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Anomaly Updates
- simonpure 10y agoAt this stage of the investigation, preliminary review of the data and debris suggests that a large breach in the cryogenic helium system of the second stage liquid oxygen tank took place. ... Pending the results of the investigation, we anticipate returning to flight as early as the November timeframe.
- samcheng 10y agoNote that the second-stage helium system was also the source of the previous explosion of a SpaceX mission to the International Space Station (which blew up during launch). https://en.wikipedia.org/wiki/SpaceX_CRS-7#Launch_failure https://en.wikipedia.org/wiki/SpaceX_CRS-7#Launch_failure
- DangerousPie 10y agoBut: > Through the fault tree and data review process, we have exonerated any connection with last year’s CRS-7 mishap.
- api 10y agoI found that puzzling too... doesn't this mean it was the same component, though perhaps failing in a different way? Sounds like that pressurization system needs to be taken out back and shot.
- daeken 10y agoFrankly, that's how you increase your failure rate. If a system fails, you figure out why, figure out any other failure cases that may have been missed, and you fix them. You don't ditch something that largely works, and replace it with something brand new, for which you have zero data. That's how you lose rockets, cargo, and lives.
- HeyLaughingBoy 10y agoSame thing applies to software: you encounter an error, you analyze why it happened. Then ask: what other places could have this error? Can I eliminate this entire class of error by design or other method or do I need to fix them all individually? You organically end up with a more robust system that way. Don't throw out the baby with the bathwater.
- SEJeff 10y agoAnd then there is the "Did you turn it off and on again" school of thought. I've had to fight against that so hard before when the correct issue is inducing something to drop core, or fix a leaky program using valgrind.
- dandelany 10y agoAssuming they were correct about the first incident, it was caused by a faulty strut that was supposed to hold the helium COPV in place, but failed. If they've already ruled out a strut failure in this case, it seems pretty safe to say that they are unrelated.
- hencq 10y agoThough it must be said that NASA apparently never signed off on the strut explanation. So conceivably it was never the strut, in which case it could be the same issue. Then again, I assume the people working on this are much smarter than me and have much more information, so they probably considered and rejected that too.
- zardo 10y agoThe same system. There would be multiple components of the helium pressurization system that have failure modes causing tank overpressure.
- Diederich 10y agoThe previous failure was with a strut holding the tank. That's not really the same 'component', depending on one's specific definition.
- SEJeff 10y agoPerhaps taken out back and blown up would be more apropos?
- _ph_ 10y agoOnly in a loose sense. The CRS-7 failure was a strut failing which held the tank. This time, the tank itself is suspected to have failed. These are probably completely unrelated.
- kijin 10y agoThey might turn out to be related in an unexpected way. For example, they might have redesigned the strut in such a way as to cause excessive stress on the surface of the tank near the attachment point, leading to rupture. These systems are probably more complex than the cruddiest Enterprise software that any poor soul has ever had to maintain, so I guess anything is possible.
- jacquesm 10y agoGeorge Carlin would have a field day with that wording.
- imaginenore 10y agoThe most interesting hypothesis I've heard is intentional sabotage, like with a sniper rifle shot. Snipers have been known to hit human targets from 1.5 miles away. It seems like a huge rocket can get shot from a much larger distance.
- hood_syntax 10y agoIt's possible, and there could be motive from competing companies, but frankly it seems a bit far-fetched.
- imaginenore 10y agoNot just companies, countries like Russia. SpaceX is eating their space lunch.
- wyager 10y agoThere's also the whole conspiracy theory with Israel not wanting the launch to go through because it was a condition for the sale of the Israeli Spacecom to the Chinese, and Israel wanted to maintain control of their space industry.
- dogma1138 10y agoThe Israeli government approved the sale, they could've said no if they wanted too. If some one doesn't want Israel to transfer satellite technology to China it's not really the Israeli government. Also Spacecom is just a satellite operator, the satellite was built by IAI and other contractors, IAI is a state owned corporation which builds Israel's satellites and space launch vehicles. For the most part Spacecom doesn't have anything of real worth the transfer (other than their commercial operations), they do not operate Israel's military satellites they do not even operate Israel's commercial dual-use earth observing satellites.
- olalonde 10y agoEven more far fetched, someone shorting a large amount of SpaceX stock. That would make for a decent movie plot though.
- imaginenore 10y agoRELATED: "just had dinner with a credible source i trust that spacex is about 99% sure a COPV issue was the cause. 'explosion' originated in the LOX tank COPV container that had some weird harmonics while loading LOX." (COPV = Composite Overwrapped Pressure Vessel, they are titanium bottles wrapped in layers of continuously wound carbon fiber + resin) https://www.reddit.com/r/spacex/comments/545dju/unconfirmed_rumors_that_spacex_found_the_issue/ https://www.reddit.com/r/spacex/comments/545dju/unconfirmed_...
- erikpukinskis 10y agoI wonder if a general policy of using randomly fluctuating flow curves instead of flat ones would decrease the likelihood of harmonics.
- vannevar 10y agoPresumably, loss of the cryogenic helium through a "large breach" would lead to rapid warming of the liquid oxygen and equally rapid over-pressurization of the tank. So this is consistent with the source's contention that the explosion originated in the LOX tank, although the COPV may not be the root cause in that case, depending on the over-pressure it was rated for.
- emeraldd 10y agoWould it be the LOX or the HE rapidly warming? (I thought helium would have the lower starting temperature ...)
- dogma1138 10y agoThe helium isn't "cryogenic" the LOX is, Oxygen is liquid at 182.9c, SpaceX cools it down to ~-206c when they load their fuel in cryogenic mode. Helium boils at -268.9c, basically when liquid helium meets liquid oxygen it boils and expands to 757 times it's volume, which means boom.
- deleted 10y ago[deleted]
- mikeytown2 10y ago3 helium tank issues in 3 years 2014 https://en.wikipedia.org/wiki/Falcon_9_Flight_10 https://en.wikipedia.org/wiki/Falcon_9_Flight_10 (delayed by SpaceX due to a first stage helium leak) 2015 https://en.wikipedia.org/wiki/SpaceX_CRS-7 https://en.wikipedia.org/wiki/SpaceX_CRS-7 (failure of a strut which secured a high-pressure helium bottle inside the second stage's liquid oxygen tank) 2016 (a large breach in the cryogenic helium system of the second stage liquid oxygen tank took place)
- tropo 10y agoI note that the helium tank is inside the oxygen tank. I'm sure there is a reason, but there have got to be some major downsides.
- meepmorp 10y agoIt's probably to help keep the helium cold. Since you already have to maintain a large reservoir of a cryogenic fluid, why not make it do a little extra work to cool a substance with a lower boiling point.
- dogma1138 10y agoThe helium is used to keep the pressure on the oxygen tank constant once the tank starts to empty (basically the helium is used to push the oxygen down). It's probably inside for mechanical reasons pumping liquid helium is a nightmare it sips through pretty much everything (it can even go through glass when sufficiently cooled), in this case you don't really need to worry about all that stuff since you simply let the helium out and the difference in density would sort everything. As for the reason it's not used to "cool the helium" it's because helium boils at -268.9c the liquid oxygen is cooled to -182.9c or to ~-206c in cryogenic mode, this is still way above the boiling temperature of helium. This would be about as effective at cooling, as cooling boiling oil with boiling water, incidentally it's also about as explosive ;)
- yazaddaruvala 10y ago
- ythl 10y agoI love/hate the carefully curated language. "Three weeks ago, SpaceX experienced an anomaly at our Launch Complex 40 (LC-40) at Cape Canaveral Air Force Station. This resulted in the loss of one of our Falcon 9 rockets and its payload." == "Three weeks ago, SpaceX experienced a catastrophic failure at our Launch Complex 40 (LC-40) at Cape Canaveral Air Force Station. This resulted in a massive explosion/fireball that completely destroyed the rocket and its payload."
- eric_h 10y agoPersonally I love the euphemism they use when they blow up: "rapid unscheduled disassembly"
- drspacemonkey 10y agoNo word of a lie, I do that all the time in Kerbal Space Program. I didn't crash, the mission terminated due to unscheduled lithobraking. My rocket design didn't explode, it had a excessive surplus oxidisation.
- namank 10y agoPrecision, people. Precision with language is the mark of a clear mind. <snark>
- digi_owl 10y agoI think i have seen NASA use that one before.
- jackweirdy 10y agoReminds me of the first episode of the west wing, after President Bartlett apparently rode his bike into a tree. "What do you want me to tell the press? That the president, while riding his bike, came to a sudden arboreal halt?"
- mikeash 10y agoRUD is at least used ironically. I don't get the impression that "anomaly" has the same tone.
- eth0up 10y agoAnyone remember the Russian Proton Rocket failure of 5/15/2014? Some may immediately judge me a twit for mentioning this, but it seems quite factual (and interesting to me) that in both instances (SpaceX and the Proton) an aerial object appears from the right and passes the rocket almost simultaneous to the malfunctions. If interested, please see: https://www.youtube.com/watch?v=cdY1W9A2fbg https://www.youtube.com/watch?v=cdY1W9A2fbg - Set the vid to the highest resolution possible, slow the speed to 0.25, and look at the right-edge of the screen mid height at minute 1:22. A blurry object is seen approaching the rocket and upon direct proximity, the failure occurs, or seems to. As stated, a similarly peculiar aerial object was spotted simultaneous to the Falcon 9 explosion.