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At least 1,639 records · Page 91

Space Shuttle stability and control flight test techniques

A unique approach for obtaining vehicle aerodynamic characteristics during entry has been developed for the Space Shuttle. This is due to the high cost of Shuttle testing, the need to open constraints for operational flights, and the fact that all flight regimes are flown starting with the first flight. Because of uncertainties associated with predicted aerodynamic coefficients, nine flight conditions have been identified at which control problems could occur. A detailed test plan has been developed for testing at these conditions and is presented. Due to limited testing, precise computer initiated maneuvers are implemented. These maneuvers are designed to optimize the vehicle motion for determining aerodynamic coefficients. Special sensors and atmospheric measurements are required to provide stability and control flight data during an entire entry. The techniques employed in data reduction are proven programs developed and used at NASA/DFRC.

Cooke, D. R.↗

NASA DEVELOP’s Approach to Building Capacity to Apply Earth Observations for Coastal and Marine Decision Making

Part of NASA’s Applied Sciences, the DEVELOP Program builds capacity through 10-week interdisciplinary feasibility studies that identify how NASA Earth observations can be integrated into decision making processes. The program is a dual capacity building effort that fosters programmatic participants (early and transitioning career professionals, students, and recent graduates) to apply Earth observations to partner organizations’ decision making needs. The program conducts 50-60 projects annually, with about 10-15% of those focused on coastal and marine community concerns. These projects explore the use of satellite data and model outputs for measuring and mapping shoreline delineation, barrier island transgression, mangrove health and extent, sedimentation and water quality, and tropical cyclone impacts to coastal regions. This presentation will introduce DEVELOP and a series of project case studies, an overview of the organizations engaged and Earth observations utilized, and lessons learned.

Capacity Building↗

A computer program for fitting smooth surfaces to three-dimensional aircraft configurations

A computer program developed to fit smooth surfaces to the component parts of three-dimensional aircraft configurations was described. The resulting equation definition of an aircraft numerical model is useful in obtaining continuous two-dimensional cross section plots in arbitrarily defined planes, local tangents, enriched surface plots and other pertinent geometric information; the geometry organization used as input to the program has become known as the Harris Wave Drag Geometry.

Craidon, C. B.↗

Development of an Advanced Trapezoidal Axially Grooved (ATAG) heat pipe

This paper discusses the breadboard development of an Advanced Trapezoidal Axially Grooved (ATAG) heat pipe, which will satisfy space constructible radiator heat rejection requirements for large space power systems. The ATAG heat pipe development program includes a technology demonstration of Space Station heat load and temperature requirements through the design, fabrication, and testing of breadboard and preprototype units. A parametric analysis was conducted to determine trapezoidal groove geometries that could meet the transport performance goal and could be fabricated by available extrusion technology for a diameter chosen to be compatible with an existing development test unit of a cylindrical, pressure-actuated contact heat exchanger. Performance test results for the breadboard heat pipes are presented.

Richter, R. F. G.↗

Human and Robotic Space Mission Use Cases for High-Performance Spaceflight Computing

Spaceflight computing is a key resource in NASA space missions and a core determining factor of spacecraft capability, with ripple effects throughout the spacecraft, end-to-end system, and mission. Onboard computing can be aptly viewed as a "technology multiplier" in that advances provide direct dramatic improvements in flight functions and capabilities across the NASA mission classes, and enable new flight capabilities and mission scenarios, increasing science and exploration return. Space-qualified computing technology, however, has not advanced significantly in well over ten years and the current state of the practice fails to meet the near- to mid-term needs of NASA missions. Recognizing this gap, the NASA Game Changing Development Program (GCDP), under the auspices of the NASA Space Technology Mission Directorate, commissioned a study on space-based computing needs, looking out 15-20 years. The study resulted in a recommendation to pursue high-performance spaceflight computing (HPSC) for next-generation missions, and a decision to partner with the Air Force Research Lab (AFRL) in this development.

use cases↗

Variable conductance heat pipe technology

Research and development programs in variable conductance heat pipe technology were conducted. The treatment has been comprehensive, involving theoretical and/or experimental studies in hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, and materials compatibility, in addition to the principal subject of variable conductance control techniques. Efforts were not limited to analytical work and laboratory experimentation, but extended to the development, fabrication and test of spacecraft hardware, culminating in the successful flight of the Ames Heat Pipe Experiment on the OAO-C spacecraft.

Marcus, B. D.↗

B-52 stability augmentation system reliability

The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability.

Bowling, T. C.↗

Satellite power system (SPS) magnetron tube assessment study

Taks performed to extend the data base and to define a technology development program for the magnetron directional amplifier for the SPS are reviewed. These include: (1) demonstrating the tracking of phase and amplitude of the microwave output to phase and amplitude references; (2) expanding the range of power over which the directional amplifier will operate; (3)recognizing the importance of amplitude control in overall system design and in simplifying power conditioning; (4) developing a preliminary design for the overall architecture of the power module; (5) demonstrating magnetron starting using the amplitude control system; (6) mathematically modelling and performing a computerized study of the pyrolytic graphite radiating fin; (7) defining the mass of the magnetic circuit for the SPS tube; (8) noise measurement; (9) achieving harmonic suppression by notch reflection filters; (10) estimating the mass of the transmitting antenna; (11) developing a magnetron package with power generation, phase control, and power condition functions; and (12) projecting magnetron package characteristics.

Source record↗

Linking medical records to an expert system

This presentation will be done using the IMR-Entry (Intelligent Medical Record Entry) system. IMR-Entry is a software program developed as a front-end to our diagnostic consultant software MEDAS (Medical Emergency Decision Assistance System). MEDAS (the Medical Emergency Diagnostic Assistance System) is a diagnostic consultant system using a multimembership Bayesian design for its inference engine and relational database technology for its knowledge base maintenance. Research on MEDAS began at the University of Southern California and the Institute of Critical Care in the mid 1970's with support from NASA and NSF. The MEDAS project moved to Chicago in 1982; its current progress is due to collaboration between Illinois Institute of Technology, The Chicago Medical School, Lake Forest College and NASA at KSC. Since the purpose of an expert system is to derive a hypothesis, its communication vocabulary is limited to features used by its knowledge base. The development of a comprehensive problem based medical record entry system which could handshake with an expert system while creating an electronic medical record at the same time was studied. IMR-E is a computer based patient record that serves as a front end to the expert system MEDAS. IMR-E is a graphically oriented comprehensive medical record. The programs major components are demonstrated.

Naeymi-Rad, Frank↗

Battery Separator Characterization and Evaluation Procedures for NASA's Advanced Lithium-Ion Batteries

To address the future performance and safety requirements for the electrical energy storage technologies that will enhance and enable future NASA manned aerospace missions, advanced rechargeable, lithium-ion battery technology development is being pursued within the scope of the NASA Exploration Technology Development Program s (ETDP's) Energy Storage Project. A critical cell-level component of a lithium-ion battery which significantly impacts both overall electrochemical performance and safety is the porous separator that is sandwiched between the two active cell electrodes. To support the selection of the optimal cell separator material(s) for the advanced battery technology and chemistries under development, laboratory characterization and screening procedures were established to assess and compare separator material-level attributes and associated separator performance characteristics.

Baldwin, Richard S.↗

Software Approach for the Regenerative Fuel Cell Project

The Regenerative Fuel Cell (RFC) project is developing a system that combines a fuel cell subsystem for energy production with an electrolysis subsystem for energy storage. The system is primarily being developed at the Glenn Research Center with support from Johnson Space Center under the Space Technology Mission Directorate / Game Changing Development Program. Currently, the intent is to operate the RFC system in an equivalent environment to a lunar equator location for a period of several lunar day/night cycles with minimal operator input. Demonstrating an automated RFC system in this environment is a step towards showing the extensibility to a flight system. This paper describes the RFC software team’s approach for development of the monitoring and control software that allows for the automated operation of the RFC system. We describe the rationale for the choice of Core Flight System architecture, as well as the plan for software/hardware integration.

Mathew J Mccaskey↗

Modal analysis and dynamic stresses for acoustically excited shuttle insulation tiles

Improvements and extensions to the RESIST computer program developed for determining the normalized modal stress response of shuttle insulation tiles are described. The new version of RESIST can accommodate primary structure panels with closed-cell stringers, in addition to the capability for treating open-cell stringers. In addition, the present version of RESIST numerically solves vibration problems several times faster than its predecessor. A new digital computer program, titled ARREST (Acoustic Response of Reusable Shuttle Tiles) is also described. Starting with modal information contained on output tapes from RESIST computer runs, ARREST determines RMS stresses, deflections and accelerations of shuttle panels with reusable surface insulation tiles. Both programs are applicable to stringer stiffened structural panels with or without reusable surface insulation titles.

Ojalvo, I. U.↗

User manual and programmer reference manual for the ATS-6 navigation model AOIPS and McIDAS versions, part 2

Development of a navigation system for a given satellite is reported. An algorithm for converting a satellite picture element location to earth location and vice versa was defined as well as a procedure for measuring the set of constants needed by the algorithm. A user manual briefly describing the current version of the navigation model and how to use the computer programs developed for it is presented.

Chatters, G. C.↗

SC3 - A wing concept for supersonic maneuvering

A supersonic wing design concept that overcomes the problems associated with nonlinear inviscid pressure distribution is presented together with a summary of the supporting theoretical and experimental development program. The key design feature is a conical panel supporting a controlled supercritical conical camber (SC3) crossflow expansion and recompression which permits lift on the upper surface to be obtained without producing an adverse pressure gradient or crossflow shock wave strong enough to separate the boundary layer. The role of aerodynamics in the design implementation is discussed, as are the concept development, the initial design validation on a fabricated and tested SC3 design, and the body and canard interaction effect. The design and testing of an isolated wing with a planform and thickness distribution representative of a practical application are described. Wind-tunnel results show that significant performance gains can be obtained for fighter aircraft using this concept.

Mason, W. H.↗

Validation of a nonintrusive optical technique for the measurement of liquid mass distribution in a two-phase spray

This work is the continuation of an optical technique development program initiated as part of the 1992 Summer Faculty Fellowship Program. The 1992 work consisted of the formulation and implementation of a technique ivolving the spatial deconvolution of fluorescence data from a uniformly illuminated, seeded densed spray to obtain quantitative measurements of the liquid density profiles. This measurement approach largely overcomes substantial scattering problems associated with other optical approaches for two-phase flows. However, to apply this measurement approach with confidence to unknown flows, the technique must be validated. Consequently, technique validation using classical grid patternator techniques has been focus of the current work. This work has included the design and construction of a patternator rig and the implementation of a test program designed for the comparison of patternator data with the deconvolved optical data. The flow field used for the validation is the plume of an axisymetric swirl coaxial LOX injector being considered for use in the Space Transportation System Main Engine. The flow facility is an improved version of the test rig which was constructed in 1992 for the initial technique development. This report includes a brief description of the optical measurement technique and the patternator rig and a presentation of the data comparisons.

Hartfield, Roy, Jr.↗

Space Based Solar Power

Space based solar power (SBSP) entails in-space collection of solar energy, transmission of that energy to one or more stations on Earth, conversion to electricity, and delivery to the grid or to batteries for storage. Experts in both the aerospace and energy sectors are debating the benefits of SBSP as more organizations globally begin SBSP technology development programs. We conducted a study to evaluate the potential benefits, challenges, and options for NASA to engage with growing global interest in SBSP. We performed a first order lifecycle study of two representative SBSP designs for 2 GW utility-scale power generation that, for the purposes of the study, are presumed to begin in 2050. We assumed baseline capabilities to develop, assemble, operate, maintain, and dispose of the SBSP systems are a mix of capabilities that are above, below, or comparable to capabilities demonstrated to date. We then compared the lifecycle cost of electricity and lifecycle GHG emission intensity of the SBSP designs to alternative terrestrial renewable electricity production technologies. Our findings indicate the SBSP designs may produce lifecycle GHG emissions per unit of electricity that are comparable to terrestrial alternatives, pending further studies of upper atmosphere responses to launch emissions. We find the SBSP designs are more expensive than terrestrial alternatives and may have lifecycle costs per unit of electricity that are 12-80 times higher. Though, we do find cost competitiveness may be achieved if a favorable combination of cost and capability improvements related to launch and manufacturing that are beyond the advancements assumed in the baseline assessment can be attained.

Erica Rodgers↗

Space Based Solar Power Study

Space based solar power (SBSP) entails in-space collection of solar energy, transmission of that energy to one or more stations on Earth, conversion to electricity, and delivery to the grid or to batteries for storage. Experts in both the aerospace and energy sectors are debating the benefits of SBSP as more organizations globally begin SBSP technology development programs. We conducted a study to evaluate the potential benefits, challenges, and options for NASA to engage with growing global interest in SBSP. We performed a first order lifecycle study of two representative SBSP designs for 2 GW utility-scale power generation that, for the purposes of the study, are presumed to begin in 2050. We assumed baseline capabilities to develop, assemble, operate, maintain, and dispose of the SBSP systems are a mix of capabilities that are above, below, or comparable to capabilities demonstrated to date. We then compared the lifecycle cost of electricity and lifecycle GHG emission intensity of the SBSP designs to alternative terrestrial renewable electricity production technologies. Our findings indicate the SBSP designs may produce lifecycle GHG emissions per unit of electricity that are comparable to terrestrial alternatives, pending further studies of upper atmosphere responses to launch emissions. We find the SBSP designs are more expensive than terrestrial alternatives and may have lifecycle costs per unit of electricity that are 12-80 times higher. Though, we do find cost competitiveness may be achieved if a favorable combination of cost and capability improvements related to launch and manufacturing that are beyond the advancements assumed in the baseline assessment can be attained.

solar↗

Eigenproblem solution of damped structural systems

This article presents an efficient numerical algorithm and a complete listing of the associated computer program, developed for the eigenproblem solution of discrete damped structures, including spinning ones. The numerically stable procedure is based on a combined Sturm sequence and inverse iteration technique, which fully exploits the banded form of the relevant matrices and proves to be most substantially economical when compared to similar existing softwares. Numerical results are presented for representative structures, solved by the present computer program written in FORTRAN V for the JPL UNIVAC 1108 computer.

Gupta, K. K.↗