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Third Stage Design Problem Cause of Most Recent Proton Failure

schwit1 writes: The Russian investigation into the latest Proton rocket failure has concluded that the failure was caused by a design failure in the rocket's third stage. The steering third stage engine failed due to excessive vibration as a result of an imbalance in a rotor of a pump unit. While it is always possible for new design issues to be discovered, I wonder why this problem hadn't been noticed in the decades prior to 2010, when the Proton began to have repeated failures.

72 comments

  1. Redesigned at some point, obviously by gman003 · · Score: 4, Interesting

    The Proton rocket has gone through a number of redesigns over its long life. The latest version, the Proton-M, first flew in 2001, and they kept flying the Proton-K for many years (for reasons I actually don't know). They've only done 90 flights of the Proton-M, and half of them were in that post-2010 period of "repeated failures" (although they had about as many failures for pretty much all of the 2000s as well).

    I would highly expect the faulty pump to have been redesigned with the Proton-M modifications, based simply on that analysis.

    1. Re:Redesigned at some point, obviously by garyisabusyguy · · Score: 4, Interesting

      In the Proton M there is a new upper stage that uses a store-able fuel
      There was an effort to move away from 'foreign' parts suppliers, notably Ukrainian
      http://en.wikipedia.org/wiki/P...

      --
      Wherever You Go, There You Are
    2. Re: Redesigned at some point, obviously by Anonymous Coward · · Score: 5, Interesting

      The real reason behind the switch from Proton-K to Proton-M was that the M one had a digital guidance computer, that could've been programmed by a rookie engineer, while Proton K relied on analog circuits that had to be rebuilt for every trajectory/payload combination.

      --Russian vodka engineer

    3. Re: Redesigned at some point, obviously by Anonymous Coward · · Score: 0

      It's so funny the Russia claims Ukraine but still classifies them as foreign. Just like China does with Hong Kong and Taiwan. They put them in the imported section at supermarket but still claiming they are part of China. And they put the Chinese flag for country of origin. What a disgrace.

    4. Re: Redesigned at some point, obviously by Anonymous Coward · · Score: 0

      Ukraine was very unreliable supplier even when it was on better terms with Russia, you can check for example joint project to build a plane (Antonov). No chance they would supply anything even remotely related to military now, even if they could - which I'm not sure of, as their heavy industry mostly in the eastern part of a country. So unfortunately for Russia it's not like China and HK (in case you did not know HK _is_ part of China), just an only way to guarantee uninterrupted supply.

    5. Re: Redesigned at some point, obviously by Anonymous Coward · · Score: 0

      ukraine is a hellhole of corruption and kneejerk nationalism. of the supernasty euro variety.

      they have good propaganda because zion is on their side. otherwise good riddance to them.

    6. Re: Redesigned at some point, obviously by Anonymous Coward · · Score: 0

      Is that better than the supernasty USian version?

  2. Duh! by Anonymous Coward · · Score: 1

    "I wonder why this problem hadn't been noticed in the decades prior to 2010, when the Proton began to have repeated failures"

    They took advice from Microsoft.

  3. Telemetry by Anonymous Coward · · Score: 2, Interesting

    Improved telemetry and sensors may have helped.

  4. two envelopes by roman_mir · · Score: 5, Funny

    So I read that this problem dates back to 1988 (so they say). Reminds me of a two envelope joke. A president steps down due to scandals, gives his replacement 2 envelopes. Tells him to open the first one when there is the first serious problem he cannot handle and the second one in case of another problem.

    The replacement starts on the job, eventually there is a serious political problem he cannot solve. He opens the first envelope and it says: blame everything on the previous guy. So he does and the problem goes away. Later there is another problem that cannot be solved, the guy opens the second envelope and in says: prepare 2 envelopes.

    I think somebody opened the first envelope.

    1. Re: two envelopes by Anonymous Coward · · Score: 0

      Or do like our current administration and blame things on Bush even for things that sometimes Clinton signed into law.

    2. Re: two envelopes by Anonymous Coward · · Score: 1

      Or like the current opposition and blame Obama for doing things that Bush actually did and which they supported at the time (like bank bailouts)

    3. Re: two envelopes by Anonymous Coward · · Score: 0

      Or do like our current administration and blame things on Bush even for things that sometimes Clinton signed into law.

      If it was Republicans who wrote the law, Republicans are to blame for what they wrote. If it was Bush who followed through on enforcement and failed to do so, it's Bush who is to blame.

    4. Re:two envelopes by rhodium_mir · · Score: 1

      Presidents MUST NOT, and are not authorized to, exist. Your joke only furthers the slavery that is representative democracy. Please report to the fine mesh screen for slurrying.

      --
      You can't spell "oneiromancy" without "roman".
  5. Design flaw? by Anonymous Coward · · Score: 1

    The steering third stage engine failed due to excessive vibration as a result of an imbalance in a rotor of a pump unit.

    Sounds more like a manufacturing/QA flaw to me.

    1. Re:Design flaw? by trout007 · · Score: 4, Interesting

      Not necessarily. I am a Mechanical Engineer and I work in a machine shop. Every part you design has tolerances on every dimension. But if you work with machinists with lots of pride like I do they will tend to try to hit the tightest tolerance they can just to keep up good practice and produce nice parts. So I can have a design that when I send it to my shop works flawlessly. But if I send the same drawings to an outside shop and they take full advantage of the tolerances I allowed I might be in for a surprise.

      The same could be true here. The design worked because one shop produced parts that exceeded the specifications but might fail for a certain combination of tolerances that are still within the allowed design.

      --
      I love Jesus, except for his foreign policy.
    2. Re:Design flaw? by Anonymous Coward · · Score: 0

      The same could be true here. The design worked because one shop produced parts that exceeded the specifications but might fail for a certain combination of tolerances that are still within the allowed design.

      Isn't that what QA is for?

    3. Re:Design flaw? by Shadow+of+Eternity · · Score: 1

      If it fails while still being inside of tolerances then by definition you need to change your tolerances.

      --
      A bullet may have your name on it but splash damage is addressed "To whom it may concern."
    4. Re:Design flaw? by trout007 · · Score: 1

      Nope. QA makes sure the parts are within engineering specs. It's the engineers job to make sure the design meets the requirements.

      --
      I love Jesus, except for his foreign policy.
    5. Re:Design flaw? by trout007 · · Score: 1

      And that is a design flaw which was my point.

      --
      I love Jesus, except for his foreign policy.
    6. Re:Design flaw? by Rei · · Score: 1

      Because if there's one thing Russia is famous for, it's QA ;)

      --
      "Who the **** put an emergency exit in the interrogation room?!" -- Police chief, "Jesus Christ Supercop"
    7. Re:Design flaw? by Antique+Geekmeister · · Score: 1

      QA also doesn't get to test a lot of complete systems. It's very expensive, and for testing entire rocket systems including the third stage, it's pretty destructive.

    8. Re: Design flaw? by oobayly · · Score: 3, Interesting

      To be fair, the Soviets made some amazing equipment during the cold war. The Americans for example were amazed by the NK-33 rocket engine. One of Lockheed's engineers described how they couldn't have made a similar engine in the US because of design concepts. Russian design engineers gave the design to the manufacturing engineers who in turn would refine the design during manufacturing. The design was then built, tested and refined iteratively. American engineers were less likely to build a design that was likely to fail - the design had to be refined before it was built which meant that they were more likely to be conservative.

      UK's Channel 4 had a series called Equinox that did an episode on it.

    9. Re:Design flaw? by PPH · · Score: 1

      Isn't that what QA is for?

      That depends on whether you have implemented some sort of feedback to engineering from QA. If you start to se some variance in the dimensions (or other parameters) from a manufacturing step, even if these are still within tolerances you can see if there is a correlation to increases in problems in service.

      --
      Have gnu, will travel.
    10. Re: Design flaw? by Rei · · Score: 1

      It also made them a lot more sensitive to the manufacturer, however. Underfunding a project almost certainly led it to being a disaster (the N1 rocket being a classic example). They generally were willing to sacrifice performance for ease of production and quantity - it was very much a widespread phenomenon.

      A friend of mine once served as a translator for the military during one of the late mutual nuclear disarmament treaties (don't remember which one). She described them as pretty much a scam, in that both sides wanted to get rid of their old weapons anyway and it gave them an excuse to put funds toward development of new, treaty-compliant weapons. But anyway, they were allowed to inspect any area small enough to contain a "treaty limited item". To figure out whether they could inspect it, the teams were equipped with sophisticated laser measuring devices - if it determined that the space was large enough, they could inspect it. The Russians were really impressed with it. They sent their teams over with... a stick. If the stick fit, they could inspect it. ;)

      Another example she mentioned was driving licenses. You know, if you get stopped in the US, they take your license, run your number through their computer, it connects to remote databases, they look up past offenses, they register a new one, etc, and give you your license back. In the USSR it was much simpler: the officer took your license and punched a hole in it. If you had too many holes, they kept it. ;)

      I know it's such a stereotype that the Russians preferred low tech solutions vs. the US, but she said that the stereotype was totally well deserved. ;) She also found that they weren't as inclined to get a joke. She and some the guys on her team found it rather sad that these incredible weapons delivery systems were just being destroyed, literally crushed - devices that could deliver a payload anywhere on Earth with precision. So for fun they did some calculations for what they would have to do to reengineer one such that you could load up frozen pizzas onto racks and have them cook on reentry then parachute to the surface - they figured that given the reengineering and operations costs, a person ordering a very large order of pizza could get them for about $20 per pizza, delivered by decommissioned ICBM. They wrote up a formal "proposal" with all the calculations and budgetting and had her talk with what she described as the Soviet equivalent of a colonel about their "Intercontinental Pizza Delivery System". She said he stared at her like she was mad. ;) Totally didn't get the concept that it was a joke and thought that the US team was honestly proposing a private pizza-delivery-by-ICBM venture.

      --
      "Who the **** put an emergency exit in the interrogation room?!" -- Police chief, "Jesus Christ Supercop"
    11. Re: Design flaw? by Anonymous Coward · · Score: 0

      any serious program does ground testing of engines and verniers. plus a load of other tests because this increases chances of succes to ariane levels.

      ground test are magnitudes cheaper than flight failures debugged by telemetry.

    12. Re:Design flaw? by Anonymous Coward · · Score: 0

      Nope. QA makes sure the parts are within engineering specs. It's the engineers job to make sure the design meets the requirements.

      I understand tolerances.

      But, it's a rotor in a pump, it rotates at high speed. It not only has to be within tolerance, but it has to be balanced.

      There's no QA step for "make sure this rotor which is going to rotate a thousand RPM is balanced"?

      Even Sears balances my tires when they install them.

    13. Re: Design flaw? by saigon_from_europe · · Score: 1

      They generally were willing to sacrifice performance for ease of production and quantity

      Generally, it is easy to get into situation where a few percent in performance improvement can make your cost double. E.g. current jet fighters, tanks. Or even better example - medical treatments. And at the end its old F-16 or cefalexin that gets the most of the job done.

      --
      No sig today.
    14. Re: Design flaw? by Anonymous Coward · · Score: 0

      Humour doesn't translate all that well. Russians humour is dark and extremely cynical. The IPDS is something that would generally be considered too silly for them to think of as being funny.

    15. Re: Design flaw? by Rei · · Score: 1

      Unfortunately, when it comes to rockets, a couple percent difference in performance means a huge difference in the first stage.

      The Russians make quite good early-stages for their rockets - but they've long had trouble with the upper stages. The N1 being the glaring exception, even the first stage was big trouble... they just couldn't handle the necessary level of QA for such a complex design to work, at least not on the budget they were given.

      --
      "Who the **** put an emergency exit in the interrogation room?!" -- Police chief, "Jesus Christ Supercop"
    16. Re: Design flaw? by Anonymous Coward · · Score: 0

      trade off payload grams of pizza for CC of vodka
      and see how fast they sign on.

    17. Re: Design flaw? by Anonymous Coward · · Score: 0

      surely there is ground testing with accel sensors. and then they fly some sensors plus telemetry at all times. since 1960 or even earlier.

      you can also qa designs. pros spend more money on this than initial development.

  6. The real reason. by Anonymous Coward · · Score: 2, Informative

    The Proton series once had a world record for the longest uninterrupted series of succesful launches.

    The real reason behind the switch from Proton-K to Proton-M was that the M one had a digital guidance computer, and they were able to find peope to program them, while the K modification had analog computer that had to be rebuilt for every payload.

    --Russian vodka engineer

    1. Re:The real reason. by Rei · · Score: 1

      13% of Proton launches (46 of 355) have ended in failure - it's not a very impressive record.

      --
      "Who the **** put an emergency exit in the interrogation room?!" -- Police chief, "Jesus Christ Supercop"
  7. Boston 3rd Stage by Anonymous Coward · · Score: 0

    3rd Stage is still one of my favourites of Boston:
    https://www.youtube.com/watch?v=OIGVT_YfdU4

    1. Re:Boston 3rd Stage by smittyoneeach · · Score: 3, Funny

      I saw Third Stage Design Problem open for Flaming Reentry in Kalamazoo, MI in '87.

      --
      Get thee glass eyes, and, like a scurvy politician, seem to see things thou dost not.--King Lear
  8. It's always Stage III by Etherwalk · · Score: 3, Interesting

    The Proton rocket has gone through a number of redesigns over its long life. The latest version, the Proton-M, first flew in 2001, and they kept flying the Proton-K for many years (for reasons I actually don't know). They've only done 90 flights of the Proton-M, and half of them were in that post-2010 period of "repeated failures" (although they had about as many failures for pretty much all of the 2000s as well).

    I would highly expect the faulty pump to have been redesigned with the Proton-M modifications, based simply on that analysis.

    IIRC, Stage III failures are responsible for a very high percentage of launch failures.

    Although IIRC, Clancy once wrote about one being faked in order to put a spy satellite into orbit without people realizing it was a spy satellite. Of course, the tech wasn't as good then...

    1. Re:It's always Stage III by robbak · · Score: 4, Interesting

      That is really not that surprising. All the design constraints in rocketry really come to a head in the last stages. Every kilogram of mass in your last stage is a kilogram less payload you can carry, and it is where you really need the most efficiency, the peak isp, so you want to push the pressures and temperatures as high as you can.

      As light as you can make it, as powerful as you can make it. This leads to fine tolerances and making the design only as strong as it needs to be.

      --
      Prediction for end of Universe #42: Fencepost error in Quantum_bogosort.cpp
    2. Re:It's always Stage III by Anonymous Coward · · Score: 1

      Yeah and the third stage gets the snot shook out of it by stages one and two before it has to light off. (Don't know if that's actually a problem)

      When I was younger I tried running the numbers on stages and for a first stage you can compensate by simply making the thing bigger and you don't pay much of a price. Each stage after that though excess weight cascades exponentially through the design. From memory, an extra pound of weight on the third stage is equivalent to 30 pounds of extra weight on the first.

      I think too, not sure, but with the third stage usually you're fully ballistic when it's running. (don't need to fight gravity) So you can play games with smaller engines, longer burn times. Explain, first stages job is to heave the thing into space. So lots of raw thrust is important. Take the weight of the rocket and subtract that from the first stage thrust, just throw it and all the fuel consumed to product it. Raw efficiency isn't as important, thrust to weight is. The third stages job is dominated by the need for speed. Efficiency and tight design margins are everything.

      Captcha: recoil }:'

    3. Re:It's always Stage III by Anonymous Coward · · Score: 5, Interesting

      I think too, not sure, but with the third stage usually you're fully ballistic when it's running. (don't need to fight gravity)

      Absolutely right. Play Kerbal Space Program for a few hours, and you really feel this. All your upper-stage engine needs to do is give you enough horizontal velocity to stay in orbit. So you want it to be as efficient as possible, and as weak as possible (since a weak engine is lighter), while still allowing it to finish its burn before you fall back into the atmosphere.

      The first stage is quite different. As you said, the first 1g of acceleration it gives you is wasted fighting gravity, so you want the thrust-to-weight to be as high as possible to minimise this fractional loss. On the other hand, go too fast too soon, and you're losing energy to drag. You don't want to go really fast until you're above most of the atmosphere. The mathematical formulation of this is called "Goddard's problem", and the optimum solution is something like: accelerate flat-out until you reach the speed where atmospheric drag becomes significant, then cut your thrust back, and gradually ramp your acceleration back up to max again as the air thins out.

    4. Re:It's always Stage III by 140Mandak262Jamuna · · Score: 1

      I think too, not sure, but with the third stage usually you're fully ballistic when it's running. (don't need to fight gravity)

      Earth's gravitational field is so vast, it has the Moon in its clutches, you never get so far you don't feel gravity. The term escape velocity much misunderstood, you don't escape Earth's gravity. It means the centripetal acceleration (v/r) is greater than gravitational acceleration. It means the orbit is not a closed curve (ellipse) but an open one (parabola or hyperbola). After some altitude the air resistance falls to near zero and you don't have to fight the drag, that is all. Also the term ballistic comes from the word "ball", as in cannon ball. The study of trajectories of cannon balls, shells etc. In the ballistic stage of the flight, there is no thrust from the rocket engines and the vehicle moves purely like a ball shot of an artillery piece, governed by gravity and air resistance.

      --
      sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
    5. Re:It's always Stage III by Rei · · Score: 1

      Absolutely true. Soyuz too has had tons of third stage failures. It's something that just keeps biting them.

      --
      "Who the **** put an emergency exit in the interrogation room?!" -- Police chief, "Jesus Christ Supercop"
    6. Re: It's always Stage III by Anonymous Coward · · Score: 0

      wr have shitloads of sensors and telemetry devices since decades. if they only found out by now means russia is affected by mba disease badly.

    7. Re:It's always Stage III by gman003 · · Score: 2

      IIRC, Stage III failures are responsible for a very high percentage of launch failures.

      Well, let's see what statistics has to say.

      I ignored failures of the payload, non-propulsion systems, or any failures where I could not identify which stage failed. Failures of staging mechanisms were rounded up to the higher stage. Flights with missing stages were still counted. All variants of each rocket family were included - Soyuz includes R7 launches, Thor/Delta includes Japanese licensed derivatives.

      Soyuz: 25 first-stage failures, 18 second-stage failures, 29 third-stage failures
      Proton: 9 first-stage failures, 11 second-stage failures, 17 third-stage failures
      Ariane: 4 first-stage failures, 0 second-stage failures, 4 third-stage failures
      Thor/Delta: 5 booster failures, 22 first-stage failures, 16 second-stage failures, 11 third-stage failures

      Soyuz and Thor racked up a lot of early failures of the first stage, which seems attributable to simple inexperience (each had one failure from failing to fill the fuel tanks before launch). Even compensating for that, it seems the first stage is a dangerous stage, prone to failure.

      However, your statement seems to bear out - the third stage does seem disproportionately dangerous. Oddly, it often seems to be control of the third stage that fails, not always the rocket itself.

  9. We Find Design Fault by l0ungeb0y · · Score: 1

    Fault was with Sergey. Sergey was replaced with Alexey at 14:00 hours.

  10. why none noticed? by aglider · · Score: 1

    Maybe because nine cared!

    --
    Sent as ripples into the electromagnetic field. No single photon has been harmed in the process.
  11. Malware Install Problem Cause of /. Media Failure by Khyber · · Score: 0, Offtopic

    https://plus.google.com/+gimp/...

    Even the GIMP people don't want you bundling GIMP with your shitware.

    --
    Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
  12. And... by Anonymous Coward · · Score: 0

    that's where politics (no matter the country, party, etc - in cases like this it's "office politics") comes into such discussions:

    The designer can say "the design is fine, but manufacturing did a bad job of fabricating and testing"

    The manufacturer can say "the design is flawed, it did not take real-world manufacturing into account and design a system that would not have the problem"

    Both are right to a degree, and both are wrong to a degree, so the default human behavior is to bring-on the "spin" and discover who is better at assigning blame. Given that this is Putin's Russia, the winner will be whoever has the argument that best supports a Putin ally/crony assuming power.

    1. Re: And... by Anonymous Coward · · Score: 0

      ground testing should catch almost all vibration issues.

      telemetry the rest.

      but since the 80s the russians were in decline, economically.

      also, their leaders were either gerontic or naive idiots like gorbachev.

    2. Re: And... by Anonymous Coward · · Score: 0

      when arianespace tried to mba on software ground testing, it cost 500 millions.

  13. Re:Is this the same Russian investigation team by Anonymous Coward · · Score: 0

    Missed blame putin article for a while already.

  14. In Soviet Russia by Anonymous Coward · · Score: 0

    Rocket redesigns you!

  15. Real Life Problem Solving is Hard by BBF_BBF · · Score: 1

    "While it is always possible for new design issues to be discovered, I wonder why this problem hadn't been noticed in the decades prior to 2010, when the Proton began to have repeated failures. "

    Building rockets is hard, finding out exactly why they fail is even harder, especially if it fails in space and all the bits burn up in the atmosphere or stay in orbit around the earth.

    Maybe you think that we can send Bruce Willis up with a rag-tag band of hard partying non-professional astronauts to rendevous with a wrench wielding Russian on the space station and they'll solve the problem by whacking a rocket with a wrench in slow motion montages with Aerosmith playing in the background. ;-)

  16. CIA did their job? by Anonymous Coward · · Score: 1

    There is a strong, undeniable evidence, they even put it on YouTube:
    https://www.youtube.com/watch?v=REyO1EOOG8Y

  17. Re:Is this the same Russian investigation team by phayes · · Score: 3, Insightful

    Continually lying to the world eventually gets the world to see you as a habitual lier. Putin can rig Russia to stifle dissent but not the world.

    --
    Democracy is a sheep and two wolves deciding what to have for lunch. Freedom is a well armed sheep contesting the issue
  18. Lack of technical expertise by smooth+wombat · · Score: 3, Interesting

    With Russia's invasion of Ukraine not going quite as planned, and Russia now building up another invasion force on its border with Ukraine, the trained specialists who would have caught this error have been rerouted to help produce more advanced rockets for the military.

    The problem is the sanctions imposed on Russia for its invasion are hurting its ability to pay its people. Some have gone as long as four months without pay and even when they are paid, it's not the full amount. Since there is no money to be made working on their space program, these people go to the military side which Putin continues to pour money into while grocery shelves start to go bare around the country.

    Expect to see more such accidents until Russian troops are out of Ukraine and there is cooperation with the West who can provide technical guidance in these matters.

    --
    We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
    1. Re:Lack of technical expertise by dbIII · · Score: 1

      With Russia's invasion of Ukraine not going quite as planned

      How do we know that? Putin has troops there but gets to deny he has, which is a bit harder to do if he sends in entire regiments. It's a very shitty situation for everyone apart from Putin - he's an evil bastard but he's still getting treated as if he has not invaded Ukraine because of the way it's been done.

      The problem is the sanctions imposed on Russia for its invasion are hurting its ability to pay its people

      The oil price is probably causing a lot more pain.

      there is cooperation with the West who can provide technical guidance in these matters.

      On every topic other than rockets I would agree with you, but in the case of rockets it's US companies that are buying Russian rocket motors and not the other way around.

    2. Re:Lack of technical expertise by Anonymous Coward · · Score: 0

      I think there was a deal done back when we were all good buddies with the Russians to use one of their engines. We have plenty of great engine designs and the one we have been buying is now being phased out.

    3. Re:Lack of technical expertise by Anonymous Coward · · Score: 0

      Putin could have at least said something regarding those "volunteers"... pretend that he's doing something to stop them. But he plays the "I can't do anything" card for some reason. Poor, powerless, Putin...

    4. Re: Lack of technical expertise by Anonymous Coward · · Score: 0

      he just pulls american style shit with russian flavor.

      he clearly read tom clancy.

  19. Because it isn't a design defect. by tombeard · · Score: 1

    It was a manufacturing defect that should have been discovered by the most basic of acceptance testing. That this wasn't discovered before the pump was installed indicates they are doing NO quality testing and they are not executing their quality control procedures. Cost cutting corruption, somebody pocketed a thousand dollars at the cost of an entire rocket and payload. And I thought stripping copper out of AC units for scrap was wasteful. Furrfu!

    --
    The reason we subjugate ourselves to law is to better procure justice. If law does not accomplish this purpose then it m
    1. Re:Because it isn't a design defect. by Anonymous Coward · · Score: 0

      Before you get all high and mighty, remember the o-rings.

  20. Re:Beautify the world! by JavaBear · · Score: 3, Interesting

    Maybe it is time to sterilize racist bigots, and Anonymous Cowards.

    Until then, maybe it's time /. added a block on Anonymous Cowards for the first 2-3 hours after a post is published, or has at least 100 messages.

  21. Slapped by The Tail of the Failure Distribution by Irate+Engineer · · Score: 5, Informative

    The reasons why this flaw was not identified previously was because it was a low probability occurrence. The shaft was just barely adequate to survive most of the launches, but sometimes it failed before engine cutoff. Since the debris is hard to access, gathering evidence that this was indeed the culprit was very difficult, especially when they didn't know what to look for. The engineers got some hints from previous failures that caused them to put vibration sensors in an area of the rocket that allowed them to identify the current failure mechanism.

    This is a problem in rocket design where you have two opposing constraints - they need a pump that works reliably all the way to orbit, but since the rocket is disposable and extra mass reduces payload, overbuilding the pump is not ideal either. This pushes one toward a design that is just barely good enough and no better. It turns out that they wanted a pump that would work for 99.9% of the flights, but they got one that worked 86% of the flights instead.

    This was actually a pretty challenging problem in engineering forensics. I hope this fixes their issue. The Proton is a pretty solid rocket otherwise.

    --

    Left MS Windows for Linux Mint and never looked back!

    Vote for Bernie in 2016!

    1. Re:Slapped by The Tail of the Failure Distribution by Anonymous Coward · · Score: 0

      Angora development may also have impacted the availability of resources to improve the rocket. If your rocket is going to be replaced soon, then why spend the money to make the old rocket better.

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  24. Re: Slapped by The Tail of the Failure Distributio by Anonymous Coward · · Score: 0

    bingo. politicos and managers are the prime reason for engineering issues.