Determining liquid fill fraction on a spacecraft
First Claim
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1. An apparatus for determining the volume of a liquid contained within at least two rigid tanks disposed within a spacecraft, the tanks revolving about an axis about which they are rigidly and axisymmetrically disposed, the apparatus comprising:
- predicting means for nonempirically predicting, for a number of possible quantities of liquid in the tanks, frequency, amplitude and phase oscillatory constituents of the spacecraft resulting from a small acceleration about its equilibrium position;
actuating means for applying force or torque to the spacecraft to produce the relatively small acceleration;
measuring means for measuring frequency, amplitude and phase oscillatory constituents resulting from the relatively small acceleration of the spacecraft; and
comparing means for comparing the predicted frequency, amplitude and phase oscillatory constituents with those measured, a match thereby identifying the quantity of liquid in said tanks.
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Abstract
A method and apparatus of determining the fill fraction of a liquid in a spacecraft in weightless space is disclosed. A small motion is introduced about the center of mass of the spacecraft undergoing steady spin and/or thrust, and resulting spacecraft oscillations are sensed. The measured frequency, amplitude and phase of the spacecraft oscillations are compared with counterpart values predicted for possible liquid quantities by a nonempirically computed model of spacecraft dynamics.
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Citations
18 Claims
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1. An apparatus for determining the volume of a liquid contained within at least two rigid tanks disposed within a spacecraft, the tanks revolving about an axis about which they are rigidly and axisymmetrically disposed, the apparatus comprising:
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predicting means for nonempirically predicting, for a number of possible quantities of liquid in the tanks, frequency, amplitude and phase oscillatory constituents of the spacecraft resulting from a small acceleration about its equilibrium position; actuating means for applying force or torque to the spacecraft to produce the relatively small acceleration; measuring means for measuring frequency, amplitude and phase oscillatory constituents resulting from the relatively small acceleration of the spacecraft; and comparing means for comparing the predicted frequency, amplitude and phase oscillatory constituents with those measured, a match thereby identifying the quantity of liquid in said tanks. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for determining the volume of a liquid contained within at least one pair of rigid tanks disposed within a spacecraft, the tanks revolving about an axis about which they are rigidly and axisymmetrically disposed, the method comprising the steps of;
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predicting nonempirically, for a number of possible quantities of liquid in the tanks, frequency, amplitude and phase oscillatory constituents of the spacecraft to a small acceleration about its equilibrium position; applying a force to the spacecraft to produce the relatively small acceleration thereof; measuring frequency, amplitude and phase oscillatory constituents resulting from the relatively small acceleration of the spacecraft; and comparing the predicted frequency, amplitude and phase oscillatory constituents with those measured, a match thereby identifying the quantity of liquid in the tanks. - View Dependent Claims (16, 17, 18)
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Specification