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When a rocket launch fails, typically launches for that rocket type are halted while an investigation takes place to identify and correct the root cause of the failure. However, it is possible that the cause of the failure couldn't be conclusively identified, or that it was misidentified through misleading data.

This has happened before in aviation, most notably the De Havilland Comet which was brought back into service following an initial investigation in early 1954, only for a subsequent crash to finally ground the fleet until the true root cause of fatigue cracking was definitively identified.

Has something similar ever happened in the field of rocketry, where an incomplete or inaccurate investigation has led to further flights and failures of a launch vehicle?

kgutwin
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    The Soviet N1 moon rocket with its four consecutive launch failures is a likely candidate. – dan04 Apr 28 '23 at 16:31
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    @dan04, each of the four failures of the N1 was from a different cause (although there's a fair chance that the cause of failure #2 was mis-identified). – Mark Apr 28 '23 at 18:45
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    I'm thinking primarily of cases where the failure cause was missed in the first investigation; not necessarily cases where a rocket under development has multiple intersecting failures. I'm not sure whether the N1 counts under that criteria or not... – kgutwin Apr 28 '23 at 19:07
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    I wonder if a newer aviation example might be the Boeing Co. 737 Max 8 repeated crashes? – uhoh Apr 28 '23 at 23:39
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    @uhoh: The cause was not mis-identified. In fact, on the first airplane that crashed, the same thing had happened the day before, and was correctly identified and averted by the flight crew. The second crash happened before the investigation of the first was finished, so the identification of the cause cannot possibly have influenced it. In both cases, the cause was correctly identified as a malfunctioning MCAS system due to faulty sensor data (due to a lack of redundancy) which was not correctly understood by the flight crew due to insufficient training guidance by Boeing. – Jörg W Mittag Apr 29 '23 at 17:27
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    The ultimate root cause was that Boeing had underestimated the effect a malfunctioning MCAS system could have and thus designed it without sensor redundancy, thinking that it was merely a "convenience" system but not safety-critical. The FAA, in turn, did not spot this due to the fact that owing to a long and – until then very successful – history of cooperation, they essentially allowed Boeing to perform their own safety certification testing, merely reviewing Boeing's procudures but not the actual results. – Jörg W Mittag Apr 29 '23 at 17:29
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    @JörgWMittag That's a very Boeing friendly version of the story. Afaik, management had downplayed the importance of MCAS to avoid full recertification of the aircraft, and consequently requiring pilots to obtain special license for being allowed to fly it. The entire story bears all the signs of systematic management failure due to political goals getting more important than safety considerations. Quite comparable to the cause for the Challenger disaster and the VW "defeat device" invention, imho, (though the VW case was "just" pollution, not safety, it was the most plain criminal). – cmaster - reinstate monica Apr 29 '23 at 23:01
  • Perhaps the Challenger disaster would not count on your strict criteria as the events causing the disaster had previously been seen but the impact had been vastly understated, which is only a little like misidentifying it. – matt_black Apr 30 '23 at 22:16
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    @matt_black The specification said that safety was not guaranteed, and that launch should not happen at the given temperatures. However, there was also a lot of political pressure to proceed with the launch. So, the higher up managers basically talked the lower level guys into saying ok against their own best knowledge because no one said "only over my dead body". Which is quite typical with those safety thresholds where you don't go from all-good to certain failure. No one knew at which temperature failure would actually occur, only that it would occur at too low temperatures. – cmaster - reinstate monica Apr 30 '23 at 23:18
  • @JörgWMittag: I'd say that the root cause of the 737 MAX crashes was that airlines were simultaneously demanding (1) a modernized plane with higher fuel efficiency and longer range, and (2) that the new plane model still be "a 737" so they wouldn't have to retrain all their 737 pilots and mechanics. Problem is, the 737 just wasn't designed to accommodate the physically larger engines that were needed, so the engineers had to pile on a bunch of hacks to deal with the changed aerodynamics and handling. And MCAS was the hackiest part. – dan04 May 01 '23 at 15:44

2 Answers2

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The root cause of External Tank foam shedding, which initiated the chain of events leading to the destruction of the Columbia orbiter on re-entry during the STS-107 mission, was initially mis-identified as "defects in the application of the foam insulation".

We informed the foam technicians at our plant in Michoud Louisiana that they were the cause of the loss of Columbia and then worked them overtime in training with new and exhaustive techniques on how to apply foam with no defects.

(Wayne Hale, How We Nearly Lost Discovery)

The next launch, a massive chunk of foam was shed, fortunately not destroying the vehicle and killing the crew this time.

Another long investigation and stand-down followed. Which resulted in:

It turns out that the thermal cycles associated with filling the tank could crack the foam, especially in areas where there were two or more layers of foam....Finally, this explained the Columbia foam loss. And the Discovery foam loss. And it had nothing to do with the improper installation of the foam.

Organic Marble
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    "We informed the foam technicians at our plant in Michoud Louisiana that they were the cause of the loss of Columbia and then worked them overtime" - this is downright dystopian when taken in context with the rest of the answer! Imagine your boss comes to you and says "You personally murdered 7 people, so we're going to need you to work 80 hours a week from now on." and then it turns out it wasn't actually your fault. – user253751 May 03 '23 at 03:01
  • @user253751 Yeah, I agree. Mr. Hale says in the article that he personally went and apologized to them, but still. – Organic Marble May 03 '23 at 03:40
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The Taurus XL launches of the Orbiting Carbon Observatory and the Glory satellites in 2009 and 2011 both failed due to fairing separation problems. Orbital spent two years after the OCO launch working on what they believed to be a fix for the issue, only to have the problem recur on the very next flight.

I don't think it's been publicly disclosed what the exact fixes they attempted were, but the actual problem turned out to be defective extruded aluminum components from Sapa Profiles, Inc that had had their test results falsified.

Christopher James Huff
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    Man, the US industrial-military complex sure is a sweet gig. SPI's falsifications went on for nearly 2 decades, caused a loss to the government of over $700 million on the aforementioned satellites alone (ignoring all of the other contracts that SPI won during that period), yet all that the company had to do to "make it right" was pay a measly $46 million fine. – Ian Kemp Apr 30 '23 at 22:44
  • @IanKemp not to mention all the engineering resources spent on trying to figure out why the fairing separation failed. – Christopher James Huff May 02 '23 at 03:06