Home

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.

Posted in: Briefs, TSP

Read More >>

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.

Posted in: Briefs, TSP

Read More >>

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.

Posted in: Briefs, TSP

Read More >>

Energy-Based Acoustic Measurement System for Rocket Noise

Marshall Space Flight Center, Alabama Development of the next generation of spaceflight vehicles has prompted a renewed focus on sound source characterization and near-field propagation modeling. Without advancements in these areas, large uncertainties in vibro-acoustic loading estimates on space vehicles and payloads may result in structural designs that are either insufficient or excessive.

Posted in: Briefs

Read More >>

Mass Gauging Demonstrator for Any Gravitational Conditions

Marshall Space Flight Center, Alabama This concept uses an optical interferometric method to determine the density and/or pressure of the gas state contained with tank ullage. The system is similar to compression tank volume methods. By using an optical interferometric technique to determine gas density and/or pressure, a much smaller compression volume or higher-fidelity measurement is possible.

Posted in: Briefs

Read More >>

Multiport Hat Coupler for Electronically Steerable Antenna Testing

This technology provides the same performance as an anechoic closet, but at two orders of magnitude lower cost. Lyndon B. Johnson Space Center, Houston, Texas This invention provides a lower-cost means for verifying the scanning functionality of an electronically steerable (i.e. phased array) antenna (PAA) compared to existing methods that use a scanning probe or scanning test fixture and surrounding anechoic enclosure. This design is comprised of a standard test hat that has been modified to include additional probes located in the positive and negative directions of each scan axis. RF measurements taken from these additional probes provide an estimate of the beam-pointing angle. This solves the problem of verifying the platform-installed antenna’s beam-pointing functionality without the relatively high cost of a conventional anechoic chamber with a scanning probe or scanning test fixture.

Posted in: Briefs

Read More >>

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

Read More >>