I had seen reports that the balloon was the length of 3-4 school busses but it appears that was misreported and just repeated. The PAYLOAD was the length of 3-4 school busses.
I haven’t been following this much until today/ vaguely aware as an amusing background story.
But, has anyone seen high res photos of the balloon or someone doing back of the envelope math on the size of the balloon portion?
I ask simply because a payload the length of 3-4 school busses (apparently 45 feet) would be quite large and the ballon itself much much larger than I was imagining
Judging from the videos that pan from the moon to the balloon: the balloon was about 3x smaller in the sky than the moon. Knowing the altitude of the balloon was 68,000 feet, we can fudge the distance from the observer to the balloon as 100,000 feet. Knowing the distance to the moon and the radius of the moon we can use like triangles to estimate that the balloon was ~285 feet across, +/- 20% for estimates.
Edit: updated the estimate. I got radius and diameter mixed up.
This is a clever method and I appreciate that you posted the Wolfram alpha link - always happy when people show their work and I did not realize that you could do things like include (diameter of moon) as variables with it. This is a nit, but if you're busting out an AI enhanced calculator there is no need to make a 40% rounding of 70K to 100k. I got ~200 ft across.
I saw it from my car today while driving before I knew it was going to be in my area. It was very visible to the naked eye. It was large enough that the perspective made it seem a lot lower altitude than it actually was.
It looks like the large size is mostly just solar panels (I'm assuming that's what they were; they could have been 'sails' to help steer it) and their scaffolding. From some of the available photos there's two wings, each with eight panels.
There's a tradeoff between the weight of the solar panels vs simply using batteries (though batteries don't like the cold, and solar panels do), so I think maybe they were hoping the thing would stay aloft for a long time?
My guess is that the actual package of equipment - batteries and sensors - is quite small. Maybe a telescope and gyro stabilizer or gimbal was part of the setup. Insulation probably bulked it up quite a bit; it's very, very cold at that altitude.
I'd be curious what sort of uplink they were using, assuming the thing was actually fully functional as a spying device. I'd say there is a decent chance it was largely a dummy, designed to see what our reaction would be.
I don't particularly like the precedent we just set. There's no evidence it was a weapon, its flight path was easily tracked and slow so our military could hardly argue it was a surveillance threat especially compared to satellites, it's well outside commercial aviation flight ranges.
If they want to send balloons over us at 80,000 feet...let them? Who cares? They can task commercial satellites and get as good or better imagery.
We can hardly point fingers. The U2 flew at similar altitudes, we still use them to this day, and they almost certainly contain far more powerful spying equipment.
Sails are useless in a balloon. The only way to steer a balloon without a propeller is to raise and lower its altitude seeking a wind blowing in the right direction.
> I don't particularly like the precedent we just set
especially in view of the fact that the upper limit of sovereign airspace is not defined by international law. In fact there are proposals to treat the 18-160km zone as a transitional region of reduced sovereignty akin to EEZs.
> Legally however, it is an indistinct region where it is not clear whether the operations that take place are covered by aviation or space conventions and treaties, in particular with reference to the freedom of overflight that applies to space orbital operations
Also:
> Although outer space is free, if states are allowed to claim vertical sovereignty up to the point where orbital dynamics are possible, other states will be precluded from having free access to space
> John A. Johnson, General Counsel of [NASA] and [of USAF], said in 1964 "there should therefore be no legal basis for protesting, merely on grounds of unpermitted presence, the overflight of national territory by ascending and descending spacecraft, regardless of altitude."
When an aircraft doesnt have a transponder, doesnt respond to radio calls, no flight plan on file, and seems to be adrift, it is a hazard to navigation irrespective of altitide. Such things get intercepted and, if in any way dangerous, are shot down. Post-9/11, there are even protocols for shooting down unresponsive airliners.
> The U2 flew at similar altitudes, we still use them to this day, and they almost certainly contain far more powerful spying equipment.
And if they could, other countries would love to shoot them out of the air and it would be fair. You don't put planes like the U2 in operation without being aware of the risks.
I don't understand what you're trying to achieve by pointing that out.
It could’ve actually been a “science experiment” just launched at the behest of the military as a test like you say. So they’d have plausible deniability like the “fishing boats” in the South China Sea
>They can task commercial satellites and get as good or better imagery.
Is that true? Just from quickly poking around, LEO satellites seem to orbit at about triple the height, moving far faster than a balloon lazily floating along the jetstream. Probably can use a larger variety of instruments as well.
I don't know why you are downvoted but I agree with your point that the shooting down feels a bit like an overreaction.
For instance, the Pentagon has just reported that several Chinese balloons have been crossing US airspace in the recent years [1], also during Trump presidency. These were not shut down, they were not even reported at the time AFAIK.
The big question is why China would send a balloon. My best guess is it carried electronic warfare sensors to try and collect specific information about US radar and missile capabilities. They may have in fact wanted us to shoot it down, ideally first painting it with advanced radar (both air and ground based) and then firing an advanced missile at it. Data could be streamed out until the moment of impact and used to create better ways to jam or avoid US missiles. Sending it over sensitive sites may have been an attempt to force the US to take such action.
I’ve heard rumors that it was shot down by an AIM 9X, which is IR guided, a good choice as its seeker doesn’t use radar and thereby expose the terminal radar guidance information. I’m going to go way out on a limb here and theorize the delay was due to brand new upgrades required to the AIM 9X software to be able to lock on to and hit a balloon, which they probably were not originally capable of.
There was a case in the 90s I think of a Canadian weather balloon that they tried to shoot down with (fighter plane) guns and had a pretty tough time of it. Guns at that altitude too could be an issue as you lose control authority in thin air and the gun destabilizes flight controls even more.
The balloon was at a very high altitude (66,000ft). The F-22 launched its missile at 58,000 feet, probably right at the edge of its loaded service ceiling, and the missile travelled rest of the way up. Given the height, I don't think it would've been easy to shoot it down with a cannon.
Among other reasons many fighter aircraft have max altitude of 50k to 55k and starts requiring more specialized equipment. And the balloon was at 60k feet. So perhaps they don't want to reveal which aircraft have capabilites beyond their advertised or something like that?
One reason I heard is that guns wouldn't have been that effective on a balloon the size of a football field; mere pinpricks, basically. The balloon would leak, but not nearly fast enough to bring it down in a reasonable amount of time.
Unless, of course, they unloaded thousands of rounds into it, which is probably more dangerous and less practical than taking it out of the sky with a missile.
I'm not sure it's worth making such advanced guesses about the intentions until it's proven that it could even steer itself and navigate with any accuracy at all.
Your comment is the equivalent of "sit down and shut up" which is contrary to the whole point of having this forum or any sort of intellectual discussion on any topic on HN.
Since nobody has answered your question: I assume that China simply sent a balloon to spy on the US. Why a balloon? Because it's much closer to earth than a satellite and can carry a heavier payload. And why they were not worried if it would be detected? Well, according to the Pentagon, China has sent several balloons over the US in recent years and nobody made a fuss about it until now.
... why didn't they simply declared it a shooting range target? thousands of volunteers would have tried to shoot it down with bullets and various DIY things! it would have been endless streaming content!
They explicitly asked the public not to do this. It was something like 60k feet in the air. People shooting up would have a laughably low chance of hitting it, plus create a rain of bullets somewhere else far away.
Randomly Firing thousands of round at a target about ten miles up at an angle making the trajectories of misses to be something like 30 mi arcs sounds like a great idea doesn’t it? Does a ground fired bullet even go that high? They’ll obviously know their bullets are landing in safe areas right and no Minneapolis or wherever?
Statistically unlikely to hit someone, but not surprising if it happened.
I don’t think F-22 pilots get to paint their aircraft. It would destroy the stealth coatings, which are so specialized they are measured to the milligram when removed (to ensure an adversary hasn’t taken some for analysis).
I feel like the balloon takedown was seriously mishandled.
Imo it should have been shot down right after it crossed our borders and before it started move over populated areas. That way there would be no surveillance and you could examine the payload.
Now that it’s in the water, you may not even find it.
The US has great radar capabilities, so we obvious knew it was there. I think that raises the question of why we didn't shoot it down. Maybe we were curious where it was going and we wanted to see how capable at navigating it was? Is it too dangerous to shoot down over land? What was the diplomatic communication with the Chinese? There's many questions that may never be answered in public.
It seems more than likely that this had little surveillance abilities that a satellite doesn't already have, so little intelligence risk. Maybe we went as far as to plant a false target for it.
Alternatively, if this had weapons on it, dropping it on land seems pretty dangerous compared to off the coast.
Additionally, out of diplomacy, we should communicate with the Chinese that we're about to blow their stuff up, especially when they politely pretend it's civilian. Civilized nations need to play political games before we can blow up "civilian" equipment.
Beyond all this, some other comments here have claimed that these balloons have been going on for a few presidencies now, without any being shot down. So why is it a concern now? I'd be worried about suddenly war-hawking something that hasn't been a problem. There's enough going on in the world without a degrading US-Chinese relationship. This is probably simply the case that it's a non-issue that got too much attention and needed to be addressed publicly.
I think you're being overly generous in attributing competency/capability. Just thinking about the physics of it, robustly jamming an unknown signal of a transmitter 60KM high seems like a rather impossible task. If the air force were somehow broadcasting several megawatts of broad spectrum noise over a populated area, somebody would have noticed.
The authorities in charge have no real idea what's going on or what the payload is. This whole situation is just weird. Maybe it is just some irresponsible private organization. The Baidu equivalent of Project Loon?
I disagree. The spy balloon was likely inspected shortly before it entered US territory and the military deemed it as something that was not critical and simply moved anything sensitive out of the way of the a balloon. Meanwhile they likely monitored the emissions of the balloon to do intelligence collecting of Chinese capabilities. The DoD said they were aware of the balloon shortly after it left China and were monitoring it even before it flew over Alaska.
The US probably gained more from this than China gained.
Meanwhile the general public and US media got very invigorated about it so helped stock public opinion against China in general which helps prevent more stealing of secrets to China but increasing the cautiousness of the general populace.
Well China gained a very important piece of information and international agreement.
One, that region is considered the countries airspace.
Two, we can distroy and keep spy gear.
Both are useful rules to bring up in the future.
The U-2 and SR-71 both stopped flying due to the risk of being downed and not moral consequences. Similarly the US (probably) stopped spying on allies due to the risk of another whistleblower and not moral reasons.
At the same time, similar events have happened to establish that space spy satillites are okay.
Finally, this is easy to forget esp. if you're a US citizen. Most of the world considers this incident a bit of a joke. Official responses are along standard narrative lines.
But no one really cares, the US reacted like this because it didn't know why China would want to use this balloon to spy and so wants to nip this activity in the bud.
If this is a military item I would be very surprised if it doesn't have a lot of self destruct capability. Surely it will have a package that kicks in if it starts an uncontrolled descent without some sort of override signal from its operators. Especially as it's unmanned.
If I was in charge there would be magnesium strips and bars laced all over it and all that anyone would get from it would be ashes. At a minimum there would be stuff rigged to burn it if it suffered a 10G shock or more - I mean why not? It's junk at that point anyway, why risk it being interesting junk?
Do you think that did not occur to the military? I’m sure that if they blundered, it was not in some way that was so obvious. Either they simply didnt know about it until it was too late, or they had some reason to not shoot it then that you’re not aware of. The idea that they decided not to do so for no good reason is silly.
NYTimes is reporting that this is actually the fifth balloon to cross into our airspace. First four were seemingly ignored, three times under the Trump administration and once before during Biden’s.
The implication of that being the shootdown was a media-initiated event. After civilians saw the balloon from the ground, and it became lead story on every news site, with the MAGA press calling Biden "weak", something had to be done, whether it makes military sense or not.
As mentioned in the article, so the order was there the moment it crossed the border.
> The high-altitude balloon was initially spotted over Billings, Montana, on Wednesday.
> Biden gave authorization on Wednesday to take down the balloon as soon as it could be done “without undue risk to American lives under the balloon’s path,” Lloyd said.
None of it makes sense. They shot it down over the US coast where you are similarly likely to hit a boat or a bather than hitting someone in some empty fields of the midwest (and what about the canadian mountains!). They say it doesn't pose any threat to aviation but nevertheless closed the airports on its path. They say that they are confident it is an intelligence gathering operation by the chinese, but that they don't get anything more than they would get from a satellite (why would they use balloons then, are we suggesting the chinese are stupid?).
I have no idea what's the real story here but it is obvious we are being bullshitted.
Sidestepping the geopolitical issues with this for a moment ...
What advantage is there to using a high altitude balloon for surveillance? I have to imagine there are some - like longer loiter time over a specific point, maybe better optics because you are still in atmosphere, it's obviously cheaper than launching a satellite - but I don't really know enough about this kind of hardware to say.
Or maybe the point wasn't to actually look at anything, but instead see how the US would respond?
The one advantage it really has over satellites is how long it can stay on station and still be relatively near to the target. I'd personally guess it's a signals intelligence platform rather than anything telescopic.
Significantly closer to the ground, so can capture better resolution pictures. If browsing Google Earth, the high-resolution data around cities originates from airplanes, not satellites.
Turnaround/prototyping. Getting a sensor onto a spy sat is a multi-year process of testing and validating. But a new balloon can probably be built and flown in a matter of weeks. So any country trying to learn how to spy from above might want to build up the relevant corporate knowledge using balloons.
Radiometrics - being closer than orbit and having a much longer linger time drastically increases the signal count to any gamma spectrum gear that might be on board.
Whether or not that reveals any non usual background signal of interest is an interesting ponder.
One of the most technically challenging things about reconnaissance satellites is dealing with the high speed at which the satellite moves over the target. A balloon flies much lower and vastly more slowly. It can loiter over an area, sucking in electronic signals and taking photographs with extremely high fidelity.
I don’t think the Chinese meant for this balloon to cross the United States. I believe they were testing it for use over other countries or perhaps for use during wartime. Their apology was way too quick for this to have been anything other than a genuine accident.
Did they actually apologize? I thought all they said is that it was a weather balloon. Regardless, I'm very interested in what hardware was actually on this thing. Hopefully the public gets a summary of what USN pulls up during recovery.
The precursor to a strategic balloon arms race that it chills the blood to contemplate. All it takes is one push of the button and, 14 days later, death comes drifting in from above.
The fact that this became a story at all is purely geopolitical in my opinion. Perhaps to do Blinkens up coming Beijing visit (which has since been canned). As far as I can tell the chinese dislike bad press like this. Having the balloon become a fiasco becomes a reason to cancel the trip. Can't exactly tell the why's but this is my guess.
100%. If the balloon was a threat, why wasn't it shot down over Alaska? Or earlier on it's trip over the continental US. There was no threat... Here's an opportunity to drum up a lot of FUD and use it as a geopolitical lever.
Also painting China bad is a great method of painting yourselves in better light domestically. Both sides of politics in the US have vested interest in this narrative.
Technically the ballon isn't moving itself in anyway at all, it instead is depending on the wind. As the atmospheric pressure lowers the maximum speed of the wind can increase greatly. For example the speed of the jet stream commonly exceeds 275 miles per hour. It looks like the strongest jet winds were closer to canada, had the jet been in the US it could have made it across the country in a day.
There was mention by the Chinese that is had some motive power of its own, or at least strongly implied when their PR said some the thing like “limited maneuvering capability”. That seems to indicate that it had some. It would a bit surprising if a payload the size of 2-3 school buses wasn’t outfitted with a reasonable amount of controllability, at least some control surfaces even if they inexplicably excluded even minimal and limited propulsion.
The jetstream is fast enough that it factors into any flight at altitude when it comes to fuel estimations and path calculations, up to 12% difference or so iirc.
Indeed this is really obvious to anyone who regularly travels to California and back to the somewhere on the eastern half of the US (or vice versa). The time it takes for the east bound leg is way faster than the west bound leg. Going from San Francisco to Detroit for example is about an hour faster on the east bound direction.
Readit News
Chinese surveillance balloon spotted over U.S., Pentagon says - https://news.ycombinator.com/item?id=34634304 - Feb 2023 (404 comments)
I haven’t been following this much until today/ vaguely aware as an amusing background story.
But, has anyone seen high res photos of the balloon or someone doing back of the envelope math on the size of the balloon portion?
I ask simply because a payload the length of 3-4 school busses (apparently 45 feet) would be quite large and the ballon itself much much larger than I was imagining
Edit: updated the estimate. I got radius and diameter mixed up.
http://www.wolframalpha.com/input/?i=100000%2A%28diameter%20...
For example, I could find that this ballon reaches 200ft diameter at 100,000 feet.
https://remus.jpl.nasa.gov/balloon.htm
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Edit: Different balloon https://www.msn.com/en-us/news/world/when-a-weather-balloon-...
EDIT how lazy of me, 285ft diameter, and assuming spherical shell, gives 166 Olympic pools.
There's a tradeoff between the weight of the solar panels vs simply using batteries (though batteries don't like the cold, and solar panels do), so I think maybe they were hoping the thing would stay aloft for a long time?
My guess is that the actual package of equipment - batteries and sensors - is quite small. Maybe a telescope and gyro stabilizer or gimbal was part of the setup. Insulation probably bulked it up quite a bit; it's very, very cold at that altitude.
I'd be curious what sort of uplink they were using, assuming the thing was actually fully functional as a spying device. I'd say there is a decent chance it was largely a dummy, designed to see what our reaction would be.
I don't particularly like the precedent we just set. There's no evidence it was a weapon, its flight path was easily tracked and slow so our military could hardly argue it was a surveillance threat especially compared to satellites, it's well outside commercial aviation flight ranges.
If they want to send balloons over us at 80,000 feet...let them? Who cares? They can task commercial satellites and get as good or better imagery.
We can hardly point fingers. The U2 flew at similar altitudes, we still use them to this day, and they almost certainly contain far more powerful spying equipment.
Sails are useless in a balloon. The only way to steer a balloon without a propeller is to raise and lower its altitude seeking a wind blowing in the right direction.
It is a lot easier to take pictures and collect data at 60,000 ft (balloon) than from a satellite in low earth orbit, which is closer to 6,000,000 ft.
especially in view of the fact that the upper limit of sovereign airspace is not defined by international law. In fact there are proposals to treat the 18-160km zone as a transitional region of reduced sovereignty akin to EEZs.
https://iaass.space-safety.org/wp-content/uploads/sites/24/2...
> Legally however, it is an indistinct region where it is not clear whether the operations that take place are covered by aviation or space conventions and treaties, in particular with reference to the freedom of overflight that applies to space orbital operations
Also:
> Although outer space is free, if states are allowed to claim vertical sovereignty up to the point where orbital dynamics are possible, other states will be precluded from having free access to space
> John A. Johnson, General Counsel of [NASA] and [of USAF], said in 1964 "there should therefore be no legal basis for protesting, merely on grounds of unpermitted presence, the overflight of national territory by ascending and descending spacecraft, regardless of altitude."
https://scholar.smu.edu/cgi/viewcontent.cgi?article=1126&con...
Also see:
https://aviation.stackexchange.com/questions/43439/is-there-...
https://en.wikipedia.org/wiki/Air_sovereignty
And if they could, other countries would love to shoot them out of the air and it would be fair. You don't put planes like the U2 in operation without being aware of the risks.
I don't understand what you're trying to achieve by pointing that out.
Is that true? Just from quickly poking around, LEO satellites seem to orbit at about triple the height, moving far faster than a balloon lazily floating along the jetstream. Probably can use a larger variety of instruments as well.
Or perhaps both at once. I really hope the details of this craft are published, the machine nerd in me needs to know.
For instance, the Pentagon has just reported that several Chinese balloons have been crossing US airspace in the recent years [1], also during Trump presidency. These were not shut down, they were not even reported at the time AFAIK.
[1] https://www.businessinsider.com/conservatives-blame-biden-ch...
I’ve heard rumors that it was shot down by an AIM 9X, which is IR guided, a good choice as its seeker doesn’t use radar and thereby expose the terminal radar guidance information. I’m going to go way out on a limb here and theorize the delay was due to brand new upgrades required to the AIM 9X software to be able to lock on to and hit a balloon, which they probably were not originally capable of.
Unless, of course, they unloaded thousands of rounds into it, which is probably more dangerous and less practical than taking it out of the sky with a missile.
oh, well, maybe the next one. :(
Statistically unlikely to hit someone, but not surprising if it happened.
https://en.wikipedia.org/wiki/List_of_aircraft_shootdowns
Acknowledged and unacknowledged kills are counted separately, and it's OK to call it the first kill in the sense of acknowledged kills.
(That's my understanding anyway)
Edit: ceejayoz: JINX!
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It seems more than likely that this had little surveillance abilities that a satellite doesn't already have, so little intelligence risk. Maybe we went as far as to plant a false target for it.
Alternatively, if this had weapons on it, dropping it on land seems pretty dangerous compared to off the coast.
Additionally, out of diplomacy, we should communicate with the Chinese that we're about to blow their stuff up, especially when they politely pretend it's civilian. Civilized nations need to play political games before we can blow up "civilian" equipment.
Beyond all this, some other comments here have claimed that these balloons have been going on for a few presidencies now, without any being shot down. So why is it a concern now? I'd be worried about suddenly war-hawking something that hasn't been a problem. There's enough going on in the world without a degrading US-Chinese relationship. This is probably simply the case that it's a non-issue that got too much attention and needed to be addressed publicly.
They didn't shoot our balloons down.
By letting it saunter all the way across they also probably got a lot of good info on its capabilities.
The authorities in charge have no real idea what's going on or what the payload is. This whole situation is just weird. Maybe it is just some irresponsible private organization. The Baidu equivalent of Project Loon?
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The US probably gained more from this than China gained.
Meanwhile the general public and US media got very invigorated about it so helped stock public opinion against China in general which helps prevent more stealing of secrets to China but increasing the cautiousness of the general populace.
One, that region is considered the countries airspace.
Two, we can distroy and keep spy gear.
Both are useful rules to bring up in the future.
The U-2 and SR-71 both stopped flying due to the risk of being downed and not moral consequences. Similarly the US (probably) stopped spying on allies due to the risk of another whistleblower and not moral reasons.
At the same time, similar events have happened to establish that space spy satillites are okay.
Finally, this is easy to forget esp. if you're a US citizen. Most of the world considers this incident a bit of a joke. Official responses are along standard narrative lines.
But no one really cares, the US reacted like this because it didn't know why China would want to use this balloon to spy and so wants to nip this activity in the bud.
If I was in charge there would be magnesium strips and bars laced all over it and all that anyone would get from it would be ashes. At a minimum there would be stuff rigged to burn it if it suffered a 10G shock or more - I mean why not? It's junk at that point anyway, why risk it being interesting junk?
They might not even care that much, if they've seen this model of ballooncraft before.
https://www.foxnews.com/media/biden-weak-response-chinese-su...
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> The high-altitude balloon was initially spotted over Billings, Montana, on Wednesday.
> Biden gave authorization on Wednesday to take down the balloon as soon as it could be done “without undue risk to American lives under the balloon’s path,” Lloyd said.
I have no idea what's the real story here but it is obvious we are being bullshitted.
At that point they issued a national security no-fly zone, ground stops at three airports, and issued notices to marine traffic to clear the area.
What advantage is there to using a high altitude balloon for surveillance? I have to imagine there are some - like longer loiter time over a specific point, maybe better optics because you are still in atmosphere, it's obviously cheaper than launching a satellite - but I don't really know enough about this kind of hardware to say.
Or maybe the point wasn't to actually look at anything, but instead see how the US would respond?
Whether or not that reveals any non usual background signal of interest is an interesting ponder.
I don’t think the Chinese meant for this balloon to cross the United States. I believe they were testing it for use over other countries or perhaps for use during wartime. Their apology was way too quick for this to have been anything other than a genuine accident.
If true, that's unlikely to be a mistake.
After your "weighing paint" comment I think you should probably stop talking.
That is interesting!