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  1. #1
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    SpaceX Landing Attempt 14 April 2015

    CRS-6 First Stage Landing

    (22 seconds)

    https://www.youtube.com/watch?v=BhMSzC1crr0
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  2. #2
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    That was close.

  3. #3
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    i'm guessing that wasn't supposed to happen..
    you will attract more flies with honey than with vinegar, but you can attract the most with a dead cat

  4. #4
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    Quote Originally Posted by Bald Menace View Post
    i'm guessing that wasn't supposed to happen..
    Nothing in particular was "supposed" to happen.

    It was a test (aka "experiment"). It was designed to see what would happen.

    It was a step on the road to success.

    The goal is a successful landing, but several more tests are needed before a successful landing can reasonably be expected.
    Vacuum Technology:
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  5. #5
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    That barge looked so tiny! Probably an indication of their high expectations. Of course, getting to barge has been proven to work. I wonder if they did test landings on dry land first. Maybe the barge's motion on open water is the problem. Trying to make a level landing on a rocking platform. And then the platform has added movement when the rocket's exhaust hits it.
    I'd love to be involved in a project like that.

  6. #6
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    That's a pretty distant view, but it seems obvious they're trying to land a very tall vehicle on top of something that is non-steady.

    In this case, they would need to add some sort of thruster and accelerometer package up near the top to keep the thing upright until some sort of mechanism can grasp the vehicle and fix it to the barge.
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  7. #7
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    Whatever they're doing to adjust the rocket's angle, to match the angle of the barge's deck, just think: every adjustment changes the angle at which the exhaust hits the deck, which changes the position of the deck, which necessitates a change in the rocket's angle, which results in a change to the deck, which necessitates a change in the rocket's angle, and round and round and round and...

    Seems to me a larger barge would have less movement, along with some kind of stabilizer on the barge. Like cruise ships have.

    These are smart people, I'm sure they have thought of such things, but I think simply a larger barge would go a long way in simplifying things.

  8. #8
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    "Some sort of mechanism" would likely make the target area even smaller. But then, the ability to hit the existing target (the "tiny" barge) is pretty impressive. So maybe a smaller target is no problem.

    Here's a thought: forget about preventing it from leaning, but rather allow for it. Imagine a very large children's ball pit. Filled with appropriately sized balls, made from a material that won't burn or be quickly destroyed by fire from the rocket exhaust. Floating so the bulk of it is below water - to prevent the barge from tipping over. If it's possible to make those balls heavy enough to prevent an excessive number from being blasted out of the pit, yet still able to float (if we're concerned with recovering them, and not polluting), then maybe we could let the rocket settle into the pit, in the hole left from some of the balls having been blasted out (by the rocket exhaust), with the remaining being crowded around the perimeter of the pit - piled to the top of the pit walls. As the rocket sets down on the bottom of the pit, and powered down, the balls fall in around it and hold it upright.
    Just a thought.

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  10. #9
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    A better thought: Make the landing platform in the shape of a vertical, hollow cylinder, again with most of it submerged, to add stability. A sufficiently large target to hit. As the rocket gets closer to setting down on the bottom of the cylinder, both an upper and a lower "capture mechanism" (as TB suggested), would move in and capture, hold, and support the rocket. Even if it is less than fully successful (that is, if the idea works, but there is a malfunction) the rocket is still there.

    I like this one. Wonder if they're hiring...

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  12. #10
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    Quote Originally Posted by Nuclrchiller View Post
    Whatever they're doing to adjust rocket's angle, to match the angle of the barge's deck, just think: every adjustment changes the angle at which the exhaust hits the deck, which changes the position of the deck, which necessitates a change in the rocket's angle, which results in a change to the deck, which necessitates a change in the rocket's angle, and round and round and round and...

    Seems to me a larger barge would have less movement, along with some kind of stabilizer on the barge. Like cruise ships have.

    These are smart people, I'm sure they have thought of such things, but I think simply a larger barge would go a long way in simplifying things.

    My suggestion makes the assumption that they also stabilize the barge.

    My idea about the capture mechanism is based on the idea that it could capture the rocket anywhere on the barge surface.
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  13. #11
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    A few other people had some nifty ideas as well.
    Check out the comments:

    New, longer video hits Internet and shows Falcon’s landing demise
    http://spaceflightnow.com/2015/04/15...falcon-demise/
    Vacuum Technology:
    CRUD = Contamination Resulting in Undesirable Deposits.
    CRAPP = Contamination Resulting in Additional Partial Pressure.

    Change your vacuum pump oil now.

    Test. Testing, 1,2,3.

  14. #12
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    SpaceX Launch You Up
    https://www.youtube.com/watch?v=yypBjVpDJZY

    Preliminary report on the landing attempt:
    SpaceX Checks Throttle Valve After Flawed Falcon 9 Recovery Attempt
    http://aviationweek.com/space/spacex...covery-attempt

    Another video:
    https://www.youtube.com/watch?v=vmJK_v5wRZw
    Vacuum Technology:
    CRUD = Contamination Resulting in Undesirable Deposits.
    CRAPP = Contamination Resulting in Additional Partial Pressure.

    Change your vacuum pump oil now.

    Test. Testing, 1,2,3.

  15. #13
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    They already have a theory of what happened: "the issue was stiction (static friction) in the biprop throttle valve, resulting in control system phase lag".

    Exciting times for a bunch of engineers. And those of us who follow such things.

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