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NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

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Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#71

Post by Nextgrid »

desert_rue wrote: post #64
bambax wrote: post #49

Earlier quoted context omitted.

Cameron did several TV interviews about the Titan, why would they redact his name? He didn't mince his words either; he was extremely critical of the whole thing before and after the disaster.

Maybe it is policy. If you have three experts in the field and you redact the details for two of the interviews taken, you can’t work it out that Bob was one of the two. Granted, they borked the redaction here.

Same policy that "redacted" the brand of the SD card, even though anyone that would be able to do anything with that information would immediately recognize it as a SanDisk.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#72

Post by franktankbank »

bambax wrote: post #48
cloudbonsai wrote: post #22

Earlier quoted context omitted.

Among the interviews, one with the former engineering director was the most eye-opening for me. https://data.ntsb.gov/Docket/Document/docBLOB?ID=17236880&Fi... It appears that all the engineers -- system designer, material engineer and structural analyst -- thought that OceanGate CEO was going to kill himself: If you ever find , he’s not going to have a whole lot of nice to say. He was very frustrated with the compan…

The number of stupid decisions that went in the design and construction of the Titan is astonishing. One of my favorites was that, after putting on the carbon fiber around the tube, they would sand imperfections to make the surface perfectly smooth, severing layers in the process! It shouldn't require an engineering degree from MIT to recognize this as ill-advised.

I don't like this interpretation of things. Its worthwhile to experiment and try things. They were basically mentally ill as a group and rejected genuine concern. Everyone wants to shit on the build but it was the human relations that killed it.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#73

Post by Nextgrid »

kasabali wrote: post #61
londons_explore wrote: post #58

Earlier quoted context omitted.

The hardware is still there - they don't make a new asic for the consumer version

doesn't mean it's active.

"Active" with those systems just means the encryption key is now user-supplied instead of being stored on the controller/drive. The actual encryption is always active; which makes sense, if anything it means you have one less configuration to test.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#74

Post by dh2022 »

jiggawatts wrote: post #15
userbinator wrote: post #12

Earlier quoted context omitted.

They thought the camera’s file system was unencrypted, when it was encrypted. Unfortunately this situation is likely to get more common in the future as the "security" crowd keep pushing for encryption-by-default with no regard to whether the user wants or is even aware of it. Encryption is always a tradeoff; it trades the possibility of unauthorised access with the possibility of even the owner losing access permane…

This is why I always shake my head when the Reddit armchair security experts say "The data wasn't even encrypted!? Amateur hour!" in response to some PII leak. Sure, sure buddy, I'll encrypt all of my PII data so nobody can access it... including the web application server. Okay, fine, I'll decrypt it on the fly with a key in some API server... now the web server had unencrypted access to it, which sounds bad, but th…

Re: encrypting data that would be served via web server: why would anyone bother to encrypt data meant to be shared externally worldwide? It makes no sense to begin with…

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#75

Post by analog31 »

daemonologist wrote: post #8
rozab wrote: post #7

What's with the entire dev board crammed in there? Is that... normal? What board is it?

It appears to be a Teensy 3.2 The "carrier" that everything rides on within the housing is clearly FDM printed as well. I assume these cameras (rated to 6,000 meters) are rather low volume products.

I came here to say "that's definitely a Teensy 3.2"

The black cable goes dangerously close to the pushbutton of death. ;-)

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#76

Post by switknee »

quamserena wrote: post #20
rozab wrote: post #7

What's with the entire dev board crammed in there? Is that... normal? What board is it?

I have seen engineers slap Teensies on a PCB and call it a day, so it’s definitely normal. It’s faster than having to route your MCU, USB, debugger, etc. manually, so there isn’t really a drawback as long as it physically fits there.

Yup, if it works in your testing, why bother changing it?

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#77

Post by owenversteeg »

lazide wrote: post #51
bambax wrote: post #48

Earlier quoted context omitted.

The number of stupid decisions that went in the design and construction of the Titan is astonishing. One of my favorites was that, after putting on the carbon fiber around the tube, they would sand imperfections to make the surface perfectly smooth, severing layers in the process! It shouldn't require an engineering degree from MIT to recognize this as ill-advised.

Even without that, the material is just wrong. It’s strong in tension, not so much compression. Tends towards sudden brittle fractures. Doesn’t like impacts, as it tends to have issues with delaminating. It’s just not what you ever want as a sub hull. It’s dumb. And weight is not even a huge issue for a sub!

“Strong in tension, not compression” is a meme, and obviously wrong. It is certainly stronger in tension, but it is also remarkably strong in compression. That’s why it’s used - yes, in compression - in modern passenger aircraft. You don’t even need to know that, though; the simple fact is that the Titan had a double-digit number of deep dives. If it was weak in compression it would not have survived diving to 3.7 kilometers deep or even a fraction of that depth _once_.

That said, yes, it’s a difficult material to use properly, and they were a bunch of cowboys slapping things together. It’s no surprise that they missed several critical steps and created a sub doomed to fail.

N.b. all of this was kickstarted by James Cameron saying that carbon fiber has “no strength in compression” in a New York Times “science” article, which the Times printed directly.

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#78

Post by lazide »

owenversteeg wrote: post #77
lazide wrote: post #51

Earlier quoted context omitted.

Even without that, the material is just wrong. It’s strong in tension, not so much compression. Tends towards sudden brittle fractures. Doesn’t like impacts, as it tends to have issues with delaminating. It’s just not what you ever want as a sub hull. It’s dumb. And weight is not even a huge issue for a sub!

“Strong in tension, not compression” is a meme, and obviously wrong. It is certainly stronger in tension, but it is also remarkably strong in compression. That’s why it’s used - yes, in compression - in modern passenger aircraft. You don’t even need to know that, though; the simple fact is that the Titan had a double-digit number of deep dives. If it was weak in compression it would not have survived diving to 3.7 ki…

Aircraft fuselages are typically loaded in tension. It’s a key part of the design.

Carbon fiber compressive strength is only ~ 30-50% of it’s tensile strength because of the way the fibers and the epoxy interact. When compressed, the carbon fibers don’t do as much. [https://www.sciencedirect.com/science/article/abs/pii/S02638...]

But don’t believe me, actually read a useful paper on the subject.

In fact, it’s a major factor limiting it’s wider use. As is it’s fatigue behavior, which would probably also explain why it eventually imploded!

I never followed James Cameron’s interview, but it sounds like he knows what he is talking about!

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#79

Post by gosub100 »

JCM9 wrote: post #39

Amusing that the bits the “manufacturer asked to be redacted” in the images appear to be the identifiers for common off-the-shelf electronic components, including a standard memory card. Is that really super secret IP?

could be a PR / brand identity management thing. They dont want their slogan to be come "The official Storage Medium of Deadly Disasters".

Re: NTSB report: Decryption of images from the Titan submersible camera [pdf] (2024)

#80

Post by buildbot »

lazide wrote: post #78
owenversteeg wrote: post #77

Earlier quoted context omitted.

“Strong in tension, not compression” is a meme, and obviously wrong. It is certainly stronger in tension, but it is also remarkably strong in compression. That’s why it’s used - yes, in compression - in modern passenger aircraft. You don’t even need to know that, though; the simple fact is that the Titan had a double-digit number of deep dives. If it was weak in compression it would not have survived diving to 3.7 ki…

Aircraft fuselages are typically loaded in tension. It’s a key part of the design. Carbon fiber compressive strength is only ~ 30-50% of it’s tensile strength because of the way the fibers and the epoxy interact. When compressed, the carbon fibers don’t do as much. [ https://www.sciencedirect.com/science/article/abs/pii/S02638... ] But don’t believe me, actually read a useful paper on the subject. In fact, it’s a maj…

Speaking of which I heavily recommend reading interview the prime ancestor comment to this chain linked. It’s really clear he knows what he is talking about.
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