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NASA Finds Critical Assembly Fault in Shuttle

Posted by michael on from the lucked-out dept.

mzs writes "During corrosion inspection on Discovery, technicians noticed that one of the gears in a rudder actuator had been installed backwards. This particular actuator was the top-most of four that control the air brakes on the tail. As luck turns out, if it had been the bottom-most actuator, loss of the shuttle and crew would have been nearly inevitable. Plans are in place to have four spares by the time Shuttle missions resume next year."

12 of 383 comments (clear)

  1. Simple solution, really. by grub · · Score: 5, Funny


    Could they not stamp "THIS SIDE UP" or whatever on the components?

    --
    Trolling is a art,
    1. Re:Simple solution, really. by Lattitude · · Score: 5, Insightful

      Even better, they are going to machine them so they mechanically impossible to put in backwards.

    2. Re:Simple solution, really. by fbform · · Score: 5, Funny


      Could they not stamp "THIS SIDE UP" or whatever on the components?

      They did something similar with the modified 747 that carries the shuttle orbiter back after landing. See this picture. This is supposed to be a sign on top of the 747, where the orbiter links to the top of the 747's fuselage. It reads "Place Orbiter Here...Black Side Down".

      If this is real, they have one hell of a sense of humor.

      --
      Time flies like an arrow. Fruit flies like a banana.
    3. Re:Simple solution, really. by Kenja · · Score: 5, Funny
      "Could they not stamp "THIS SIDE UP" or whatever on the components?"

      There is no "up" in space....

      --

      "Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
    4. Re:Simple solution, really. by Anonymous Coward · · Score: 5, Funny

      Impossible? Nah, they'll just need a bigger hammer.

    5. Re:Simple solution, really. by s20451 · · Score: 5, Interesting

      This is the original definition of Murphy's Law: If it is possible to do something in more than one way, and one of those ways leads to catastrophe, someone will inevitably do it the wrong way.

      In fact the original inspiration for Murphy's Law was a G-force meter that was installed backwards, thereby taking meaningless readings. (It probably didn't go below zero.)

      Another example is the 1969 gearbox fire on the Canadian navy ship, HMCS Kootenay. A gearbox bearing was installed backwards, which restricted its flow of lubrication oil (on a naval vessel, the gearbox is the size of a car and absorbs tremendous loads). Apparently it did say which way to install it, but the installation was made in a foreign shipyard where the workers could not read English. The poorly lubricated bearing overheated and caused an explosion during a full-power trial; nine sailors were killed and dozens injured.

      The moral of all these stories is: if it's important which way something is installed, make it asymmetric so that it's physically impossible to install it the wrong way. Labels are not enough.

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      Toronto-area transit rider? Rate your ride.
    6. Re:Simple solution, really. by Stitch_626 · · Score: 5, Funny

      They could stamp "If you can read this, turn gear around and install correctly" on one side and "There you go Einstein...you finally got it right" on the other.

      --
      Ohana means family. Family means nobody gets left behind or forgotten.
  2. How can a fault go unnoticed for so long? by amigoro · · Score: 5, Interesting
    Discovery flew safely 30 times with the defective actuator since its first launch August 30, 1984, and no one suspected a problem until the actuator was taken apart to check for corrosion.

    I thought they even checked Airplanes more thoroughly

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    Nothing to see here
  3. Transparency. by commo1 · · Score: 5, Interesting

    I'm quite surprised they're being quite so upfront about this. Kudos to them... On the other hand, I believe it to be a part of the healing process to convince the general public that they are, in fact taking the Columbia disaster extremely seriously, and want to show progress in the inspection and faliure-cathing procedures that obviously did not work for Columbia.

    It was, however, just a matter of time before a Columbia-type disaster occured. The suttle program has a remarkable safety record, Challenger and Columbia no matter.

  4. I'm betting... by Anonymous Coward · · Score: 5, Funny

    ...I'll be running Duke Nukem: Forever on Microsoft Longhorn before the next shuttle launches.

  5. Twice?! by 2marcus · · Score: 5, Interesting

    And if you read the article, you realize that NASA installed defective actuators not once, but twice! The first being the one that was successfully flown 30 times, and the second in the spare actuators.

    Given the complexity of a system like the shuttle, it is not surprising that out of 1000s of components there could be a mistake in one of them (and given some redundancy and robustness, it is not surprising that the shuttle could fly 30 times with one or more poorly installed components, though one would not normally want to bet on that...).

    However, two errors out of 8 actuators checked implies some serious quality control issues.

    -Marcus

  6. Stuff happens; learn from it. by Kozar_The_Malignant · · Score: 5, Interesting

    In this case nobody died and several lessons were learned, including something about fault-tolerance in actuators. I think two of the most valuable space flights from this point of view were Apollo 13 and the Mir mission that caught fire.

    Things will go wrong. Learning how to cope when the evil wind blows is critical. In this case, we now know that the thing can be flown with one actuator in upside down. If the bottom one malfs, swap it out in orbit with the top one, and you still might get home. People are going to get killed doing this. People got killed learning to sail the Mediterranean. It's still worth doing.

    --
    Some mornings it's hardly worth chewing through the restraints to get out of bed.