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Position Sensing and Formation Flying Using Optical Beacons

Two beacons on the starshade do the job. NASA’s Jet Propulsion Laboratory, Pasadena, California One way of imaging exoplanets around nearby stars is to use a starshade in conjunction with a space telescope. Typically, the starshade, which resembles a sunflower in outline, is ~ 30 meters in diameter. The starshade is flown about 50,000 km in front of the telescope, and when positioned directly in the telescope’s line of sight to the star, blocks the starlight, casting a deep shadow onto the telescope. Exoplanets orbiting the star and having a small angle to the line of sight will be visible because the starlight is extinguished. During the observation period, the position of the telescope needs to be maintained within about 1 m of the center of the shadow for maximum shading of the starlight.

Posted in: Briefs, Sensors

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Multiple-Frequency-Band Software-Defined Radiometer

Goddard Space Flight Center, Greenbelt, Maryland Remote sensing — the use of spacebased satellite technologies to obtain information on environmental variables — in combination with other types of data, can provide information on changes in the Earth’s surface and atmosphere that are critical for weather forecasting and responding to human welfare issues (disease outbreaks, food shortages, and floods). Satellites and other remote sensing tools have gathered a great deal of useful data on the Earth’s climate systems, drainage systems, geologic structures, thermal anomalies, geomorphologic features, and distribution of vegetation.

Posted in: Briefs, TSP, Sensors

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Ultra-High-Power W-Band/F-Band Schottky Diode-Based Frequency Multipliers

These multipliers can be used in millimeter-wave radars or radiometers in national security applications such as standoff personnel screening, mass transit security, and perimeter intrusion. NASA’s Jet Propulsion Laboratory, Pasadena, California All-solid-state, room-temperature, multipixel, sub milli meter-wave re ceiv ers are in demand for efficient spatial mapping of a planet’s atmosphere composition and wind velocities for future NASA missions to Venus, Jupiter, and its moons. Roomtemperature operation based on Schottky diode technology is a must in order to avoid cryogenic cooling and enable long-term missions. This technology is also being successfully applied for very-high-resolution imaging radars for standoff detection of concealed weapons. For submillimeter-wave radar imaging, the main issue is that, in order to reach video frame rates with high image pixel density, multi-pixel focal plane transceiver arrays are needed to illuminate targets with many radar beams simultaneously.

Posted in: Briefs

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FPGA Reconfiguration with Accelerated Bitstream Relocation

Goddard Space Flight Center, Greenbelt, Maryland Partial bitstream relocation (PBR) on field programmable gate arrays (FPGAs) is a technique to re-scale parallelism of accelerator architectures at run time and enhance fault tolerance. PBR techniques have focused on reading inactive bitstreams stored in memory, on-chip or off-chip, whose contents are generated for a specific partial reconfiguration region (PRR) and modified on demand for configuration into a PRR at a different location.

Posted in: Briefs, TSP

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Real-Time LiDAR Signal Processing FPGA Modules

Goddard Space Flight Center, Greenbelt, Maryland A scanning LiDAR, by its inherent nature, generates a great deal of raw digital data. To generate 3D imagery in real time, the data must be processed as quickly as possible. One method of discerning time-of-flight of a laser pulse for a LiDAR application is correlating a Gaussian pulse with a discretely sampled waveform from the LiDAR receiver.

Posted in: Briefs, TSP

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Advanced, Ultra-Low-Loss, High-Frequency Package Module

This module could improve performance of radiometers, high-resolution spectrometers, radars, and communication receivers and/or transmitters. NASA’s Jet Propulsion Laboratory, Pasadena, California As electronic circuits approach submillimeter wavelength frequencies (300 GHz) and higher, the traditional low-loss method of packaging electronic circuits in waveguide modules for guiding the signal requires more attention. The reasons are that circuits at higher frequencies have lower signal power levels due to limited gain and output power of semiconductor devices. As a result, the power lost by signals in the waveguide propagation environment becomes even more important at higher frequencies. In addition, previous efforts have based higher-frequency waveguide modules on existing lower-frequency module concepts and internal components.

Posted in: Briefs

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Miniature, Multi-Functional, Self-Braking Vehicle

This vehicle is actuated by piezoelectric stacks through the fuselage walls. NASA’s Jet Propulsion Laboratory, Pasadena, California A novel, miniature, low-mass vehicle has been created that is driven by piezoelectric stacks and a resonance structure. Preliminary tests on similar mechanisms that are used to transmit electrical power across the wall showed efficiencies of the order of 90%. The transmitted mechanical power, and signals through metallic walls using the direct and indirect piezoelectric effects in similar motors, is of the order of 50%. The transmitted power is generated inside the vehicle body, and the mechanism is applicable to any robotic system that may require an ambulation of locomotion mechanism such as a rover, a miniature vehicle, a crawler, or a flying device.

Posted in: Briefs, TSP

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