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Government Watchdog Says SpaceX Falcon 9s Are Prone To Cracks (engadget.com)

An anonymous reader shares an Engadget article: SpaceX's Falcon 9 rockets apparently have a serious issue that could delay the company's manned missions. According to the Wall Street Journal, the Government Accountability Office investigated both Boeing and SpaceX -- the corporations that won NASA's space taxi contracts -- and found that Falcon 9's turbine blades suffer from persistent cracks. GAO's preliminary report says these turboblades' tendency to crack is a "major threat to rocket safety," since they pump fuel into Falcon 9's rocket engines. NASA's acting administrator Robert Lightfoot told the WSJ that government officials have known about the issue for months or even years. The agency even told SpaceX that the cracks are too much risk for manned flights. A spokesperson said SpaceX has "qualified [its] engines to be robust" to cracks, but it's now "modifying the design to avoid them altogether."

11 of 139 comments (clear)

  1. Funny by Luthair · · Score: 3, Insightful

    How all the positive stories about Tesla and SpaceX make reference to Elon but all the negative stories don't even mention him in the summary and often (as in this case) in the article.

  2. This is not a serious issue. This is very minor by hkultala · · Score: 5, Informative

    Falcon 9 and the space shuttle are the only rockets whose engines have survived the launch so that they could have been inspected. And similar cracks have been found on shuttle engines too. Many other rocket engines very probbly have generated similar cracks during their burn, but those have not been inspected because the engines have gone to the bottom of the ocean.

    There have been 28 launches of falcon. During those 28 launches, 279 Merlin 1-series engines have been used, with only 1 major engine problem. And even in that case, the rocket delivered the primary payload to the desired orbit; Each falcon 9 has 10 engines and only on of those 10 engines is critical whose failure leads to mission failure.

    So, until now, the engines have had 99.64% reliability, and due the engine redundancy, only 10% of engine failures means mission failure on most launches(upper stage engine may not fail), meaning mission failure probability of 0.04% due failing engine if the engines keep working equally well in the future than they previously have been working.

    No, the this turbine thing is not a big problem. Bigger problems are elsewhere, and spaceX is improving the turbine blades. They will continue launching the version with the weak turbine blanes for some time, and it's very unlikely it will cause ANY problems at all, and then later the will release the block 5 model of the rocket with more robust turbine blades.

    It seem that the whole issue is "leaked" by some guy who is pissed to spaceX/Elon for something and the media is always eager to post this kind of "leaks" without really understanding what it is all about.

    1. Re:This is not a serious issue. This is very minor by OldMugwump · · Score: 4, Informative

      No, he didn't say reliability was unimportant. He said this is extremely unlikely to affect reliability.

      --
      "Shoot, a fella could have a pretty good weekend in Vegas with all that stuff."
    2. Re:This is not a serious issue. This is very minor by zuckie13 · · Score: 4, Informative

      Plenty of other engines have been inspected on the ground after running one or more full flight cycles on engine test stands (like every engine ever used), so there is actually data on more engine types than just those two. The damage comes from the part where they run the turbines at ludicrous speed for several minutes, not the fact that they re-enter

      Standards when a human is on board are way more stringent than for cargo. They have to meet an overall 1 in 500 probability of failure during ascent, and it sounds like the blades are bad enough that that hurts them on meeting this requirement.

      That being said, there are plenty of other parts I'm worried about, like structural failures in fuel tanks (they've had two of those that have actually destroyed rockets).

    3. Re:This is not a serious issue. This is very minor by rijrunner · · Score: 3, Interesting

      That's actually a much higher safety rating than NASA'a man rating requirement. It is also a much higher safety rating than any manned system to date.

  3. Nothing to worry about by 93+Escort+Wagon · · Score: 4, Funny

    As Elon would say, the cracks may simply lead to Rapid Unscheduled Passenger Disembarkation.

    --
    #DeleteChrome
  4. Re:Musk always ignores safety by rhazz · · Score: 5, Insightful

    He hasn't taken quality control seriously in any of his ventures, that is why they are all get-rich-quick schemes.

    You want to back that up with... anything?

  5. Re:Musk always ignores safety by ShanghaiBill · · Score: 5, Insightful

    they are all get-rich-quick schemes.

    1. He was already rich.
    2. If he wanted to get richER, then an aerospace company would have been about the worst possible way to do that. Historically, aerospace tends to make large fortunes into small fortunes rather than the other way around.

  6. Re:Can someone explain the turbine here? by gman003 · · Score: 3, Informative

    It's a fuel pump. Unlike a reciprocating engine, where you can inject the fuel at low pressure and then compress it, a rocket engine has to inject the propellant at the same pressure it's burned at, and thermodynamics wants that pressure to be as high as possible in order to get maximum efficiency (imagine a car engine that injected fuel at the top of the cylinder stroke instead of the bottom). Combined with the sheer amount of propellant being used, that means you need an absolutely insane amount of power in your fuel and oxidizer pumps.

    So they use a turbopump. A small amount of fuel and oxidizer are tapped off and burned. The resulting hot CO2 and H2O are used to run a turbine, which drives the pump. In the Merlin engines, and in many other engines, it ends up just exhausting, generating no additional thrust. Other designs, including Raptor, find ways to re-use that exhaust to generate a bit more power.

  7. Re:Musk always ignores safety by Anonymous Coward · · Score: 5, Funny

    I don't think you understand the making an aerospace company could make him richer.

    I don't think you understand that aerospace is a very, very risky way to become richer.

    If your goal is simply to become richer, being a asshole, owning a bunch of real estate and stiffing the people who work for you is a much more surefire method.

  8. Re:Musk always ignores safety by thegarbz · · Score: 4, Insightful

    2. If he wanted to get richER, then an aerospace company would have been about the worst possible way to do that.

    Reminds me of the Richard Branson quote:
    "If you want to be a Millionaire, start with a billion dollars and launch a new airline."