NASA on SpaceX's 2015 big boom: Bargain bin steel liberated your pressure vessel NASA has fingered design failings by SpaceX in a much-delayed report (PDF) on the 2015 explosion of a Falcon 9 on its way to the ISS. The 28 June 2015 launch followed six successful flights to the orbiting outpost (two on the original Falcon 9 v1.0 and four on the v1.1 incarnation). Unlucky number seven began normally enough …
Dear god, not using aerospace grade materials in a frigging rocket??? All those who provided the signatures to sign off on that should be receiving their pink slip immediately. The quality person who signed should be the first one out the door!
There are reasons you use aerospace grade material. It might cost the earth, but you can guarantee that the material properties wont be the reason for failure (failures due to design (undersizing, messing up your stress analysis, etc) are another matter entirely). We dont use it in aerospace because we like giving money to the metal manufacturers. Sheesh!
Trying to save a few dollars by skimming on the materials - it ALWAYS bites you on the a$$...
At the time, SpaceX blamed it on the quality control/testing/certification of the part, made by an external supplier. SpaceX tested the other stock parts that had been supplied and found them to be below grade/spec.
Nasa seems to be saying that SpaceX's own spec was below par (too), which seems something SpaceX omitted, after the event.
"Usually just means exactly the same part with extra paperwork"
Speaking as an engineer in the aerospace industry, you could use "industrial grade" materials, but only if you perform tests on a statistically significant quantity of every batch of material. From experience, it's surprising how often the cheap industrial structural steels don't have the stated properties.
If the design is safety critical, then you must never trust an industrial grade material to have the properties stated on the datasheet, because no-one guarantees that it will meet the minimum strength or the strain to failure specifications for that material type.
Plenty of safety critical systems use industrial grade materials, specifically because, when you purchase those products they tell you at what strength they are to fail at. You think a hi rize skeleton is not a safety critical system or are you going to tell me we use aerospace grade materials in all our buildings key structures?
Moral of the story is, don't advertise something if it's not true.
"From experience, it's surprising how often the cheap industrial structural steels don't have the stated properties."
Didn't the same thing happen with some nuclear reactor domes?
Steel prices have been a race to the bottom, it will be no good having tariffs if the result is still substandard material.
"The Shuttle's SRBs and their o-rings were 'aerospace grade'".
But used outside their safe temperature range, as explained in fairly simple language by Richard Feynman.
Because PHBs couldn't stand to disappoint the President, and maybe lose out on their promotions and visits to the White House.
A slew of successful launches since then means there won't be anything to worry about when Musk starts playing with really big rockets in 2019.
Because lightning never strikes twice?
Blowing up a $ 200 million satellite has an immediate and lasting affect on insurance premiums. The Falcon Heavy is a new rocket and needs to establish its own track record before companies will think about putting their even more expensive satellites on it. Not that Musk really cares because the Heavy is less suited to launching satellites than flinging people at Mars.
NASA still has a LOT of knowledge about how things should be done. It's finding are sound. The fact NASA can't develop anything decent is because it's hamstrung by politics and a culture built upon those same politics. That doesn't make it any less qualified to investigate accidents like this.
This isn't 'smack talk' from an embarrassed NASA. It's an in-depth fault analysis containing things which SpaceX very likely knew already, but chose not to make public for commercial reasons. NASA are making it public because it is their mandate, and because it will help educate all engineers, not just the ones at SpaceX.
OK maybe not $5 but still...
critical parts need a spec/paper trail. The U.S. Navy has a program called 'SUBSAFE' that deals with a couple of nuke boats that were lost in the 60's. In short, anything that is related to a safety system or the hull goes through a paper trail and inspection gauntlet. So the $5 bolt becomes a $500 bolt. It also doesn't sink the ship due to failure.
Similar program for rockets, I'd think.
However it sinks the business - NASA is not a commercial enterprise - if it pays over the odds for a part then it is the US taxpayers that foot the bill. For a commercial launching business, the cost of the launch must be low enough for the customer to use it. If all the parts are stupidly overpriced by insisting on aerospace everything then the company would fail as no one would use their rockets.
In a rocket, the majority of the parts are critical.
Considering most companies get receipts it's likely a paper trail was the easy part. The problem is that $500 bolt still runs the risk of doing just as much damage as the $5 one, with the exception that if something still goes wrong your out half a billion instead of 60 million.
"In short, anything that is related to a safety system or the hull goes through a paper trail and inspection gauntlet. So the $5 bolt becomes a $500 bolt. It also doesn't sink the ship due to failure."
However, there is also the possibility that, say, a $50 bolt (made of superior source material in a controlled facility) might only need, say, $100 of paper trail and so end up a lot cheaper.
At one time the company I worked for had safety critical parts manufactured on one of those presses that actually monitored the force profile in each forming stage. It was a hugely expensive piece of kit but it was capable of picking up the least change in the input material, thus effectively providing 100% inspection at the very start of the process. Supplier #2 had a 30% lower part cost because they were using old machinery - but gave enormous trouble further down the line. Eventually even accountants were got to understand that first cost influences final cost.
If you got external accountants and/or business consultants to understand that, well done! Often legal is a safer route, ie explaining where the liability stops if the part fails. Especially given the recent issue of Japanese steel companies faking test results.
But that's why safety critical stuff is expensive. Some responsibility may be offloaded to suppliers, but often not accountability. And if sub-standard stuff fails, there's the potential of very expensive litigation and reputational damage that can very quickly sink the company. See airbags for more info. A cost cutting measure in the gas generator lead to fatalities, injuries and a hugely expensive recall & replacement program. And that was a 'simple' component for cars, not a critical component expected to work in a highly stressed, cryogenic environment.
As well as the strut failure, the NASA report also mentioned that steel cables used as stress members weren't pre-tensioned/stretched, so another component selection issue. But this is why safety-critical stuff is expensive. Not just in design and procurement, but also QA testing to make sure components behave the way they're expected to. Which also applies to re-using rockets, so being able to strip those down and test that critical components aren't fatigued and out of spec.
"The Falcon 9 exploded but the Dragon cargo freighter survived and continued transmitting data up until it disappeared over the horizon."
I don't know all the background, but that sounds like a promising or possibly amazing outcome. The uppermost stage goes kablooey, and the payload portion survived (well, for some time). That sounds like it wouldn't be a far gap to add in an abort option for manned flight. Granted, maybe it's more dumb luck that the front end stayed far enough away from the explodey parts.
That abort option exists for the manned Dragon but not on cargo Dragon, the capsule would have survived if they had had a command in the system to deploy the chutes. The failure in this case was a pretty low energy one, compared to the energetic RUDs that have occurred on other launch vehicles, which is why the payload survived. If the rocket had actually exploded iso crumpling like it did the payload would have been destroyed right there.
SpaceX was trying really hard to keep any NASA report from being made public. It was some politicians that wanted to see why an expensive load of gear meant for ISS was donated to the fishies. There is an article with more information on parabolicarc.com.
There is nothing wrong with using COTS (commercial off the shelf) parts, but they do have to be throughly inspected. One item covered in the report was wire rope. The manufacturer recommended that the wire rope be pre-stressed before being used in a critical application. SpaceX wasn't even reading the manufacturers recommendations much less doing their own testing and conditioning of items that were destined to be used on their spacecraft. Every piece of flight hardware I've ever worked on got Tested with a capital T. It was then sequestered away until showtime to keep the damn interns from touching it.
Yet it was the components they were testing that failed to live up to their stated tolerances. Considering the launch record of the F9 I would say they are one of the few companies that can claim to fully test every aspect of their vehicles. After all, no other company can refly rockets and there is no way to test a rocket experiencing it's max stresses without a launch.
IMNHO it was a very bad move for NASA to allow independent purveyors to have anything to do with the U.S. space station. SpaceX and Musk don't exactly have a stellar rep or history of success. I certainly would not place my life or commercial goods in the hands of either SpaceX or Musk who hasn't made a dime in his house of cards Tesla Motors operation despite spending billions and missing deadlines and promises countless times. The lawsuits just keep mounting for Tesla due to deaths related to the "autopilot" feature on the model S.
I certainly would not place my life or commercial goods in the hands of either SpaceX or Musk
So what, you'd place them in NASA's hands instead? The organisation that developed the space shuttle, unique in having no useful launch abort system to could separate astronauts from explodey rocket engines.
this was exactly the conclusion that spacex came too in its initial investigation. Spacex uses a myriad of commercial parts in their rockets and has been since its inception with NASA's approval. This is one of the reasons Spacex rockets are so much less expensive. The part in question failed to live up to its design specifications and since then spacex took the necessary precautions to ensure it did not occur again.
The whining about aerospace vs non aerospace grade materials is silly since the part failed to live up to the companies specifications that manufactures it. If a bolt on a race car fails to meet its structural integrity does that mean all race cars should have bolts designed specifically for the racing industry, no, it just means when you buy a part it should be able to handle what it claims to handle.
Granted this was so long ago that the vehicle in use has very little in common with it besides the common design structure, spacex has been constantly upgrading the F9 for years and since we have no had such an anomaly since, I would say they addressed the problem.
Not astronaut parts, astronaut pants.
The astronauts were already safely on board the ISS but waiting for their clean laundry to arrive. Having said that, I honestly doubt that pants worn by astronauts - either American (trousers) or British (underwear) - are returned to Earth, cleaned, and then sent up to space again. Expensive as it must be, I expect that they wear clothes once, then throw them away.
Even though a washing machine was promised for them by The Register itself in 2011, here.
https://www.theregister.co.uk/2011/11/30/astronauts_to_get_clean_underwear/
I'm going to guess that the test of the spin dryer was notable... given that the space station itself isn't bolted to anything.
"in a face-plantingly foolish test involving fuelling and firing up the engines while the payload was attached."
That's not foolish, it's well reasoned and thought out. The reason the payload is already attached for a test fire is also well explained on several websites. I'm not even going to bother explain here.
It's not foolish to have a wet dress rehearsal in advance. It gives you a chance to identify any issues that might cause the launch window to be missed on the day. Nor is it foolish to include the payload in the dress rehearsal. It makes the rehearsal more complete, saves time taking the rocket back to where the payload can be installed after the rehearsal, and avoids introducing problems after the rehearsal by all that movement, opening up the fairing and closing it again, etc.
Note: it was not a test to see if the rocket would explode.
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