There are strict rules about their mass and density. Basically the payload has to be smaller and softer than a bird, and the string can't be too strong either.
While I'm not disagreeing that these rules exist, but I have not seen them. I say this as someone that did quite a bit of research before actually doing an amateur weather balloon launch myself. I would like see what your definition of a bird is that the payload must be smaller than, because birds come in all sizes. My payload was the size of a small tackle box. Slightly smaller than the footprint of the 15" MBP that I'm typing currently typing this message. It was about 4.5"-5" tall as well. It was made out of whatever type of plastic. Now, I've never been hit by a bird or a plastic tackle box, but I'm thinking the tackle box would not qualify as softer than a bird either.
So, if you have a link to these strict rules that are defined as you've stated, I'd love to read them just to know exactly how bad I broke the laws (shut up Beavis).
(i) Carries a payload package that weighs more than four pounds and has a weight/size ratio of more than three ounces per square inch on any surface of the package, determined by dividing the total weight in ounces of the payload package by the area in square inches of its smallest surface;
(ii) Carries a payload package that weighs more than six pounds;
(iii) Carries a payload, of two or more packages, that weighs more than 12 pounds; or
(iv) Uses a rope or other device for suspension of the payload that requires an impact force of more than 50 pounds to separate the suspended payload from the balloon."
Translation: To be exempt from the rules of high altitude balloons your balloon must have no more then two payloads at 6lb per payload, cord no stronger than 50lb (fairly weak / most fishing line is too strong), and not be too dense.
Your payload sounds probably fine unless it contains a chunk of tungsten for some reason.
There's also a maximum balloon size and some other rules worth reviewing.
Those definitely read much more like what I remember reading. I definitely remember reading about the dual payload as at one point, we thought that might be something we might try.
The references to size of birds and softness definitely was questioning my recollection of the rules I had read.
Purely out of curiosity, the article mentions that one of these balloons has circled the globe several times. Do you need to follow other countries laws or has it never really been a problem until now?
Seems like the type of issue which would normally be solved with politics. If it happens enough to “bubble up” the bureaucracy, then diplomats could request a change in another countries behavior. If it was particularly important, economic pressure could be applied or delaying/holding up deals/votes that the offending nation cares more about than they care about violating our rules.
Well, you see what happens when your balloon doesn't follow the rules ;-) So, if you didn't check with each country's rules and regulations before plotting your course, you only have yourself to blame with it gets slammed with an AIM-9 missile.
Getting my balloon slammed with a missile wouldn't be my concern, it'd be sad that the balloon was destroyed before it's time but it was released to eventually crash. It's getting a warrant sent to me or getting a bill for a missile that would concern me.
And there's no real indication this balloon didn't follow the rules, neither of us know what Canada's rules are.
It depends on the total mass. At low masses, nothing, as the collision risk is low. As mass increase regulations on design become applicable that include maximum payload separation force, NOTAMs on launch, radar reflectors, and eventually the balloon is just considered an aircraft.
