Abstract: A first part, a second part, and a seal ring are fastened together to form a pressure structure configured for a spacecraft structure of a spacecraft, wherein the first part and the second part are each formed from a single workpiece.

Abstract: The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

Abstract: A first part, a second part, and a seal ring are fastened together to form a pressure structure configured for a spacecraft structure of a spacecraft, wherein the first part and the second part are each formed from a single workpiece.

Abstract: A first part, a second part, and a seal ring are fastened together to form a pressure structure configured for a spacecraft structure of a spacecraft, wherein the first part and the second part are each formed from a single workpiece.

Abstract: An integrated instrumentation system includes a body comprising a thermal protection system (TPS) material (e.g., an ablatable material), one or more sensors embedded within the body, and a processor (e.g., an FPGA or the like) communicatively coupled to the plurality of sensors. The processor is configured to acquire sensor signals from the plurality of sensors and produce digital sensor data associated therewith. The sensors may include, for example, recession sensors, pressure transducers, thermocouples, and accelerometers.

Abstract: An integrated instrumentation system includes a body comprising a thermal protection system (TPS) material (e.g., an ablatable material), one or more sensors embedded within the body, and a processor (e.g., an FPGA or the like) communicatively coupled to the plurality of sensors. The processor is configured to acquire sensor signals from the plurality of sensors and produce digital sensor data associated therewith. The sensors may include, for example, recession sensors, pressure transducers, thermocouples, and accelerometers.

Abstract: The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

Abstract: An optical fiber wound onto an exterior surface of a composite structure in a two-dimensional pattern and adhered thereto to detect damage to the structure caused by impacts to or handling of the composite structure.

Abstract: An optical fiber is wound onto an exterior surface of a composite structure in a two-dimensional pattern and adhered thereto to detect damage to the structure caused by impacts to or handling of the composite structure.

Abstract: An enhanced method and system for unloading magnetic heads are disclosed. The system limits the maximum and minimum speed of the actuator while unloading the heads during a power failure. A BEMF control circuit monitors the velocity of the actuator using the BEMF of the actuator as a gauge of the velocity. The BEMF control circuit uses a sense resistor to remove the inherent resistive component of the actuator from its BEMF measurement. If the velocity of the actuator increases above a safe level the BEMF control circuit decreases actuator current to prevent further acceleration. If the velocity of the actuator decreases below a safe level the BEMF control circuit increases the actuator current to accelerate the actuator to a safe level.

Abstract: An adaptive servo system for a disk drive compensates for a track being off center or distorted by analyzing the spectral content of the radial variation of the centerline of a track relative to a rotation axis, generating multiple component signals having frequencies that are harmonics of the rotation frequency, and combining the component signals in a positioning signal for an actuator. Analyzing the spectral content of the radial variation can be accomplished by a discrete Fourier transform of a position error signal while generating a correction signal that cancels all or part of previously determined components of the position error signal. The system converges to generating a periodic signal that compensates for multiple harmonics in the radial variation in the position of the track.

Abstract: A disk drive apparatus is disclosed for primary use with portable, laptop or other information storage systems. The disk drive apparatus includes one or more about 2.5 inch hard disks. The disk drive apparatus also has electronics, including hardware and software, for detecting a lapse of first and second predetermined time intervals since a last disk access. The disk drive apparatus also includes power conservation means which power down a first portion of disk drive components after a first predetermined time interval has elapsed and for powering down a second portion of disk drive components after a second predetermined time interval has elapsed.

Abstract: Disclosed is a rigid disk drive information storage device which includes a rigid disk having an outside diameter in the range of about 33-34 mm., with a housing having a footprint that includes a width of about 35 mm. and utilizing a rotary actuator for positioning read/write recording elements across the surface of the disk. The disk storage devices further includes a footprint with length of about 50.8 mm., and includes in one embodiment dynamic head loading apparatus for loading the read/write recording elements into operative relationship with the disk. In another embodiment the rigid disk drive utilizes contact start stop loading and unloading of the read/write recording elements. An inertial latch is also provided for preventing rotation of the actuator when the drive is subjected to a rotational force.

Abstract: A secondary servo compensator, in a miniature disk drive having at least one disk and a servo system to position an actuator driven read/write head over any one of a number of tracks on the disk, provides on-line real-time compensation for disk runout that occurs during operation of the miniature disk drive. The servo system includes a servo compensator that has a gain and that generates an actuator position signal for positioning the read/write head over the track in response to a position error signal. The secondary servo compensator functions independently of the servo compensator. Specifically, the secondary servo compensator receives the position error signal and analyzes the disk runout and simultaneously generates a runout compensation signal during operation of the disk drive, i.e., while the disk drive is idle, reading, or writing.

Abstract: A silent seek servo controller is used in a low profile miniature disk drive to minimize acoustic noise and the problems associated therewith. The silent seek servo controller of this invention reduces acoustic noise generation at the expense of seek performance. Since the silent seek servo controller of this invention minimizes acoustic noise, the controller helps to eliminate vibrations within the computer. The silent seek servo controller is a one mode continuous position servo seek controller that accelerates and decelerates the actuator using a smooth, continuous and completely symmetric acceleration trajectory. Specifically, for a seek time t, the disk drive actuator is accelerated for one-half the seek time, i.e, time t/2, and decelerated for the other half of seek time t. The peak acceleration occurs at time t/4 and the peak deceleration occurs at time 3t/4. The symmetry of each acceleration phase assures that any acoustic noise generated by uneven acceleration is eliminated.

Abstract: A silent seek servo controller is used in a low profile miniature disk drive to minimize acoustic noise and the problems associated therewith. The silent seek servo controller of this invention reduces acoustic noise generation at the expense of seek performance. Since the silent seek servo controller of this invention minimizes acoustic noise, the controller helps to eliminate vibrations within the computer. The silent seek servo controller is a one mode continuous position servo seek controller that accelerates and decelerates the actuator using a smooth, continuous and completely symmetric acceleration trajectory. Specifically, for a seek time t, the disk drive actuator is accelerated for one-half the seek time, i.e, time t/2, and decelerated for the other half of seek time t. The peak acceleration occurs at time t/4 and the peak deceleration occurs at time 3t/4. The symmetry of each acceleration phase assures that any acoustic noise generated by uneven acceleration is eliminated.

Abstract: A disk drive apparatus is disclosed for primary use with portable, laptop or other information storage systems. The disk drive apparatus includes one or more about 2.5 inch hard disks. A rotary actuator is utilized and includes an arm assembly having a cam follower member for use in dynamically loading/unloading read/write head(s). The cam follower member moves along a ramp, which forms a cam surface, for loading/unloading. The spin motor assembly of the disk drive apparatus includes rotor having a clamp ring that enables a more powerful spin motor to be incorporated, as well as facilitating and enhancing the connection of the hard disks to the spin motor. The disk drive apparatus also includes servo electronics responsive to a back emf generated signal for use in the servo operation, which use has the potential to increase the servo bandwidth.

Abstract: A disk drive apparatus is disclosed for primary use with portable, laptop or other information storage systems. The disk drive apparatus includes one or more about 2.5 inch hard disks. A rotary actuator is utilized and includes an arm assembly having a cam follower member for use in dynamically loading/unloading read/write head(s). The cam follower member moves along a ramp, which forms a cam surface, for loading/unloading. The spin motor assembly of the disk drive apparatus includes a rotor having a clamp ring that enables a more powerful spin motor to be incorporated, as well as facilitating and enhancing the connection of the hard disks to the spin motor. The disk drive apparatus also includes servo electronics responsive to a back emf generated signal for use in the servo operation, which use has the potential to increase the servo bandwidth.

Abstract: A method and apparatus are provided to compensate for the runout that commonly occurs during the reading from or writing of information on the surface of a disk medium using a read/write head. The runout relates to the distance the head is located away from a disk track center during the rotation of the disk. To maintain the head in alignment with the track center during the complete revolution of the disk, position information is obtained. This position information is used with discrete fourier transform techniques to provide a representation of the disk runout. From this representation, a compensating signal can be generated to provide movement of the head that compensates for the runout and keeps the head positioned in alignment with the track center at all times during the disk rotation.

Abstract: A method and apparatus are provided in an embedded servo system for controllably moving, using a linear motor, a carriage assembly and one or more accompanying heads relative to one or more disk surfaces. Each disk surface includes sectors for reading and writing information. Each disk surface also includes servo fields spaced between the read/write sectors. The servo fields have preset servo or position information for each of the tracks on the disk. The position information is in the form of Normal and Quadrature generated signals used to determine the exact position of the head when it is located between track centers. Using the determined position of the head and knowing a target position on the disk surface, the distance remaining to the target position is found. Using the value of the distance remaining to the target position, a head velocity can be determined and the proper amount of current can be supplied to the linear motor so that the head arrives at the target position in minimal time.