Test & Measurement

ORCA Prototype Ready to Observe Ocean

If selected for a NASA flight mission, the Ocean Radiometer for Carbon Assessment (ORCA) instrument will study microscopic phytoplankton, the tiny green plants that float in the upper layer of the ocean and make up the base of the marine food chain.Conceived in 2001 as the next technological step forward in observing ocean color, the ORCA-development team used funding from Goddard’s Internal Research and Development program and NASA’s Instrument Incubator Program (IIP) to develop a prototype. Completed in 2014, ORCA now is a contender as the primary instrument on an upcoming Earth science mission.The ORCA prototype has a scanning telescope designed to sweep across 2,000 kilometers (1,243 miles) of ocean at a time. The technology collects light reflected from the sea surface that then passes through a series of mirrors, optical filters, gratings, and lenses. The components direct the light onto an array of detectors that cover the full range of wavelengths.Instead of observing a handful of discrete bands at specific wavelengths reflected off the ocean, ORCA measures a range of bands, from 350 nanometers to 900 nanometers at five-nanometer resolution. The sensor will see the entire rainbow, including the color gradations of green that fade into blue. In addition to the hyperspectral bands, the instrument has three short-wave infrared bands that measure specific wavelengths between 1200 and 2200 nanometers for atmospheric applications.The NASA researchers will use ORCA to obtain more accurate measurements of chlorophyll concentrations, the size of a phytoplankton bloom, and how much carbon it holds. Detecting chlorophyll in various wavelengths also will allow the team to distinguish between types of phytoplankton. Suspended sediments in coastal regions could also be detected by the instrument.SourceAlso: Learn about a Ultra-Low-Maintenance Portable Ocean Power Station.

Posted in: News, Optics, Photonics, Sensors, Measuring Instruments

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Method for Performing GPS L1 C/A Measurements in Wideband Jamming and Interference

John F. Kennedy Space Center, Florida For effective range safety, global positioning system (GPS) metric tracking must be robust to interference with, and jamming of, GPS signals. The conventional approach to mitigating interference and jamming is to use a Controlled Reception Pattern Antenna (CRPA). These few-element phased arrays are used to steer nulls in the directions of interference sources, and/or to point beams in the directions of GPS satellites. The use of CRPAs is limited by their cost and size, as well as the difficulties of integrating the array into a platform. The problems are compounded for a launch vehicle, which must acquire and track GPS signals at high speed and acceleration, and undergo vibration and temperature conditions not common to CRPA use.

Posted in: Articles, Briefs, TSP

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JWST IV&V Simulation and Test (JIST) RT Logic T501 Emulator

Emulator using only software implements the behavior of a processor. Goddard Space Flight Center, Greenbelt, Maryland In order to develop a software-only test environment for the James Webb Space Telescope (JWST) mission, a solution was needed to send commands and receive telemetry between the TCTS (Telemetry and Command Test Set) and CMM-S card. The as-is solution requires the utilization of commercial off-the-shelf hardware (RT Logic Telemetrix T501 processor) and custom CMM-S hardware.

Posted in: Articles, Briefs, TSP, Electronics & Computers

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Cooling Test Samples With a Combined Convective and Conductive System to Rapidly Reach 77 K

This innovation enables rapid cooling to 77 K of James Webb Space Telescope shields, which enables hypervelocity impact testing with micro-particle spheres. Lyndon B. Johnson Space Center, Houston, Texas In this innovation, a team successfully developed and implemented a combined convective and conductive cooling system that permits rapid cooling. Using a spray system, liquid nitrogen (LN2) was injected into a test article enclosure located in the target tank that was evacuated to a lower pressure than the surrounding ambient pressure of the White Sands Test Facility (WSTF). According to the saturation curve for nitrogen, temperatures lower than 77 K can be achieved by using the evaporative process as long as the pressure remains above the triple point where nitrogen ice is formed.

Posted in: Articles, Briefs, TSP

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Guarded Two-Dimensional Flat Plate Insulation Test Calorimeter with Attach Points

Consistent test results are obtained in a cost-effective, safe, reliable, and practical manner. John F. Kennedy Space Center, Florida Insulation systems usually do not operate on their own; they must work together with a structural system that is designed to support the article being insulated. Typically this structure penetrates the insulation, degrading it in some manner, and gives a pathway for the conduction of unwanted heat. High-performance insulation systems that use reflective foils are highly anisotropic (the heat flows more easily in one direction than the others), so disturbing the temperature gradients through the material can cause much greater effects than are due to the disturbances alone.

Posted in: Articles, Briefs, TSP, Data Acquisition, Sensors

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Test, Calibration, and Training Target for a Microwave Sensor

NASA’s Jet Propulsion Laboratory, Pasadena, California Human subjects are unsuitable for objective performance testing of victim detection radar because their heart and respiration rates are not controllable or repeatable. There are limitations on human targets from a safety standpoint as well. It is difficult to relate the ground truth to the measured data for a human target without needing additional equipment that must be attached to the human subject. Artificial targets using pneumatics do not provide sufficient fidelity of the radar return for development of identification algorithms.

Posted in: Articles, Briefs, TSP, Sensors

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Energy Harvesting Could Help Power Spacecraft of the Future

A consortium is working on a project to maximize energy harvesting on a spacecraft of the future. The initiative seeks to find energy-saving and -maximizing solutions to enable eco-friendly aircraft to stay in space for long periods of time without the need to return to Earth to re-fuel, or to avoid carrying vast amounts of heavy fuel on long-stay journeys.

Posted in: News, Aviation, Energy Efficiency, Energy Harvesting

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