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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Directionally Sensitive Silicon Radiation Sensor (VCELL)

Sensors are a mission critical element in many NASA programs and require some very unique properties such as small size, low power, high reliability, low weight. Low cost sensors offer the possibility of technology transfer to the public domain for commercial applications. One sensor application that is important to many NASA programs is the ability to point at a radiation source, such as the sun. Such sensors may be an integral part of the guidance and control systems in space platforms and in remote exploratory vehicles. Sun/solar pointing is also important for ground-based systems such as solar arrays. These systems are not required to be small and lightweight. However, if a sensor with a sun pointing capability was developed that is very small, rugged, lightweight and at the same time low cost, it certainly could be used in existing and perhaps many new ground based applications. The objective of the VCELL (Directionally Sensitive Silicon Radiation Sensor) research is to develop a new and very unique silicon based directionally sensitive radiation sensor which can be fabricated using conventional monolithic IC technologies and which will meet the above requirements. The proposed sensor is a novel silicon chip that is directionally sensitive to incident radiation, providing azimuth and elevation information on the incident radiation. The resulting sensor chip will be appropriate for integration into a silicon IC or useful in a hybrid structure to be interfaced with a standard IEEE 1451 bus interface IC to create an Intelligent Sensor. It is presently estimated that it will require about three man-years of effort to complete the VCELL research and development. This includes the optical, electrical, mechanical and silicon fabrication and testing as well as computer simulations and theoretical analysis and modeling including testing in simulated space environments. This report summarizes the sensor research completed this summer as part of the Summer Faculty Fellowship Program. The primary effort was focused on activity necessary to fabricate prototype sensor.

Koy B. Cook↗
NASA NTRS1974

ATS-6 spacecraft design/performance

A description is given of major program objectives and experiment requirements established for ATS-6. The ability to slew across the earth's disk in less than 30 min was needed to support tightly scheduled communication operations involving different parts of the earth. Two major experiments were developed which involve direct satellite relay of educational color television programs to simple ground receivers. Details of spacecraft configuration are discussed along with aspects of spacecraft ground testing. The ATS-6 was successfully launched on schedule from Cape Canaveral on May 30, 1974, with the aid of a Titan IIIC. The in-orbit performance of the spacecraft communication subsystem has been excellent.

Redisch, W. N.↗
NASA NTRS1995

Flight test evaluation of the Stanford University/United Airlines differential GPS Category 3 automatic landing system

Test flights were conducted to evaluate the capability of Differential Global Positioning System (DGPS) to provide the accuracy and integrity required for International Civil Aviation Organization (ICAO) Category (CAT) 3 precision approach and landings. These test flights were part of a Federal Aviation Administration (FAA) program to evaluate the technical feasibility of using DGPS based technology for CAT 3 precision approach and landing applications. A United Airlines Boeing 737-300 (N304UA) was equipped with DGPS receiving equipment and additional computing capability provided by Stanford University. The test flights were conducted at NASA Ames Research Center's Crows Landing Flight Facility, Crows Landing, California. The flight test evaluation was based on completing 100 approaches and autolandings; 90 touch and go, and 10 terminating with a full stop. Two types of accuracy requirements were evaluated: 1) Total system error, based on the Required Navigation Performance (RNP), and 2) Navigation sensor error, based on ICAO requirements for the Microwave Landing System (MLS). All of the approaches and autolandings were evaluated against ground truth reference data provided by a laser tracker. Analysis of these approaches and autolandings shows that the Stanford University/United Airlines system met the requirements for a successful approach and autolanding 98 out of 100 approaches and autolandings, based on the total system error requirements as specified in the FAA CAT 3 Level 2 Flight Test Plan.

Kaufmann, David N.↗
NASA NTRS1973

Skylab Medical Experiments Altitude Test (SMEAT)

The Skylab Medical Experiments Altitude Test (SMEAT) was an integral part of the Skylab Program. SMEAT served both to gather vital baseline biomedical data and to resolve many of the requirement and procedural problems which otherwise might have impaired Skylab. To all persons and organizations who worked on the SMEAT program, I would like to extend my sincere thanks. The preparation for and completion of SMEAT required individual dedication, a desire to get the job done, and a willingness to go that “second mile.” Without such outstanding performance, it would not have been possible to complete this difficult and complex test program. Everyone should be proud of the contributions which have been made to the Skylab Program.

Richard S Johnston↗
NASA NTRS1984

Conceptual design of a monitoring system for the Charters of Freedom

A conceptual design of a monitoring system for the Charters of Freedom was developed for the National Archives and Records Service. The monitoring system would be installed at the National Archives and used to document the condition of the Charters as part of a regular inspection program. The results of an experimental measurements program that led to the definition of analysis system requirements are presented, a conceptual design of the monitoring system is described and the alternative approaches to implementing this design were discussed. The monitoring system is required to optically detect and measure deterioration in documents that are permanently encapsulated in glass cases. An electronic imaging system with the capability for precise photometric measurements of the contrast of the script on the documents can perform this task. Two general types of imaging systems are considered (line and area array), and their suitability for performing these required measurements are compared. A digital processing capability for analyzing the electronic imaging data is also required, and several optional levels of complexity for this digital analysis system are evaluated.

Cutts, J. A.↗
NASA NTRS1988

Benchmark solutions for the galactic ion transport equations with spatial and energy coupling

In order to anticipate future space shielding requirements, NASA has initiated an effort to formulate computational methods to simulate radiation effects in space. As part of the program, numerical transport algorithms have been developed for the deterministic Boltzman equation describing galactic cosmic ray (GCR) interactions with matter. It thus becomes necessary to assess the accuracy of proposed deterministic algorithms. For this reason, analytical benchmark solutions to mathematically tractable galactic cosmic ray equations have recently been obtained. Even though these problems involve simplifying assumptions of the associated physics, they still contain the essential features of the basic transport processes. The solutions obtained are features of the basic transport processes. The solutions obtained are compared to results from numerical algorithms in order to ensure proper coding and to provide a measure of the accuracy of the numerical methods used in the algorithm. For the first time, mathematical methods have been applied to the galactic ion transport (GIT) equations in the straight ahead approximation with constant nuclear properties. The approach utilizes a Laplace transforms inversion yielding a closed form benchmark solution which is also computationally efficient.

Ganapol, Barry D.↗
NASA NTRS1992

Slush hydrogen pressurized expulsion studies at the NASA K-Site Facility

An experiment test series of the slush hydrogen (SLH2) project at the NASA LeRC Plum Brook K-Site Facility was completed. This testing was done as part of the characterization and technology database development on slush hydrogen required for the National Aero-Space Plane (NASP) Program. The primary objective of these experiments was to investigate tank thermodynamic parameters during the pressurized expulsion of slush hydrogen. To accomplish this, maintenance of tank pressure control was investigated during pressurized expulsion of slush hydrogen using gaseous hydrogen and gaseous helium pressurant. In addition, expulsion tests were performed using gaseous helium for initial pressurization, then gaseous hydrogen during expulsion. These tests were conducted with and without mixing of the slush hydrogen. Results from the testing included an evaluation of tank pressure control, pressurant requirements, SLH2 density change, and system mass and energy balances.

Whalen, Margaret V.↗
NASA NTRS1992

Overview of National Launch System with emphasis on cargo transfer vehicle

As a result of the Augustine Committee's recommendation to the National Space Council, NASA and the DOD have embarked on a joint program to provide a new capability for transporting payloads into space. Vehicles within the National Launch System (NLS) family are to be robust designs allowing more streamlined ground processing with corresponding reductions in operations cost. A primary NASA objective is access to space and the space station independent of the Space Shuttle. This requires the program to provide more than a simple payload-to-orbit capability. This capability is provided in large part by the cargo transfer vehicle.

Buchanan, Harry↗
NASA NTRS1992

Slush hydrogen pressurized expulsion studies at the NASA K-Site Facility

An experiment test series of the slush hydrogen (SLH2) project at the NASA LeRC Plum Brook K-Site Facility was completed. This testing was done as part of the characterization and technology database development on slush hydrogen required for the National Aero-Space Plane (NASP) Program. The primary objective of these experiments was to investigate tank thermodynamic parameters during the pressurized expulsion of slush hydrogen. To accomplish this, maintenance of tank pressure control was investigated during pressurized expulsion of slush hydrogen using gaseous hydrogen and gaseous helium pressurant. In addition, expulsion tests were performed using gaseous helium for initial pressurization, then gaseous hydrogen during expulsion. These tests were conducted with and without mixing of the slush hydrogen. Results from the testing included an evaluation of tank pressure control, pressurant requirements, SLH2 density change, and system mass and energy balances.

Whalen, Margaret V.↗
NASA NTRS2003

A Probabilistic Risk Analysis (PRA) of Human Space Missions for the Advanced Integration Matrix (AIM)

The Advanced Integration Matrix (AIM) Project u7ill study and solve systems-level integration issues for exploration missions beyond Low Earth Orbit (LEO), through the design and development of a ground-based facility for developing revolutionary integrated systems for joint human-robotic missions. This paper describes a Probabilistic Risk Analysis (PRA) of human space missions that was developed to help define the direction and priorities for AIM. Risk analysis is required for all major NASA programs and has been used for shuttle, station, and Mars lander programs. It is a prescribed part of early planning and is necessary during concept definition, even before mission scenarios and system designs exist. PRA cm begin when little failure data are available, and be continually updated and refined as detail becomes available. PRA provides a basis for examining tradeoffs among safety, reliability, performance, and cost. The objective of AIM's PRA is to indicate how risk can be managed and future human space missions enabled by the AIM Project. Many critical events can cause injuries and fatalities to the crew without causing loss of vehicle or mission. Some critical systems are beyond AIM's scope, such as propulsion and guidance. Many failure-causing events can be mitigated by conducting operational tests in AIM, such as testing equipment and evaluating operational procedures, especially in the areas of communications and computers, autonomous operations, life support, thermal design, EVA and rover activities, physiological factors including habitation, medical equipment, and food, and multifunctional tools and repairable systems. AIM is well suited to test and demonstrate the habitat, life support, crew operations, and human interface. Because these account for significant crew, systems performance, and science risks, AIM will help reduce mission risk, and missions beyond LEO are far enough in the future that AIM can have significant impact.

Jones, Harry W.↗
NASA NTRS2005

Vision Based Localization in Urban Environments

As part of DARPA's MARS2020 program, the Jet Propulsion Laboratory developed a vision-based system for localization in urban environments that requires neither GPS nor active sensors. System hardware consists of a pair of small FireWire cameras and a standard Pentium-based computer. The inputs to the software system consist of: 1) a crude grid-based map describing the positions of buildings, 2) an initial estimate of robot location and 3) the video streams produced by each camera. At each step during the traverse the system: captures new image data, finds image features hypothesized to lie on the outside of a building, computes the range to those features, determines an estimate of the robot's motion since the previous step and combines that data with the map to update a probabilistic representation of the robot's location. This probabilistic representation allows the system to simultaneously represent multiple possible locations, For our testing, we have derived the a priori map manually using non-orthorectified overhead imagery, although this process could be automated. The software system consists of two primary components. The first is the vision system which uses binocular stereo ranging together with a set of heuristics to identify features likely to be part of building exteriors and to compute an estimate of the robot's motion since the previous step. The resulting visual features and the associated range measurements are software component, a particle-filter based localization system. This system uses the map and the then fed to the second primary most recent results from the vision system to update the estimate of the robot's location. This report summarizes the design of both the hardware and software and will include the results of applying the system to the global localization of a robot over an approximately half-kilometer traverse across JPL'S Pasadena campus.

unmanned-ground vehicles↗
NASA NTRS2000

Automation of the CFD Process on Distributed Computing Systems

A script system was developed to automate and streamline portions of the CFD process. The system was designed to facilitate the use of CFD flow solvers on supercomputer and workstation platforms within a parametric design event. Integrating solver pre- and postprocessing phases, the fully automated ADTT script system marshalled the required input data, submitted the jobs to available computational resources, and processed the resulting output data. A number of codes were incorporated into the script system, which itself was part of a larger integrated design environment software package. The IDE and scripts were used in a design event involving a wind tunnel test. This experience highlighted the need for efficient data and resource management in all parts of the CFD process. To facilitate the use of CFD methods to perform parametric design studies, the script system was developed using UNIX shell and Perl languages. The goal of the work was to minimize the user interaction required to generate the data necessary to fill a parametric design space. The scripts wrote out the required input files for the user-specified flow solver, transferred all necessary input files to the computational resource, submitted and tracked the jobs using the resource queuing structure, and retrieved and post-processed the resulting dataset. For computational resources that did not run queueing software, the script system established its own simple first-in-first-out queueing structure to manage the workload. A variety of flow solvers were incorporated in the script system, including INS2D, PMARC, TIGER and GASP. Adapting the script system to a new flow solver was made easier through the use of object-oriented programming methods. The script system was incorporated into an ADTT integrated design environment and evaluated as part of a wind tunnel experiment. The system successfully generated the data required to fill the desired parametric design space. This stressed the computational resources required to compute and store the information. The scripts were continually modified to improve the utilization of the computational resources and reduce the likelihood of data loss due to failures. An ad-hoc file server was created to manage the large amount of data being generated as part of the design event. Files were stored and retrieved as needed to create new jobs and analyze the results. Additional information is contained in the original.

Tejnil, Ed↗
NASA NTRS1974

A numerically efficient finite element hydroelastic analysis. Volume 2: Implementation in NASTRAN, part 1

Details are presented of the implementation of the new formulation into NASTRAN including descriptions of the DMAP statements required for conversion of the program and details pertaining to problem definition and bulk data considerations. Details of the current 1/8-scale space shuttle external tank mathematical model, numerical results and analysis/test comparisons are also presented. The appendices include a description and listing of a FORTRAN program used to develop harmonic transformation bulk data (multipoint constraint statements) and sample bulk data information for a number of hydroelastic problems.

Coppolino, R. N.↗
NASA NTRS1986

National Space Transportation and Support Study/technology requirements and plans

This paper presents a generic technology plan which has been developed as part of the National Space Transportation and Support Study. This program, which addresses a wide variety of potentially high payoff technology areas, is structured to promote both enhanced vehicle performance and greatly improved operational efficiency and includes both evolutionary and breakthrough technologies. The plan is presented in terms of disciplinary plan elements, which were developed by joint NASA/USAF disciplinary working groups, and as a set of demonstration projects which serve as focal points for the overall plan and drive the development of the many interrelated disciplinary activities.

Walberg, G. D.↗
NASA NTRS2003

Computational Aspects of Data Assimilation and the ESMF

The scientific challenge of developing advanced data assimilation applications is a daunting task. Independently developed components may have incompatible interfaces or may be written in different computer languages. The high-performance computer (HPC) platforms required by numerically intensive Earth system applications are complex, varied, rapidly evolving and multi-part systems themselves. Since the market for high-end platforms is relatively small, there is little robust middleware available to buffer the modeler from the difficulties of HPC programming. To complicate matters further, the collaborations required to develop large Earth system applications often span initiatives, institutions and agencies, involve geoscience, software engineering, and computer science communities, and cross national borders.The Earth System Modeling Framework (ESMF) project is a concerted response to these challenges. Its goal is to increase software reuse, interoperability, ease of use and performance in Earth system models through the use of a common software framework, developed in an open manner by leaders in the modeling community. The ESMF addresses the technical and to some extent the cultural - aspects of Earth system modeling, laying the groundwork for addressing the more difficult scientific aspects, such as the physical compatibility of components, in the future. In this talk we will discuss the general philosophy and architecture of the ESMF, focussing on those capabilities useful for developing advanced data assimilation applications.

daSilva, A.↗
NASA NTRS1987

RE-1000 free-piston Stirling engine hydraulic output system description

The NASA Lewis Research Center was involved in free-piston Stirling engine research since 1976. Most of the work performed in-house was related to characterization of the RE-1000 engine. The data collected from the RE-1000 tests were intended to provide a data base for the validation of Stirling cycle simulations. The RE-1000 was originally build with a dashpot load system which did not convert the output of the engine into useful power, but was merely used as a load for the engine to work against during testing. As part of the interagency program between NASA Lewis and the Oak Ridge National Laboratory, (ORNL), the RE-1000 was converted into a configuration that produces useable hydraulic power. A goal of the hydraulic output conversion effort was to retain the same thermodynamic cycle that existed with the dashpot loaded engine. It was required that the design must provide a hermetic seal between the hydraulic fluid and the working gas of the engine. The design was completed and the hardware was fabricated. The RE-1000 was modified in 1985 to the hydraulic output configuration. The early part of the RE-1000 hydraulic output program consisted of modifying hardware and software to allow the engine to run at steady-state conditions. A complete description of the engine is presented in sufficient detail so that the device can be simulated on a computer. Tables are presented showing the masses of the oscillating components and key dimensions needed for modeling purposes. Graphs are used to indicate the spring rate of the diaphragms used to separate the helium of the working and bounce space from the hydraulic fluid.

Schreiber, Jeffrey G.↗
NASA NTRS1985

Operational maintenance data base development for kinematic Stirling engines

In the initial stages of developing the automotive Stirling engine (ASE), data has been accumulated under the program's Quality Assurance Report (QAR) program to identify problem areas encountered during engine operation. This data has been used as the basis for developing design modifications to existing hardware, identifying diagnostic techniques and instrumentation, and providing guidance towards component and system development requirements for future engine designs, such as the Mod II engine currently in the initial design stage. The QAR has proven itself to be an essential part of the ASE Program, and has successfully guided the development of the automotive application of this emerging engine technology.

Richey, A.↗