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Artemis II is not safe to fly

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Re: Artemis II is not safe to fly

#261

Post by inaros »

Mikhail_K wrote: post #205
oritron wrote: post #25

I haven't kept up with Artemis development but I've read extensively about Challenger and Columbia. These two parts of the article stood out to me: > Moon-to-Mars Deputy Administrator Amit Kshatriya said: “it was very small localized areas. Interestingly, it would be much easier for us to analyze if we had larger chunks and it was more defined”. A Lockheed Martin representative on the same call added that "there was…

> Challenger: no gasses were supposed to make it past the o-rings no matter what, > but when it became clear that gasses were escaping and the o-rings were being > damaged, there was a push to suggest that it's an acceptable level. Interestingly, the article https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz... > by heat shield expert and Shuttle astronaut Charles Camarda, the former Director of Engineering…

>>I find that highly surprising, because "it was the O-rings" explanation seems universally believed and sanctified by no lesser authority than the Nobel prize laureate Richard Feynman.

Essentially you are mischaracterizing what Feynman did or say, although this is also Feynman fault :-), by doing the famous public demonstration, with the ice water in a glass [2], although even there he only said it has "significance to the problem...". In other words, we should not simplify, even for the general public, what are complex subtle engineering issues. This is also the reason why current AI, will fail spectacularly, but I digress...

Feynman documented the joint rotation problem in his written Appendix F, but his televised demonstration became the explanation...[3]

Camarda is correct here. There was a fundamentally flawed field joint design, meaning the tang-and-clevis joint opened under combustion pressure instead of closing. This meant the O-rings were being asked to chase a widening gap something the O-ring manufacturer explicitly told Thiokol O-rings were never designed to do. Joint rotation was known as early as 1977, a full nine years before the disaster.

The cold temperature made things worse by stiffening the rubber so it could not chase the gap as quickly, but O-ring erosion and blow-by were occurring on flights in warm weather too and nearly every flight in 1985 showed damage.

The proof is how they fixed. NASA redesigned the joint metal structure with a capture feature to prevent rotation, added a third O-ring for redundancy, and installed heaters but kept the exact same Viton rubber. If the O-rings were the real problem, you would change the O-rings. They did not need to.

The report [1] is public for everybody to read...but not from the NASA page... who funnily enough has a block on the link from their own page, so I had to find an alternative link...

[1] - https://www.govinfo.gov/content/pkg/GPO-CRPT-99hrpt1016/pdf/...

[2] - https://youtu.be/6TInWPDJhjU

[3] - https://calteches.library.caltech.edu/3570/1/Feynman.pdf

Re: Artemis II is not safe to fly

#262

Post by VoodooJuJu »

oulu2006 wrote: post #47
delichon wrote: post #22

I am very not brave but I'd volunteer. The trip is far more awesome than anything I have planned for the rest of my life. And if the shield fails on reentry it would only hurt for a few seconds. So if the crew and the backups and their backups read this and have second thoughts, ping me.

This is an interesting comment -- your life is precious brother, you might have something in store down the road :)

[dead]

Re: Artemis II is not safe to fly

#263

Post by inaros »

voidUpdate wrote: post #210
Mikhail_K wrote: post #205

Earlier quoted context omitted.

> Challenger: no gasses were supposed to make it past the o-rings no matter what, > but when it became clear that gasses were escaping and the o-rings were being > damaged, there was a push to suggest that it's an acceptable level. Interestingly, the article https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz... > by heat shield expert and Shuttle astronaut Charles Camarda, the former Director of Engineering…

Using the same o-rings afterwards is surprising, I've heard that the manufacturer was surprised that they were being used for that purpose because they weren't rated for that. Also I'm not sure the assertion is correct. If the sealant and O-Rings were adequate, the joint would not have failed. It was suboptimal, and increased risk, sure, but it in itself wasn't the reason for the accident. It was the joint and the o-…

>> Using the same o-rings afterwards is surprising, I've heard that the manufacturer was surprised that they were being used for that purpose because they weren't rated for that.

Not surprising if you understand what the real cause was: https://news.ycombinator.com/item?id=47585889

Re: Artemis II is not safe to fly

#264

Post by phantom784 »

bertylicious wrote: post #79
delichon wrote: post #22

I am very not brave but I'd volunteer. The trip is far more awesome than anything I have planned for the rest of my life. And if the shield fails on reentry it would only hurt for a few seconds. So if the crew and the backups and their backups read this and have second thoughts, ping me.

I'm sure the other astronauts are really looking forward to fly with a person showing signs of suicidal ideation.

I read this as "accepting a risk of death in exchange for getting to have the incredible experience of flying to the Moon", not that they want to die.

Re: Artemis II is not safe to fly

#265

Post by eru »

goodcanadian wrote: post #200
eru wrote: post #175

Earlier quoted context omitted.

NASA does both manned and unmanned stuff. Don't conflate those when you are looking at returns. Look at this joke of a list https://www.nasa.gov/missions/station/20-breakthroughs-from-... for an illustration. And those were the 20 best things they could come up with.

There are actually a lot of really interesting discoveries on that list. I haven't thought deeply about whether it represents value for money, but I would say that that is anything but "a joke of a list."

And 'Stimulating the low-Earth orbit economy' is a joke. Spending money not as a means to an end, but as the end in itself?

Apart from the research into the effects of microgravity on humans, pretty much everything else could have been done cheaper and better without humans.

Or take this example:

> Deployment of CubeSats from station: CubeSats are one of the smallest types of satellites and provide a cheaper way to perform science and technology demonstrations in space. More than 250 CubeSats have now been deployed from the space station, jumpstarting research and satellite companies.

Cubesats are great! But you don't exactly need a manned space station to deploy them. Similar with many other 'achievements' like the 'Alpha Magnetic Spectrometer'.

See also how they don't mention any actual impact. Only stuff like "This achievement may provide insight into fundamental laws of quantum mechanics."

And this is supposed to be the list of highlights. The best they have to offer.

Re: Artemis II is not safe to fly

#266

Post by eru »

TheOtherHobbes wrote: post #213
eru wrote: post #106

Earlier quoted context omitted.

Have you heard of opportunity costs? About war: in our universe we got the first digital computers because of military efforts during the second world war. However, without a war IBM and Konrad Zuse and others would have gotten there, too. With much less human suffering.

It's unlikely computing would have developed as quickly as it did without the Cold War. IBM's Sage and MIT's TX0 were both Cold War projects - one for a national early warning system, the other as an R&D platform for flight simulators. Most US investment in associated tech - including the Internet - came through DARPA. Not pointing this out because I support war, but to underline that the US doesn't have a culture of…

Why does it have to be government R&D?

Re: Artemis II is not safe to fly

#267

Post by eru »

gmerc wrote: post #184
eru wrote: post #106

Earlier quoted context omitted.

Have you heard of opportunity costs? About war: in our universe we got the first digital computers because of military efforts during the second world war. However, without a war IBM and Konrad Zuse and others would have gotten there, too. With much less human suffering.

Now do the opportunity cost of AI model virtue signalling to investors for several years

As long as they mostly spend VC money, who am I to judge? It's no worse than rich people buying yachts.

Just don't spend tax payer money.

Re: Artemis II is not safe to fly

#268

Post by Havoc »

bertylicious wrote: post #79
delichon wrote: post #22

I am very not brave but I'd volunteer. The trip is far more awesome than anything I have planned for the rest of my life. And if the shield fails on reentry it would only hurt for a few seconds. So if the crew and the backups and their backups read this and have second thoughts, ping me.

I'm sure the other astronauts are really looking forward to fly with a person showing signs of suicidal ideation.

Suicide ideation and someone willing to take massive risks for something awesome are very different things

Re: Artemis II is not safe to fly

#269

Post by cmsefton »

GMoromisato wrote: post #77

This is a more balanced take, in my opinion: https://arstechnica.com/space/2026/01/nasa-chief-reviews-ori... Camarda is an outlier. The engineers at NASA believe it is safe. The astronauts believe it is safe. Former astronaut Danny Olivas was initially skeptical of the heat shield but came around. And note that the OP believes it is likely (maybe very likely) that the heat shield will work fine. It's hard for me to r…

Minor nitpick: OP didn't say "maybe very likely". He said "hopefully very likely". They are, in my mind, different things.

Re: Artemis II is not safe to fly

#270

Post by pfdietz »

rob74 wrote: post #223
Mikhail_K wrote: post #205

Earlier quoted context omitted.

> Challenger: no gasses were supposed to make it past the o-rings no matter what, > but when it became clear that gasses were escaping and the o-rings were being > damaged, there was a push to suggest that it's an acceptable level. Interestingly, the article https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz... > by heat shield expert and Shuttle astronaut Charles Camarda, the former Director of Engineering…

Without being too familiar with the subject - another commenter referred to the "swiss cheese model": the O-ring design, the temperature etc. weren't the single cause, they were contributing factors , and the more contributing factors you eliminate, the more certain you can be that you won't have a repeat accident. AFAIK there weren't any more Shuttle launches at such low temperatures after that anymore either?

That's right, the accident launch was by far the coldest. They also added joint heaters.
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