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AMOS 6 - Falcon 9-029 - Канаверал SLC-40 - 3-4 сентября 2016, (взрыв на старте)

January 2, 2017, 9:00am EST
Over the past four months, officials at the Federal Aviation Administration (FAA), the U.S. Air Force (USAF), the National Aeronautics and Space Administration (NASA), the National Transportation Safety Board (NTSB), along with several industry experts, have collaborated with SpaceX on a rigorous investigation to determine the cause of the anomaly that occurred September 1 at Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station in Florida. This investigation team was established according to SpaceX's accident investigation plan as approved by the FAA. As the primary federal licensing body, the FAA provided oversight and coordination for the investigation.
Investigators scoured more than 3,000 channels of video and telemetry data covering a very brief timeline of events – there were just 93 milliseconds from the first sign of anomalous data to the loss of the second stage, followed by loss of the vehicle. Because the failure occurred on the ground, investigators were also able to review umbilical data, ground-based video, and physical debris. To validate investigation analysis and findings, SpaceX conducted a wide range of tests at its facilities in Hawthorne, California and McGregor, Texas.
The accident investigation team worked systematically through an extensive fault tree analysis and concluded that one of the three composite overwrapped pressure vessels (COPVs) inside the second stage liquid oxygen (LOX) tank failed. Specifically, the investigation team concluded the failure was likely due to the accumulation of oxygen between the COPV liner and overwrap in a void or a buckle in the liner, leading to ignition and the subsequent failure of the COPV.
Each stage of Falcon 9 uses COPVs to store cold helium which is used to maintain tank pressure, and each COPV consists of an aluminum inner liner with a carbon overwrap. The recovered COPVs showed buckles in their liners. Although buckles were not shown to burst a COPV on their own, investigators concluded that super chilled LOX can pool in these buckles under the overwrap. When pressurized, oxygen pooled in this buckle can become trapped; in turn, breaking fibers or friction can ignite the oxygen in the overwrap, causing the COPV to fail. In addition, investigators determined that the loading temperature of the helium was cold enough to create solid oxygen (SOX), which exacerbates the possibility of oxygen becoming trapped as well as the likelihood of friction ignition.
The investigation team identified several credible causes for the COPV failure, all of which involve accumulation of super chilled LOX or SOX in buckles under the overwrap. The corrective actions address all credible causes and focus on changes which avoid the conditions that led to these credible causes. In the short term, this entails changing the COPV configuration to allow warmer temperature helium to be loaded, as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads. In the long term, SpaceX will implement design changes to the COPVs to prevent buckles altogether, which will allow for faster loading operations.​
SpaceX is targeting return to flight from Vandenberg's Space Launch Complex 4E (SLC-4E) with the Iridium NEXT launch on January 8. SpaceX greatly appreciates the support of our customers and partners throughout this process, and we look forward to fulfilling our manifest in 2017 and beyond.
Гугл переводчик.
Просто красивая фраза:
Поскольку авария произошла на земле, исследователи также смогли проанализировать данные пуповины, наземное видео и физического мусора.
Но в виде обломков различных ракет
Останутся наши следы!
В последнем апдейте по-прежнему говорится про возгорание. Не пойму, таки взорвался карбон в кислороде или нет?   :oops:

Взрыв, который мы видели - это взрыв карбона, или карбон лишь повредил баллон и дальше всё развивалось из-за избытка давления гелия?
Изменено: Georgea - 08.01.2017 17:00:26

We know SpaceX have returned to using four COPVs. Does anyone recall when they first moved to three?


I found from webcast video that three COPVs were first at F9-016 with ABS-3A/Eutelsat 115 West B. Previous flights had four vessels.
Изменено: Зловредный - 10.01.2017 19:34:32
Ну вот скорее всего  - изменение конфигурации COPV - это они на оставшихся "ТРЕХ-баллонных COPV" ракетах будут аккуратней заправку проводить, более теплым гелием и медленнее чем 1-го сентября,
А изменение конструкции COPV - это на вновь изготовляемых ракетах 4-й COPV вернут взад.

Вот и весь расклад, имхо
Главное не наличие проблем, главное способность их решать.
У каждой ошибки есть Имя и Фамилия
"Были когда-то и мы рысаками!!!"
Salo пишет:
Lindy told me she thought the explanation was credible—it doesn't take much to start a catastrophic conflagration in a liquid oxygen environment.
Стр 167
Штуцер пишет:
SpaceX Falcon 9 считает сбой был вызван, когда композит над обернутой сосуда высокого давления (COPv или гелия бутылка) "отпустить" в жидкий кислород (LOX) бак;
Надо ли полагать, что рабочего давления гелия в COPv еще не было?
Может, LOX каким то образом воспламенил углерод композита?
Но в виде обломков различных ракет
Останутся наши следы!
According to SpaceX, supercool liquid oxygen may have seeped into the gaps that formed between the two liners. Helium doesn't liquify until -269 degrees Celsius - just four degrees warmer than absolute zero.
That means the gaseous helium inside the COPV could have chilled the liquid oxygen trapped in the liner gaps even further - enough to solidify it, which occurs at -219 degrees Celsius.

At that point, SpaceX believes either friction or the snapping of a carbon fiber strand near the gap started the explosion that destroyed the rocket.

Lindy told me she thought the explanation was credible - it doesn't take much to start a catastrophic conflagration in a liquid oxygen environment. And SpaceX said tests showed the colder the oxygen, the more likely this scenario was to occur.

"I think the general concept is feasible," she said.
"The explanation, for me, is a bit simplistic, but an engineer is always going to say that."
Изменено: ronatu - 11.01.2017 22:50:06
Когда жизнь экзаменует - первыми сдают нервы.
Полностью здесь:

Когда жизнь экзаменует - первыми сдают нервы.
SpaceX aims to restore damaged launch pad to service by end of summer


Spacecom’s IAI-built Amos-6 was destroyed Sept. 1 when its Falcon 9 rocket, on the launch pad to prepare for a static firing. The wisdom of placing a satellite on the rocket for the test firing, which saves time and money in the launch-preparation process, has been much debated in the industry since the explosion.
It was IAI, and not Spacecom, that carried the insurance policy. Spacecom’s policy would be triggered on intentional ignition of the rocket in a launch attempt.
Weiss said IAI understood the difficulties on Spacecom imposed by the failure and that IAI paid Spacecom its share of the insurance proceeds.
Again because it was not a launch attempt, the explosion was not considered a launch failure, meaning Spacecom did not collect an insurance payments under its launch-plus-one-year policy.
Industry officials said it also meant that Spacecom did not recover its $50 million in payments to SpaceX.
Spacecom was an early customer for SpaceX with Amos-6, and paid about $50 million for the launch. Since then, SpaceX prices have risen with the company’s new-version Falcon 9 Full Thrust version, and are now around $65 million for a standard telecommunications satellite heading to geostationary-transfer orbit.
Despite what would appear to be a strong incentive — with $50 million sitting in SpaceX’s account — Spacecom has not announced a launch provider for Amos-17. The satellite is scheduled for launch in 2019.
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