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The soccer ball that survived the Challenger explosion

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Re: The soccer ball that survived the Challenger explosion

#71

Post by mncharity »

ddoolin wrote: post #61
mncharity wrote: post #48

> The failure allowed heated, pressurized propellants to leak out onto the external fuel tank, causing catastrophic structural failure. Seventy-three seconds into its 10th flight, the space shuttle Challenger broke apart, killing all seven members of its crew. It was 11:39 a.m. Sigh. It's perhaps silly of me in an age of Bush, Obama, and Trump, but I'm saddened to see this line repeated yet again, 30 years on. Perhap…

Or, given the overall tone of the piece, she didn't feel it necessary to go into those details. I'm sure there are plenty of other details that also went glossed over. Your own tone implies they're lying for a possibly nefarious reason -- what is it? If I'm right, it might be more accurate to point out how she failed to mention the engineer's warnings to NASA and other supervisors about the high risk of failure of th…

> your own tone implies they're lying for a possibly nefarious reason

Nefarious? Flagrantly wicked, abominable, impious? No, just PR spin - long-term repeated misrepresentation. Unremarkable in politics. Much less accepted in engineering. The question of "to what standards should NASA PR be held?", is indeed a root issue. For NTSB, it would be shocking. For DHS, unsurprising. NASA struggles to survive in a niche much more like DHS than NTSB. But the question repeatedly asked over the years, both within and without, is whether NASA PR weighs political concerns too heavily - to a degree sometimes simply unnecessary - and engineering/science-style honesty too lightly.

> she didn't feel it necessary to go into those details

My focus is not on the piece in isolation. Though one might object to the piece in isolation reinforcing a widespread misconception. But my sadness stemmed from context. From yet again seeing the same, not "trope"... "spin"? - descriptive devices that have repeatedly been used to mislead people.

"Seventy-three seconds [...] broke apart, killing all seven members of its crew. It was 11:39 a.m." Other versions have had timestamps down to hundredths of a second, as if that somehow mattered. Comments like 'too fast for even the computers to notice', or 'if you blinked, you'd have missed it'. Crew deaths from ocean impact have little more connection with T+74 disassembly, than with T+58 plume. Crew experience has little connection with computer and ground observer experience. But NASA PR repeatedly used these same tricks of phrasing to establish and reinforce a misconception. I was just sad to see them yet again, so many years later.

> failed to mention the engineer's warnings

My focus isn't on what is absent, but on what is present - this familiar structure of misdirection.

> as some degree of respect to the families

It's been thirty years. Is the cost-benefit tradeoff really still in favor of continuing to use this same misleading description?

But here's a more upbeat interpretation: Perhaps the author simply modeled the paragraph on one decades old - it is "pretty" - and didn't run it by anyone. So maybe we're just seeing an unfortunate blast from the NASA PR past, rather than anything contemporary.

Re: The soccer ball that survived the Challenger explosion

#72

Post by Rebelgecko »

CamperBob2 wrote: post #41
madrox wrote: post #34

Earlier quoted context omitted.

The post hoc ergo propter hoc going on in this comment and its responses are wild. The O-ring failed because it was a bad O-ring, and no one in positions that matters appreciated it was a bad O-ring. Politicizing it into a witch hunt to make congress look bad doesn't do anyone favors. It just feeds existing rage.

Didn't the O-ring fail because it was used outside its specifications? My recollection is a bit hazy but it seems that it was more of a political problem than an engineering problem.

To slightly oversimplify, it wasn't beyond spec, the spec for the part just wasn't really defined. The conversation the night before launch went something like this:

Contractor: "We don't want to launch, we're worried about how the cold will affect the O-ring"

NASA: "Do you have any data showing that the O-rings will fail at 50°F?"

Contractor: "No, but we don't have any data showing that they won't fail at 50°F"

NASA: "We launched when it was cold before and nothing went wrong" (The coldest launch before Challenger was successful, although both of the SRBs had badly charred O-rings)

Contractor: "Once, and there is circumstantial evidence that the O-rings had issues on that launch. (managers kicks engineers out of the room). We're not telling you not to launch."

That said, the hardness of the O-rings wasn't the only issue (at least, by itself it may not have caused the Challenger to explode). There was some putty around the O-rings that had problems. It was known to let water in, and the night before the launch it rained and was cold enough that the water that got in next to the O-rings could've frozen and kept them from maintaining their seal. There were primary and secondary O-rings, but the secondary O-rings didn't really give good redundancy.

Re: The soccer ball that survived the Challenger explosion

#73

Post by caseysoftware »

giodamelio wrote: post #38
jedberg wrote: post #6

> You may not know it, but you carry some of his words with you in your own earthly exploration, printed in every U.S. passport. This whole article was fantastic, but this was the coolest part for me. To learn that his quote is on every passport. I've never read the quotes on my passport before, but now I have.

Exactly. That was a chills down the the spine moment. I will definitely be taking a closer look at the quotes in my passport when I get home today.

I just went and grabbed mine to check. It's there. That's badass.

Re: The soccer ball that survived the Challenger explosion

#74

Post by TheOtherHobbes »

Gibbon1 wrote: post #70
InclinedPlane wrote: post #55

Earlier quoted context omitted.

This is a well studied problem, it wasn't overthinking, it was "go fever", specifically in the form of "Normalization of Deviance" [1]. Morton-Thiokol and NASA set criteria for safety margins on the Shuttle system. And the Shuttle kept on violating those safety margins again and again. Instead of grounding the fleet or studying the problem further or attempting to ameliorate the problem the safety margins were loosen…

> that a Shuttle loss was a 1 in 100,000 probability I'm not sure how anyone could say that with a straight face. Serious events happen with commercial aircraft at a rate of about 1 in 1M. Figure that a rocket is inherently 100X more dangerous. And that the lack of repetitive experience with rockets bumps the risk another 1:100. Meaning you build a lot of aircraft and fly them all the time you get good at knowing whe…

A much more rigorous analysis was done for the Shuttle program, and the estimate of the risk of vehicle loss turned out to be very close to reality.

There was some coverage of the relatively high risk values in the popular science press well before Challenger happened.

Re: The soccer ball that survived the Challenger explosion

#75

Post by TeMPOraL »

greglindahl wrote: post #35
runciblespoon wrote: post #7

"the solid rocket boosters ignited and somewhere in the right booster, a 0.280-inch-wide O-ring failed due to the cold." The 'solid rocket boosters' being constructed in segments because they had to be transported by rail from Utah. They had to be constructed in that state as part of the deal to get the politicians to vote in the finances.

Segmented SRBs are used on Ariane 5 and Northrop Grumman's upcoming Omega rocket, while Vega, Vega-C, and Ariane 6 will use a single-segment SRB. It's a choice that was dictated by politics for the Shuttle, but it's also a choice that can be made for other reasons, like a smaller composite segment using a cheaper tool (Omega and the Boeing 787 fuselage tube).

In general, "need to be segmented for transport" is not necessarily a political thing. Russians have the Proton rocket which looks as if it had boosters bolted to it, where in fact those are parts of the first stage. I heard recently that the reason for this design is precisely because if those side parts were internal, the rocket wouldn't fit on a railcar.

Re: The soccer ball that survived the Challenger explosion

#76

Post by mirimir »

mncharity wrote: post #48

> The failure allowed heated, pressurized propellants to leak out onto the external fuel tank, causing catastrophic structural failure. Seventy-three seconds into its 10th flight, the space shuttle Challenger broke apart, killing all seven members of its crew. It was 11:39 a.m. Sigh. It's perhaps silly of me in an age of Bush, Obama, and Trump, but I'm saddened to see this line repeated yet again, 30 years on. Perhap…

See retrogradeorbit's post (likely below) linking to a report about the crew's fate: http://www.space-shuttle.com/challenger1.htm

Re: The soccer ball that survived the Challenger explosion

#77

Post by RyJones »

joering2 wrote: post #67
ridgeguy wrote: post #59

On Challenger's last day, I had met very early that morning with a couple of angel investors who signed a funding commitment for my first company. Went home, watched Challenger explode. An hour later, angel investors called to say "never mind". Watching Challenger blow up hurt worse. Especially in following months when failure analysis showed it could have been avoided by launching within the allowable temperature wi…

They probably did you a favor by not being forced to deal with them down the road. Unless you were as an engineer directly on Challenger O-Rings, I don't see any reason why anyone would cancel their financial commitment toward a startup project, because of this obvious tragedy.

I suspect the timing was a coincidence.

Re: The soccer ball that survived the Challenger explosion

#80

Post by CloudNetworking »

mehrdadn wrote: post #26
rmason wrote: post #23

I was visiting farmers reviewing plans for the next crop year. I'd just arrived and the farmer says do you mind if we watch the Challenger launch before starting? It's got that teacher going up in space. I told him that my high school government teacher had been one of the ten finalists so I took a pretty keen interest myself. I can remember the numbness I felt in his living room as we watched the Challenger explode.…

> The night before the launch, Ebeling and four other engineers had tried to stop the launch. Their managers and NASA overruled them. That night, he told his wife, "It's going to blow up." This sent chills down my spine... the world just shouldn't be like this.

It's amazing how I've never heard of this story before and how much I've heard about Gagarin's friend knowingly dying to save Gagarin's life...
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