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System for Estimating Horizontal Velocity During Descent

Estimates are generated from images and other sensor outputs. The descent image motion estimation system (DIMES) is a system of hardware and software, designed for original use in estimating the horizontal velocity of a spacecraft descending toward a landing on Mars. The estimated horizontal velocity is used in generating rocket-firing commands to reduce the horizontal velocity as part of an overall control scheme to minimize the landing impact. DIMES can also be used for estimating the horizontal velocity of a remotely controlled or autonomous aircraft for purposes of navigation and control.

Posted in: Information Sciences, Briefs

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POD Model Reconstruction for Gray-Box Fault Detection

Low-order models that give robust, close approximations can be constructed. Proper orthogonal decomposition (POD) is the mathematical basis of a method of constructing low-order mathematical models for the “gray-box” fault- detection algorithm that is a component of a diagnostic system known as beaconbased exception analysis for multimissions (BEAM). POD has been successfully applied in reducing computational complexity by generating simple models that can be used for control and simulation for complex systems such as fluid flows. In the present application to BEAM, POD brings the same benefits to automated diagnosis.

Posted in: Information Sciences, Briefs

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CO2-Reduction Primary Cell for Use on Venus

A document proposes a CO2-reduction primary electrochemical cell as a building block of batteries to supply electric power on the surface of Venus. The basic principle of the proposed cell is similar to that of terrestrial Zn-air batteries, the major differences being that (1) the anode metal would not be Zn and (2) CO2, which is about 96.5 mole percent of the Venusian atmosphere, would be used, instead of O2, as the source of oxygen. The cell would include a solid electrolyte that could withstand operation at a temperatures as high as 1,000 °C and, hence, could withstand operation at the Venusian surface temperature of ≈460 °C.

Posted in: Physical Sciences, Briefs, TSP

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Resonant Tunneling Spin Pump

Electrons in opposite spin states would flow in opposite directions across a spin filter. The resonant tunneling spin pump is a proposed semiconductor device that would generate spin-polarized electron currents. The resonant tunneling spin pump would be a purely electrical device in the sense that it would not contain any magnetic material and would not rely on an applied magnetic field. Also, unlike prior sources of spin-polarized electron currents, the proposed device would not depend on a source of circularly polarized light.

Posted in: Physical Sciences, Briefs, TSP

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Enhancing Spin Filters by Use of Bulk Inversion Asymmetry

Current spin polarization could be maximized through appropriate choice of collection angle. Theoretical calculations have shown that the degrees of spin polarization in proposed nonmagnetic semiconductor resonant tunneling spin filters could be increased through exploitation of bulk inversion asymmetry (BIA). These enhancements would be effected through suitable orientation of spin collectors (or spin- polarization- inducing lateral electric fields), as described below.

Posted in: Physical Sciences, Briefs

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Measuring Dynamic Transfer Functions of Cavitating Pumps

Flow and pressure perturbations are imposed; transfer functions are computed from responses. A water-flow test facility has been built to enable measurement of dynamic transfer functions (DTFs) of cavitating pumps and of inducers in such pumps. Originally, the facility was intended for use in an investigation of the effects of cavitation in a rocket-engine low-pressure oxygen turbopump. The facility can also be used to measure DTFs of cavitating pumps in general.

Posted in: Mechanical Components, Briefs

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Robot Would Climb Steep Terrain

This walking robot could even climb under overhangs. The figure depicts the steep terrain access robot (STAR) — a walking robot that has been proposed for exploring steep terrain on remote planets. Robots based on the STAR concept could also be used on steep terrain on Earth for diverse purposes that could include not only scientific exploration but also military reconnaissance and search-and-rescue operations.

Posted in: Mechanical Components, Briefs, TSP

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