Test & Measurement

Neutron Spectrometer for Inner Radiation Belt Studies

The instrument is inherently robust, cost-effective, compact, and modular.

Goddard Space Flight Center, Greenbelt, Maryland

The Earth’s magnetosphere offers a wealth of information on particle dynamics, acceleration, and trapping. Fast neutrons, produced in the Earth’s atmosphere by the impact of galactic cosmic rays (GCRs) and solar energetic particles (SEPs), are an important but poorly measured component of the radiation environment in the inner magnetosphere. Cosmic ray albedo neutron decay (CRAND), whereby atmospheric neutrons beta-decay into protons and electrons, is a significant source of energetic protons in the inner radiation belt. Current models of the inner proton belt rely heavily on Monte Carlo simulations for the CRAND component, validated primarily by a handful of single-point balloon measurements from the 1970s.

Posted in: Briefs, TSP, Test & Measurement, Data acquisition, Data acquisition (obsolete), Satellites
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High-Energy Instrumentation for Small Satellite Platforms

A key asset of the instrument design is the ability to measure a broad range of radiation.

Goddard Space Flight Center, Greenbelt, Maryland

Given the increased availability of small satellite opportunities either through CubeSats or the Air Force’s University Nanosat program, and the limited availability of larger platforms, it is challenging to develop new instrumentation that not only fits within the envelope of small satellites, but also addresses the diverse science applications available in low Earth orbit (LEO). While small-platform instrumentation is limited in sensitivity, the ability to populate LEO with a fleet of instruments opens new science objectives not available with larger standalone payloads. Furthermore, coordinated observations of a variety of radiation species that either enter LEO from the Sun or heliosphere directly, or that reside within the radiation belts themselves, are necessary to fully reach closure on complex processes that govern particle acceleration and transport.

Posted in: Briefs, Test & Measurement, Sensors and actuators, Satellites
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Variable Acceleration Force Calibration System

Langley Research Center, Hampton, Virginia

A variable acceleration calibration system combines an innovative mechanical system and a statistical design of experiments to calibrate multi-axis force transducers. This system can reduce calibration time, allow for improved calibration of large-scale transducers, provide mobility for on-site calibrations, allow multiple transducers to be calibrated simultaneously, and accommodate dynamic force calibration.

Posted in: Briefs, TSP, Test & Measurement, Statistical analysis
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A Synthetic Quadrature Phase Detector/ Demodulator for Fourier Transform Spectrometers

This method makes it possible to use simple, low-cost, high-resolution audio digitizers.

Langley Research Center, Hampton, Virginia

Fourier transform spectroscopy works by measuring a spectral/light signal through a Michelson interferometer. In order to know the wavelength of the signal, one must use a stable reference, which is typically a metrology laser. In a standard Fourier transform spectrometer (FTS) system, the laser signal also runs through the interferometer and the laser beam is guided to a separate detector that is then used to trigger an analog-to-digital converter, which then captures the spectral signal.

Posted in: Briefs, TSP, Test & Measurement, Optics, Data acquisition, Data acquisition (obsolete)
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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
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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, Automation, Monitoring, Test facilities, Spacecraft
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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
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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, Medical, Lasers & Laser Systems, Instrumentation, Test & Measurement, Medical, health, and wellness
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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, Optics, Instrumentation, Measuring Instruments, Test & Measurement, Optics, Diagnostics, Test equipment and instrumentation
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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, Lasers & Laser Systems, Instrumentation, Measuring Instruments, Test & Measurement, Test equipment and instrumentation
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