Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Finding the B-21's hangar location from the stars in its press image

twitter.com

Post reply on HN
Print view View original

111–120 of 228 posts

Re: Finding the B-21's hangar location from the stars in its press image

#111

Post by Merad »

supernova87a wrote: post #98

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 imag…

> 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...

Re: Finding the B-21's hangar location from the stars in its press image

#112

Post by amiga386 »

calvinmorrison wrote: post #15

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 discussi…

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

Re: Finding the B-21's hangar location from the stars in its press image

#113

Post by dylan604 »

mk_stjames wrote: post #24

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'…

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.

Re: Finding the B-21's hangar location from the stars in its press image

#114

Post by 323 »

folli wrote: post #56
pifm_guy wrote: post #50

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 obscuri…

Very interesting! Any links for further reading?

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).

Re: Finding the B-21's hangar location from the stars in its press image

#116

Post by thunderbird120 »

kevin_thibedeau wrote: post #94
ForHackernews wrote: post #39

Earlier quoted context omitted.

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.

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.

Re: Finding the B-21's hangar location from the stars in its press image

#117

Post by 14u2c »

kevin_thibedeau wrote: post #94
ForHackernews wrote: post #39

Earlier quoted context omitted.

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.

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

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.

Re: Finding the B-21's hangar location from the stars in its press image

#118

Post by sophacles »

Johnny555 wrote: post #99
supernova87a wrote: post #98

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 imag…

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.

Re: Finding the B-21's hangar location from the stars in its press image

#119

Post by quesera »

runlaszlorun wrote: post #109
runjake wrote: post #70

Earlier quoted context omitted.

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…

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.

Re: Finding the B-21's hangar location from the stars in its press image

#120

Post by NotYourLawyer »

johnmcelhone wrote: post #86
httpz wrote: post #77

Earlier quoted context omitted.

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.
Post reply on HN