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High-Precision Encoders for GEO Space Applications

These encoders are designed for precision pointing in high-duty-cycle applications. High-precision encoders are used by earth observation instruments and in mechanisms for laser communication terminals (LCTs). A micro-radian resolution encoder for the LCT was designed for precision pointing applications, especially in geosynchronous Earth orbit (GEO) environments with a 15-year lifetime, and in high-duty-cycle applications.

Posted in: Mechanics, Mechanical Components, Machinery & Automation, Briefs

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Magnetostrictive Alternator

This innovation replaces the linear alternator presently used in Stirling engines with a continuous-gradient, impedance-matched, oscillating magnetostrictive transducer that eliminates all moving parts via compression, maintains high efficiency, costs less to manufacture, reduces mass, and eliminates the need for a bearing system.

Posted in: Mechanics, Mechanical Components, Machinery & Automation, Briefs, TSP

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A Kinematic Calibration Process for Flight Robotic Arms

The Mars Science Laboratory (MSL) robotic arm is ten times more massive than any Mars robotic arm before it, yet with similar accuracy and repeatability positioning requirements. In order to assess and validate these requirements, a higher-fidelity model and calibration processes were needed.

Posted in: Mechanics, Mechanical Components, Machinery & Automation, Briefs

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Method to Increase Performance of Foil Bearings Through Passive Thermal Management

Bearing load capacity is improved by multiples and reliability is enhanced. This invention is a new approach to designing foil bearings to increase their load capacity and improve their reliability through passive thermal management. In the present case, the bearing is designed in such a way as to prevent the carryover of lubricant from the exit of one sector to the inlet of the ensuing sector of the foil bearing. When such passive thermal management techniques are used, bearing load capacity is improved by multiples, and reliability is enhanced when compared to current foil bearings. This concept has recently been tested and validated, and shows that load capacity performance of foil bearings can be improved by a factor of two at relatively low speeds with potentially greater relative improvements at higher speeds. Such improvements in performance with respect to speed are typical of foil bearings. Additionally, operation of these newly conceived bearings shows much more reliability and repeatable performance. This trait can be exploited in machine design to enhance safety, reliability, and overall performance. Finally, lower frictional torque has been demonstrated when operating at lower (non-load capacity) loads, thus providing another improvement above the current state of the art.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Propellant-Flow-Actuated Rocket Engine Igniter

A pneumatically driven hammer initiates ignition. A rocket engine igniter has been created that uses a pneumatically driven hammer that, by specialized geometry, is induced into an oscillatory state that can be used to either repeatedly impact a piezoelectric crystal with sufficient force to generate a spark capable of initiating combustion, or can be used with any other system capable of generating a spark from direct oscillatory motion.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Unibody Composite Pressurized Structure

An integrated, generic unibody composite pressurized structure (UCPS) combined with a positive expulsion device (PED), consisting of an elastomeric bladder for monopropellant hydrazine, has been quasi-standardized for spacecraft use. The combination functions as an all-composite, nonmetallic, propellant tank with bladder. The integrated UCPS combines several previous innovations — specifically, the linerless, all-composite cryogenic tank technology; all-composite boss; resin formulation; and integrated stringer system. The innovation combines the UCPS with an integrated propellant management device (PMD), the PED or bladder, to create an entirely unique system for in-space use.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads

A factor-of-five or better reduction in mass is achieved. Astrophysical observations at millimeter wavelengths require large (2-to-5- meter diameter) telescopes carried to altitudes above 35 km by scientific research balloons. The scientific performance is greatly enhanced if the telescope is cooled to temperatures below 10 K with no emissive windows between the telescope and the sky. Standard liquid helium bucket dewars can contain a suitable telescope for telescope diameter less than two meters. However, the mass of a dewar large enough to hold a 3-to-5-meter diameter telescope would exceed the balloon lift capacity.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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