Information Technology & Software

Electronic Storage and Retrieval of Engineering Documents

Drawings can be retrieved from a remote central site, manipulated, and printed locally.

The KSC Electronic Documentation System (KEDS) is a computer-intranet system at Kennedy Space Center (KSC) for the storage and retrieval of engineering drawings and other engineering documents that have been officially released. Prior to the development of the KEDS, microfilm copies of engineering documents were stored in an archive at the Engineering Document Center (EDC) in the KSC headquarters building; engineers and drafters had to travel from remote sites to the EDC to view microfilm images of drawings, and the cost of fulfilling requests for documents (including printing paper copies) was considerable.

Posted in: Briefs, Information Sciences, Data management, Documentation, Technical review

Software Assists in the Development of Optimization Models

This program automates much of the model-development process.

Optimization Modeling Assistant (OMA) is an expert-system computer program that assists its users in the development of mathematical and algorithmic models for optimization. As used here, "optimization" refers to a suite of powerful decision-support techniques that enable the modeling of any decision-making environment in terms of the objectives, the decisions that potentially influence the objectives, and a set of constraints that bind the decisions. Optimization analysis helps decision makers in identifying decisions that optimize their objectives. Domains in which optimization modeling are applied include real-time scheduling, logistics, planning, and financial management.

Posted in: Briefs, TSP, Information Sciences, Optimization, Simulation and modeling, Computer software and hardware

Interface Program for Generation of Computational Grids

Computer Aided Grid Interface (CAGI) is a computer program that serves as an interface between computer-aided design/computer-aided manufacturing (CAD/CAM) programs and computational fluid dynamics (CFD) programs. CAGI reads Initial Graphics Exchange Specification (IGES) files from CAD/CAM programs and converts from CAD/CAM geometries to nonuniform rational B-splice (NURBS) surfaces to be manipulated or written out in forms appropriate for generation of grids for CFD.

Posted in: Briefs, Information Sciences, CAD, CAM, and CAE, Computational fluid dynamics, Communication protocols, Computer software and hardware

Analyzing Time Series Using EMD and Hilbert Spectra

Complicated sets of data can be decomposed into finite collections of intrinsic mode functions.

A recently developed theoretical and computational method is especially well suited for analyzing time-series data that represent nonstationary and nonlinear processes. The method stands in contrast to classical methods, including Fourier analysis, that are generally applicable only to periodic or stationary data that represent linear processes. The present method is based principally on the concept of empirical mode decomposition (EMD), according to which any complicated set of data can be decomposed into a finite (and often small) number of functions, called "intrinsic mode functions" (IMFs), that admit well-behaved Hilbert transforms.

Posted in: Briefs, TSP, Information Sciences, Analysis methodologies

Software Collects Planning and Scheduling Requirements

Interim User's Requirements Collection (IURC) is a software system that generates an interactive graphical user interface that enables users of the International Space Station (ISS) to specify their payload-planning and -scheduling requirements via the World Wide Web (WWW). IURC includes (1) a Java applet that is dynamically distributed via the WWW and (2) four application programs that run on a dedicated host computer with a web server at Marshall Space Flight Center (MSFC).

Posted in: Briefs, Information Sciences, Computer software and hardware, Internet, Human machine interface (HMI), Spacecraft

Software for Ground Processing of Data From Landsat 7

Three computer programs have been developed for ground processing of Enhanced Thematic Mapper Plus (ETM+) data from Landsat 7. The three programs and their functions are the following:

Posted in: Briefs, Information Sciences, Computer software and hardware, Data acquisition and handling

Fast Observers for Spacecraft Pointing Control

A report discusses the design of fast stochastic observers for spacecraft pointing control. In this special context, "observers" signifies mathematical algorithms, implemented on computers aboard spacecraft, through which one processes sensory data (principally, the outputs of star trackers and gyroscopes) to estimate the states (attitudes and angular velocities) of the spacecraft. The development in the report was motivated by the presence of an attitude-dependent bias error in the star-tracker measurement associated with NASA's upcoming SIRTF (Space Infra-Red Telescope Facility) space telescope. This attitude-dependent bias term lies outside of basic linear estimation assumption, and the well-established Kalman theory is no longer optimal. The attitude-dependent bias term forces a step response through the dynamics of the onboard estimator each time the spacecraft is repositioned. If an optimal Kalman filter were used, its sluggish dynamics would create a long undesirable lingering output drift in the pointing response. While this drift error is small (e.g., at the arcsecond level) it cannot be ignored for space telescope applications, and is the main reason that Kalman filters are routinely replaced by simple observers on important missions with stringent pointing requirements such as the Hubble Space Telescope and SIRTF.

Posted in: Briefs, TSP, Information Sciences, Physical Sciences, Mathematical models, Air data computers, Optics, Spacecraft guidance

Program for Viewing Remotely Generated Summary Data

The Beacon Visualization (BeaVis) computer program provides a ground-based computing environment for displaying, tracking, storing, and maneuvering through telemetric data streams that contain summaries of engineering data generated aboard a spacecraft. BeaVis can also serve as a general-purpose software tool for monitoring data of other specific types. In the original spacecraft-to-ground application, BeaVis enables the user to scroll through a graphical depiction of telemetry downlinks to select desired data. Summary data are represented graphically, with hypertext links to strip charts of sensor channels represented by summary data packets. BeaVis also generates time-line and tabular displays. A time line depicts when, during a spacecraft mission, summary downlinks and beacon tone detections have occurred. The tabular and strip-chart displays are available through hypertext links from the time-line display. BeaVis also provides graphical user interface elements that show such specific summary data components as changes in mission activities, snapshot telemetry, episode data, and user summary data. The program also includes a software tool for creating tables of parameters that are uploaded to a spacecraft.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Data acquisition and handling, Imaging and visualization, Telemetry

Numerical Speed of Sound

This concept is applicable to flows at all speeds.

The numerical speed of sound is a variable that is used in the numerical solution of flows from low to high speeds. The numerical speed of sound is an effective speed of sound associated with Mach numbers used in the numerical splitting of a flow into upwind and downwind mass-flux components that are defined on the faces of cells of a computational grid into which a flow volume is divided. Depending on the details of a given flow problem and the algorithm chosen to solve it, the numerical speed of sound may or may not equal the physical speed of sound.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Noise

Knowledge-Based Software for Generating and Changing Plans

Effects of changes in requirements and resources are automatically taken into account.

A methodology of computer-aided planning has been developed to (1) accelerate the generation of plans for activities within complex systems of personnel and equipment; (2) increase the quality of the plans thus generated; and (3) decrease the difficulty of predicting and responding to the effects of changes in plans, requirements, resources, and/or other constraints. Originally intended for application to planning of missions of the space shuttle and other spacecraft, the methodology could also be applied to strategic business planning, management of projects, general scheduling, and planning of manufacturing processes and systems.

Posted in: Briefs, Information Sciences, Artificial intelligence, Computer software and hardware, Systems management, Spacecraft

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