Test & Measurement

Live-Cell Microscopy and Traction Force Measurements with Simulated Microgravity “Clinochip”

Goddard Space Flight Center, Greenbelt, Maryland The deleterious effects of microgravity are undeniable: reduced bone mineral density, muscle atrophy, vascular remodeling, etc. These health issues may derive from both systemic factors, and from direct alterations to intracellular components and in the local microenvironment around cells. To understand the biological mechanisms at play, detailed studies have been performed in spaceflight. However, because experiments on the International Space Station (ISS) can be prohibitively expensive, clinostats are an alternative ground-based analogue for cellular studies. Clinostats “randomize” the orientation of gravity with respect to the cell fixed-frame, thereby simulating microgravity by eliminating a preferential gravity direction.

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Comparison of Three Methods for Measuring Distortion in Optical Windows

A new method for quantifying distortion based on phase-shifting interferometry has been developed. John F. Kennedy Space Center, Florida The primary function of a window is to allow observation of, and protection from, a potentially hazardous environment. Yet, from the window designer’s point of view, ensuring protection from weather conditions in home windows; from wind, temperature, and airborne debris in automotive windows; and from extreme pressures and temperatures in aircraft and spacecraft windows has almost always taken precedence over image quality. It is more important to protect an astronaut from the vacuum of space than to provide clear imagery, yet these are not exclusive requirements. Advances in materials and material processing allow the designer to attain better optical performance while not sacrificing important material specifications such as strength. In addition, increased performance demands on spacecraft windows — which are now used for photography, telescope observation, and laser communications — require greater consideration of optical clarity.

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Improved Combustion Products Monitor for the ISS

Applications include fire and environmental analyzers in aircraft, submarines, and industrial plants. John H. Glenn Research Center, Cleveland, Ohio Fire safety in space vehicles is of utmost importance, especially for manned flight. On the International Space Station (ISS), events that may lead to fires, especially smoldering, must be detected quickly and their location found. The analyzer used on the ISS must be automated, portable, and sensitive to the gases that are most likely to indicate the presence of a fire or pre-ignition event. In addition, after any fire event, the monitor must be useful to indicate that toxic gas levels have subsided for safe reentry of the crew to the affected area. Gases of interest may originate from the smoldering of Teflon wires, polyurethane foams, Delrin, and other plastics and furnishings in the ISS.

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Vector Network Analyzer Calibration for Quasi-Optical Dual Ports

Goddard Space Flight Center, Greenbelt, Maryland It is desirable to measure the electromagnetic properties of devices and materials in the millimeter part of the spectrum. For guided wave-based devices and materials (waveguides, coaxial devices), a vector network analyzer (VNA) is an excellent tool for this purpose since it provides full reflection and transmission characterization at high precision.

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Optically Modulated Miniature Magnetometer

This instrument may replace two separate instruments that are often needed together to study magnetic fields. Goddard Space Flight Center, Greenbelt, Maryland The optically modulated miniature magnetometer (OMMM) is intended to replace two separate instruments (each with their respective mass and power allotments) that are commonly needed together for scientific studies of magnetic fields — a triaxial fluxgate vector magnetometer and an optically pumped alkali vapor scalar magnetometer. For all vector instruments, the scalar data is necessary for calibrating the vector data.

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Quantitative Analysis of Failure Mode in Adhesively Bonded Test Specimens

A fluorescence visualization technique is used. Langley Research Center, Hampton, Virginia After adhesively bonded mechanical test specimens have been tested to failure, the failure mode must be interpreted and quantified. Areas of the adherent that are bare (no residual adhesive remains) have undergone adhesive failure. The remainder of the surface has undergone cohesive failure. The ability to distinguish and accurately quantify the relative amounts of cohesive and adhesive failure on a failed bonding surface is of tremendous importance in the field of mechanical testing, and for the development of bonded assemblies. Some adhesives (and adherents) are fluorescent, meaning they re-emit light at a different wavelength after being irradiated by some lighting source. This property allows for quantitative analysis of the adhesive failure mode (adhesive and cohesive). A digital image of the fluorescing adhesive or adherent can be analyzed and quantified using publicly available software to determine the relative areas of exposed and covered adherent surface.

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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.

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