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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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A raw computer resource capable of one billion floating point operations per second will have multiple parallel and/or segmented functional units to obtain such a speed. The system programmers, software writers and users are faced with the task of writing operating systems, compilers and application programs to utilize such a capability efficiently. The software problem of giving the user access to the available power of the machine is discussed.
Propellant requirements, tankage configurations, preferred propellant management techniques, propulsion systems weights, and technology deficiencies for low thrust expendable propulsion systems are examined. A computer program was utilized which provided a complete propellant inventory (including boil-off for cryogenic cases), pressurant and propellant tank dimensions for a given ullage, pressurant requirements, insulation requirements, and miscellaneous masses. The output also includes the masses of all tanks; the mass of the insulation, engines and other components; total wet system and burnout mass; system mass fraction; total impulse and burn time.
The fabrication parameters of GaAs MESFET solid-state amplifiers considering a power added conversion efficiency of at least 80% and power gains of at least 10dB were determined. Operating frequency was 2.45 GHz although 914 MHz was also considered. Basic circuit to be considered was either Class C or Class E amplification. Two modeling programs were utilized. The results of several computer calculations considering differing loads, temperatures, and efficiencies are presented. Parametric data in both tabular and plotted form are presented.
A regenerable CO2 removal system was developed for potential use on the shuttle as an alternate to the baseline lithium hydroxide (LiOH) system. It uses a solid amine material to adsorb CO2 from the atmosphere. The material is regenerated by heating it with steam from a zero gravity water evaporator. A full sized, thermally representative breadboard canister and a preprototype water evaporator were built and tested to shuttle requirements for CO2 control. The test program was utilized to evaluate and verify the operation and performance of these two primary components of the SAWD system.
A brief review is presented of a three-part project (partially supported by NASA), which promotes greater utilization of social survey data for gaining new information about human response to environmental noise. The goal is accomplished by (1) publishing a catalog of existing social surveys on environmental noise, (2) establishing a data archive for noise survey data sets, and (3) reanalyzing selected surveys to address substantial and methodological issues. A finding about annoyance scales illustrates the use of a comparative analysis.
SKYMAP is collection of computer programs and utility software for creating and maintaining master star catalog and hierarchical set of derivative star catalogs. Developed to provide accurate stellar position and magnitude information for attitude-determination and analysis systems utilizing star sensor observations. Current master star catalog includes all documented stars with blue or visual magnitudes brighter than magnitude 9.0
A computer program has been developed that predicts the unsteady aerodynamic forces that impinge on the empennage surface due to its interactions with the main rotor wake. The program was utilized to determine the vibration airloads acting on the Black Hawk horizontal stabilizer and on the CH-53A stabilizer under high speed forward flight conditions. The results demonstrate that it is possible to compute the high frequency empennage vibration airloads efficiently by utilizing suitable analysis techniques; a CH-53A case required only 1.3 minutes of computer time. Numerical problems associated with the unsteady Kutta condition have been minimized. Even though the analysis is of transient nature, the results for harmonic cases show a very fast convergence to periodicity. In general, good correlation was shown between the predicted vibratory airloads and the measured stabilizer airloads for a CH-53A helicopter operating at high speed flight conditions.
A major laboratory dedicated to biological-medical research is proposed for the Space Platform. The laboratory would focus on sensor physiology and biochemistry since sensory physiology represents the first impact of the new space environment on living organisms. Microgravity and the high radiation environment of space would be used to help solve the problems of prolonged sojourns in space but, more importantly, to help solve terrestrial problems of human health and agricultural productivity. The emphasis would be on experimental use of microorganisms and small plants and small animals to minimize the space and time required to use the Space Platform for maximum human betterment. The Alpha Helix Concept, that is, the use of the Space Platform to bring experimental biomedicine to a new and extreme frontier is introduced so as to better understand the worldly environment. Staffing and instrumenting the Space Platform biomedical laboratory in a manner patterned after successful terrestrial sensory physiology laboratories is also proposed.
Commercial fishermen are interested in the safety of their crews, boats, and gear, and in making the best catch for their time and money. Rising fuel costs, increased competition from foreign fisheries, improved knowledge about fish habits and the new 200 mile economic zone have all had an impact on the U.S. fishing industry. As a consequence, the modern fisherman, more than ever, requires reliable and timely information about the marine environment. This paper describes an experimental program to utilize satellite observations of the ocean surface, in conjunction with conventional observations and products, to prepare special fisheries aids charts for daily radio facsimile broadcasts to commercial fishermen. These special fisheries products aggregate a broad set of ocean observations, including ocean color structure, to depict oceanographic conditions of importance to commercial fishing tactics. Results to date have shown that improved safety at sea and decreased fuel costs can be achieved through the applied use of these special fisheries charts.
Preliminary results are presented from the analysis of the Galileo spacecraft axial delta-V algorithm. The Galileo spacecraft is a dual spin interplanetary spacecraft which will study the four Galilean moons of Jupiter as well as the Jovian environment and atmosphere. In order to achieve orbit about Jupiter and accurately deliver the probe to the planet's upper atmosphere, the Galileo spacecraft must be capable of performing many trajectory corrections or delta-V maneuvers. Twelve 10 Newton thrusters and one 400 Newton engine are utilized for this purpose. There are many maneuver modes and control algorithms available to the spacecraft. In this paper only the analysis of the axial delta-V algorithm will be discussed. The analysis consists of two parts: an analytic study and a simulation study. The analytic results are based on rigid body dynamics, while the simulation includes the first order effect of the flexible magnetometer boom and nutation damper. The simulation utilizes a program developed at JPL which allows flexible body effects to be simulated by modeling a collection of rigid bodies attached together by hinges, springs and dampers. In this preliminary study of the Galileo only two rigid bodies were used in the simulation, but many more can and will be used in the final tests. In this analysis, the algorithm appears to be working correctly and the analytic and simulation results agree very well.
Two programs smooth and scale arbitrary airfoil coordinates. Airfoil smoothing program (AFSMO) utilizes both least-squares polynomial and leastsquares cubic-spline techniques to smooth iteratively second derivatives of y-axis airfoil coordinates with respect to transformed x-axis system that unwraps airfoil and stretches nose and trailing-edge regions.
Software Comparison Package (SCP) compares similar files. Normally, these are 90-character files produced by CDC UPDATE utility from program libraries that contain FORTRAN source code plus identifier. SCP also used to compare load maps, cross-reference outputs, and UPDATE corrections sets. Helps wherever line-by-line comparison of similarly structured files required.
A generalized computer program for analysis of pressure and composition in a multiple-volume system has been developed by NASA. This paper describes the development of the program, outlines the program's capabilities, and illustrates the application of the program to Space Shuttle-related atmospheric pressure and composition control analyses. The program's features include the calculation of transient partial pressures of four gases in four volumes, an option for either isothermal or temperature-transient analyses, simulation of pressure and composition control hardware, and simulation involving 0-10 crewmembers. This computer program has been used successfully for a variety of Shuttle-related analyses to support hardware design, develop operating procedures, and provide real-time Shuttle mission support. Due to the versatility of this computer program, it will be utilized for Space Station program analyses.
The successful parametric modeling of the aerodynamics for an airplane operating at high angles of attack or sideslip is performed in two phases. First the aerodynamic model structure must be determined and second the associated aerodynamic parameters (stability and control derivatives) must be estimated for that model. The purpose of this paper is to document two versions of a stepwise regression computer program which were developed for the determination of airplane aerodynamic model structure and to provide two examples of their use on computer generated data. References are provided for the application of the programs to real flight data. The two computer programs that are the subject of this report, STEP and STEPSPL, are written in FORTRAN IV (ANSI l966) compatible with a CDC FTN4 compiler. Both programs are adaptations of a standard forward stepwise regression algorithm. The purpose of the adaptation is to facilitate the selection of a adequate mathematical model of the aerodynamic force and moment coefficients of an airplane from flight test data. The major difference between STEP and STEPSPL is in the basis for the model. The basis for the model in STEP is the standard polynomial Taylor's series expansion of the aerodynamic function about some steady-state trim condition. Program STEPSPL utilizes a set of spline basis functions.
An average of 51 Voyager 1 IRIS spectra of Jupiter's North Tropical Zone was analyzed to infer the abundance, vertical extent, and size distribution of the particles making up the ammonia cloud in this region. It is assumed that the cloud base coincides with the level at which 100% saturation of ammonia vapor occurs. The vertical distribution of particulates above this level is determined by assuming a constant total ammonia mixing ratio and adjusting the two phases so that the vapor is saturated throughout the cloud. A constant scaling factor then adjusts the base number density. A radiative transfer program is used that includes the effects of absorption and emission of all relevant gases as well as anisotropic scattering by cloud particles. Mie scattering from a gaussian particle size distribution is assumed. The vertical thermal structure is inferred from a temperature retrieval program that utilizes the collision induced S(0) and S(1) molecular hydrogen lines between 300 and 700.cm, and the 1304.cm methane band.
The aerodynamic design procedure for a new blade tip suitable for operation at transonic speeds is illustrated. For the first time, 3 dimensional numerical optimization was applied to rotor tip design, using the recent derivative of the ROT22 code, program R22OPT. Program R22OPT utilized an efficient quasi-Newton optimization algorithm. Multiple design objectives were specified. The delocalization of the shock wave was to be eliminated in forward flight for an advance ratio of 0.41 and a tip Mach number of 0.92 at psi = 90 deg. Simultaneously, it was sought to reduce torque requirements while maintaining effective restoring pitching moments. Only the outer 10 percent of the blade span was modified; the blade area was not to be reduced by more than 3 percent. The goal was to combine the advantages of both sweptback and sweptforward blade tips. A planform that featured inboard sweepback was combined with a sweptforward tip and a taper ratio of 0.5. Initially, the ROT22 code was used to find by trial and error a planform geometry which met the design goals. This configuration had an inboard section with a leading edge sweep of 20 deg and a tip section swept forward at 25 deg; in addition, the airfoils were modified.
PAN AIR is a computer program for predicting subsonic or supersonic linear potential flow about arbitrary configurations. The program was applied to a highly complex single-engine-cruise V/STOL fighter/attack aircraft. Complexities include a close-coupled canard/wing, large inlets, and four exhaust nozzles mounted directly under the wing and against the fuselage. Modeling uncertainties involving canard wake location and flow-through approximation through the inlet and the exhaust nozzles were investigated. The recently added streamline capability of the program was utilized to evaluate visually the predicted flow over the model. PAN AIR results for Mach numbers of 0.6, 0.9, and angles of attack of 0, 5, and 10 deg. were compared with data obtained in the Ames 11- by 11-Foot Transonic Wind tunnel, at a Reynolds number of 3.69 x 10 to the 6th power based on c bar.
An overview of reduced gravity research performed in NASA ground-based facilities sponsored by the Microgravity Science and Applications Program of the NASA Office of Space Science and Applications is presented. A brief description and summary of the operations and capabilities of each of these facilities along with an overview of the historical usage of them is included. The goals and program elements of the Microgravity Science and Applications programs are described and the specific programs that utilize the low gravity facilities are identified. Results from two particular investigations in combustion (flame spread over solid fuels) and fluid physics (gas-liquid flows at microgravity conditions) are presented.