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Piezo-Operated Shutter Mechanism Moves 1.5 cm

This shutter is designed for use as part of an atomic clock. The figure shows parts of a shutter mechanism designed to satisfy a number of requirements specific to its original intended application as a component of an atomic clock to be flown in outer space. The mechanism may also be suitable for use in laboratory and industrial vacuum systems on Earth for which there are similar requirements. The requirements include the following:

Posted in: Mechanical Components, Briefs, TSP

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Two SMA-Actuated Miniature Mechanisms

These mechanisms represent two different approaches to latch/release operation. The figures depict two miniature mechanisms actuated by strips made of shape-memory alloy (SMA). A typical SMA is a nickel-titanium alloy known by the trade name “Flexinol” or “Nitinol.” In preparation for a typical application, a suitably sized and shaped piece of an SMA is deformed by a predetermined amount at the lower of two operating temperatures, then mounted in a mechanism. When stroking of the mechanism in one direction is desired, the piece of SMA is heated above a transition temperature to make it return to the “remembered” undeformed state. When stroking of the mechanism in the opposite direction is desired, the SMA is cooled below the transition temperature to make it return to the deformed state.

Posted in: Mechanical Components, Briefs

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Two-Step Laser Ranging for Precise Tracking of a Spacecraft

A document proposes a two-step laser ranging technique for precise tracking of a coasting interplanetary spacecraft to determine the degree to which leakage of fuel, solar wind, and/or solar-radiation pressure causes it to deviate from a purely gravitational trajectory.

Posted in: Mechanics, Photonics, Mechanical Components, Briefs, TSP

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Ball Bearings Equipped for In Situ Lubrication on Demand

Operational lifetimes can be prolonged. In situ systems that provide fresh lubricants to ball/race contacts on demand have been developed to prolong the operational lives of ball bearings. These systems were originally intended to be incorporated into ball bearings in mechanisms that are required to operate in outer space for years, in conditions in which lubricants tend to deteriorate and/or evaporate. These systems may also be useful for similarly prolonging bearing lifetimes on Earth.

Posted in: Mechanical Components, Briefs

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Formation Flying of Tethered and Nontethered Spacecraft

A paper discusses the effect of the dynamic interaction taking place within a formation composed of a rigid and a deformable vehicle, and presents the concept of two or more tethered spacecraft flying in formation with one or more separated freeflying spacecraft.

Posted in: Mechanical Components, Briefs, TSP

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Microwave-Spectral Signatures Would Reveal Concealed Objects

This technique should prove superior to conventional ground-probing radar. A proposed technique for locating concealed objects (especially small antipersonnel land mines) involves the acquisition and processing of spectral signatures over broad microwave frequency bands. This technique was conceived to overcome the weaknesses of older narrow-band electromagnetic techniques like ground-probing radar and low-frequency electromagnetic induction.

Posted in: Physical Sciences, Briefs

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Part 2 of a Computational Study of a Drop-Laden Mixing Layer

This second of three reports on a computational study of a mixing layer laden with evaporating liquid drops presents the evaluation of Large Eddy Simulation (LES)models.The LES models were evaluated on an existing database that had been generated using Direct Numerical Simulation (DNS).The DNS method and the data- tively coated thin electroactive-polymer (EAP)films be developed for use in spaceborne microwave and optical systems.

Posted in: Physical Sciences, Briefs, TSP

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