it's not a fundamental difference.


The lesson here isn’t to strip exif data, though. It’s to identify information that can be connected to anything to infer metadata that you want to keep hidden.

If you always wipe exif data, and don’t investigate your pictures, then you will eventually neglect some combination of data points someone could use to infer richer context.


No, Exif is an image format.

https://en.wikipedia.org/wiki/Exif


I assumed that was the joke? If they're finding the location based on the stars in the image, you'd need to strip out the actual image data (not metadata) to prevent that.


metadata is actually a form of data, believe it or not.


The data’s data!


Metadata is data, but without legs


I mean, they livestreamed the rollout on YouTube on the Edward’s AFB YouTube channel and said it was at NG’s Palmdale facility (paraphrasing). I’m not sure any of this was a secret…


This is acknowledged by the author: https://twitter.com/johnmcelhone8/status/1600683636029652993

Which I think is also why the thread is so X-marks-the-spot / parallel-reconstruction-y. I think it's more of a "here's the kind of thing we can do with these star-matching tools, applied to an interesting image as an example" than an expose.


Also the Airforce and Northrop Grumman must be familiar with the idea of celestial navigation. And the shot was clearly taken in the evening on purpose (I assume, at least, that a PR shot has to justify being taken outside of maximum daylight).

They probably want it to feel vaguely spacey for the sci-fi vibes.

They’ve got at least as good star charts as the rest of us, so if they really wanted to be jokers they could photoshop some stars in, make it look like it is flying over an adversary’s country…


Not only that, they had three bombers (B1, B2, and B52) fly over during the live stream of the unveiling that could be tracked live on commercial flight tracking websites. This simply wasn’t a secret at all.


This livestream is the best caricature of American culture I've seen, thank you.

It is the unveiling of a bomber, with the national anthem sung by an employee of the company who built it, as in a proper performance, while more bombers fly ahead so loudly he has to stop. Then it proceeds to have the CEO read an engineered speech from a teleprompter, completely devoid of her own existence. Followed by a hollywood action movie style reveal, with the attendees going wild, clapping and shouting for the new, shiny bomber. It is a gift that keeps on giving.

https://www.youtube.com/watch?v=chJlJgrvfBY


Yeah, clearly only Americans do this. Ignore the fact that monarchs have been christening ships for thousands of years.


In fact, knowing the moment photo was taken from EXIF, there was no need to "plot the line". They could point the exact location by using orientation of the stars - stellar time (assuming the horizon is level which, in the airfield, is a very very good assumption to make).

Procedure is as follows:

Right ascension of the culminating star ("celestial longitude", taken from the star catalog/star map, of any star which is right above the celestial pole/"Polar star"), is the stellar time.

Knowing date (from EXIF), you get local solar time (which is equal to the stellar time on the spring solstice day, then makes a 24 hour loop over the year).

Difference between local time found this way and UTC time (taken from EXIF), gives longitude, because the Earth is round.

If EXIF does not contain the time zone, that gives 3 points in the U.S., one for each time zone, but it must be super easy to pick one. But most probably, EXIF contains the time zone.


The flock and skysat orbits he showed are for san francisco based planet labs satellites, the vast bulk of which are in sun synchronous orbits to always take photos in daylight. The screenshots amount to "it's dark at 1:30am."


Hahaha this is a neat bit of investigation but my favorite part is that the final conclusion is that the sexy new bomber is hiding……… at the Air Force base where they held the press conference announcing the new bomber!


This is peek internet. Amazing!


That's not how you spell... Nevermind. Well done.


Perhaps parent crafted a subtle pun?


In my opinion peek internet was either the shoes in salad guy or the flagpole with only sky visible.


One of my favorite internet happenings is when 4Chan (I think it was 4Chan) used stars and airplane data to get Shia LaBeouf's flag location and steal it. Not because of the political message, but because it was just entertaining and impressive in general. I think it ended up being in Tennessee somewhere. In any case, this wasn't exactly a secret, journalists were invited (though they had their cellphones confiscated at the gate, apparently.) If they really wanted, they could use obfuscation to make the sky, etc unrecognizable or in a totally different location.


That went on for a few months. I think he ended up sticking it on a blank wall in an airbnb. They still figured it out. Because he decided to go out and have a few drinks. Also because info is wildly leaky. It is interesting how leaky info is and how little it takes to narrow it down. Advertisers use that non intuitive fact to do browser fingerprinting.


Heh. This makes me remember how the same technique was used in the "he will not divide us" trolling campaign to locate a video feed of a flag. Internet Historian has a video about IIRC.


He seems to use the hour estimate of 1:30am being a time when very few satellites are likely overhead as a sort of confirming factor. (I guess because many satellites are sun-synchronous around noon, and the USAF would purposely time the photo to not expose the aircraft to observation).

But is that a very strong confirming factor? Is it likely that NG / USAF would be actively avoiding the potential for satellite imagery? Does it mean all the time it was being built, they avoided having it outside during the daytime?


> Is it likely that NG / USAF would be actively avoiding the potential for satellite imagery? Does it mean all the time it was being built, they avoided having it outside during the daytime?

During the Cold War black projects like the F-117 did exactly that. IIRC they weren't necessarily limited to being out side only at night, but they were very careful about satellite orbits to make sure the secret aircraft wouldn't be caught on camera.

When the B-2 bomber was unveiled, the USAF didn't really want people to get good photos of the wing's shape due to some of the stealth technology incorporated into it. Aviation Week famously [0] got the drop on them by flying a Cessna right over the rollout. Considering how many very high quality cameras are in orbit today I imagine they put some thought into preventing Russia, China, etc. from getting good photos of the B-21.

0: https://aviationweek.com/defense-space/aircraft-propulsion/s...


Not just secret projects.

When I was in the 82nd Airborne we had days where we didn’t do any outside training because the Soviet spy satellites were overhead. Estimated troop strength, deployment schedules, blada, blada.

Kind of nice because they generally left us alone as long as we stayed out of sight.


I forget where, but there was a video I was watching that claimed the US was so far ahead in tech that instead of letting others know our capabilities we play with other countries by "accidentally" leaving things open to satellites which makes other countries trying to copy us go nuts trying to reverse engineer nonsense.

That comment was after mentioning how the "super sonic" plane built for the latest Top Gun was probably left out, on purpose, so it'd confuse adversaries on what the US is actually working on.


Does it mean all the time it was being built, they avoided having it outside during the daytime

Aren't airplanes built entirely in a hangar? Especially secret ones?


Depends on how you scope the word "build". If you mean literal assembly, of course. If you mean "the process of iterating engineering, testing and assembly" including prototyping etc (a common way to use the word build, especially in software circles) it makes more sense.


Historically, yes, they’ve scheduled outdoor activity to avoid satellite overflight, if we’re not misled by books.

Maybe it’s not a strong factor here, because it was a few days before public announcement anyway. But you’d expect them to follow the same protocol or at least pick a more convenient time than 1:30am if they were not.


> Is it likely that NG / USAF would be actively avoiding the potential for satellite imagery?

Yes, we still haven't seen the back of the B-21 (those at the unveiling could only view it from the front). There was also an incident when the B-2 was unveiled and a photographer flew over and got pictures of it.


misleading. was more like:

* he got the approximate latitude from the stars (34 or 35)

* independently, he found the most plausible airbase based on other information and then noticed that the base is indeed around that latitude


The process can still be done using entirely the star pattern and no Google Maps. There wasn't any reason to exclude other information I could use, so I didn't.


I believe it's exactly how 4chan would keep finding Shia LeBeouf's flags shown on webcam he was was hiding at remote locations.


With added train sounds and honking I believe. Excellent work!


This was downvoted probably from lack of context. They used the sound of honking to find the exact location of the webcam.


Sounds like an old Hawai’i 5-0 plot.


Wait, this didn’t even rely on the constellations though. Get the latitude from the North Star and then look for matching air bases.


I thought so too but I think you need to know the constellations first to identify the North Star in the photo.


This is correct. The brightness of the stars made them a bit difficult to identify by eye, I'm sure someone more familiar with sky charts could have done it. The constellations helped me align the sky on Stellarium (from their angles) and the north star helped me find the approximate latitude by using the angle from the horizon.


Ok that makes more sense.


Its pretty amazing some of the stories coming out of Ukraine. People posting on social media then getting blown up soon after. https://www.businessinsider.com/russia-news-exposed-mortar-c...


This is quite the boondoggle, not a lot of change out of billion dollars per aircraft, remember that as you work yourself to death.

"Stealth" has such a limited life span of utility. Even in the 90s Serbian air defence managed to acquire and shoot down "stealth" aircraft. It required humint but that's part of a real theatre of war.


This is objectively false though. We could take a deep dive into the relevance of the Serbian shoot down but it’s kind of irrelevant.

The fact of the matter is, stealth technology means that an aircraft needs to be significantly closer to a radar for it to be detected compared to a normal aircraft. That also means it has to be closer still for a threat radar to develop a weapons quality track. Theres not really any known radar technology that can mitigate this, it’s basic physics. It’s much easier to see an object on radar that returns orders of magnitude more energy to the radar.

Stealth does not a limited utility. In fact it’s rapidly going to become an absolute bare minimum for any tactical aircraft.


So in the next 10-20 years we wont have any significant advances in detection technology or methodologies?

Even if, for arguments sake, the aircraft is at the moment leaps and bounds ahead of the nearest peer competitor military there is going to be limit to how effective a new coat of paint will be for the B-21 in 10 years time.

To get your monies worth from this thing you'd want a lot greater effective service life than that and without stealth the B-21 would have dramatically diminished it's dollar to effectiveness ratio.


Even just 20 years of strategic deterrence is probably worth the price tag.


This is the EXACT reason the government is never dispels alien sightings with "oh, that was us, not aliens! lol".

If you say tic-tac was lens-flare, the Chinese govt will figure out how to obsolete the F22 targeting system in a week :-)

Hyperbole for sure but amazing how much info you can get from seemingly innocent data leaks.

Loose lips sink ships...


I mean, cool and all. But I didnt have to do that to know where it was. I stood outside that hanger (with a B-2 inside) in 1989 at Northrop's 50th anniversary airshow.

If I can remember that, from 30+ years ago, I'm pretty sure the russians/chinese/whateverese also know.


Is there any software library that can find approximate gps location of photo just from knowing the date & time of the image and knowing the horizon? I saw somewhere that bombers in 2nd world war were using stars for navigation.


Related unrelated question : how come this is public?

F117 was a dark skunk project shown years after being operational. That made sense to me for a super secret project with wildly new technologies and capabilities.

I don't understand the announcements of such projects from the vision stage, with the details of capability, purpose, strategy, photos,etc.

Is it commoditized sufficiently? Is it deterrence? Is there enough misinformation?


  Kirk: Bones, did you ever hear of a doomsday machine?

  McCoy: No. I'm a doctor, not a mechanic.

  Kirk: It's a weapon built primarily as a bluff. It's never meant to be used. So strong, it 
  could destroy both sides in a war. Something like the old H-Bomb was supposed to be. 
  That's what I think this is. A doomsday machine that somebody used in a war uncounted 
  years ago. They don't exist anymore, but the machine is still destroying.

  — Star Trek: The Original Series, "The Doomsday Machine"

  Dr. Strangelove: Of course, the whole point of a Doomsday Machine is lost, if you keep it 
  a secret! Why didn't you tell the world, eh?!!

  Russian Ambassador Sadesky: It was to be announced at the Party Congress on Monday. As you 
  know, the Premier loves surprises.

  — Dr. Strangelove


The secretary of defense mentioned "deterrence" as part of the reasoning. Maybe not-so-coincidentally, the aircraft (at least as they showed it) skips the old school black paint job for one that looks more like anti-flash white[0].

Part of it is probably also that this is a refinement of an existing aircraft and not anything with drastically different capabilities-- if you're planning on war with the US, you're probably already thinking about B-2s, and if you're worried about B-2s then a B-21 isn't that different.

[0]: https://en.wikipedia.org/wiki/Anti-flash_white


Looks more like a typical gray color that practically all Western air forces use today, than anti-flash white. I'd speculate the implications of this are:

- They plan on operating it during the day as well as night, so they need better protection against visual observation?

- The B2 was much darker due to the coating technology it used wasn't compatible with lighter grays? And operating only at night it didn't really matter?


I've read some things that suggest the B-21 may not offer radical new capabilities (over say, the B-2) but it will be way way cheaper to build and operate.

There were only 21 B-2s ever built. The Air Force has already ordered 100 B-21s.


> There were only 21 B-2s ever built. The Air Force has already ordered 100 B-21s.

Planned, not ordered. Just like they initially planned 130+ B-2s, which Congress eventually cut to 21.


From what I've read (which I guess is largely speculation, although by people more familiar with the topic than me), the B-21 doesn't really push the envelope. The only really new thing is the airframe itself, but that largely piggybacks on stealth technology development over the past several decades (RAM coatings, shaping etc.) compared to the B-2, and not some entirely new R&D done only for the purpose of the B-21 program. The engines apparently come from the F-35, but obviously without the afterburners (an entirely sensible choice considering the F-35 is supposed to be manufactured in very large numbers and supported for a long time into the future). Electronics is supposedly stuff already developed. Etc. etc.

If true, then yes, the B-21 has potential to be relatively cheap to build and operate.


That number will shrink. There were supposed to be 100+ B2s and no B1Bs.


I doubt it. The B-2 was cut because the cold war ended and because it was absurdly expensive to maintain thanks to its 1980s stealth tech. The radar-absorbent material used for the B-2 degraded very quickly and it's a large aircraft, so that means absolutely constant work to keep it functioning as intended. The B-2s are based out of Missouri and when they go on a mission they fly all the way to the other side of the wold and then back to the central USA. Why? Because Whiteman Airforce base is the only one which has the massive climate-controlled hangars you need to stick the B-2s in to keep them from falling apart while on the ground. If the US built a fleet of 100+ B-2s in the 1990s we'd have ended up with a fleet of cutting edge bombers which cost more than $100,000 per flight-hour to operate and no one to use them against. A fleet of 100+ B-2s during the 2000s would have been a massive white elephant.

The B-21 is different in two important ways.

First, the B-21s stealth tech is derived from lessons learned from the F-35 program. The F-35 is a tactical fighter which the US and most of its allies are buying in very large numbers. They need to be stationed just about anywhere and can't require ridiculous maintenance to keep their skin from falling off. That would be impractical for a large fleet of aircraft. As such, a lot of work went into making the radar absorbent material used on the F-35 dramatically more durable. The B-21 gets to piggyback off of that and as a result it will be much more feasible to actually have a large fleet of them.

Second, there's a new cold war heating up with China. Anyone whose ever looked at the Pacific ocean might notice that it's kind of large. This makes range a major concern for combat aircraft. A medium stealth bomber with extreme range is essentially perfect for this environment because it can reach anywhere and is very hard to actually find once in flight. If you are a surface warship force, being hunted by a bunch of nearly undetectable aircraft which can be anywhere at anytime and can each carry more than a dozen large anti-ship missiles is going keep you up at night. The B-21 will likely end up being a very important piece in the US naval strategy in the pacific.

I wouldn't be surprised to see significantly more than 100 get built.


> and no one to use them against

Oh, you can use them just as they were used - to do the things B-52, or hell, even B-29 could do. /snark

> being hunted by a bunch of nearly undetectable aircraft which can be anywhere at anytime and can each carry more than a dozen large anti-ship missiles

Now this is a question. My memory was rusty so I consulted Wikipedia and looks like there is not that many options.

SM6 is too weak and doesn't yet have AS capability, LRASM exists with a proper qualities (speed and payload) but is quite big even for B-1. And Tomahawk with no AS cap. and ... not fast.

So there is a question about "a dozen large anti-ship missiles" though it can be mitigated with a sheer numbers, which is probably the way it is designed.

> I wouldn't be surprised to see significantly more than 100 get built.

Depends on what would happen in tjhe world the next 10 years.


The near term anti-ship armament would be LRASMs, which are not actually very large. A B-1 can carry 24 of them internally at one time and the B-2 can carry 16. The B-21 is smaller but still large enough for a good load. 12 or more would not be surprising. No one is air-launching tomahawks or SM-6s (probably). The future is OASuW Increment II (HALO) which is a hypersonic anti-ship missile. The LRASM is basically a stop-gap until that happens. That missile will likely be a similar size to the LRASM given the size limitations of the platforms the navy wants to launch it from.

The security situation in the Pacific is also very unlikely to improve over the next 10 years.


Possibly, or possibly it will follow the same pattern as the F-22 / F-35 where the aircraft that was the true breakthrough (F-22) was expensive and had production slashed but the "cost optimized" version (F-35) is now being produced in large numbers [1].

1. I'm aware the F-35 development program itself was a boondoggle, but there are still building a ton of them right now.


> Related unrelated question : how come this is public?

Because trying to hide the existence of strategic bombers is expensive, ineffective, and not particularly helpful to keeping the actually secret technology they use secret.

> F117 was a dark skunk project shown years after being operational

With the F-117, the shape was part of the secret sauce. The B-21 doesn’t seem to be a big departure that way.

> I don't understand the announcements of such projects from the vision stage,

This wasn't announced in the vision stage, except that a new strategic bomber was being developed. The unveiling was well past vision, and competition, stages.

> Is it commoditized sufficiently? Is it deterrence? Is there enough misinformation?

Deterrence is a big consideration,


> With the F-117, the shape was part of the secret sauce. The B-21 doesn’t seem to be a big departure that way.

The world has also changed substantially. When the F-117 was developed, being able to simulate the RF interactions with faceted geometry was ground breaking stuff. Now anyone that can afford an ANSYS license can simulate that with far, far, greater fidelity against much more complex shapes.


The most important benefit of the public announcement is that showing successfully completed projects like this helps the defense industry with recruitment and encourages more students to become aeronautical and mechanical engineers.


There's of course the slightly conspiratorial idea that they made this public because it's obsolete compared to whatever their newest toys are and so revealing this as a show of technological superiority is fine.


it may be its operational capabilities are more important to keep secret. It has an unmanned mode which is very interesting to me. Does it need to be piloted by a guy in an office cube like the Predator drone or is it more autonomous?


> It has an unmanned mode

Maybe. “Designed to accommodate unmannef operations” is... fairly vague as a description.


Impressive.

Now do it without using a computer, the old fashioned way, with books, paper maps, star charts, slide rulers, sextants, compasses, and pens. I'm sure some people would be able to.


I wonder how long this thing has existed. Or if it is even “current gen”. The existence of the f117 and b2 were not acknowledged for a long time.


The existence of the b2 was always acknowledged from early in its development, just like the b21 was. The primary purpose for strategic bombers like the b21 and the b2 is deterrence, and deterrence doesn’t really work if it isn’t known about. The f117 on the other hand was a tactical aircraft that was built in anticipation of a sudden need to precisely strike a very specific target no matter how well defended. For that purpose it needed to remain unacknowledged. It was also the first stealth aircraft and presented a larger leap from existing aircraft than the b-2 did at the time.


This reminds me of the Elon plane tracking dude. Such a neat use of technology and know-how.


*Hangar


Yet another twitter thread that could have made an excellent blog post.


Yeah well the readers killed blogs, not the writers.


Sky obfuscation to avoid stellar triangulation as a service?


Omg I opened a Twitter thread and when that dreaded moment came where that black takes over the screen and I can’t even scroll back anymore… now I was able to just tap an X and keep reading! Hooray for Elon?


This is fun to see. Reminds me of the capture the flag done on Shia LaBeouf’s Trump protest flag that 4chan got together to figure out it’s hidden location and stole his flag and replaced it with a Trump hat. https://www.news.com.au/entertainment/celebrity-life/celebri...


Nit: It's “hangar”, not “hanger”.


Why would anyone hang a B-21?


finally a plane that can bomb climate change away.


Enhance already!


so interesting


Or we could save all that effort and just check the Wikipedia page... https://en.wikipedia.org/wiki/United_States_Air_Force_Plant_...




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