Physical Sciences

Analytical Expression of Elevation-Dependent Relative Air Mass for Atmospheric Extinction Simulations

This software enables one to calculate elevation-dependent relative air mass. When imaging a setting or rising Sun on the ground or from space, the shape and the intensity distribution of a captured image are affected by the following three factors: limb-darkening of the solar-disk, atmospheric extinction, and atmospheric refraction. This method is about the relative air mass needed in the estimation of atmospheric extinction.

Posted in: Briefs, Physical Sciences, Software, Mathematical analysis, Simulation and modeling, Computer software and hardware, Imaging and visualization

Quantification of Trace Chemicals Using the Vehicle Cabin Atmosphere Monitor

A software program analyzes data measured by the Vehicle Cabin Atmosphere Monitor (VCAM) and quantifies the concentrations of trace chemicals detected by VCAM. The software contains a unique way to quantify the signal measured by VCAM, to establish the concentration curve, and to decide which gain mode data to use for concentration estimation. It solves the problem of quantifying the concentration of trace chemicals in the International Space Station (ISS) internal air using the VCAM miniature gas-chromatograph/mass spectrometer instrument.

Posted in: Briefs, Physical Sciences, Software, Analysis methodologies, Computer software and hardware, Passenger compartments, Chemicals, Spacecraft

Improved Math Model for Multiphoto Measurement Systems

Enhanced bundle adjustment demonstrates improved reliability and accuracy with reduced total processor time.

The bundle adjustment, or more specifically, the colinearity math model it is based on, is undisputedly the most accurate method to perform 3D scene reconstruction from multiple images. It has been the gold standard since first developed in 1957–1959. The limitations of the method have motivated this investigation into how it could be improved.

Posted in: Briefs, Physical Sciences, Software, Mathematical models, Computer software and hardware, Imaging and visualization, Test equipment and instrumentation

Multipurpose Attitude and Pointing System (MAPS) Version 6.2

MAPS is a suite of software tools used for pre-flight planning, real-time support, and post-flight analysis of spacecraft attitude and pointing for the International Space Station (ISS), HII Transfer Vehicle (HTV), Automated Transfer Vehicle (ATV), and other low Earth orbit (LEO) vehicles.

Posted in: Briefs, Physical Sciences, Software, Computer software and hardware, Spacecraft

Steady-State Thermal Test Methodology

This method allows the production of multiple test points from a single test.

This innovation provides the following thermal properties data from a single steady-state test run: the effective thermal conductivity value (ke) for the full temperature difference, and multiple thermal conductivity values (λ) for intermediate temperatures. The test specimen (or material) is instrumented with one or more intermediate temperature sensors to allow the calculation of the multiple λ data points within the material and through its thickness. The methodology is particularly effective when coupled with any of the cryogenic boil-off calorimetry instruments (cryostats) developed by the Cryogenics Test Laboratory at NASA-KSC.

Posted in: Briefs, TSP, Physical Sciences, Test equipment and instrumentation, Test procedures, Thermal testing

Silicon Carbide Power Processing Unit for Hall Effect Thrusters

Prototype achieved 96.5% peak efficiency.

A high-efficiency, rad-hard, 3.5-kW SiC power supply was developed for the power processing unit (PPU) of Hall effect thrusters. This work specifically targets the design of a PPU power supply for the HiVHAC (High Voltage Hall Accelerator) thruster. The PPU power supply under development utilizes components that were irradiated under TID (total ionizing dose) conditions to greater than 3 Mrad with little to no change in device performance.

Posted in: Briefs, TSP, Physical Sciences, Power electronics

Intensity-Calibrated Hydrogen Flame Spectrum

Knowing the intensity spectrum of a hydrogen fire helps in evaluating fire detection methods.

The National Aeronautics and Space Administration (NASA) uses large quantities of liquid hydrogen and has expended significant effort in the development, testing, installation, and maintenance of hydrogen fire detectors based on ultraviolet, near-infrared, mid-infrared, and/or far-infrared flame emission bands. Yet, prior to this work, there was no intensity-calibrated broadband hydrogen-air flame spectrum in the literature, making it difficult to compare the merits of different radiation-based hydrogen fire detectors.

Posted in: Briefs, TSP, Physical Sciences, Fire detection

Exciting and Detecting Electromagnetic Energy in a High-Temperature Microwave Cavity

This weak-coupling approach can be used by industry for temperature-dependent dielectric measurements of high-value materials.

There is a need to perform accurate, high-temperature, complex dielectric constant measurements at microwave frequencies on materials, such as those on the surface of Venus (surface temperature 460 °C). One approach is to excite and detect a TE10n mode resonance in a waveguide cavity heated in a high-temperature furnace. The standard way is to use commercial high-temperature transition adapters attached to cavity end plates containing small iris holes that weakly couple microwave energy into and out of the cavity. These high-temperature transition adapters are not simple to make, and are rather large in size. The addition of the transition adapter units to the waveguide cavity leads to a long combined system that in many cases makes it difficult, if not impossible, to insert in conventional high-temperature furnaces.

Posted in: Briefs, TSP, Physical Sciences

Hollow aErothermal Ablation and Temperature (HEAT) Sensor for Tracking Isotherm Through TPS Material

This sensor can “see” through insulation.

The Hollow aErothermal Ablation and Temperature (HEAT) sensor is a multifunction sensor designed to track an isotherm by making an independent transient measurement at a defined location in the sensor that is equal to the temperature at which its constituent materials char. By this same operating principle, the HEAT sensor tracks the transient char depth progression within a thermal protection system (TPS) material. In the case of a material that sublimes (such as Teflon), or when the aerothermal environment induces steady-state ablation, the HEAT sensor measures material ablation directly.

Posted in: Briefs, TSP, Physical Sciences, Sensors and actuators, Insulation

Hydrogen Measurement in a Cryogen Flow Stream Reduces Waste of Helium

Energy conservation and sustainability technologies are applied for propellant conservation.

The purpose of this research was to develop an improved method for measuring hydrogen concentrations in a cryogen flow stream to minimize helium waste during the purge process. Currently, this type of measurement is performed manually with a sniffer, and involves obtaining periodic measurements that are not accurate or repeatable and do not optimize the conservation of hydrogen. The goal of this project was to create an autonomous real-time method for continuously measuring hydrogen that potentially offers not only cost saving advantages by conserving expensive resources that are used for purging, but also for providing an additional safety mechanism to monitor hydrogen in a cryogenic flow stream.

Posted in: Briefs, Physical Sciences, Sensors and actuators, Sustainable development, Energy conservation, Propellants

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