A study of navigation measurement schedules for LEM rendezvous.
Measurement schedules effect on work load of astronaut performing navigation function, stressing tradeoff between number of measurements and accuracy level
ASTRONAUT PERFORMANCE↗
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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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The NASA role in major areas of human concern: Communication
After introducing some of the general factors that have affected progress in the area of communication, NASA program elements are examined to illustrate relevant points of contact. Interpretive steps are taken throughout the report to show a few of the more important ways people's lives have been affected as a result of the work of NASA and other organizations functioning in this area. The principal documents used and interviews conducted are identified.
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The NASA role in major areas of human concern: Environmental quality
After introducing some of the general factors that have affected progress in the area of environmental quality, NASA program elements are examined to illustrate relevant points of contact. Interpretive steps are taken throughout the report to show a few of the more important ways people's lives have been affected as a result of the work of NASA and other organizations functioning in this area. The principal documents used and interviews conducted are identified.
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The NASA role in major areas of human concern: Transportation
After introducing some of the general factors that have affected progress in the transportation area, NASA program elements are examined to illustrate relevant points of contact. Interpretive steps are taken throughout the statement to show a few of the more important ways people's lives have been affected as a result of the work of NASA and other organizations functioning in this area. The principal documents used and interviews conducted are identified after the conclusion of this statement. This statement, it should be noted, is incomplete in many respects, primarily because it reflects only a small number of the technical, economic, and social forces affecting American life. Taken as a summary statement, however, it hopefully will provide a useful basis for better understanding NASA's role in the national attempt to upgrade the quality of transportation services.
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Perturbation theory of structure in classical liquid mixtures: Application to metallic systems near phase separation
The partial structure factors of classical simple liquid mixtures near phase separation are dicussed. The theory is developed for particles interacting through pair potentials, and is thus appropriate both to insulating fluids, and also to metallic systems if these may be described by an effective ion-ion pair interaction. The motivation arose from consideration of metallic liquid mixtures, in which resistive anomalies have been observed near phase separation. A mean field theory correction appropriate to 3 pair potential for the effects of correlated motions in the reference fluid is studied. The work is cast in terms of functions which are closely related to the direct correlation functions of Ornstein and Zernike. The results are qualitatively in accord with physical expectations. Quantitative agreement with experiment seems to turn on the selection of the hard core reference potential in terms of the metallic effective pair potential. It is suggested that the present effective pair potentials are perhaps not properly used to calculate the metallic structure factors at long wavelength.
Henderson, R. L.↗
Particle motion in atmospheric boundary layers of Mars and Earth
To study the eolian mechanics of saltating particles, both an experimental investigation of the flow field around a model crater in an atmospheric boundary layer wind tunnel and numerical solutions of the two- and three-dimensional equations of motion of a single particle under the influence of a turbulent boundary layer were conducted. Two-dimensional particle motion was calculated for flow near the surfaces of both Earth and Mars. For the case of Earth both a turbulent boundary layer with a viscous sublayer and one without were calculated. For the case of Mars it was only necessary to calculate turbulent boundary layer flow with a laminar sublayer because of the low values of friction Reynolds number; however, it was necessary to include the effects of slip flow on a particle caused by the rarefied Martian atmosphere. In the equations of motion the lift force functions were developed to act on a single particle only in the laminar sublayer or a corresponding small region of high shear near the surface for a fully turbulent boundary layer. The lift force functions were developed from the analytical work by Saffman concerning the lift force acting on a particle in simple shear flow.
White, B. R.↗
Parameters affecting electrostatic cooling
A high voltage electrostatic field is discussed which enhances the rate of normal convective cooling. This cooling rate is a function of starting temperature and voltage applied, and an inverse function of atmospheric pressure or the heat capacity of the surrounding media. It appears that the cooling rate is also a function of current flow; however, additional work is needed to separate other variables from the effect of current flow. The maximum increase in heat loss over the normal convective cooling was approximately 0.167 C/sec (0.3 F/sec) at 316 C (600 F) and 20,000 V. From the data taken it is assumed that the addeded rate of cooling would be increased with higher temperatures and higher voltages. It appears that a high voltage field disrupts the molecular layer of air surrounding a hot body and increases the rate of convective cooling.
Demorest, K. E.↗
The Incorporation of Truncated Fourier Series into Finite Difference Approximations of Structural Stability Equations
A new trigonometric approach to the finite difference calculus was applied to the problem of beam buckling as represented by virtual work and equilibrium equations. The trigonometric functions were varied by adjusting a wavelength parameter in the approximating Fourier series. Values of the critical force obtained from the modified approach for beams with a variety of boundary conditions were compared to results using the conventional finite difference method. The trigonometric approach produced significantly more accurate approximations for the critical force than the conventional approach for a relatively wide range in values of the wavelength parameter; and the optimizing value of the wavelength parameter corresponded to the half-wavelength of the buckled mode shape. It was found from a modal analysis that the most accurate solutions are obtained when the approximating function closely represents the actual displacement function and matches the actual boundary conditions.
Hannah, S. R.↗
The 25 kW power module evolution study. Part 3: Conceptual designs for power module evolution. Volume 2: Program plans
A plan is presented for the evolutionary development and deployment of the power module system with performance capabilities required to support the 1983 to 1990 user requirements. Aspects summarized include program functional, operational, and hardware elements; program work breakdown and specification items; development plans and schedules for developmental and technology milestones; test concepts and timeliness; and ground and orbit operations concepts.
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Cell module and fuel conditioner development
The efforts performed to develop a phosphoric acid fuel cell (PAFC) stack design having a 10 kW power rating for operation at higher than atmospheric pressure based on the existing Mark II design configuration are described. The work involves: (1) Performance of pertinent functional analysis, trade studies and thermodynamic cycle analysis for requirements definition and system operating parameter selection purposes, (2) characterization of fuel cell materials and components, and performance testing and evaluation of the repeating electrode components, (3) establishment of the state-of-the-art manufacturing technology for all fuel cell components at Westinghouse and the fabrication of short stacks of various sites, and (4) development of a 10 kW PAFC stack design for higher pressure operation utilizing the top down systems engineering approach.
Feret, J. M.↗
International ultraviolet explorer observatory operations
This volume contains the Final Report for the International Ultraviolet Explorer (IUE) Observatory Operations contract, NAS5-28787. The report summarizes the activities of the IUE Observatory over the 13-month period from November 1985 through November 1986 and is arranged in sections according to the functions specified in the Statement of Work (SOW) of the contract. In order to preserve numerical correspondence between the technical SOW elements specified by the contract and the sections of this report, project management activities (SOW element 0.0.) are reported here in Section 7, following the reports of technical SOW elements 1.0 through 6.0. Routine activities have been summarized briefly whenever possible; statistical compilations, reports, and more lengthy supplementary material are contained in the Appendices.
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Robot design for a vacuum environment
The cleanliness requirements for many processing and manufacturing tasks are becoming ever stricter, resulting in a greater interest in the vacuum environment. Researchers discuss the importance of this special environment, and the development of robots which are physically and functionally suited to vacuum processing tasks. Work is in progress at the Center for robotic Systems in Microelectronics (CRSM) to provide a robot for the manufacture of a revolutionary new gyroscope in high vacuum. The need for vacuum in this and other processes is discussed as well as the requirements for a vacuum-compatible robot. Finally, researchers present details on work done at the CRSM to modify an existing clean-room compatible robot for use at high vacuum.
Belinski, S.↗
Key technology issues for space robotic systems
Robotics has become a key technology consideration for the Space Station project to enable enhanced crew productivity and to maximize safety. There are many robotic functions currently being studied, including Space Station assembly, repair, and maintenance as well as satellite refurbishment, repair, and retrieval. Another area of concern is that of providing ground based experimenters with a natural interface that they might directly interact with their hardware onboard the Space Station or ancillary spacecraft. The state of the technology is such that the above functions are feasible; however, considerable development work is required for operation in this gravity-free vacuum environment. Furthermore, a program plan is evolving within NASA that will capitalize on recent government, university, and industrial robotics research and development (R and D) accomplishments. A brief summary is presented of the primary technology issues and physical examples are provided of the state of the technology for the initial operational capability (IOC) system as well as for the eventual final operational capability (FOC) Space Station.
Schappell, Roger T.↗
The three stages of magma ocean cooling
Models of magma ocean (MO) cooling and crystallization can provide important constraints on MO plausibility for a given planet, on the origin of long term, stable crusts, and even on the origin of the solar system. Assuming the MO is initially extensive enough to have a mostly molten surface, its first stage of cooling is an era of radiative heat loss from the surface, with extremely rapid convection below, and no conductive layer in between. The development of the chill crust starts the second stage of MO cooling. Heat loss is now limited by conduction through the crust. The third stage of cooling starts when the near surface MO evolves compositionally to the point of saturation with feldspar. At this point, the cooling rate again precipitously diminishes, the rate of crustal thickness growth as a function of temperature suddenly increases. More work on incorporating chemical constraints into the evolving physical models of MO solidification would be worthwhile.
Warren, Paul H.↗
Parameter identification for nonlinear aerodynamic systems
Continuing work on frequency analysis for transfer function identification is discussed. A new study was initiated into a 'weighted' least squares algorithm within the context of the Fourier modulating function approach. The first phase of applying these techniques to the F-18 flight data is nearing completion, and these results are summarized.
Pearson, Allan E.↗
Long-term storage of salivary cortisol samples at room temperature
Collection of saliva samples for the measurement of cortisol during space flights provides a simple technique for studying changes in adrenal function due microgravity. In the present work, several methods for preserving saliva cortisol at room temperature were investigated using radioimmunoassays for determining cortisol in saliva samples collected on a saliva-collection device called Salivettes. It was found that a pretreatment of Salivettes with citric acid resulted in preserving more than 85 percent of the salivary cortisol for as long as six weeks. The results correlated well with those for a sample stored in a freezer on an untreated Salivette.
Chen, Yu-Ming↗
Diffusion on Cu surfaces
Understanding surface diffusion is essential in understanding surface phenomena, such as crystal growth, thin film growth, corrosion, physisorption, and chemisorption. Because of its importance, various experimental and theoretical efforts have been directed to understand this phenomena. The Field Ion Microscope (FIM) has been the major experimental tool for studying surface diffusion. FIM have been employed by various research groups to study surface diffusion of adatoms. Because of limitations of the FIM, such studies are only limited to a few surfaces: nickel, platinum, aluminum, iridium, tungsten, and rhodium. From the theoretical standpoint, various atomistic simulations are performed to study surface diffusion. In most of these calculations the Embedded Atom Method (EAM) along with the molecular static (MS) simulation are utilized. The EAM is a semi-empirical approach for modeling the interatomic interactions. The MS simulation is a technique for minimizing the total energy of a system of particles with respect to the positions of its particles. One of the objectives of this work is to develop the EAM functions for Cu and use them in conjunction with the molecular static (MS) simulation to study diffusion of a Cu atom on a perfect as well as stepped Cu(100) surfaces. This will provide a test of the validity of the EAM functions on Cu(100) surface and near the stepped environments. In particular, we construct a terrace-ledge-kink (TLK) model and calculate the migration energies of an atom on a terrace, near a ledge site, near a kink site, and going over a descending step. We have also calculated formation energies of an atom on the bare surface, a vacancy in the surface, a stepped surface, and a stepped-kink surface. Our results are compared with the available experimental and theoretical results.
Karimi, Majid↗
Integrated risk management
The purpose of this report is to first present a basis or foundation for the building of an integrated risk management plan and them to present the plan. The integration referred to is across both the temporal and the hierarchical dimensions. Complexity, consequence, and credibility seem to be driving the need for the consideration of risk. Reduction of personal bias and reproducibility of the decision making process seem to be driving the consideration of a formal risk plan. While risk can be used as either a selection tool or a control tool, this paper concentrates on the selection usage. Risk relies on stated purpose. The tightness of the definition of purpose and success is directly reflected in the definition and control of risk. Much of a risk management plan could be designed by the answers to the questions of why, what, who, when, and where. However, any plan must provide the following information about a threat or risk: likelihood, consequence, predictability, reliability, and reproducibility. While the environment at NASA is seen as warm, but not hot, for the introduction of a risk program, some encouragement is seen if the following problems are addressed: no champion, no commitment of resource, confused definitions, lack of direction and focus, a hard sell, NASA culture, many choices of assessment methods, and cost. The plan is designed to follow the normal method of doing work and is structured to follow either the work break down structure or a functional structure very well. The parts of the plan include: defining purpose and success, initial threat assessment, initial risk assessment, reconciling threats and parameters, putting part of the information down and factoring the information back into the decision process as it comes back up, and developing inferences. Two major suggestions are presented. One is to build an office of risk management to be used as a resource by managers in doing the risk process. Another is to form a pilot program to try out the details in the plan and modify the method where needed.
Hunsucker, J. L.↗