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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Advanced satellite workstation: An integrated workstation environment for operational support of satellite system planning and analysis

A prototype integrated environment, the Advanced Satellite Workstation (ASW), is described that has been developed and delivered for evaluation and operator feedback in an operational satellite control center. The current ASW hardware consists of a Sun Workstation and Macintosh II Workstation connected via an ethernet Network Hardware and Software, Laser Disk System, Optical Storage System, and Telemetry Data File Interface. The central mission of ASW is to provide an intelligent decision support and training environment for operator/analysts of complex systems such as satellites. There have been many workstation implementations recently which incorporate graphical telemetry displays and expert systems. ASW is a considerably broader look at intelligent, integrated environments for decision support, based upon the premise that the central features of such an environment are intelligent data access and integrated toolsets. A variety of tools have been constructed in support of this prototype environment including: an automated pass planner for scheduling vehicle support activities, architectural modeler for hierarchical simulation and analysis of satellite vehicle subsystems, multimedia-based information systems that provide an intuitive and easily accessible interface to Orbit Operations Handbook and other relevant support documentation, and a data analysis architecture that integrates user modifiable telemetry display systems, expert systems for background data analysis, and interfaces to the multimedia system via inter-process communication.

Sutton, Stewart A.↗
NASA NTRS2003

Performance Evaluation of Electrochem's PEM Fuel Cell Power Plant for NASA's 2nd Generation Reusable Launch Vehicle

NASA's Next Generation Launch Technology (NGLT) program is being developed to meet national needs for civil and commercial space access with goals of reducing the launch costs, increasing the reliability, and reducing the maintenance and operating costs. To this end, NASA is considering an all- electric capability for NGLT vehicles requiring advanced electrical power generation technology at a nominal 20 kW level with peak power capabilities six times the nominal power. The proton exchange membrane (PEM) fuel cell has been identified as a viable candidate to supply this electrical power; however, several technology aspects need to be assessed. Electrochem, Inc., under contract to NASA, has developed a breadboard power generator to address these technical issues with the goal of maximizing the system reliability while minimizing the cost and system complexity. This breadboard generator operates with dry hydrogen and oxygen gas using eductors to recirculate the gases eliminating gas humidification and blowers from the system. Except for a coolant pump, the system design incorporates passive components allowing the fuel cell to readily follow a duty cycle profile and that may operate at high 6:1 peak power levels for 30 second durations. Performance data of the fuel cell stack along with system performance is presented to highlight the benefits of the fuel cell stack design and system design for NGLT vehicles.

Kimble, Michael C.↗
NASA NTRS2010

FAILSAFE Health Management for Embedded Systems

The FAILSAFE project is developing concepts and prototype implementations for software health management in mission- critical, real-time embedded systems. The project unites features of the industry-standard ARINC 653 Avionics Application Software Standard Interface and JPL s Mission Data System (MDS) technology (see figure). The ARINC 653 standard establishes requirements for the services provided by partitioned, real-time operating systems. The MDS technology provides a state analysis method, canonical architecture, and software framework that facilitates the design and implementation of software-intensive complex systems. The MDS technology has been used to provide the health management function for an ARINC 653 application implementation. In particular, the focus is on showing how this combination enables reasoning about, and recovering from, application software problems.

Horvath, Gregory A.↗
NASA NTRS2014

T-MATS Toolbox for the Modeling and Analysis of Thermodynamic Systems

The Toolbox for the Modeling and Analysis of Thermodynamic Systems (T-MATS) is a MATLABSimulink (The MathWorks Inc.) plug-in for creating and simulating thermodynamic systems and controls. The package contains generic parameterized components that can be combined with a variable input iterative solver and optimization algorithm to create complex system models, such as gas turbines.

system modeling↗
NASA NTRSDate not supplied

Runtime Monitoring for Unmanned Aerospace Systems with Neural Network Components

AI components (e.g., Deep Neural Networks) are increasingly used in unmanned Aerospace systems for safety-relevant applications. Rigorous Verification and Validation methods for such components are still in their infancy and thus, monitoring of the AI's behavior during runtime is essential. In this paper, we will present a runtime-monitoring architecture, which combines the advanced statistical analysis framework SYSAI (System Analysis using Statistical AI) with temporal and probabilistic runtime monitoring carried out by R2U2 (Realizable, Responsive, and Unobtrusive Unit). Learned statistical models of complex systems with AI components are produced by the SYSAI framework and provide detailed information to enable the R2U2 runtime monitor to efficiently perform advanced safety and performance checks in nominal and off-nominal conditions. We will present initial results of our tool set and architecture on a case study, a DNN-based autonomous centerline tracking system (ACT).

Yuning He↗
NASA NTRS1994

Object-oriented Technology for Compressor Simulation

An object-oriented basis for interdisciplinary compressor simulation can, in principle, overcome several barriers associated with the traditional structured (procedural) development approach. This paper presents the results of a research effort with the objective to explore the repercussions on design, analysis, and implementation of a compressor model in an object oriented (OO) language, and to examine the ability of the OO system design to accommodate computational fluid dynamics (CFD) code for compressor performance prediction. Three fundamental results are that: (1) the selection of the object oriented language is not the central issue; enhanced (interdisciplinary) analysis capability derives from a broader focus on object-oriented technology; (2) object-oriented designs will produce more effective and reusable computer programs when the technology is applied to issues involving complex system inter-relationships (more so than when addressing the complex physics of an isolated discipline); and (3) the concept of disposable prototypes is effective for exploratory research programs, but this requires organizations to have a commensurate long-term perspective. This work also suggests that interdisciplinary simulation can be effectively accomplished (over several levels of fidelity) with a mixed language treatment (i.e., FORTRAN-C++), reinforcing the notion the OO technology implementation into simulations is a 'journey' in which the syntax can, by design, continuously evolve.

Drummond, C. K.↗
NASA NTRS1991

Simulation-based instruction of technical skills

A rapid intelligent tutoring development system (RAPIDS) was developed to facilitate the production of interactive, real-time graphical device models for use in instructing the operation and maintenance of complex systems. The tools allowed subject matter experts to produce device models by creating instances of previously defined objects and positioning them in the emerging device model. These simulation authoring functions, as well as those associated with demonstrating procedures and functional effects on the completed model, required no previous programming experience or use of frame-based instructional languages. Three large simulations were developed in RAPIDS, each involving more than a dozen screen-sized sections. Seven small, single-view applications were developed to explore the range of applicability. Three workshops were conducted to train others in the use of the authoring tools. Participants learned to employ the authoring tools in three to four days and were able to produce small working device models on the fifth day.

Towne, Douglas M.↗
NASA NTRS1996

Enhanced Molecular Sieve CO2 Removal Evaluation

The objective of this research is to quantitatively characterize the performance of two major types of molecular sieves for two-bed regenerative carbon dioxide removal at the conditions compatible with both a spacesuit and station application. One sorbent is a zeolite-based molecular sieve that has been substantially improved over the materials used in Skylab. The second sorbent is a recently developed carbon-based molecular sieve. Both molecular sieves offer the potential of high payoff for future manned missions by reducing system complexity, weight (including consumables), and power consumption in comparison with competing concepts. The research reported here provides the technical data required to improve CO2 removal systems for regenerative life support systems for future IVA and EVA missions.

Rose, Susan↗
NASA NTRS2011

Simulating New Drop Test Vehicles and Test Techniques for the Orion CEV Parachute Assembly System

The Crew Exploration Vehicle Parachute Assembly System (CPAS) project is engaged in a multi-year design and test campaign to qualify a parachute recovery system for human use on the Orion Spacecraft. Test and simulation techniques have evolved concurrently to keep up with the demands of a challenging and complex system. The primary simulations used for preflight predictions and post-test data reconstructions are Decelerator System Simulation (DSS), Decelerator System Simulation Application (DSSA), and Drop Test Vehicle Simulation (DTV-SIM). The goal of this paper is to provide a roadmap to future programs on the test technique challenges and obstacles involved in executing a large-scale, multi-year parachute test program. A focus on flight simulation modeling and correlation to test techniques executed to obtain parachute performance parameters are presented.

Morris, Aaron L.↗
NASA NTRS2005

Challenges of Developing New Classes of NASA Self-Managing Mission

NASA is proposing increasingly complex missions that will require a high degree of autonomy and autonomicity. These missions pose hereto unforeseen problems and raise issues that have not been well-addressed by the community. Assuring success of such missions will require new software development techniques and tools. This paper discusses some of the challenges that NASA and the rest of the software development community are facing in developing these ever-increasingly complex systems. We give an overview of a proposed NASA mission as well as techniques and tools that are being developed to address autonomic management and the complexity issues inherent in these missions.

Hinchey, M. G.↗
NASA NTRS1989

Integrated control-system design via generalized LQG (GLQG) theory

Thirty years of control systems research has produced an enormous body of theoretical results in feedback synthesis. Yet such results see relatively little practical application, and there remains an unsettling gap between classical single-loop techniques (Nyquist, Bode, root locus, pole placement) and modern multivariable approaches (LQG and H infinity theory). Large scale, complex systems, such as high performance aircraft and flexible space structures, now demand efficient, reliable design of multivariable feedback controllers which optimally tradeoff performance against modeling accuracy, bandwidth, sensor noise, actuator power, and control law complexity. A methodology is described which encompasses numerous practical design constraints within a single unified formulation. The approach, which is based upon coupled systems or modified Riccati and Lyapunov equations, encompasses time-domain linear-quadratic-Gaussian theory and frequency-domain H theory, as well as classical objectives such as gain and phase margin via the Nyquist circle criterion. In addition, this approach encompasses the optimal projection approach to reduced-order controller design. The current status of the overall theory will be reviewed including both continuous-time and discrete-time (sampled-data) formulations.

Bernstein, Dennis S.↗
NASA NTRS1979

Crosstalk cancellation on linearly and circularly polarized communications satellite links

The paper discusses the cancellation network approach for reducing crosstalk caused by depolarization on a dual-polarized communications satellite link. If the characteristics of rain depolarization are sufficiently well known, the cancellation network can be designed in a way that reduces system complexity, the most important parameter being the phase of the cross-polarized signal. Relevant theoretical calculations and experimental data are presented. The simplicity of the cancellation system proposed makes it ideal for use with small domestic or private earth terminals.

Overstreet, W. P.↗
NASA NTRS1990

Potential for integrated optical circuits in advanced aircraft with fiber optic control and monitoring systems

Fiber optic technology is expected to be used in future advanced weapons platforms as well as commercial aerospace applications. Fiber optic waveguides will be used to transmit noise free, high speed data between a multitude of computers as well as audio and video information to the flight crew. Passive optical sensors connected to control computers with optical fiber interconnects will serve both control and monitoring functions. Implementation of fiber optic technology has already begun. Both the military and NASA have several programs in place. A cooperative program, called FOCSI (Fiber Optic Control System Integration), between NASA Lewis and the NAVY to build, environmentally test and flight demonstrate sensor systems for propulsion and flight control systems is currently underway. Integrated Optical Circuits (IOC's) are also being given serious consideration for use in advanced aircraft systems. IOC's will result in miniaturization and localization of components to generate, detect optical signals and process them for use by the control computers. In some complex systems IOC's may be required to perform calculations optically if the technology is ready, replacing some of the electronic systems used today. IOC's are attractive because they will result in rugged components capable of withstanding severe environments in advanced aerospace vehicles. Manufacturing technology developed for microelectronic integrated circuits applied to IOC's will result in cost effective manufacturing. This paper reviews the current FOCSI program and describes the potential role of IOC's in FOCSI applications.

Robert Baumbick↗
NASA NTRS2018

Assessing Alternatives in the Systems Engineering Process: Case Study of an Earth Observing Satellite Concept

Defining design alternatives constitutes one of the critical initial steps of the systems engineering process. Once these design alternatives have been identified, assessing which alternatives best satisfy the project’s objectives can prove to be challenging when dealing with complex decision frameworks. Complex systems often involve the participation of different interest groups, who have different value systems and are focused on distinct aspects of the project. For example, design alternatives might be assessed predominantly for their technical merit by one group of stakeholders, while a different group might be more inclined to assess the design alternatives primarily based on programmatic values. MESCAL (Monitoring the Evolving State of Clouds and Aerosol Layers) is an ongoing NASA / CNES (Centre National d’Etudes Spatiales) joint study for an active remote sensing Earth observing satellite. Several design alternatives have been identified and the assessment of these alternatives requires consideration of a variety of factors. This paper presents the approach that was used to support a global assessment of the MESCAL design alternatives. A mapping of the interactions between mission, instrument, and science requirements was modeled to support the assessment of the trade space. In addition, a set of metrics was developed to structure the assessment that was conducted. Finally, this paper also discusses the general applicability of these metrics to other science mission concepts in the formulation phase.

Ivanco, Marie L.↗
NASA NTRS2025

HabSim: A Modular Coupled Virtual Testbed for Simulating ExtraTerrestrial Habitat Systems

Extraterrestrial habitats involve a tightly coupled combination of hardware, software, and humans while operating in an unforgiving environment that poses many risks, both anticipated and unanticipated. Traditional approaches with such systems of systems focus on reliability, robustness, and redundancy. These approaches seek to avoid failure rather than reduce overall risk. However, faults are inevitable, and understanding and managing the complex and emergent behavior and cascading events of such a complex system is critical. This study describes the development of HabSim, a computational simulation environment intended to support research to establish the know-how to design and operate resilient and autonomous SmartHabs. HabSim is a modular virtual testbed composed of many of the coupled dynamic systems expected in a typical SmartHab. A heterogeneous set of interconnected physics-based and phenomenological models is used to represent the essential functions of a SmartHab. HabSim further considers disruptions and models damage and repair of certain components. This paper discusses a) system and subsystem requirements of the deep space habitat included in the HabSim platform; b) architectural choices made in response to the requirements; c) technical considerations for developing, verifying, configuring, and executing HabSim; and d) illustrative sample results from a simulation of a representative disruption scenario.

Mohsen Azimi↗
NASA NTRS2010

Evaluation of Grounding Impedance of a Complex Lightning Protective System Using Earth Ground Clamp Measurements and ATP Modeling

A new Lightning Protection System (LPS) was designed and built at Launch Complex 39B (LC39B), at the Kennedy Space Center (KSC), Florida, which consists of a catenary wire system (at a height of about 181 meters above ground level) supported by three insulators installed atop three towers in a triangular configuration. A total of nine downconductors (each about 250 meters long, on average) are connected to the catenary wire system. Each of the nine downconductors is connected to a 7.62-meter radius circular counterpoise conductor with six equally spaced 6-meter long vertical grounding rods. Grounding requirements at LC39B call for all underground and above ground metallic piping, enclosures, raceways, and cable trays, within 7.62 meters of the counterpoise, to be bounded to the counterpoise, which results in a complex interconnected grounding system, given the many metallic piping, raceways, and cable trays that run in multiple direction around LC39B. The complexity of this grounding system makes the fall of potential method, which uses multiple metallic rods or stakes, unsuitable for measuring the grounding impedances of the downconductors. To calculate the downconductors grounding impedance, an Earth Ground Clamp (a stakeless grounding resistance measuring device) and a LPS Alternative Transient Program (ATP) model are used. The Earth Ground Clamp is used to measure the loop impedance plus the grounding impedance of each downconductor and the ATP model is used to calculate the loop impedance of each downconductor circuit. The grounding impedance of the downconductors is then calculated by subtracting the ATP calculated loop impedances from the Earth Ground Clamp measurements.

Mata, Carlos T.↗