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WinPlot

WinPlot is a powerful desktop graphical analysis tool that allows the user to generate displays of unrestrictive amounts of data. It is designed to operate on a Windows 98/NT/2000 based desktop platform. WinPlot was developed to fulfill the need for fast and easily managed graphical displays of NASA test articles and facilities with extreme amount of test data in a desktop-computer environment. WinPlot features include seamless displays of real-time and post-test-time data with time and event synchronization of data from multiple sources. WinPlot also processes full scripting capability for automation of processes. Entire analysis procedures may be recorded and replayed with a single command. Users may record their actions within WinPlot or may write scripts using text editor. Scripts may also call and execute other scripts, providing even greater automation of tasks. WinPlot is also unique in its ability to plot large volumes of data on a desktop workstation. Up to 1,000 test data files may be opened simultaneously with plots generated containing up to 1,000 curves per plot. WinPlot also has extensive abilities in generation of “on-the-fly” calculations, reducing or eliminating the need for external programs to generate the data. Calculations may include a series of recorded parameters, constants, and math functions. WinPlot’s ability to export plots on a single mouse click can make easy work of preparing presentation material with office applications. One simply produces the plot with desired style and click of a button on the tool bar. Plots will be saved in a predefined folder with a sortable naming convention.

Posted in: Software, Briefs

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Software for Automated Testing of Mission-Control Displays

MCC Display Cert Tool is a set of software tools for automated testing of computer terminal displays in spacecraft mission-control centers, including those of the space shuttle and the International Space Station. This software makes it possible to perform tests that are more thorough, take less time, and are less likely to lead to erroneous results, relative to tests performed manually.

Posted in: Software, Briefs

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Solar-Powered Airplane With Cameras and WLAN

High-resolution images are sent to a ground station in nearly real time. An experimental airborne remote sensing system includes a remotely controlled, lightweight, solar-powered airplane (see figure) that carries two digital-output electronic cameras and communicates with a nearby ground control and monitoring station via a wireless local-area network (WLAN). The speed of the airplane — typically <50 km/h — is low enough to enable loitering over farm fields, disaster scenes, or other areas of interest to collect high resolution digital imagery that could be delivered to end users (e.g., farm managers or disaster-relief coordinators) in nearly real time.

Posted in: Physical Sciences, Briefs

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A Resonator for Low-Threshold Frequency Conversion

A nonlinear dielectric whispering-gallery resonator would be poled for quasiphase-matching. A proposed toroidal or disklike dielectric optical resonator (dielectric optical cavity) would be made of an optically nonlinear material and would be optimized for use in parametric frequency conversion by imposition of a spatially periodic permanent electric polarization. The poling (see figure) would suppress dispersions caused by both the material and the geometry of the optical cavity, thereby effecting quasi-matching of the phases of high-resonance-quality (high-Q) whispering-gallery electromagnetic modes. The quasi-phase-matching of the modes would serve to maximize the interactions among them. Such a resonator might be a prototype of a family of compact, efficient nonlinear devices for operation over a broad range of optical wavelengths.

Posted in: Physical Sciences, Briefs, TSP

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Helicity in Supercritical O2/H2 and C7H16/N2 Mixing Layers

This report describes a study of databases produced by direct numerical simulation of mixing layers developing between opposing flows of two fluids under supercritical conditions, the purpose of the study being to elucidate chemical species-specific aspects of turbulence, with emphasis on helicity. The simulations were performed for two different fluid pairs — O2/H2 and C7H16/N2 — at similar values of reduced pressure.

Posted in: Physical Sciences, Briefs, TSP

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Alternative Attitude Commanding and Control for Precise Spacecraft Landing

A report proposes an alternative method of control for precision landing on a remote planet. In the traditional method, the attitude of a spacecraft is required to track a commanded translational acceleration vector, which is generated at each time step by solving a two-point boundary value problem. No requirement of continuity is imposed on the acceleration. The translational acceleration does not necessarily vary smoothly. Tracking of a nonsmooth acceleration causes the vehicle attitude to exhibit undesirable transients and poor pointing stability behavior. In the alternative method, the two-point boundary value problem is not solved at each time step. A smooth reference position profile is computed. The profile is recomputed only when the control errors get sufficiently large. The nominal attitude is still required to track the smooth reference acceleration command. A steering logic is proposed that controls the position and velocity errors about the reference profile by perturbing the attitude slightly about the nominal attitude. The overall pointing behavior is therefore smooth, greatly reducing the degree of pointing instability.

Posted in: Mechanical Components, Briefs, TSP

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Nanocarpets for Trapping Microscopic Particles

Properties of nanocarpets can be tailored for selective trapping. Nanocarpets — that is, carpets of carbon nanotubes — are undergoing development as means of trapping microscopic particles for scientific analysis. Examples of such particles include inorganic particles, pollen, bacteria, and spores. Nanocarpets can be characterized as scaled-down versions of ordinary macroscopic floor carpets, which trap dust and other particulate matter, albeit not purposefully. Nanocarpets can also be characterized as mimicking both the structure and the particle-trapping behavior of ciliated lung epithelia, the carbon nanotubes being analogous to cilia (see figure).

Posted in: Materials, Briefs, TSP

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