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At least 667 records · Page 37

A report on the USL NASA/RECON project. Part 2: PC-based R and D in support of IS and R applications

This Working Paper Series entry describes the PC R and D development effort initiated as part of the NASA/RECON Project at the University of Southwestern Louisiana. This effort involves the development of a PC-based environment for the prototyping and evaluation of various tools designed to enhance the interaction between scientists and engineers and remote information systems. The design of PC-based tools for the enhancement of the NASA/RECON university-level courses is described as well as the design of a multi-functional PC-based workstation to support access to and processing of information from local, distributed, and remote sources. Course preparation activities are described in a companion report entitled A Report on the USL NASA/RECON Project: Part 1, the Development of a Transportable, University-Level, IS and R Educational Program, by Suzy Gallagher and Martin Granier, USL/DBMS NASA/RECON Working Paper Series report number DBMS.NASA/RECON-7.

Dominick, Wayne D.↗

Computational methods and software systems for dynamics and control of large space structures

The deployment, assembly and mission-oriented maneuvering of space structures in orbit will trigger large motions of flexible, truss-type structures. In addition, the presence of on-board controls both for attitude stabilization and specified vibration tolerance requirements may further complicate the dynamic behavior of the orbiting structures. Because of safety and cost considerations, the dynamic response of the combined structural and control systems must be predicted reliably. This need can only be met through the development of reliable and efficient simulation capabilities, since there is general agreement that on-orbit experiments should be limited because of cost, time and facility constraints. The long-term objective of this research effort is to develop a next-generation computer simulator for the dynamics and control of large space structures. The simulator will be based on integrating four research thrusts: a new multibody dynamics formulation methodology, modeling capabilities in long/slender truss-beam components with realistic joints, efficient computational procedures that can be implemented either in sequential or concurrent computers, and prototype simulation modules that can be easily processed into a modern large-scale engineering software system such as the NASA/Computational Structural Mechanics (CSM) testbed.

Park, K. C.↗

An engineering approach to automatic programming

An exploratory study of the automatic generation and optimization of symbolic programs using DECOM - a prototypical requirement specification model implemented in pure LISP was undertaken. It was concluded, on the basis of this study, that symbolic processing languages such as LISP can support a style of programming based upon formal transformation and dependent upon the expression of constraints in an object-oriented environment. Such languages can represent all aspects of the software generation process (including heuristic algorithms for effecting parallel search) as dynamic processes since data and program are represented in a uniform format.

Rubin, Stuart H.↗

Systems Engineering and Integration (SE and I)

The issue of technology advancement and future space transportation vehicles is addressed. The challenge is to develop systems which can be evolved and improved in small incremental steps where each increment reduces present cost, improves, reliability, or does neither but sets the stage for a second incremental upgrade that does. Future requirements are interface standards for commercial off the shelf products to aid in the development of integrated facilities; enhanced automated code generation system slightly coupled to specification and design documentation; modeling tools that support data flow analysis; and shared project data bases consisting of technical characteristics cast information, measurement parameters, and reusable software programs. Topics addressed include: advanced avionics development strategy; risk analysis and management; tool quality management; low cost avionics; cost estimation and benefits; computer aided software engineering; computer systems and software safety; system testability; and advanced avionics laboratories - and rapid prototyping. This presentation is represented by viewgraphs only.

Chevers, ED↗

Design, Progressive Modeling, Manufacture, and Testing of Composite Shield for Turbine Engine Blade Containment

An effective design methodology was established for composite jet engine containment structures. The methodology included the development of the full and reduced size prototypes, and FEA models of the containment structure, experimental and numerical examination of the modes of failure clue to turbine blade out event, identification of materials and design candidates for future industrial applications, and design and building of prototypes for testing and evaluation purposes.

Binienda, Wieslaw K.↗

Prototype Tool Support for SEI Process and Risk Knowledge

We have developed a prototype of tool support for risk assessment that uses selected components of the Software Engineering Institute (SEI) information, specifically: Capability Maturity Model (CMM) process activities, CMM process goals and the SEI taxonomy of software project risks.

risk management risk assessment SEI CMM software r↗

"Smart" Sensor Module

An assembly that contains a sensor, sensor-signal-conditioning circuitry, a sensor-readout analog-to-digital converter (ADC), data-storage circuitry, and a microprocessor that runs special-purpose software and communicates with one or more external computer(s) has been developed as a prototype of "smart" sensor modules for monitoring the integrity and functionality (the "health") of engineering systems. Although these modules are now being designed specifically for use on rocket-engine test stands, it is anticipated that they could also readily be designed to be incorporated into health-monitoring subsystems of such diverse engineering systems as spacecraft, aircraft, land vehicles, bridges, buildings, power plants, oilrigs, and defense installations. The figure is a simplified block diagram of the "smart" sensor module. The analog sensor readout signal is processed by the ADC, the digital output of which is fed to the microprocessor. By means of a standard RS-232 cable, the microprocessor is connected to a local personal computer (PC), from which software is downloaded into a randomaccess memory in the microprocessor. The local PC is also used to debug the software. Once the software is running, the local PC is disconnected and the module is controlled by, and all output data from the module are collected by, a remote PC via an Ethernet bus. Several smart sensor modules like this one could be connected to the same Ethernet bus and controlled by the single remote PC. The software running in the microprocessor includes driver programs for operation of the sensor, programs that implement self-assessment algorithms, programs that implement protocols for communication with the external computer( s), and programs that implement evolutionary methodologies to enable the module to improve its performance over time. The design of the module and of the health-monitoring system of which it is a part reflects the understanding that the main purpose of a health-monitoring system is to detect damage and, therefore, the health-monitoring system must be able to function effectively in the presence of damage and should be capable of distinguishing between damage to itself and damage to the system being monitored. A major benefit afforded by the self-assessment algorithms is that in the output of the module, the sensor data indicative of the health of the engineering system being monitored are coupled with a confidence factor that quantifies the degree of reliability of the data. Hence, the output includes information on the health of the sensor module itself in addition to information on the health of the engineering system being monitored.

Mahajan, Ajay↗

Development, Implementation, and Pilot Evaluation of a Model-Driven Envelope Protection System to Mitigate the Hazard of In-Flight Ice Contamination on a Twin-Engine Commuter Aircraft

Fatal loss-of-control accidents have been directly related to in-flight airframe icing. The prototype system presented in this report directly addresses the need for real-time onboard envelope protection in icing conditions. The combination of prior information and real-time aerodynamic parameter estimations are shown to provide sufficient information for determining safe limits of the flight envelope during inflight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system was designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. The utility of the ICEPro system for mitigating a potentially hazardous icing condition was evaluated by 29 pilots using the NASA Ice Contamination Effects Flight Training Device. Results showed that real time assessment cues were effective in reducing the number of potentially hazardous upset events and in lessening exposure to loss of control following an incipient upset condition. Pilot workload with the added ICEPro displays was not measurably affected, but pilot opinion surveys showed that real time cueing greatly improved their awareness of a hazardous aircraft state. The performance of ICEPro system was further evaluated by various levels of sensor noise and atmospheric turbulence.

simulation training↗

Cubesat Application for Planetary Entry (CAPE) Missions: Micro-Reentry Capsule (MIRCA)

The Cubesat Application for Planetary Entry Missions (CAPE) concept describes a high-performing Cubesat system which includes a propulsion module and miniaturized technologies capable of surviving atmospheric entry heating, while reliably transmitting scientific and engineering data. The Micro Return Capsule (MIRCA) is CAPEs first planetary entry probe flight prototype. Within this context, this paper briefly describes CAPEs configuration and typical operational scenario, and summarizes ongoing work on the design and basic aerodynamic characteristics of the prototype MIRCA vehicle. CAPE not only opens the door to new planetary mission capabilities, it also offers relatively low-cost opportunities especially suitable to university participation.

micro-return capsule↗

Full-Scale Vessel Testing of the Standard High-Solids Vessel for the Hanford Waste Treatment Plant Pretreatment Facility - 17282

Concerns over the mixing performance of the planned pulse-jet mixed (PJM) vessels for high solids applications in the Hanford Waste Treatment and Immobilization Plant (WTP) Pretreatment (PT) Facility, led to the development of a standard high-solids vessel (SHSV) design and full-scale vessel testing. The SHSV is intended as a potential replacement for several high-level waste feed receipt and lag storage vessels, ultrafiltration feed preparation vessels, and plant wash vessels. The SHSV design concept uses multiple smaller vessels (60 500 to 79 500 liters nominal batch size) to replace larger vessels, providing redundancy, improved mixing (PJM design and spargers), monitoring (multi-level bubblers), reduced material at risk, and improved structural features. The SHSV also requires qualification of a single vessel design for high solids Newtonian and non-Newtonian slurry processing, rather than earlier multiple vessel designs. Qualification of the SHSV design for mixing will be achieved through full-scale vessel testing (FSVT) with a prototypic SHSV under a set of most adverse design conditions in conjunction with additional engineering analyses. An Integrated Technical Team consisting of the U.S. Department of Energy (DOE), Bechtel National, Inc. (BNI), and independent experts was established to accelerate and provide oversight and direction to the test program and SHSV qualification. This paper will present an overview of the SHSV, full-scale vessel test and qualification program, and the management program to achieve closure of technical issues associated with PJM vessel mixing and control systems. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Full-Scale Vessel Testing for the Hanford Waste Treatment and Immobilization Plant - 18333

Concerns over the mixing performance of the planned pulse jet mixed (PJM) vessels for high-solids applications in the Hanford Waste Treatment and Immobilization Plant (WTP) Pretreatment (PT) Facility, led to the development of a standard high-solids vessel (SHSV) design and full-scale vessel testing program. The SHSV is intended as a potential replacement for several high-level waste feed receipt and lag storage vessels (High-Level Waste Facility lag storage and feed blending process), ultrafiltration feed preparation vessels (ultrafiltration process system), and plant wash vessels (plant wash and disposal system). The SHSV concept uses multiple smaller vessels (60 500 L - 79 500 L nominal batch size) to replace larger vessels, providing redundancy, improved mixing (PJM design and spargers), monitoring (multi-level bubblers), reduced material at risk, and improved structural features. The SHSV also requires qualification of a single vessel design for high solids Newtonian and non-Newtonian slurry processing, rather than having to qualify earlier multiple vessel designs. An Integrated Technical Team consisting of the U.S. Department of Energy, Bechtel National, Inc., and independent experts was established to accelerate and provide oversight and direction of the test program and SHSV qualification. Qualification of the SHSV for mixing has now been achieved through a comprehensive full-scale vessel testing program conducted in 2017 with a prototypic SHSV under a set of most adverse design conditions, in conjunction with additional engineering analyses. This paper will present an overview of the SHSV, results from the three-phase full-scale vessel test and qualification program completed in September 2017, and the management program to achieve resolution of the PJM mixing technical issue. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Mobility analysis, simulation, and scale model testing for the design of wheeled planetary rovers

The use of computer based techniques to model and simulate wheeled rovers on rough natural terrains is considered. Physical models of a prototype vehicle can be used to test the correlation of the simulations in scaled testing. The computer approaches include a quasi-static planar or two dimensional analysis and design tool based on the traction necessary for the vehicle to have imminent mobility. The computer program modeled a six by six wheel drive vehicle of original kinematic configuration, called the Rocker Bogie. The Rocker Bogie was optimized using the quasi-static software with respect to its articulation parameters prior to fabrication of a prototype. In another approach used, the dynamics of the Rocker Bogie vehicle in 3-D space was modeled on an engineering workstation using commercial software. The model included the complex and nonlinear interaction of the tire and terrain. The results of the investigation yielded numerical and graphical results of the rover traversing rough terrain on the earth, moon, and Mars. In addition, animations of the rover excursions were also generated. A prototype vehicle was then used in a series of testbed and field experiments. Correspondence was then established between the computer models and the physical model. The results indicated the utility of the quasi-static tool for configurational design, as well as the predictive ability of the 3-D simulation to model the dynamic behavior of the vehicle over short traverses.

Lindemann, Randel A.↗

Secure Web-based Ground System User Interfaces over the Open Internet

A prototype has been developed which makes use of commercially available products in conjunction with the Java programming language to provide a secure user interface for command and control over the open Internet. This paper reports successful demonstration of: (1) Security over the Internet, including encryption and certification; (2) Integration of Java applets with a COTS command and control product; (3) Remote spacecraft commanding using the Internet. The Java-based Spacecraft Web Interface to Telemetry and Command Handling (Jswitch) ground system prototype provides these capabilities. This activity demonstrates the use and integration of current technologies to enable a spacecraft engineer or flight operator to monitor and control a spacecraft from a user interface communicating over the open Internet using standard World Wide Web (WWW) protocols and commercial off-the-shelf (COTS) products. The core command and control functions are provided by the COTS Epoch 2000 product. The standard WWW tools and browsers are used in conjunction with the Java programming technology. Security is provided with the current encryption and certification technology. This system prototype is a step in the direction of giving scientist and flight operators Web-based access to instrument, payload, and spacecraft data.

Langston, James H.↗

A Novel Approach for Engaging Academia in Collaborative Projects with NASA through the X-Hab Academic Innovation Challenge

The X-Hab Academic Innovation Challenge, currently in its sixth year of execution, provides university students with the opportunity to be on the forefront of innovation. The X-Hab Challenge, for short, is designed to engage and retain students in Science, Technology, Engineering and Math (STEM). NASA identifies necessary technologies and studies for deep space missions and invites universities from around the country to develop concepts, prototypes, and lessons learned that will help shape future space missions and awards seed funds to design and produce functional products of interest as proposed by university teams according to their interests and expertise. Universities propose on a variety of projects suggested by NASA and are then judged on technical merit, academic integration, leveraged funding, and outreach. The universities assemble a multi-discipline team of students and advisors that invest months working together, developing concepts, and frequently producing working prototypes. Not only are students able to gain quality experience, working real world problems that have the possibility to be implemented, but they work closely with subject matter experts from NASA who guide them through an official engineering development process.

Habitats↗

A Novel Approach for Engaging Academia in Collaborative Projects with NASA through the X-Hab Academic Innovation Challenge

The X-Hab Academic Innovation Challenge, currently in its sixth year of execution, provides university students with the opportunity to be on the forefront of innovation. The X-Hab Challenge, for short, is designed to engage and retain students in Science, Technology, Engineering and Math (STEM). NASA identifies necessary technologies and studies for deep space missions and invites universities from around the country to develop concepts, prototypes, and lessons learned that will help shape future space missions and awards seed funds to design and produce functional products of interest as proposed by university teams according to their interests and expertise. Universities propose on a variety of projects suggested by NASA and are then judged on technical merit, academic integration, leveraged funding, and outreach. The universities assemble a multi-discipline team of students and advisors that invest months working together, developing concepts, and frequently producing working prototypes. Not only are students able to gain quality experience, working real world problems that have the possibility of be implemented, but they work closely with subject matter experts from NASA who guide them through an official engineering development process.

X-Hab Challenge↗

Knowledge engineering for temporal dependency networks as operations procedures

This paper presents a case study of the knowledge engineering process employed to support the Link Monitor and Control Operator Assistant (LMCOA). The LMCOA is a prototype system which automates the configuration, calibration, test, and operation (referred to as precalibration) of the communications, data processing, metric data, antenna, and other equipment used to support space-ground communications with deep space spacecraft in NASA's Deep Space Network (DSN). The primary knowledge base in the LMCOA is the Temporal Dependency Network (TDN), a directed graph which provides a procedural representation of the precalibration operation. The TDN incorporates precedence, temporal, and state constraints and uses several supporting knowledge bases and data bases. The paper provides a brief background on the DSN, and describes the evolution of the TDN and supporting knowledge bases, the process used for knowledge engineering, and an analysis of the successes and problems of the knowledge engineering effort.

Fayyad, Kristina E.↗

Simulating Avionics Upgrades to the Space Shuttles

Cockpit Avionics Prototyping Environment (CAPE) is a computer program that simulates the functions of proposed upgraded avionics for a space shuttle. In CAPE, pre-existing space-shuttle-simulation programs are merged with a commercial-off-the-shelf (COTS) display-development program, yielding a package of software that enables high-fi46 NASA Tech Briefs, September 2008 delity simulation while making it possible to rapidly change avionic displays and the underlying model algorithms. The pre-existing simulation programs are Shuttle Engineering Simulation, Shuttle Engineering Simulation II, Interactive Control and Docking Simulation, and Shuttle Mission Simulator playback. The COTS program Virtual Application Prototyping System (VAPS) not only enables the development of displays but also makes it possible to move data about, capture and process events, and connect to a simulation. VAPS also enables the user to write code in the C or C++ programming language and compile that code into the end-product simulation software. As many as ten different avionic-upgrade ideas can be incorporated in a single compilation and, thus, tested in a single simulation run. CAPE can be run in conjunction with any or all of four simulations, each representing a different phase of a space-shuttle flight.

Deger, Daniel↗

Modeling and ZVS Operation of the Isolated Modular Multilevel DC–DC Converter With a Unified Trapezoidal Wave Modulation

Here, this article introduces a unified trapezoidal wave (UTW) modulation scheme for the isolated modular multilevel dc–dc (IM2dc) converter, which consolidates multiple existing modulation strategies for the IM2dc converter, including the quasi-square wave (QSW) modulation, trapezoidal wave modulation, and sinusoidal wave modulation, into a unified framework. Furthermore, this article introduces the harmonic state-space (HSS) equations to model the IM2dc converter based on the UTW modulation method. The HSS model operates in the frequency domain, enabling it to circumvent the complexities associated with time-domain analysis and seamlessly integrate with the UTW modulation. This article proceeds to analyze the real and reactive power transfer characteristics of the IM2dc converter, as well as the power factor, considering the influence of multiple modulation parameters. Subsequently, it delves into the examination of zero voltage switching (ZVS) conditions for the IM2dc converter based on the UTW modulation and the HSS model. The complete ZVS boundaries of the IM2dc converter, taking various voltage ratios into account, are derived. This article also illustrates the effects of including harmonic orders in the modeling process, modulation parameters, and internal harmonic ripples on the ZVS boundaries. Finally, experimental validation of the analyses is conducted on a down-scaled prototype.

42 ENGINEERING↗