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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

#41

Post by CamperBob2 »

madrox wrote: post #34
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.

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.

Re: The soccer ball that survived the Challenger explosion

#42

Post by askvictor »

jedberg wrote: post #37
0xffff2 wrote: post #28

Earlier quoted context omitted.

Why do you think that? As the person you replied to said, the only reason the O-ring is there at all is to seal the joint between the sections. If the join't didn't exist, there would be no reason at all for there to be a rubber ring embedded in the structure.

Because that spot on the SRB is a flex joint to allow some movement of the nozzle as the engine fires. The joint isn't there because of transportation or other reasons.

I'm no rocket scientist either, but happened to be reading in depth about SRBs in general and Challenger in particular, and my understanding is: the joint in question was a field joint, to be assembled in the field, as opposed to factory joints which were assembled in the factory. The construction of these joints were different (asbestos insulation vs O-rings). The differing design is due to transportation and logistics.

Re: The soccer ball that survived the Challenger explosion

#43

Post by Rebelgecko »

erik_seaberg wrote: post #25
cortesoft wrote: post #22

Earlier quoted context omitted.

I mean, was the alternative to construct them on site? Is that what would have happened if not for the political pressure? It seems likely that they would have been manufactured SOMEWHERE requiring transport, no matter what.

Could have used a ship; that's how they delivered the larger Saturn V stages from New Orleans and Seal Beach to Cape Kennedy.

Would not be practical for a Vandenberg launch (which was a shuttle requirement that was never taken advantage of)

Re: The soccer ball that survived the Challenger explosion

#44

Post by jacobush »

erikpukinskis wrote: post #18
sidlls wrote: post #8

Earlier quoted context omitted.

Same here. I remember exactly where I was and what I was doing, the smells and sounds, and how my teacher rushed to turn off the television we were all watching the launch on once it was clear what was happening. Kids crying, not understanding what was happening, the feel and look of the carpet, wall decorations, everything. It's the most vivid memory of childhood I have. I don't think I'll ever forget it. I couldn't…

> how my teacher rushed to turn off the television we were all watching the launch on once it was clear what was happening It’s funny, this is what causes trauma... if you interrupt the stress reaction and try to make it go away, you hold onto it. If animals are allowed to go through their full stress cycle, they forget the trauma.

To be fair, they might have feared what more was about to come through that tv set. Or the impending wrath from parents when little Billy can't sleep at night. Was such concerns (parents) a thing in the 80s already?

Re: The soccer ball that survived the Challenger explosion

#45

Post by deelowe »

londons_explore wrote: post #40
T-hawk wrote: post #32

Earlier quoted context omitted.

One important piece of data to correlate with that: how many times previously had engineers issued similar warnings for launches that then proceeded fine? Warning fatigue is a thing and reasonable to wonder whether that happened at all here.

In some working environments issuing a warning is enough to get you off the hook for something going wrong, so it might be that nearly every flight had a warning so the engineers were never responsible...

Look up Bob Ebeling. He definitely knew it wouldn't survive.

Re: The soccer ball that survived the Challenger explosion

#46

Post by freeopinion »

londons_explore wrote: post #40
T-hawk wrote: post #32

Earlier quoted context omitted.

One important piece of data to correlate with that: how many times previously had engineers issued similar warnings for launches that then proceeded fine? Warning fatigue is a thing and reasonable to wonder whether that happened at all here.

In some working environments issuing a warning is enough to get you off the hook for something going wrong, so it might be that nearly every flight had a warning so the engineers were never responsible...

These were not throw away warnings. These were fervent efforts to stop the launch. This wasn't somebody trying to protect their job. This was somebody risking their job.

Re: The soccer ball that survived the Challenger explosion

#47

Post by InclinedPlane »

T-hawk wrote: post #32
mehrdadn wrote: post #26

Earlier quoted context omitted.

> 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.

One important piece of data to correlate with that: how many times previously had engineers issued similar warnings for launches that then proceeded fine? Warning fatigue is a thing and reasonable to wonder whether that happened at all here.

It was a specific warning about the vulnerability of the O-ring seals in low temperatures (precisely the mechanism of failure that doomed the Challenger). It was an unusual, specific, and high profile warning which was effectively overruled by NASA management. The guidance was to avoid launching in such low temperatures, the response was: "My God, Thiokol. When do you want me to launch? Next April?" That from Lawrence Mulloy at NASA MSFC. This is a pretty clearcut case and nothing like "warning fatigue".

Re: The soccer ball that survived the Challenger explosion

#48

Post by mncharity »

> 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. Perhaps Malinowski is just echoing old reporting. But a journalist of her caliber seems likely to have run this by NASA. Which suggests NASA PR is still prioritizing spin over integrity, even all these years later.

For those who haven't seen this line before, the template is " ". As in 'the explosion ripped apart the shuttle faster than the blink of an eye, killing the astronauts'. By such word-smithed sleigh-of-hand, NASA would leave readers with the impression that the crew was killed immediately, a quick non-lingering death, without flat-out lying.

One thing we're sure of is that some of the seven were not killed in the breakup at 11:39. I don't recall whether Onizuka's air pack was one of those found, and found to be manually activated. Nor whether there ended up being any evidence of cabin depressurization. But my understanding is that now, as then, there's no reason to believe that some of the seven didn't survive until cabin ocean impact minutes later.

> On the roof of the launch control tower, the families of the crew desperately searched the twin trails of smoke that twisted skyward for signs of the crew cabin.

:/ Perhaps it doesn't matter. It's not that different a story. And there's the "little white lies are fine" interpretation of integrity. Why shouldn't popular history get a prettified version? And given how NASA is funded, embracing integrity might be quite unhealthy. And yet... I'd have been happier if Malinowski wrote this paragraph a bit differently.

Re: The soccer ball that survived the Challenger explosion

#49

Post by Rebelgecko »

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.

I think that's an oversimplification of a complicated issue. It's certainly possible that the NASA administrator chose to go with Morton Thiokol to keep congressmen from Utah happy, but as far as I know there's no proof that there was any "deal", and there's plenty of technical reasons to go with a segmented design (although there's tradeoffs).

One of the bidders on the contract actually wanted to make a monolithic SRB, but that brings a new set of problems and limitations, especially at large sizes (you can look up the Aerojet 260" for some more info).

The shuttle SRBs were built in 7 segments, some of which were joined together at the factory. The multisegment design was based on the flight-proven Titan SRBs, which supposedly would help with R&D costs. However manufacturing constraints (if the SRB just used the Titan design and scaled it up, they'd need bigger hunks of metal than anyone was casting at the time) and design tweaks led to changes that degraded O-Ring performance and potentially kept both primary and secondary O-rings from being properly seated. There was really a whole confluence of things that went wrong, and a lot of missed opportunities to fix any one of the issues that led to O-ring failure.

Plenty of people still use segmented SRBs today, especially for their modularity. The (first version) of the SLS boosters are based on the shuttle design, with extra segments stuck added on.

Re: The soccer ball that survived the Challenger explosion

#50

Post by nashashmi »

InclinedPlane wrote: post #47
T-hawk wrote: post #32

Earlier quoted context omitted.

One important piece of data to correlate with that: how many times previously had engineers issued similar warnings for launches that then proceeded fine? Warning fatigue is a thing and reasonable to wonder whether that happened at all here.

It was a specific warning about the vulnerability of the O-ring seals in low temperatures (precisely the mechanism of failure that doomed the Challenger). It was an unusual, specific, and high profile warning which was effectively overruled by NASA management. The guidance was to avoid launching in such low temperatures, the response was: "My God, Thiokol. When do you want me to launch? Next April?" That from Lawrenc…

Maybe it wasn't warning fatigue then. It might be overthinking fatigue. I guess missions have gotten delayed before for so many reasons and this time they just got tired of "doing it again."
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