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Vernerator t1_j8xh92k wrote

I believe it’s considered about 60 miles (100 km) above the Earth. That’s where conventional aircraft don’t have enough atmosphere to fly.

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OudeStok t1_j8xkhr1 wrote

Using balloons is an excellent way to hurt your rivals/enemies. It costs them far more to destroy a surveillance balloon that it does to build one and fly it over their territory.

−4

Flamingotough t1_j8xkno8 wrote

The Kármán line at 100km is a fairly agreed upon estimate.

But it feels wrong to let anything just hover in place over one's airspace - it might be an idea to include a requirement for the object to be at an orbital flight speed.

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gumol t1_j8xkym4 wrote

Replying to OudeStok (#1,845,984)

meh, it's not like the US had to purchase the missile specifically for this shootdown.

It was basically just a big training exercise for the US military.

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not_that_planet t1_j8xn0hq wrote

So is it confirmed that this was a Chinese spy balloon?

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Coakis t1_j8xo6gg wrote

Replying to gumol (#1,845,896)

The article is a bit of clickbait, It's not so much legal fuzziness as more there's no one agreed upon international defined limit, many countries use the Karmann line as the legal standard whereas the US defines it as 50 miles. So it is legally defined It just depends on where you're standing on the surface of the planet

Should we call the limit on the where international waters start "fuzzy" just because the Chinese use a greater distance from their shores than the US and other countries?

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AlexHanson007 t1_j8xroua wrote

Replying to gumol (#1,846,025)

You don't think they buy replacements once they've been used?

Edit: imagine being so upset by a basic question that you feel you have to downvote it. Some people are weird.

−5

Lazerith22 t1_j8xvg6x wrote

If there’s enough atmosphere to support a balloon, it’s not space yet.

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ferrel_hadley t1_j8y3pa7 wrote

Orbit is a speed not a height. The atmosphere puts a lower bound on where that speed can be "orbital" as you loose too much speed and even burn up low enough.

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Felaguin t1_j8y41wj wrote

Stupid article title and even the premise seems like bandwagoning to get clicks. While there is no universally-accepted legal definition of where space begins, the spy balloon is nowhere near any of the proposed boundaries.

There is no dispute about being able control our national airspace at 60,000 feet.

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Vorticity t1_j8y4s2f wrote

I'd argue that, if you are able to overcome gravity via buoyancy and/or aerodynamic lift, you are not yet in space. If you need to use orbital velocity to stay up, then you're in space. That probably still leaves some room for argument, but it would be a pretty narrow range of altitudes in which to argue.

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HolyGig t1_j8y53x4 wrote

Its not fuzzy at all. You are either in orbit, or you are not.

−4

LeviathanGank t1_j8y9cvx wrote

now china cares about legalities? wonder whose balloon satellite designs they stole to fly just outside the legal definition of near space

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charaznable1249 t1_j8yge8c wrote

Well it definitely doesn't begin at 40-60k up where they were located. 🤷

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NotAHamsterAtAll t1_j8yj33z wrote

If a balloon or an oxygen-powered plane can operate at the proposed altitude, it is not space.

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Hen-stepper t1_j8ynzrw wrote

Sort of like writing an article, "what does 'invasion' really mean anyway? Doesn't Earth belong to us all?" A week after Putin invades Ukraine.

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krashlia t1_j8yrl1k wrote

Replying to Hen-stepper (#1,849,282)

I remember more conservative and bumpkin types were worried about this, and their concerns were dismissed as something almost hysterical. And only after it was shot down was it okay for everyone to be upset about a spy vehicle above us and over US territory.

A ton of people in this country *suck* when it comes to the concept of security. They seem to believe perceiving a threat from afar is more of a problem than the fact that a threat exists.

−3

StackOverflowEx t1_j8yzn6r wrote

Replying to ferrel_hadley (#1,847,518)

Stable orbit is both a velocity and an altitude. Orbital velocity is dependent on orbital altitude. The absolute minimum before Earth's atmosphere interferes too much is 160 kilometers altitude at 17700 mph. Higher altitudes mean more velocity is needed to be in orbit.

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Shrike99 t1_j8z4dkh wrote

Replying to routerg0d (#1,848,382)

It's not a practical limit, it's a theoretical one. The original calculation that the 100km/62mile definition allegedly stems from was done by Theodore von Kármán, who determined that at ~84km/52miles, an airplane would have to move so fast to produce sufficient lift that it's speed would place it in orbit. The number was rounded up in most countries to 100km, though down to 50 miles in the US.

The fact that noone has actually flown a plane in sustained flight anywhere near that high doesn't change the math. Though I'd note that there have been unpowered flights at such altitudes - the Space Shuttle, Buran, X-37B, various hypersonic glide vehicles, etc.

Perhaps the best example is the Apollo capsule - not typically something you'd think of as an aircraft, but it did produce lift, and if you look at it's reentry profile you can see that it managed to maintain (approximately) level flight at around 200,000ft for a fair distance, before finally bleeding off enough speed to continue descending.

If the Apollo capsule, or Space Shuttle, or whatever had been fitted with some form of propulsion to maintain speed, then they could theoretically have sustained level flight at over 200,000ft - at least until their heatshields gave out anyway.

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HolyGig t1_j8z50ca wrote

Replying to fighterace00 (#1,850,565)

You can argue semantics if you want to but suborbital flights that could produce any sort of surveillance capability would reach altitudes considerably higher than those necessary to complete actual orbits.

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AvcalmQ t1_j8z8edj wrote

Replying to Felaguin (#1,847,539)

18 km out of... 100km. The kármán line isn't even in space, in that you still encounter significant drag and orbit degradation.

Shit man, if 18% is "near" I've got a nearly mint car I can sell.

EDIT: added a word for ease of interpretation

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TjW0569 t1_j8z9x2h wrote

Replying to gerkletoss (#1,847,131)

Still, if you were a Chinese intelligence officer that was aware that the U.S. military had been shadowing your receiver during its overflight, how much would you trust the information you were allowed to acquire?

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FirstVariable t1_j8zcnfg wrote

So like humans are all part of the same planet? Interesting.

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Uncle_Boppi t1_j8zdtva wrote

I consider space to start whenever you're able to float around, I'm not sure how far up that is though.

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audigex t1_j8zf4xg wrote

Replying to Vorticity (#1,847,606)

Yeah, it seems a simple enough test

“Can you replace the object with an inert rock of the same mass, and expect basically no significant difference in trajectory in the next 6 months?”

If yes, you’re in orbit and therefore space, otherwise your vehicle is relying on either lift or buoyancy and is therefore not in space

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Decronym t1_j8znvmk wrote

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

|Fewer Letters|More Letters| |-------|---------|---| |FAA|Federal Aviation Administration| |GEO|Geostationary Earth Orbit (35786km)| |ICBM|Intercontinental Ballistic Missile| |LEO|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |MEO|Medium Earth Orbit (2000-35780km)| |SSTO|Single Stage to Orbit| | |Supersynchronous Transfer Orbit| |USAF|United States Air Force|

|Jargon|Definition| |-------|---------|---| |apogee|Highest point in an elliptical orbit around Earth (when the orbiter is slowest)|

^(8 acronyms in this thread; )^(the most compressed thread commented on today)^( has acronyms.)
^([Thread #8578 for this sub, first seen 18th Feb 2023, 02:40]) ^[FAQ] ^([Full list]) ^[Contact] ^([Source code])

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HolyGig t1_j8zopvz wrote

Replying to fighterace00 (#1,852,140)

Altitude is correlated to distance traveled down range unless you have a rocket motor with infinite fuel. Please, show my the viable launch position that would achieve the desired surveillance at a lower altitude than a satellite could that isn't then going to smash into US territory somewhere.

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fighterace00 t1_j8zp6zy wrote

Replying to HolyGig (#1,852,254)

What does smashing into us territory have to do with how we define space? In fact suborbital means you're going to smash anyway. In fact, altitude has 0 to do with where you land if there's no horizontal vector.

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gms01 t1_j8zph9o wrote

There are at least 3 physical arguments about where space "begins". The first was explained well by Shrike99 - a theoretical limit from von Karman that aircraft around this altitude would have to travel faster than orbital velocity to obtain enough lift to support itself. At first rounded to 100 km/62 miles in most of the world, and maybe really about 84 km/52 miles in more recent calculations. A second aerodynamic basis is a practical one. As I understand it, the USAF 50 mile definition (besides rounding down from Von Karman) is the lowest a satellite can go and still complete one orbit (because of air friction, although that would seem to depend on the shape of the satellite, so that might not be a really solid argument). A third one is not an aerodynamic argument, but from a simple observation that there is a rapid increase in atmospheric temperature below 100 km. That is suggesting that there is a qualitative boundary of sorts at that altitude, so why not call it "space" above that. It's all somewhat arbitrary anyway.

In any case, as others pointed out, all these definitions are well above the balloon height.

2

Aerostudents t1_j8zqriv wrote

Replying to AvcalmQ (#1,850,906)

>18 km out of... 100km. The kármán line isn't even in space, in that you still encounter drag and orbit degradation.

I mean you still encounter drag and orbit degradation way higher than the karman line though. The ISS also encounters drag and orbit degradation still.

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Science-Compliance t1_j8zr12r wrote

Replying to AvcalmQ (#1,850,906)

>The kármán line isn't even in space

Earth's exosphere extends out past the moon. Any definition of "space" will be squishy. Satellites in low Earth orbit experience drag, too. Objects at 100km can complete multiple orbits around the Earth before drag pulls them down into the atmosphere. I'd be willing to call that space if someone wanted to argue about it.

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gms01 t1_j8zrqig wrote

Replying to cinemascifi (#1,851,833)

Actually, the GPS satellites are not geosynchronous satellites, which would imply orbits at 22,236 miles above sea level for circular orbits. From Earth, only those orbits appear stationary (in equatorial orbit) or at least varying within a relatively small area (if not in equatorial orbit).

The GPS satellites are in Medium Earth Orbit (MEO), around 12,540 miles. The GPS satellites do not hover over one area. They don't have to hover. Each satellite broadcasts its own four dimensional position in spacetime (3 space coordinates and the time, kept by accurate atomic clocks). Based on the calculated time delays from at least 4 satellites, a GPS receiver can uniquely determine the it's position.

See the Wikipedia article on GPS: https://en.wikipedia.org/wiki/Global_Positioning_System

and on geosynchronous orbit:

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

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HolyGig t1_j8zrxp3 wrote

Replying to fighterace00 (#1,852,289)

When were we trying to define space? We are talking about valid surveillance tactics. You don't need a horizontal vector at all if the earth rotates below you and you have enough.... altitude.

Suborbital isn't a valid surveillance method because that is otherwise known as an ICBM and its gonna look exactly like one on radar. Which, returns to my original point:

>Its not fuzzy at all. You are either in orbit, or you are not.

If you aren't in orbit then you are a threat and a target.

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ToddTheReaper t1_j8zt31c wrote

If it’s not in orbit or attempting to orbit then it’s okay to shoot down. It’s pretty simple.

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peter303_ t1_j8zxoea wrote

For those who remember the 1950s, the launch of Sputnik was somewhat terrifying because there was this object from the Enemy going over our heads every 90 minutes and we couldnt do shit about it. After ten thousand satellites from everywhere people dont worry that much. Its puzzling to me why balloon-gate revives the same fears.

1

fighterace00 t1_j9032pv wrote

Replying to HolyGig (#1,852,535)

Title:

> Where does space really begin? Chinese spy balloon highlights legal fuzziness of 'near space'

You:

> Its not fuzzy at all. You are either in orbit, or you are not.

Also you:

> When were we trying to define space? We are talking about valid surveillance tactics.

Tell me again how you can be suborbital beyond the karman line and it be fuzzy if you're legally in space because the megapixels of the camera in the tourists hands is low.

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HolyGig t1_j904pxw wrote

Replying to fighterace00 (#1,853,444)

Because I don't care about the Karman line I am defining orbit as the key delineation between reasonable surveillance methods and methods which will likely result in force being a response.

Yes, you can technically have a suborbital method that is valid, but its gonna look exactly like a ballistic missile and its trajectory will be beyond lower LEO altitudes so what's the point? Just use an actual satellite at that point lol

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abstractengineer2000 t1_j9095kq wrote

I donot think there is any ambiguity. The karman line @ 100 km is already defined

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fighterace00 t1_j90ceq8 wrote

Replying to HolyGig (#1,853,565)

So your argument is national boundaries should be completely dependent on surveillance methods.

Why not make overflights valid in that case? Orbital or not has no bearing on surveillance ability. Why did it be different monitoring at 50 feet or 60,000 feet or 400,000 feet?

Because of the ability to shoot it down? Russians couldn't touch our U2's for 5 years and could probably fly over Cuba to this day. We've shot a missile from an F15. The only thing stopping satellites from shooting each other is a weak treaty and the definition of space. Maybe that's the crux of the issue then, the definition of space where we can uphold a treaty, not what distances are technically unlikely to be used force against. Once we start shooting satellites down the new definition of political space would be Lagrange points and solar orbits.

The point isn't to define boundaries based on current tech but to draw a line in the sand internationally where we will no longer engage in violence. China and Russia have already made it clear multiple times they have little respect for "international" agreements.

1

HolyGig t1_j90dsw0 wrote

Replying to fighterace00 (#1,854,124)

National boundaries are dependent on being on Earth. Each country has its airspace and whatever above that is mostly fair game, which practically speaking means satellites almost exclusively.

Orbit is protected because we all require satellites to function if we want modern life to function. That includes Russia, China and everyone else too. If you trash MEO or GEO it will be trashed for decades if not centuries. Frankly it makes some sense for everyone to not be completely in the dark on the capabilities of everyone else anyways and regulating surveillance from orbit is basically impossible

So those are the limits everyone has de facto agreed with whether there's a specific treaty outlining it or not. Nobody would be playing with balloons if they didn't produce better intelligence in some capacity. SIGINT is the most obvious.

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TopperHrly t1_j90m0qq wrote

The US is really going bat shit insane over a fucking balloon.

−1

Academic_Peanut4232 t1_j90on01 wrote

Replying to Felaguin (#1,847,539)

>There is no dispute about being able control our national airspace at 60,000 feet.

That's not true. It's still face that no one knows what the "UAPs" are/ were. There's stuff flying around that comes from above 80,000 feet into the detection-edge of Earth-based radars and then breaks the laws of physics lol. No one knows what those things are, and no one can "control" our airspace from them. What astounds me is that those things exist, and we're not dumping tons of money trying to figure out what they are and how they fly. Imagine where our space program could be if they made a serious effort at doing that lol.

−3

Felaguin t1_j90xxte wrote

Replying to Academic_Peanut4232 (#1,854,820)

The fact that 60,000 feet altitude is well within what’s considered national airspace AND that we have a right to control what’s in our airspace is 100% true. It is well-accepted international law — even the Soviet Union (now Russia) accepts it and uses it.

The “detection edge” of Earth-based radars extends well above 100,000 feet, in fact, well above 100 km altitude. See, we have these things called early warning radars that were built decades ago to do precisely this job albeit with objects that move considerably faster than balloons.

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Alexthelightnerd t1_j91ltq4 wrote

Replying to abstractengineer2000 (#1,853,896)

The problem is not everyone agrees that it's the correct line, there are several options. Even when there isn't much consequence to the distinction, people can't agree on it - see Blue Origin and New Shepherd.

When talking about international law, there's even less agreement. The mechanism for creating an international standard isn't particularly clear, nor are enough nations probably willing to agree for it to be feasible at all.

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Nickp000g t1_j91o6an wrote

Which is why we have a new branch of our military to take on these issues.

But everyone made fun of it, and made some shitty TV show trying to make fun of it.

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spork3 t1_j91w2zp wrote

Replying to Flamingotough (#1,845,996)

What I like about 100 km is that it’s place where two different fields independently agree that space begins. The Karman line is an aeronautic definition, but space physicists also define the space boundary at about 100 km based on composition. It’s about where the ionosphere begins and the mesosphere ends. As a physicist, I had never heard of the Karman line until somewhat recently, so it was interesting to learn that the what many people use to define the boundary for space is the same as what I knew it to be.

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iR0nCond0r t1_j923vdc wrote

Does it? Does it really? It’s a f%%*ing spy balloon. Shoot it down move on. If you want to spy do it like a normal person and launch a sat into low earth orbit

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AvcalmQ t1_j92usue wrote

Replying to Aerostudents (#1,852,446)

You're not wrong but you can clearly see what the comment was saying; I can't find many (any) satellites that are continuously operating at or below 100km, whereas I can for those above.

I'll add the word "significant" to further clarify this

1

Science-Compliance t1_j92wz94 wrote

Replying to AvcalmQ (#1,861,321)

The US considers anything past 50 miles in altitude to be space, and, in a manner of definition, they're not necessarily wrong. You can do more than one orbit at this altitude. "Space" is a human construct, so any definition is really going to fit human needs. In any case, 60,000 feet is not "space" by any reasonable definition.

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Academic_Peanut4232 t1_j94q94v wrote

Replying to Felaguin (#1,866,767)

We couldn't even track balloons until 2 weeks ago. There are/ were balloons flying all around our airspace, and we didn't even know about balloon until a few years ago.

So all the sudden, the things that pilots have been reporting seeing for decades, it makes sense there's no (publicly available) data on that stuff. If we can't even track balloons until recently, how could we track alien spacecraft? Or -- maybe we could/ can, but just like balloons, it was filtered out or some other reason we aren't/ didn't interpret the data correctly?

If something did actually fly into Earth from space, accelerating to ridiculous speeds and breaking the laws of physics -- would that data be looked into, or would it just be ignored as "anomalous" like the balloons were for decades?

0

Felaguin t1_j963x1x wrote

Replying to Academic_Peanut4232 (#1,866,972)

You certainly chose a worthy Reddit name. You’re conflating things that are obvious balloons, leaving the discussion of spy versus weather versus hobby aside, with pilot reports of UAPs doing extraordinary things. Some of the pilot reports are easily explained, others (including footage captured by said pilots) are still unexplained.

Your original response to me talked about stuff coming in “from above 80,000 feet into the detection-edge of Earth-based radars”. We use radars to track objects in orbit at altitudes up to 1000 km (over 3 million feet since your inability to reason suggests a further inability to do math).

You further talk wildly about breaking the laws of physics. Nothing the first spy balloon we shot down or any of the other subsequent balloons have done breaks any laws of physics.

Control of national airspace is a point of international law. Whether or not the nation in question can do anything about violations of that airspace is a question of their capability versus the violator’s capability. No one questioned the USSR’s right to shoot down Francis Gary Powers’ U2, they simply weren’t able to do it until his flight. The US “controls” the sealanes within its national waters but drug runners violate that control regularly — it’s still the US’s national right to control those sealanes.

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Flamingotough t1_j98ap4d wrote

Replying to cinemascifi (#1,868,658)

I may have just misunderstood you point?

I thought you critized my idea of taking speed into account, by saying that objects in geosynchronous orbit would be stationary as seen from the ground. I just wanted to note that although that is true enough for this argument, such an object would still travel it's orbit at a significantly different velocity compared to the spot on the ground underneath.

1