Physical Sciences

A document summarizes a proposed metrology subsystem for precisely measuring the attitude of a large and flexible structure in space.

Two documents discuss a method of characterizing advanced composite materials by use of multimode-guided ultrasonic waves. The method at an earlier stage of development was described in “High-Performance Scanning Acousto-Ultrasonic System” (LEW-17601-1), NASA Tech Briefs, Vol. 30, No. 3...

Thin-film sensors for measuring flow velocities in terms of times of flight are undergoing development. These sensors are very small and can be mounted flush with surfaces of airfoils, ducts, and other objects along which one might need to measure flows. Alternatively or in addition,...

The GOES Product Generation System (GPGS) is a set of computer codes and scripts that enable the assimilation of real-time Geostationary Operational Environmental Satellite (GOES) data into regional weather forecasting mathematical models. The GPGS can be used to derive such geophysical parameters as...

Graded-index-of- refraction dielectric optical microresonators have been proposed as a superior alternative to prior dielectric optical microresonators, which include microspheres (described in several prior NASA Tech Briefs articles) and microtori wherein electromagnetic waves propagate...

Two documents discuss improvements in traps for removing noncondensable gases (e.g., air) from heat-transfer liquids (e.g., water) in spacecraft cooling systems. Noncondensable gases must be removed because they can interfere with operation. A typical trap includes a cylindrical hydrophobic...

Miniaturized hydrogen- and hydrocarbon- gas sensors, heretofore often consisting of Schottky diodes based on catalytic metal in contact with SiC, can be improved by incorporating palladium oxide (PdOx, where 0≤x≤1) between the catalytic metal and the SiC.

A document discusses a proposal to incorporate holographic optical elements into solar photon thrusters (SPTs). First suggested in 1990, SPTs would be systems of multiple reflective, emissive, and absorptive surfaces (solar sails) that would be attached to spacecraft orbiting the Earth to derive small propulsive...

A report presents a concept for an instrument to be flown in outer space, where it would detect dust particles — especially those associated with comets. The instrument would include a flat plate that would intercept the dust particles. The anticipated spacecraft/dust-particle relative speeds...

A NOBOSS stands in contrast to compressed- gas and cryogenic air-supply systems. Compressed-gas systems necessarily include massive tanks that can hold only relatively small amounts of gases. Alternatively, gases can be stored compactly in greater quantities and at low pressures when they are...

A straightforward measurement technique provides for correction of thermal-electromotive- force (thermal-EMF) errors introduced by temperature gradients along the pins of non-thermocouple- alloy hermetic feedthrough connectors for thermocouple extension wires that must pass through bulkheads....

A method of compensating for or minimizing phase differences between orthogonal polarizations of light reflected from metallic mirrors at oblique incidence, as, for example, from weakly curved mirrors, is undergoing development. The method is intended to satisfy a need to maintain precise...