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Re: Program glitch or discovery?

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  • abelov0927
    Example from real world. (Thank you to D H) Thrusters can be used in pairs to help eliminate this cross-coupling between translational and rotational
    Message 1 of 5 , Aug 30, 2009
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      Example from real world.
      (Thank you to D H)

      Thrusters can be used in pairs to help eliminate this cross-coupling between translational and rotational acceleration. This is not always possible. For example, consider the Mars Climate Orbiter. From http://www.jamesoberg.com/mars/loss.html

      "The use of jet thrusters for attitude control raises further operational issues. In a world of perfect symmetry and unlimited payload size and budget, a spacecraft could rotate cleanly about its center of mass (often carelessly called its center of gravity) if opposing ends were equipped with jets and if those jets pointed in opposite directions and were set at right angles to the axis to be turned. In the real world, rotational jets may not be arranged in such a theoretically perfect alignment. ... On the Mars Climate Orbiter, four separate clusters of jets were located around the vehicle's waist. However, because of the large solar array extending from one side, the craft's center of mass did not coincide with the center point of the waist. Thus there was a significant imbalance each time these small thrusters fired."

      The Mars Climate Orbiter needed to use its attitude jets once or twice a day to dump angular momentum from its momentum wheels. The use of these attitude jets also made the vehicle accelerate translationally. Failing to account for this properly was the ultimate cause of the demise of the Mars Climate Orbiter. The mission controllers did try to account for this undesired acceleration, but there was a units mixup. The vehicle reported the undesired acceleration as a number in English units. The controllers interpreted that number to be in metric units.

      "According to a JPL spokesman, every maneuver intended to dump momentum added a velocity error of about 0.001 meter per second, on a probe that was traveling at a rate of tens of kilometers per second. These deflections themselves were not the problem, but their incorrect modeling was, when the computer was told the spacecraft had received a force of four or five times as great as it really had."

      The end result: The Mars Climate Orbiter entered Mars atmosphere, something it was never intended to do. The vehicle most likely blew up 70 kilometers or so above Mars.

      --- In gravitationalpropulsionstevenson@yahoogroups.com, "abelov0927" <abelov0927@...> wrote:

      Hi
      I updated my site.
      I add steps how to build these experiments on working model program (demo version)
      Please take a look.
      http://knol.google.com/k/alex-belov/paradox-of-classical-mechanics/1xmqm1l0s4ys/9#
      Thanks
      Alex
    • abelov0927
      I made 3 successful experiments with 2 pencils. All these experiment shows different velocities between pencils. The theory is CORRECT. The simulator is WRONG.
      Message 2 of 5 , Sep 10, 2009
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        I made 3 successful experiments with 2 pencils.
        All these experiment shows different velocities between pencils.
        The theory is CORRECT.

        The simulator is WRONG.
        Here is some snapshots from experiment, which shows experiment dynamic.

        http://knol.google.com/k/alex-belov/paradox-of-classical-mechanics-2/1xmqm1l0s4ys/9#



         


         


         


        --- In gravitationalpropulsionstevenson@yahoogroups.com, "abelov0927" <abelov0927@...> wrote:
        >
        > Example from real world.
        > (Thank you to D H)
        >
        > Thrusters can be used in pairs to help eliminate this cross-coupling between translational and rotational acceleration. This is not always possible. For example, consider the Mars Climate Orbiter. From http://www.jamesoberg.com/mars/loss.html
        >
        > "The use of jet thrusters for attitude control raises further operational issues. In a world of perfect symmetry and unlimited payload size and budget, a spacecraft could rotate cleanly about its center of mass (often carelessly called its center of gravity) if opposing ends were equipped with jets and if those jets pointed in opposite directions and were set at right angles to the axis to be turned. In the real world, rotational jets may not be arranged in such a theoretically perfect alignment. ... On the Mars Climate Orbiter, four separate clusters of jets were located around the vehicle's waist. However, because of the large solar array extending from one side, the craft's center of mass did not coincide with the center point of the waist. Thus there was a significant imbalance each time these small thrusters fired."
        >
        > The Mars Climate Orbiter needed to use its attitude jets once or twice a day to dump angular momentum from its momentum wheels. The use of these attitude jets also made the vehicle accelerate translationally. Failing to account for this properly was the ultimate cause of the demise of the Mars Climate Orbiter. The mission controllers did try to account for this undesired acceleration, but there was a units mixup. The vehicle reported the undesired acceleration as a number in English units. The controllers interpreted that number to be in metric units.
        >
        > "According to a JPL spokesman, every maneuver intended to dump momentum added a velocity error of about 0.001 meter per second, on a probe that was traveling at a rate of tens of kilometers per second. These deflections themselves were not the problem, but their incorrect modeling was, when the computer was told the spacecraft had received a force of four or five times as great as it really had."
        >
        > The end result: The Mars Climate Orbiter entered Mars atmosphere, something it was never intended to do. The vehicle most likely blew up 70 kilometers or so above Mars.
        >
        > --- In gravitationalpropulsionstevenson@yahoogroups.com, "abelov0927" abelov0927@ wrote:
        >
        > Hi
        > I updated my site.
        > I add steps how to build these experiments on working model program (demo version)
        > Please take a look.
        > http://knol.google.com/k/alex-belov/paradox-of-classical-mechanics/1xmqm1l0s4ys/9#
        > Thanks
        > Alex
        >
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