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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 new type of controller for scientific CCDs that has been designed and tested at NASA-Goddard is described. It features the flexibility of software waveform generation as well as the speed and accuracy of clocking by hardware. The basic CCD operation is described as well as the controller architecture; controller operation; experimental verification; and software, hardware, and data acquisition.
The standards and procedures for the generation of operational display formats to be used in the Mission Control Center (MCC) display control system are presented. The required effort, forms, and fundamentals for the design, specifications, and production of display formats are identified. The principles of display design and system constraints controlling the creation of optimum operational displays for mission control are explained. The basic two types of MCC display systems for presenting information are described.
The purpose is to describe the basic philosophies of operating and maintaining the Test, Control, and Monitor System (TCMS) equipment. TCMS is a complex and sophisticated checkout system. Operations and maintenance processes developed to support it will be based upon current experience, but will be focused on the specific needs of TCMS in support of Space Station Freedom Program (SSFP) and related activities. An overview of the operations and maintenance goals and philosophies are presented. The assumptions, roles and responsibilities, concepts and interfaces for operation, on-line maintenance, off-line support, and Operations and Maintenance (O&M) personnel training on all TCMS equipment located at KSC are described.
The ERTS-1 experimental hydrologic Data Collection Platform System that has been established at the New England Division (NED), the reasons for getting involved with the experiment, some of the initial problems associated with the data collection hardware, and a preliminary conclusion based on operating experiences are reviewed. The New England Region includes the states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island and Connecticut. The entire area consists of approximately 97,000 sq. km. (60,000 square miles), half of which is in the state of Maine. The limits of the NED are all of Maine, New Hampshire and Vermont to the western limits of the Connecticut River basin, Massachusetts, Connecticut to the western edge of the Housatonic River basin and Rhode Island. All reservoirs have flood control as a primary purpose. Other uses include water supply, recreation and low flow augmentation. However, none of the reservoirs are presently operated for hydroelectric power, navigation, or irrigation purposes. Basically then, flood control regulation is NED's primary concern.
The uncertainties and associated costs involved in selecting and designing a particulate control device to meet California's air emission regulations are considered. The basic operating principles of electrostatic precipitators and fabric filters are discussed, and design parameters are identified. The size and resulting cost of the control device as a function of design parameters is illustrated by a case study for an 800 MW coal-fired fired utility boiler burning a typical southwestern subbituminous coal. The cost of selecting an undersized particulate control device is compared with the cost of selecting an oversized device.
A study was conducted to determine the external effects caused by operation of the reaction control system during entry of the space shuttle orbiter. The effects of jet plume-external flow interactions were emphasized. Force data were obtained for the basic airframe characteristics plus induced effects when the reaction control system is operating. Resulting control amplification and/or coupling were derived and their effects on the aerodynamic stability and control of the orbiter and the reaction control system thrust were determined.
The increasing importance of airborne electronics for use in automated flight systems is briefly reviewed with attention to both basic aircraft control functions and flight management systems for operational use. The requirements for high levels of systems reliability are recognized. Design techniques are discussed and the areas of control systems, computing and communications are considered in terms of key technical problems and trends for their solution.
The topics considered are: (1) the base of the number system, (2) precision control, (3) number representation, (4) arithmetic operations, (5) other basic operations, (6) elementary functions, and (7) exception handling. The possibility of doing without fixed-point arithmetic is also mentioned. The specifications are intended to be entirely at the level of a programming language such as FORTRAN. The emphasis is on convenience and simplicity from the user's point of view. Conforming to such specifications would have obvious beneficial implications for the portability of numerical software, and for proving programs correct, as well as attempting to provide facilities which are most suitable for the user. The specifications are not complete in every detail, but it is intended that they be complete in spirit - some further details, especially syntatic details, would have to be provided, but the proposals are otherwise relatively complete.
Results of a two-year research effort on dynamics and control of detumbling a disabled spacecraft during rescue operations are summarized. Answers to several basic questions about associated techniques and hardware requirements were obtained. Specifically, efforts have included development of operational procedures, conceptual design of remotely controlled modules, feasibility of internal moving mass for stabilization, and optimal techniques for minimum-time detumbling. Results have been documented in several reports and publications.
This paper describes an experimental paradigm and a set of preliminary results which demonstrate a relationship between the level of performance on a skilled man-machine control task, the skill of the operator, the level of mental difficulty induced by an additional task imposed on the basic control task, and visual scanning performance. During a constant, simulated piloting task, visual scanning of instruments was found to vary as a function of the level of difficulty of a verbal loading task. The average dwell time of each fixation on the pilot's primary instrument increased as a function of the loading. The scanning behavior was also a function of the estimated skill level of the pilots, with novices being affected by the loading task much more than experts. The results suggest that visual scanning of instruments in a controlled task may be an indicator of both workload and skill.
An experimental paradigm and a set of results which demonstrate a relationship between the level of performance on a skilled man-machine control task, the skill of the operator, the level of mental difficulty induced by an additional task imposed on the basic control task, and visual scanning performance. During a constant, simulated piloting task, visual scanning of instruments was found to vary as a function of the level of difficulty of a verbal mental loading task. The average dwell time of each fixation on the pilot's primary instrument increased as a function of the estimated skill level of the pilots, with novices being affected by the loading task much more than the experts. The results suggest that visual scanning of instruments in a controlled task may be an indicator of both workload and skill.
This paper describes an experimental paradigm and a set of results which demonstrate a relationship between the level of performance on a skilled man-machine control task, the skill of the operator, the level of mental difficulty induced by an additional task imposed on the basic control task, and visual scanning performance. During a constant, simulated piloting task, visual scanning of instruments was found to vary with the difficulty of a verbal mental loading task. The average dwell time of each fixation on the pilot's primary instrument increased with the estimated skill level of the pilots, with novices being affected by the loading task much more than experts. The results suggest that visual scanning of instruments in a controlled task may be an indicator of both workload and skill.
The identification of the parameters of the optimal control model from input-output data of the human operator is considered. Accepting the basic structure of the model as a cascade of a full-order observer and a feedback law, and suppressing the inherent optimality of the human controller, the parameters to be identified are the feedback matrix, the observer gain matrix, and the intensity matrices of the observation noise and the motor noise. The identification of the parameters is a statistical problem, because the system and output are corrupted by noise, and therefore the solution must be based on the statistics (probability density function) of the input and output data of the human operator. However, based on the statistics of the input-output data of the human operator, no distinction can be made between the observation and the motor noise, which shows that the model suffers from overparameterization.
The various missions to be performed by the 30-cm diameter mercury bombardment thruster engine are discussed. The operating constraints imposed by the thermal environment, allowable time to reach steady state operation, and the number of start-ups required are examined. The variety of requirements is further analyzed for the impact on the basic control logic for the engine. The control logic is divided into the start-up, run, and shutdown modes of operation. The start-up mode is reported.
A small-scale wind tunnel test of a two engine hybrid model with upper surface blowing on a simulated expandable duct internally blown flap was accomplished in a two phase program. The low wing Phase I model utilized 0.126c radius Jacobs/Hurkamp flaps and 0.337c radius Coanda flaps. The high wing Phase II model was utilized for continued studies on the Jacobs/Hurkamp flap. Principal study areas included: basic data both engines operative and with an engine out, control flap utilization, horizontal tail effectiveness, spoiler effectiveness, USB nacelle deflector study and USB/IBF pressure ratio effects.
Plans for the use of the three fine guidance sensors (FGSs) of the NASA Hubble Space Telescope for direct astrometric observations are reviewed. Topics addressed include the optical elements and detectors of the FGSs, the basic and astrometric operating modes of the FGSs, spacecraft pointing control during astrometric observations, and the astrometric data-reduction software provided to HST users. Particular attention is given to the calibration procedures for optical-field angle distortion, the plate scale, filter-wedge errors, lateral color effects, secular changes, velocity aberration, and transfer function. Also discussed are the steps being taken to verify the HST orbit. It is pointed out that the performance of the interferometric FGSs should not be affected by the focusing problems of the main HST instrument.
The increasing gap between processor and memory performance has lead to new architectural models for memory-intensive applications. In this paper, we explore the performance of a set of memory-intensive benchmarks and use them to compare the performance of conventional cache-based microprocessors to a mixed logic and DRAM processor called VIRAM. The benchmarks are based on problem statements, rather than specific implementations, and in each case we explore the fundamental hardware requirements of the problem, as well as alternative algorithms and data structures that can help expose fine-grained parallelism or simplify memory access patterns. The benchmarks are characterized by their memory access patterns, their basic control structures, and the ratio of computation to memory operation.
This slide presentation describes the propulsion system for the Apollo Lunar Module (LM). It defines they systems for the LM propulsion and the control system. It lists the times during the mission at which each system was used. It describes the basic components and the operation of the Descent and Ascent Propulsion systems. It also describes LM reaction control system.