Test & Measurement

Device for Direct Measurement of the Diffusivity and Molecular Release Through Membranes and Filters

Controlled-release systems for drug delivery, molecular sieving, and single-molecule detection use micro and nano structures. Lyndon B. Johnson Space Center, Houston, Texas Concentration-driven molecular diffusion is a fundamental phenomenon essential for the transport of nutrients in cells, for oxygen exchange in the lungs, and mating of chemicals in industrial reactors and the food industry. Thus, diffusion plays a key role in a variety of disciplines. The concentration-driven diffusive transport is commonly described by Fick’s laws of diffusion. It is most often approximated by the Stokes-Einstein equation, which assumes a rigid solute sphere diffusing in a continuum of solvent at a low Reynolds number and infinite dilution.

Posted in: Briefs, Test & Measurement, Elastomers, Nanomaterials, Test equipment and instrumentation


Sampling Mechanism for a Comet Sample Return Mission

A similar sampling mechanism could be deployed in dangerous situations on Earth. Goddard Space Flight Center, Greenbelt, Maryland Sample return missions have the ability to vastly increase scientific understanding of the origin, history, current status, and resource potential of solar system objects including asteroids, comets, Mars, and the Moon. However, to make further progress in understanding such bodies, detailed analyses of samples are needed from as many bodies as possible. A standoff sample collection system concept has been developed that would quickly obtain a sample from environments as varied as comets, asteroids, and permanently shadowed craters on the Moon, using vehicles ranging from traditional planetary spacecraft to platforms such as hovering rotorcraft or balloons on Mars, Venus, or Titan. The depth of penetration for this harpoon- based hollow collector was experimentally determined to be proportional to the momentum of the penetrator in agreement with earlier work on the penetration of solid projectiles. A release mechanism for the internal, removable sample cartridge was tested, as was an automatic closure system for the sample canister.

Posted in: Briefs, TSP, Aerospace, Data Acquisition, Mechanical Components, Machinery & Automation, Monitoring, Test facilities, Spacecraft


Emily Wilson, Scientist, Goddard Space Flight Center, Greenbelt, MD

Emily Wilson developed a miniaturized laser heterodyne radiometer (mini-LHR) to measure the emissions of carbon dioxide and methane from melting permafrost. Wilson’s technology will be one of several NASA instruments sent to Alaska in June to analyze trace gases in the region’s atmosphere.

Posted in: Who's Who, Environmental Monitoring, Greenhouse Gases, Lasers & Laser Systems, Measuring Instruments, Monitoring


An Operationally Based Vision Assessment Simulator for Domes

Applications include remote visualization, flight simulation, virtual environments, and planetariums. Ames Research Center, Moffett Field, California The work described here is part of the U.S. Air Force-sponsored Operational Based Vision Assessment (OBVA) program that has been tasked with developing a high-fidelity flight simulation laboratory to determine the relationship between human vision and performance in simulated operationally relevant tasks. The OBVA simulator was designed and built to provide the Air Force School of Aerospace Medicine (USAFSAM) with a scientific testing laboratory to study human vision and testing standards.

Posted in: Briefs, Aeronautics, Computers, Simulation Software, Test & Measurement, Simulation and modeling, Human factors, Test facilities


Low Er-Doped Yttrium Gallium Garnet (YGG) as Active Media for Solid-State Lasers at 1651 nm

This technology could serve applications in the bio-medical areas such as nerve stimulation and dentistry. Goddard Space Flight Center, Greenbelt, Maryland The typical approach for producing laser output at the 1651-nm wavelength is via nonlinear frequency conversion. Lasers based on nonlinear conversion are complex, and it is very difficult to provide stability over time and over a wide range of operating temperatures. The efficiency of such optical sources is also low. A much more promising approach is the use of active media that allows for the development of solid-state lasers (SSL) with spectral emission at 1651 nm. An important requirement for this active medium is the ability to support in-band pumping with a low quantum defect since this approach leads to significant improvement in efficiency of SSLs and excellent beam characteristics due to low thermal stress of the active media.

Posted in: Briefs, TSP, Instrumentation, Medical, Lasers & Laser Systems, Test & Measurement, Medical, health, and wellness


Dual-Cavity Rayleigh Scattering Measurement System

A method and apparatus were developed for simultaneous measurement of velocity, density, temperature, and their spatial and temporal derivatives in gas flow. Langley Research Center, Hampton, Virginia Molecular-based optical diagnostics techniques capable of obtaining simultaneous measurements of multiple fluid properties are critically important for characterizing hypersonic air-breathing engines, such as scramjet engines and scramjet-rocket combined cycle engines. Correlations between those properties lead to a more detailed understanding of complex flow behavior, and aid in the development of multiparameter turbulence models required for supersonic combustion engine flow path predictions.

Posted in: Briefs, TSP, Instrumentation, Optics, Measuring Instruments, Test & Measurement, Optics, Diagnostics, Test equipment and instrumentation


Miniature Laser Magnetometer

This conceptual design includes three key innovations future space science requires while minimizing size, mass, and power. Goddard Space Flight Center, Greenbelt, Maryland Space missions using magnetometers have been very successful. However, science missions now require higher levels of accuracy and stability in order to refine existing understanding and improve modeling. In most space missions that require high-accuracy vector measurement of magnetic fields, a separate scalar magnetometer must also be included in order to calibrate the vector measurements. The miniature laser magnetometer (MLM) addresses the need for a single, high-stability magnetometer instrument that provides both scalar and vector measurements for future space science needs while minimizing size, mass, and power.

Posted in: Briefs, TSP, Aerospace, Instrumentation, Lasers & Laser Systems, Measuring Instruments, Test & Measurement, Test equipment and instrumentation


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