The Circumnavigators (2017) | Hacker News Reader

The Circumnavigators (2017)

qrp-labs.com

79 pointstyppo34 comments

I used to be, let's not say heavily involved, but eagerly observing, this community. I was lurking in #highaltitude when M0XER's B-64 crossed its launch longitude, marking a circumnavigation, and the place went _nuts_.

Then B-63, launched a few days earlier, did the same. But B-63 popped shortly thereafter, while B-64 just kept going, eventually circling 8 times over the coming 4 months. It's one thing to set a record, it's another thing to smash it so thoroughly immediately after setting it.

I want to say he was using dry-cleaning bags as envelopes early-on, but I think he switched materials to achieve that kind of durability.

Technical detail: Having crossed all meridians is generally not considered the proper criterion for circumnavigation since this is trivially done near the poles. The definition I have come across include a loop that partitions Earth's surface into two parts of comparable area.

Any two non-zero areas are comparable, but I don't think 1:10000000 will satisfy the definition. It is necessary to establish an acceptable ratio. 1:6 or something like that?

There's a tradition of having to pass through antipodal points, but that's probably too strict for a balloon.

The requirement I'm familiar with is crossing all meridians and the equator.

It is important to realize the difference in scale between amateur balloons and the Chinese spy ballloon. Some amateur ones are less than ounce of payload, the Chinese one was thousands of pounds.

The ham radio balloons mostly just transmit position. It is impressive that they do that in small size and can make multiple circumnavigations.

Can we call it the Chinese big balloon instead? Because from what I gather that thing was massive. Future big balloons also will not necessicarily be used for espionage - worse case scenarios involve dropping harmful payloads.

That was actually a tactic deployed by the Japanese during WWII to attack the US mainland. They carried and incendiary payload in hoped of starting forest fires and other damage

https://en.wikipedia.org/wiki/Fu-Go_balloon_bomb

edit:

Actually, there is a whole history of weaponized balloons, it's pretty interesting

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

Those balloon bombs caused the only US civilian casualties due to enemy action in the mainland US; one of them killed a few kids who found it in a forest. Strangely, their father later became a presumed civilian casualty in the Vietnam War, where he went missing. Tragic distinctions for that family.

I learned about it a few years back from, I think, a 99 Percent Invisible episode. I find almost as bizarre as the story itself is that it's practically unknown.

In addition to this, HAM radio rules require that radio signals are not encrypted (rules specify that they must not be obscured). While this wouldn't prevent you from having a spy balloon and sending all images back in clear, it would make it obvious what you are transmitting or obvious that you're a spy if it is encrypted.

Could you hide an encrypted signal in what appears to be a normal HAM radio signal? I know it would be illegal, but is it possible?

With steganography[1], it's certainly possible. For instance, if your balloon is only broadcasting its location, you can fuzz the highest precision bits of the longitude and latitude to emit a few bits of signal at a time. Or, for example, you can oversample from a GPS satellite, and only broadcast the locations whose high-precision bits match the signal you want to broadcast.

I do think this would be illegal, but detecting it could be quite difficult.

[1] https://en.m.wikipedia.org/wiki/Steganography

I still remember the project in college where I embedded quite a lot of information in images. While detecting would be difficult, if NSA puts its mind to it and figured it out, then it would be very clear what you were doing, you can't claim randomness in your defense

Yep, the detectability of steganography tends to increase with information density, of course. If somebody is watching GPS traffic they could discover my (hastily conceived) location-beacon scheme, for instance. Likewise, a metadata scheme (varying time between broadcasts) could be discovered through close enough examination. But, that at least has some plausible deniability baked in, random delays are better than fixed delays in terms of network congestion.

That was my point, there is no plausible deniability. Your cleaned-up data just happens to be the png image of some secret US bases? Good luck convincing a judge it's not intentional. If you encrypt it well enough, it might be that NSA never discover the underlying data, but that hinges on protecting the emitting source. If they get their hands on it, they can recover the keys.

How would you detect it then? Assuming your encryption looks like random noise and you could shape it so it looks say like sensor noise ?

> your encryption looks like random noise

well, for one, you're emitting from a balloon, so you WILL get the attention of NSA at least. Second, it's pretty trivial to find patterns in otherwise noisy signal, and NSA is expert at that and you're probably a novice. The only thing that can protect you is if you have a good enough encryption, which is hard to keep once they get their hands on the physical balloon. But even if they don't break the encryption, they can hold you in dark cells with no access to a lawyer, if they have the slightest suspicion it was indeed a spy balloon.

How on earth they'd even know who launched the baloon?

> Second, it's pretty trivial to find patterns in otherwise noisy signal,

Good encryption doesn't produce patterns

The NSA might figure it out, but I doubt they'd tell the FCC about it.

Edit: I think I got confused by reading an article a long time ago referencing the command & control exemption mentioned in another comment. I should've kept my mouth shut about a legal matter I couldn't properly articulate/didn't fully understand or at least put IANAL, my bad.

--- original comment: ---

This regulation is often misunderstood. The requirement is that it must be possible to decode the signal; the signal cannot be scrambled. It is totally legal to, for instance, have an HTTPS connection tunneled over an internet radio link, as long you could decode the radio message - it's not illegal for a message to carry an encrypted payload.

By the same token, steganography wouldn't be illegal either. This regulation isn't trying to stop you from sending secret messages, it's making it possible to introspect the messages to determine what protocol and call signs are involved. It's about managing the spectrum and figuring out who to complain to if there's interference, not about controlling cryptography.

FCC regulations say: "No amateur station shall transmit: [...] messages encoded for the purpose of obscuring their meaning".

https://www.law.cornell.edu/cfr/text/47/97.113

This isn't entirely unambiguous, and people can and do argue about how it applies to things like proprietary data protocols that aren't publicly documented. But I think it's clear that encryption, such as that used by HTTPS, is intended to be banned by this clause.

But you can obscure command and control signals to space based stations. You don't want people knowing how to reprogram or turn off your satellite.

47 CFR § 97.211 - Space telecommand station.

(b) A telecommand station may transmit special codes intended to obscure the meaning of telecommand messages to the station in space operation.

Can you post a citation for that? Everything I've heard indeed claims that any encryption is no go except for a narrow band of critical applications.

That's wrong. The prohibition is exactly on non-understandable meaning of messages, recognizable protocol and call signs is not enough.

It’s also part of why a lot of amateur radio-related sites still serve unencrypted HTTP, either optionally or exclusively.

(The other part of why is that there are an awful lot of valuable amateur radio sites that haven’t been updated in 15-20 years)

or are ran by people who can't be bothered to figure this new-fangled HTTPS stuff out

Or people who buy into the "nothing to hide" nonsense, influenced by a HAM culture of not encrypting things that emerged from the rule against it.

Steganography? Sure, but you might be better off using a code that sounds like normal speech.

There's a lot of weird stuff on radio. You don't need encryption to have codes. But this probably wouldn't be useful for sending surveillance information from a balloon. It would also draw a lot of attention.

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

(Buzzer) https://en.wikipedia.org/wiki/UVB-76

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

I would love to do this but have never considered it an option because of all the regulations I imagine exist. Could these interfere with an aircraft? What if you fly one over a military site? What about flying over other countries? The rules seem complex, but I’d love to build one.

It could interfere with an airplane but so can any bird. Should it be forbidden to release birds into the air?

There's a cost and benefit to everything. But I'm not exactly sure what is the benefit of these balloons except perhaps entertainment.

Leave it to Beaver I would say

Awesome!

I found this site which tracks current amateur radio balloons: https://habhub.org/

I really love all the random hobbies that people have

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