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Ultra-Low-Maintenance Portable Ocean Power Station

These fuel cell systems can be used for remote power generation, transportation applications, or in offshore wells. NASA’s Jet Propulsion Laboratory, Pasadena, California The goals of this research are to develop a relatively inexpensive, compact, and modular power package for deep offshore oil drilling or other undersea applications that provides 2 to 5 MW electricity, minimal maintenance, and at least 30 years of life.

Posted in: Physical Sciences, Briefs

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Mars-Optimized Solar Cells

NASA’s Jet Propulsion Laboratory, Pasadena, California Commercial triple junction solar cell designs were modified in their junction thicknesses, contact grid densities, and anti-reflective (AR) coating thicknesses to better match the Mars surface solar spectrum. Resulting cells show up to approximately 8% relative improvement in efficiency under the Mars solar spectrum, compared to non-optimized space solar cells, in testing performed at JPL.

Posted in: Physical Sciences, Briefs

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Alternating Magnetic Field Forces for Satellite Formation Flying

John F. Kennedy Space Center, Florida Orbiting a large number of satellites in fixed formations will be critical to many future space missions, especially large-scale interferometers, telescopes, antennas, and gravity wave detectors. Consequently, extensive research has been devoted over the last 20 years to formation flying architectures, concentrating not only on the mission objective, but also on the technologies required to achieve a stable satellite formation. Several proposals have been suggested for determining the location of the satellites, but the more difficult problem is developing a system that can hold the satellites at those desired locations and orientations. The two most common solutions are to use microthrusters, though these require propellant and will eventually be depleted, or to choose orbital patterns that minimize relative perturbations, but for highly precise positioning, this is not adequate. Neither of these approaches solves the problem for long-duration missions such as a multi-element telescope where the mirrors must be located and oriented to a tolerance less than an optical wavelength.

Posted in: Physical Sciences, Briefs

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Imaging Technique Could Detect Acoustically “Invisible” Cracks

It has long been understood that acoustic nonlinearity is sensitive to many physical properties including material microstructure and mechanical damage. The lack of effective imaging has, however, held back the use of this important method. Currently, engineers are able to produce images of the interior of components using ultrasound, but can only detect large problems such as cracks.

Posted in: Imaging, Test & Measurement, News

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Webb Telescope’s Heart Survives Deep-Freeze Test

After 116 days of being subjected to extremely frigid temperatures like those in space, the heart of the James Webb Space Telescope, the Integrated Science Instrument Module (ISIM) and its sensitive instruments, emerged unscathed from the thermal vacuum chamber at NASA’s Goddard Space Flight Center.

Posted in: Test & Measurement, Measuring Instruments, Monitoring, Aerospace, RF & Microwave Electronics, News

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Sensor Uses Radio Waves to Detect Subtle Pressure Changes

Stanford engineers have invented a wireless pressure sensor that has already been used to measure brain pressure in lab mice with brain injuries. The underlying technology has such broad potential that it could one day be used to create skin-like materials that can sense pressure, leading to prosthetic devices with the electronic equivalent of a sense of touch. In one simple demonstration they used this wireless pressure sensor to read a team member’s pulse without touching him.

Posted in: Materials, Metals, Plastics, Sensors, Detectors, RF & Microwave Electronics, Antennas, News

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Peak-Seeking Control Method

An algorithm optimizes performance of complex operations in real time. Neil A. Armstrong Flight Research Center, Edwards, California Peak-seeking algorithms optimize physical processes in real time and are widely used throughout a variety of industries. However, measuring associated parameters in changing conditions, and responding to them appropriately, is difficult because the measurements are typically distorted by noise. This technology addresses that problem by employing a time-varying Kalman filter. The filter is an algorithm previously developed to estimate unknown parameters within systems that are intrinsically random and uncertain. The Kalman filter is excellent at finding estimates when it encounters noisy signals. As a minimal-variant filter, it inherently produces the best estimates of a function with the smallest amount of variation from the true value. Thus, the filter can help accurately determine the optimal coordinates of the peak- seeking function as conditions in the environment change.

Posted in: Electronics & Computers, Software, Briefs

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