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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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Program is written to handle logistics of acquisition and transport of personnel, equipment, and services and to determine costs, transport schedules, acquisition schedules, and fuel requirements of cargo transport.
The results obtained in the analysis of the effects of sonic boom overpressures at ground level for a nominal Mission 3B with the current baseline guidance are reported. These results are in the form of ground level overpressures generated along the groundtrack out to lateral cutoff from Mach 3.0-1.10 at 0.10 (tenth) Mach intervals. Preliminary trajectory constraints which will reduce excess sonic boom overpressures to approximately 2.0 PSF are included.
A preliminary trajectory from entry interface to terminal area energy management interface for the first orbital flight test is presented based on information in the Strawman master flight test assignments document Reference A. The enclosed point-mass trajectory may be utilized for preliminary purposes, meeting the requirements of this document. The trajectory was derived utilizing the January 1975 analytic drag control guidance, the latest thermal protection subsystem model information from NASA ES and December 1974 Aerodynamics for a mid center-of-gravity location.
Major developments are examined which have taken place to date in the analysis of the power and energy demands on the APU/Hydraulic/Actuator Subsystem for space shuttle during the entry-to-touchdown (not including rollout) flight regime. These developments are given in the form of two subroutines which were written for use with the Space Shuttle Functional Simulator. The first subroutine calculates the power and energy demand on each of the three hydraulic systems due to control surface (inboard/outboard elevons, rudder, speedbrake, and body flap) activity. The second subroutine incorporates the R. I. priority rate limiting logic which limits control surface deflection rates as a function of the number of failed hydraulic. Typical results of this analysis are included, and listings of the subroutines are presented in appendicies.
Low energy conceptual stage designs and adaptations to existing/planned shuttle upper stages were developed and their performance established. Selected propulsion modes and subsystems were used as a basis to develop airborne support equipment (ASE) design concepts. Orbiter installation and integration (both physical and electrical interfaces) were defined. Low energy stages were adapted to the orbiter and ASE interfaces. Selected low energy stages were then used to define and describe typical ground and flight operations.
A detailed computerized building load simulation of the Operations Support Building at the Mars Deep Space Station, Goldstone, California is described. Five energy conservation suggestions were investigated prior to implementation. The results showed that cost savings of about 16 percent of present energy costs are possible.
A simulation model was developed and programmed in three languages BASIC, PASCAL, and SLAM. Two of the programs are included in this report, the BASIC and the PASCAL language programs. SLAM is not supported by NASA/MSFC facilities and hence was not included. The statistical comparison of simulations of the same HOSC system configurations are in good agreement and are in agreement with the operational statistics of HOSC that were obtained. Three variations of the most recent HOSC configuration was run and some conclusions drawn as to the system performance under these variations.
Thermohydrodynamic effects in journal bearings operating under steady load in laminar regime are investigated. An analytical model for the finite and infinitely long journal bearings is formulated. The model includes correction factors for the cavitation effects in the unloaded region of the bearing and the mixing of the recirculating oil and supply oil at the oil inlet. A finite difference computer program is developed to numerically solve the governing equations of the continuity, Reynolds, energy, Laplace heat conduction, and a viscosity-temperature relation simultaneously. The program includes a numerical technique for obtaining an isothermal shaft temperature. The numerical results of temperature distribution and the heat effects on the bearing load carrying capacity agree closely with those of experimental findings. Several different sets of simpler boundary conditions for the energy equation are studied.
The Burst and Transient Source Experiment (BATSE) large area detectors are being used to monitor hard x-ray/gamma ray sources on a daily basis for evidence of transient behavior. Flux measurements are performed using a simple earth occultation technique. Daily searches are also being performed to detect occultation steps of sources which are not being routinely monitored. Topics concerning the operational aspects of the occultation measurements are presented. Preliminary spectral results are also presented for several of the brighter sources.
The eigenvalue sensitivity for hydrodynamic stability operators is investigated. Classical matrix perturbation techniques as well as the concept of epsilon-pseudoeigenvalues are applied to show that parts of the spectrum are highly sensitive to small perturbations. Applications are drawn from incompressible plane Couette, trailing line vortex flow and compressible Blasius boundary layer flow. Parametric studies indicate a monotonically increasing effect of the Reynolds number on the sensitivity. The phenomenon of eigenvalue sensitivity is due to the non-normality of the operators and their discrete matrix analogs and may be associated with large transient growth of the corresponding initial value problem.
Except in low-bandwidth systems, knowledge of the human operator transfer function is essential for high-performance telerobotic systems. This information has usually been derived from detailed analyses of tracking performance, in which the human operator is considered as a complete system rather than as a summation of a number of subsystems, each of which influences the operator's output. Studies of one of these subsystems, the limb mechanics system, demonstrate that large parameter variations can occur that can have a profound effect on the stability of force-reflecting telerobot systems. An objective of this research was to decompose the performance of the human operator system in order to establish how the dynamics of each of the elements influence the operator's responses.
America's air transport system is currently faced with two equally important dilemmas. First, congestion and delays associated with the overburdened hub and spoke system will continue to worsen unless dramatic changes are made in the way air transportation services are provided. Second, many communities and various regions of the country have not benefited from the air transport system, which tends to focus its attention on major population centers. An emerging solution to both problems is a Small Aircraft Transportation System (SATS), which will utilize a new generation of advanced small aircraft to provide air transport services to those citizens who are poorly served by the hub and spoke system and those citizens who are not served at all. Using new innovations in navigation, communication, and propulsion technologies, these aircraft will enable users to safely and reliably access the over 5,000 general aviation landing facilities around the United States. A small aircraft transportation system holds the potential to revolutionize the way Americans travel and to greatly enhance the use of air transport as an economic development tool in rural and isolated communities across the nation.
A space mission operations system is a complex network of human organizations, information and deep-space network systems and spacecraft hardware. As in other organizations, one of the problems in mission operations is managing the relationship of the mission information systems related to how people actually work (practices). Brahms, a multi-agent modeling and simulation tool, was used to model and simulate NASA's Mars Exploration Rover (MER) mission work practice. The objective was to investigate the value of work practice modeling for mission operations design. From spring 2002 until winter 2003, a Brahms modeler participated in mission systems design sessions and operations testing for the MER mission held at Jet Propulsion Laboratory (JPL). He observed how designers interacted with the Brahms tool. This paper discussed mission system designers' reactions to the simulation output during model validation and the presentation of generated work procedures. This project spurred JPL's interest in the Brahms model, but it was never included as part of the formal mission design process. We discuss why this occurred. Subsequently, we used the MER model to develop a future mission operations concept. Team members were reluctant to use the MER model, even though it appeared to be highly relevant to their effort. We describe some of the tool issues we encountered.
In this paper, we present a performability study that analyzes the guarded operation duration for onboard software upgrading.
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Following launch in 1992, TOPEX/Poseidon began a very successful global.
The next generation of Martian rover#s to be launched by JPL are to examine polar regions where temperatures are extremely low and the absence of an earth-like atmosphere results in high levels of cosmic radiation at ground level. Cosmic rays lead to a plethora of radiation effects including Single Event Transients (SET) which can severely degrade microelectronic functionality. As such, a radiation-hardened, temperature compensated CMOS Single-On-Insulator (SOI) Operational Amplifier has been designed for JPL by the University of Tennessee and fabricated by Honeywell using the SOI V process. SOI technology has been shownto be far less sensitive to transient effects than both bulk and epilayer Si. Broad beam heavy-ion tests at the University of Texas A&M using Kr and Xebeams of energy 25MeV/amu were performed to ascertain the duration and severity of the SET for the op-amp configured for a low and high gain application. However, some ambiguity regarding the location of transient formation required the use of a focused MeV ion microbeam. A 36MeV O6(+) microbeam. the Sandia National Laboratory (SNL) was used to image and verify regions of particular concern. This is a viewgraph presentation
The development and evaluation of concepts and technology to support future air traffic management systems require a hierarchy of models ranging from real-time simulations to extensive field evaluations. Air traffic simulation models such as Airspace Concept Evaluation System, Center Tracon Automation System, Future Air traffic management Concept Evaluation Tool and others are used to design air traffic systems balancing the conflicting objectives of maximizing safety, meeting future demands for airports and airspace and increase efficiency of traffic flows in the presence of uncertain weather. The impact of aviation emissions and contrails on climate imposes another constraint on the design of aircraft and aviation operations. The understanding of the complex interaction between physical climate system, the carbon and other greenhouse gas emissions and aviation activity can be improved by the development of integrated assessment models that include emission and climate models together with air traffic simulations. The modeling of aircraft emissions and their interaction with each other to change the concentration levels of different gasses in the atmosphere and the resulting impact of the radiative forcing on the equilibrium of the Earth's atmosphere is complex and requires the use of coupled atmosphere-ocean general circulation models together with three-dimensional models of carbon cycle and chemistry of other non-CO2 greenhouse gases. These models are computationally intensive and unsuitable for studies involving the generation of multiple scenarios. Simple emission and climate models, based on the input-output relations of linear systems, capture the fundamental emission to climate impact behavior by careful selection of key variables and their dynamics. The impact of various greenhouse gases depends on the total concentration, effect per unit change in atmospheric concentration and the spatial distribution of the gas. All these quantities are influenced by the lifetime of the gas. The impact of a greenhouse gas depends on the interval of assessment, which may vary from a few decades to a few centuries. Climate metrics are aimed at providing a common scale to compare different greenhouse gases. If the metrics are to be used as a tool in developing and evaluating aviation operations, they should be transparent and easy to apply. Global Warming Potential and Aggregate Global Temperature Potential are some of the commonly used metrics. This paper integrates a national-level air traffic simulation and optimization capability with simple climate models and carbon cycle models, and climate metrics to assess the impact of aviation on climate. The capability brings together metrics, which are useful in aviation operations together with metrics used in climate studies. The capability can be used to make trade-offs between extra fuel cost and reduction in climate impact. There is considerable uncertainty in our understanding of the radiative forcing associated with emissions and contrails. The parameters in the simulation can be used to evaluate the effect of various uncertainties in emission models and contrails. It can also be used to evaluate the impact of different decision horizons. Alternatively, the optimization results from the simulation can be used as inputs to other tools that monetize global climate impacts like the FAA's Aviation Environmental Portfolio Management Tool for Impacts.