Microstructural Explorations Inside Fuel Cells

Solid oxide fuel cells (SOFCs), a promising technology that can efficiently produce energy using fossil fuels with no moving parts and low emissions, present a particularly perplexing economic challenge: current systems operate at maximum efficiency between 700 and 1000 degrees Celsius, but such high temperatures shorten their service life, requiring more frequent fuel cell stack replacements. Lowering the operating temperature makes them last longer, but requires additional cells in the stack to deliver the same performance, and that drives up costs.

Posted in: Briefs, Imaging, Photonics, Emissions control, Fuel cells, Thermodynamics, Thermodynamics, Durability, Reliability, Durability, Reliability
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The Advanced Land Imager Helped NASA Mission Exceed Expectations.

After more than 16 years of operation, NASA’s Earth Observing–1 (EO-1) spacecraft was decommissioned on March 30 of this year. The Advanced Land Imager (ALI) developed by MIT Lincoln Laboratory was aboard as an alternative to the land-imaging sensor that was used by the Landsat Earth-observing program.

Posted in: Briefs, Imaging, Photonics, Architecture, Imaging, Imaging and visualization, Architecture, Imaging, Imaging and visualization, Satellites, Spacecraft
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Digital Beamforming Interferometry

This technology effectively divides a single antenna into two antennas.

NASA Goddard Space Flight Center has developed a new radar approach that uses a single phased array antenna and a single-pass configuration to generate interferograms, known as Digital Beamforming Interferometry. A digital beamforming radar system allows the implementation of nonconventional radar techniques, known as Digital Beamforming Synthetic Aperture Radar Multimode Operation (DBSAR).

Posted in: Briefs, Photonics, Antennas, Radar, Waveguides, Antennas, Radar, Waveguides
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Additive-Manufactured, Very Lightweight, Diamond Turned Aspheric Mirror

Industrial-grade, lightweight mirrors used in military and aeronautics have tight specifications brought on by demanding performance parameters. For example, a mirror that is used in an orbiting telescope would have to be extremely lightweight, stiff, and be configured to operate in extreme temperatures. These parameters traditionally work against each other. A material that is stiff is typically heavy, and a mirror that is lightweight and machinable may greatly distort when exposed to extreme heat or cold. Furthermore, materials that fit some of these parameters may not be easily machined to create a mirror — an art that requires high-precision tooling.

Posted in: Briefs, Photonics, Mirrors, Additive manufacturing, Lightweighting
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Development of a Sodium LiDAR for Spaceborne Missions

Laser and electro-optic technologies are under development to remotely measure sodium (Na) by adapting existing LiDAR technology with spaceflight heritage. The developed instrumentation will serve as the core for planning a heliophysics mission targeted to study the composition and dynamics of Earth's mesosphere based on a spaceborne LiDAR that will measure the mesospheric Na layer.

Posted in: Briefs, Photonics, Lidar, Lidar, Sodium, Test equipment and instrumentation
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Invertible Time Invariant Linear Filtering (InTILF) Method for Pattern Detection and Modeling of Stochastic One- or Two-Dimensional Data

This tool can analyze and model surface metrology data for polishing-tool fabricators.

X-ray astronomy offers the opportunity to observe important phenomena, including the early accretion of massive black holes and detecting diffuse ionized intergalactic gas that is heated to X-ray temperatures (>106). One of the technical challenges facing X-ray astronomy is fabricating optics that are properly shaped and smooth enough to produce quality images. Surface defects on the order of the wavelength of the observed spectrum and up to the size of the optical surface must be polished out of the mirrors without leaving a detectable pattern because the detectable signal is on the order of magnitude of the noise. This leads to a cycle of polishing and metrology that adds time and expense to optics fabrication.

Posted in: Briefs, Photonics, Mirrors, Optics, Optics, Radiation
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Development of Sodium Lidar for Spaceborne Missions

The metal layers at mesospheric altitudes are excellent tracers of neutral atmosphere dynamics, and have been used since the 1960s to study the chemistry and dynamics of the mesosphere. Ablation from meteors is believed to be the chief source of metals such as Na, Mg, K, Fe, and Ca in the middle atmosphere. Due to its relative abundance, large backscatter cross-section, and visible atomic transition, sodium (Na) has been used extensively for lidar studies of the mesosphere.

Posted in: Briefs, Photonics, Lidar, Lidar, Weather and climate, Metals, Sodium, Test procedures
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Additive-Manufactured, Very Lightweight, Diamond Turned Aspheric Mirror

Industrial-grade, lightweight mirrors used in military and aeronautics have tight specifications brought on by demanding performance parameters. For example, a mirror that is used in an orbiting telescope would have to be extremely lightweight, stiff, and be configured to operate in extreme temperatures. These parameters traditionally work against each other. A material that is stiff is typically heavy, and a mirror that is lightweight and machinable may greatly distort when exposed to extreme heat or cold. Furthermore, materials that fit some of these parameters may not be easily machined to create a mirror, an art that requires high-precision tooling.

Posted in: Briefs, Photonics, Mirrors, Additive manufacturing, Lightweight materials
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Partially Transparent Circular Mask to Suppress Narrowband Laser Light

The evolved Laser Interferometry Space Antenna (eLISA) is the implementation of the original Laser Interferometry Space Antenna (LISA) concept that will be proposed for the European Space Agency's (ESA) L.3 Cosmic Visions opportunity. The eLISA observatory uses lasers to range between pairs of freely falling test masses in adjacent, widely separated spacecraft. The measurement is made continuously, requiring simultaneous transmission and reception of a 1064-nm laser beam through an optical telescope.

Posted in: Briefs, Photonics, Measurements, Antennas, Lasers, Antennas, Lasers, Spacecraft
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Characterizing Richness of Previously Unmapped Terrain and Estimating Its Impact on Navigation Performance Using 3D Range Sensors in Flight

Landers to large planetary bodies such as Mars typically use a secondary reconnaissance spacecraft to generate high-fidelity 3D terrain maps that are subsequently used for landing site selection and creating onboard maps for terrain-relative navigation systems. This luxury does not exist with small primitive bodies such as comets and asteroids. For these bodies, the landing spacecraft has to perform the 3D mapping and, with possible help from ground control, choose a feasible landing site. To enable this operation, the spacecraft would need to carry a 3D ranging sensor system such as a LIDAR. With the spacecraft placed in extended mapping orbits, 3D range measurement data is then used to create a shape model of the object. Terrain-based navigation schemes that employ cameras could then be used to image, detect, match, and track features against the map database to provide a 6-degrees-of-freedom (DOF) navigation solution during descent. Camera-based systems, however, are not robust to lighting variations, and do not provide a direct 3D position/range feedback.

Posted in: Briefs, Photonics, Cartography, Cartography, Terrain, Entry, descent, and landing, Spacecraft
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