Tech Briefs

Pseudorandom Switching for Adding Radar to the AFF Sensor

A document describes the proposed addition of a radar function to the Autonomous Formation Flying Sensor, making possible coarse relative-position control to prevent collisions in the event of failure of one of the spacecraft. According to the proposal, in addition to tracking GPS-like one-way ranging signals transmitted by the other normally functioning spacecraft, each spacecraft could simultaneously track the reflection of its own ranging signal from a disabled, non-transmitting spacecraft. From the round-trip travel time, the approximate distance to the disabled spacecraft could be estimated. To prevent jamming of the receiver by the transmitter on the same spacecraft, the receiver would be switched off during transmission.

Posted in: Briefs, TSP, Electronics & Computers

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Electro-Optical Imaging Fourier-Transform Spectrometer

Size, weight, and vibration are reduced by eliminating moving parts. An electro-optical (E-O) imaging Fourier- transform spectrometer (IFTS), now under development, is a prototype of improved imaging spectrometers to be used for hyperspectral imaging, especially in the infrared spectral region. Unlike both imaging and non-imaging traditional Fourier- transform spectrometers, the E-O IFTS does not contain any moving parts. Elimination of the moving parts and the associated actuator mechanisms and supporting structures would increase reliability while enabling reductions in size and mass, relative to traditional Fourier-transform spectrometers that offer equivalent capabilities. Elimination of moving parts would also eliminate the vibrations caused by the motions of those parts.

Posted in: Briefs, TSP, Electronics & Computers

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Holographic Plossl Retroreflectors

Lightweight, inexpensive holographic optical elements would be used in place of lenses. Goddard Space Flight Center, Greenbelt, Maryland Holographic retroreflectors that function equivalently to Plossl eyepieces have been developed and used in free-space optical communication systems that utilize laser beams. Plossl eyepieces are well known among telescope designers. They have been adopted for use as retroreflectors and as focusing elements (for reception) and collimating elements (for transmission) in optical communication systems. A retroreflector that incorporates a Plossl eyepiece is termed a cat’s eye retroreflector (see figure).

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Photonics, Lasers, Optics, Telecommunications

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High-Speed Laser Scanner Maps a Surface in Three Dimensions

Surface flaws can be scanned automatically and displayed in real time. Ames Research Center, Moffett Field, California A scanning optoelectronic instrument generates the digital equivalent of a three-dimensional (X,Y,Z) map of a surface that spans an area with resolution on the order of 0.005 in. (≈0.125mm). Originally intended for characterizing surface flaws (e.g., pits) on space-shuttle thermal-insulation tiles, the instrument could just as well be used for similar purposes in other settings in which there are requirements to inspect the surfaces of many objects. While many commercial instruments can perform this surface-inspection function, the present instrument offers a unique combination of capabilities not available in commercial instruments.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Photonics, Measurements, Lasers, Optics, Inspections

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MALDI and Biotech Push Nitrogen Laser Development

The nitrogen laser is experiencing new growth due to low cost and the MALDI technique. Stanford Research Systems, Sunnyvale, CaliforniaThe Matrix Assisted Laser Desorption and Ionization (MALDI) technique in 1987 led to a renewed interest for the nitrogen laser. MALDI allows large and fragile biomolecules to be desorbed and ionized intact, or with much less fragmentation. The technique increased the upper mass limit for mass spectrometric analyses of biomolecules to over 300,000 Da, and has enabled the analysis of large biomolecules by mass spectrometry to become easier and more sensitive.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Lasers

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Electro-Optical Imaging Fourier-Transform Spectrometer

Size, weight, and vibration are reduced by eliminating moving parts. NASA’s Jet Propulsion Laboratory, Pasadena, California An electro-optical (E-O) imaging Fourier-transform spectrometer (IFTS), now under development, is a prototype of improved imaging spectrometers to be used for hyperspectral imaging, especially in the infrared spectral region. Unlike both imaging and non-imaging traditional Fourier-transform spectrometers, the E-O IFTS does not contain any moving parts. Elimination of the moving parts and the associated actuator mechanisms and supporting structures would increase reliability while enabling reductions in size and mass, relative to traditional Fourier-transform spectrometers that offer equivalent capabilities. Elimination of moving parts would also eliminate the vibrations caused by the motions of those parts.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Imaging and visualization, Test equipment and instrumentation

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Architecture Adaptive Computing Environment

Architecture Adaptive Computing Environment (aCe) is a software system that includes a language, compiler, and run-time library for parallel computing. aCe was developed to enable programmers to write programs, more easily than was previously possible, for a variety of parallel computing architectures. Heretofore, it has been perceived to be difficult to write parallel programs for parallel computers and more difficult to port the programs to different parallel computing architectures. In contrast, aCe is supportable on all high-performance computing architectures. Currently, it is supported on LINUX clusters. aCe uses parallel programming constructs that facilitate writing of parallel programs. Such constructs were used in single-instruction/multiple-data (SIMD) programming languages of the 1980s, including Parallel Pascal, Parallel Forth, C*, *LISP, and MasPar MPL. In aCe, these constructs are extended and implemented for both SIMD and multiple-instruction/multiple-data (MIMD) architectures. Two new constructs incorporated in aCe are those of (1) scalar and virtual variables and (2) pre-computed paths. The scalar-and-virtual-variables construct increases flexibility in optimizing memory utilization in various architectures. The pre-computed paths construct enables the compiler to pre-compute part of a communication operation once, rather than computing it every time the communication operation is performed.

Posted in: Briefs, Bio-Medical, Medical, Architecture, Computer software and hardware, Performance upgrades

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