1. An attitude control device for space station comprising a space station structure including habitable area, a plurality of solar arrays, a plurality of propellant tanks, a plurality of propulsion systems, a plurality of docking ports; a plurality of state sensors for measuring a plurality of states of the space station such as three attitude angles about three principal axes and time derivatives thereof; and a plurality of thrusters for generating control torque and for stabilizing the three attitude angles, the attitude control device comprising:
an identification frequency selecting device finding a plurality of frequencies of disturbance torque applying a frequency analysis method such as Fourier transform to the three attitude angles measured by the plurality of state sensors while speed proportional control of the space station is conducted, and selecting an identification frequency away from a plurality of frequencies dominant in the three attitude angles, that is used in identification of moment of inertia of the space station;
a moment of inertia identification operator calculation unit calculating a moment of inertia identification operator, a three by three matrix with components that are functions of a second order time derivative of a frequency component of the three attitude angles at the identification frequency, and polynomials of a first order time derivative of a frequency component of the three attitude angles at the identification frequency;
a moment of inertia identification device calculating the moment of inertia of the space station as a frequency component of control torque at the identification frequency pre-multiplied by an inverse of the moment of inertia identification operator from the moment of inertia identification operator calculation unit;
a disturbance torque identification device calculating disturbance torque due to solar wind as a difference between the moment of inertia of the space station from the moment of inertia identification device pre-multiplied by a three by three matrix with components that are functions of a second order time derivative of the three attitude angles, and polynomials of a first order time derivative of the three attitude angles, and the control torque; and
a control torque calculation unit calculating a control signal that causes a plurality of thrusters to generate the control torque stabilizing the space station as a linear combination of a three dimensional vector with components proportional to a time derivative of the three attitude angles, three dimensional vector with components proportional to a sinusoidal function oscillating at the identification frequency, a three dimensional vector nonlinear with respect to the time derivative of the three attitude angles, and the disturbance torque from the disturbance torque identification device.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An electronic module substrate assembly comprising:
a substrate;
an electronic device electrically connected to said substrate;
an elastomer barrier, said barrier having a cutout configured to sealably affix to chip edges defining said electronic device, the cutout providing fluid communication to a back surface of the electronic device exposed through the cutout while said barrier seals said substrate from said fluid communication; and
at least one passive electronic device electrically connected to said substrate, wherein said elastomer includes a second cutout aligned with said at least one passive electronic device, said second cutout defined by a second perimeter larger than a first perimeter defining said at least one passive electronic device.
2. The apparatus of claim 1, wherein said substrate assembly includes a plurality of said electronic devices and a plurality of cutouts in said barrier aligned with a corresponding electronic device.
3. The apparatus of claim 1, wherein said second perimeter is dimensioned to avoid contact with said at least one passive electronic device.
4. The apparatus of claim 1, wherein said elastomer barrier includes butyl rubber.
5. The apparatus of claim 1, wherein said barrier is hermetically sealed to said chip edges of said electronic device by mechanical means allowing rework of said electronic device.
6. The apparatus of claim 5, wherein said mechanical means is configured to reduce mechanical stress to said electronic device.
7. The apparatus of claim 1, wherein said barrier is sealably affixed to said electronic device by stretching said cutout to fit around said chip edges defining said electronic device.
8. The apparatus of claim 1, further comprising a means to bring water in fluid communication with said electronic device without wetting said substrate and interconnects between said substrate and said electronic device.
9. The apparatus of claim 8, wherein said means includes a heat sink water box, said barrier disposed between said substrate and said heat sink water box.
10. The apparatus of claim 9, wherein said heat sink water box is mechanically fastened to said substrate using mechanical fasteners.
11. The apparatus of claim 10, wherein said mechanical fasteners include a biasing member configured to prevent said barrier from stress relaxing.
12. The apparatus of claim 11, wherein said mechanical fasteners includes bolts and biasing member includes belleville washers.
13. The apparatus of claim 10, wherein said heat sink water box includes a ridge extending from a facing surface thereof, said ridge substantially aligned with a perimeter defining said cutout, said ridge configured to press into a facing surface of said barrier and increase compression of said edges defining said cutout on said chip edges.
14. An electronic module comprising:
a substrate;
an electronic device electrically connected to said substrate;
an elastomer barrier, said barrier having a cutout configured to sealably affix to chip edges defining said electronic device, the cutout providing fluid communication to a back surface of the electronic device exposed through the cutout while said barrier seals said substrate from said fluid communication;
a module cap sealably affixed to an upper surface of said barrier, said cap and said barrier forming an internal volume containing an aqueous cooling fluid;
a fluid inlet and a fluid outlet; and
at least one passive electronic device electrically connected to said substrate, wherein said elastomer includes a second cutout aligned with said at least one passive electronic device, said second cutout defined by a second perimeter larger than a first perimeter defining said at least one passive electronic device.
15. The apparatus of claim 14, wherein said module includes a ridge extending from a facing surface thereof, said ridge substantially aligned with a perimeter defining said cutout, said ridge configured to press into a facing surface of said barrier and increase compression of said edges defining said cutout on said chip edges.
16. A method for liquid cooling an electronic device without wetting underside hardware of the electronic device and a substrate to which it is attached, the method comprising:
disposing a first surface defining an elastomer barrier over the substrate, said elastomer barrier having a cutout aligned with the electronic device;
mechanically sealing edges defining said cutout with chip edges defining the electronic device so as to allow complete disassembly and re-workability of the electronic device;
sealably affixing a module cap to a second surface opposite said first surface of said barrier, said module cap configured to provide fluid communication of an aqueous cooling fluid with an exposed surface of the electronic device extending though said cutout;
configuring a ridge extending from a surface of said module cap in communication with said second surface of said elastomer barrier, said ridge substantially aligned with a perimeter defining said cutout, said ridge configured to press into said second surface proximate said perimeter defining said cutout of said barrier and increase compression of said edges defining said cutout on said chip edges to enhance a seal therebetween; and
configuring a second cutout aligned with each at least one passive electronic device extending from the substrate, wherein each corresponding said second cutout is defined by a second perimeter larger than a first perimeter defining each corresponding said at least one passive electronic device.