Tech Briefs

Master Clock and Time-Signal-Distribution System

This system has a modular, flexible architecture and is user-friendly.

A timing system comprising an electronic master clock and a subsystem for distributing time signals from the master clock to end users is undergoing development to satisfy anticipated timing requirements of NASA’s Deep Space Network (DSN) for the next 20 to 30 years. The developmental system is intended to supplant the aging DSN frequency and timing subsystem (FTS), which, while historically reliable, is complex, has limited distribution capacity and has become increasingly difficult to operate and sustain. This system has a modular, flexible, expandable architecture that is easier to operate and maintain than the present FTS. Replicas of this system could be useful in laboratories and other facilities in which there are stringent timing requirements that could include requirements to distribute precise time signals over long distances.

Posted in: Briefs, TSP, Electronics & Computers, Calibration, Architecture, Wireless communication systems, Spacecraft

Synchronous Phase-Resolving Flash Range Imaging

Complete range images are generated, without scanning, at a video frame rate.

The figure is a simplified diagram of an apparatus, now undergoing development, for range imaging based on measurement of the round-trip phase delay of a pulsed laser beam. Variants of this apparatus could be used to provide range information needed for navigation of autonomous robotic ground vehicles and robotic aircraft, and for navigation and aiming in numerous military applications.

Posted in: Briefs, TSP, Electronics & Computers, Imaging and visualization, Lasers, Navigation and guidance systems, Robotics, Autonomous vehicles, Unmanned aerial vehicles

Bar-Code System for a Microbiological Laboratory

Time is saved and the incidence of errors is greatly reduced.

A bar-code system (see figure) has been assembled for a microbiological laboratory that must examine a large number of samples. The system includes a commercial bar-code reader, computer hardware and software components, plus custom-designed database software. The software generates a user-friendly, menu-driven interface.

Posted in: Briefs, TSP, Electronics & Computers, Identification, Test facilities

Integrated Radial Probe Transition From MMIC to Waveguide

Packaging based on wire bonding would be supplanted by monolithic integration.

A radial probe transition between a monolithic microwave integrated circuit (MMIC) and a waveguide has been designed for operation at frequency of 340 GHz and to be fabricated as part of a monolithic unit that includes the MMIC. Integrated radial probe transitions like this one are expected to be essential components of future MMIC amplifiers operating at frequencies above 200 GHz. While MMIC amplifiers for this frequency range have not yet been widely used because they have only recently been developed, there are numerous potential applications for them — especially in scientific instruments, test equipment, radar, and millimeter- wave imaging systems for detecting hidden weapons.

Posted in: Briefs, TSP, Semiconductors & ICs, Integrated circuits, Waveguides, Test equipment and instrumentation

MMIC Amplifier Produces Gain of 10 dB at 235 GHz

This is the fastest MMIC amplifier reported to date.

The first solid-state amplifier capable of producing gain at a frequency >215 GHz has been demonstrated. This amplifier is an intermediate product of a continuing effort to develop amplifiers having the frequency and gain characteristics needed for a forthcoming generation of remote-sensing instruments for detecting water vapor and possibly other atmospheric constituents. There are also other potential uses for such amplifiers in wide-band communications, automotive radar, and millimeter- wave imaging for inspecting contents of opaque containers.

Posted in: Briefs, TSP, Semiconductors & ICs, Amplifiers, Remote sensing, Test equipment and instrumentation

Better Finite-Element Analysis of Composite Shell Structures

A computer program implements a finite-element-based method of predicting the deformations of thin aerospace structures made of isotropic materials or anisotropic fiber-reinforced composite materials. The technique and corresponding software are applicable to thin shell structures in general and are particularly useful for analysis of thin beamlike members having open cross-sections (e.g. I-beams and C-channels) in which significant warping can occur.

Posted in: Briefs, TSP, Software, Aircraft structures, Finite element analysis, Computer software and hardware, Composite materials, Fibers

Computing Spacecraft-Pointing Vectors for Limb Tracking

LMBTRK is a computer program that is used together with two software libraries known as ERHAND and HYBRRD to generate spacecraft-pointing vectors for limb-tracking maneuvers needed for experiments on propagation of radio signals through planetary atmospheres. LMBTRK determines, as a function of time, the direction in which one must point a ray (representing a radio beam) emitted by a spacecraft in order to make the ray pass through a planetary atmosphere on its way to a receiving station at a known location. LMBTRK was written for Sun computers running the Solaris operating system and has been running on a cluster of such computers used in the Radio Science System of the Cassini Spacecraft mission.

Posted in: Briefs, TSP, Software, Computer software and hardware, Spacecraft

Enhanced Master Controller Unit Tester

The Enhanced Master Controller Unit Tester (EMUT) software is a tool for development and testing of software for a master controller (MC) flight computer. The primary function of the EMUT software is to simulate interfaces between the MC computer and external analog and digital circuitry (including other computers) in a rack of equipment to be used in scientific experiments. The simulations span the range of nominal, off-nominal, and erroneous operational conditions, enabling the testing of MC software before all the equipment becomes available.

Posted in: Briefs, TSP, Software, Computer simulation, Computer software and hardware

Rover Graphical Simulator

Rover Graphical Simulator (RGS) is a package of software that generates images of the motion of a wheeled robotic exploratory vehicle (rover) across terrain that includes obstacles and regions of varying traversability. The simulated rover moves autonomously, utilizing reasoning and decision-making capabilities of a fuzzy-logic navigation strategy to choose its path from an initial to a final state. RGS provides a graphical user interface for control and monitoring of simulations.

Posted in: Briefs, TSP, Software, Wheels, Computer simulation, Fuzzy logic, Terrain, Robotics, Autonomous vehicles

Increasing Durability of Flame-Sprayed Strain Gauges

Low-oxygen heat treatments and internal platinum oxygen-diffusion barriers extend lifetimes.

Thermally sprayed dielectric ceramic coatings are the primary means of attaching strain and temperature gauges to hot-section rotating parts of turbine engines. As hot-section temperatures increase, lifetimes of installed gauges decrease, and seldom exceed one hour above 2,000 °F ( ≈1,100 °C). Advanced engine components are expected to operate at temperatures approaching 2,200 °F ( ≈1,200 °C), and the required high-temperature lifetime is 10 hours minimum.

Posted in: Briefs, Materials, Ceramics, Coatings, colorants, and finishes, Gas turbines, Test equipment and instrumentation

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