SEARCH · Engineering Papers
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The textbook provides a semantical explanation accompanying a complete set of GOAL syntax diagrams, system concepts, language component interaction, and general language concepts necessary for efficient language implementation/execution.
This study tested the prediction, derived from the goal-setting hypothesis, that the facilitating effects of knowledge of results (KR) in a simple vigilance task should be related directly to the level of the performance standard used to regulate KR. Two groups of Ss received dichotomous KR in terms of whether Ss response times (RTs) to signal detections exceeded a high or low standard of performance. The aperiodic offset of a visual signal was the critical event for detection. The vigil was divided into a training phase followed by testing, during which KR was withdrawn. Knowledge of results enhanced performance in both phases. However, the two standards used to regulate feedback contributed little to these effects.
The GOAL (Ground Operations Aerospace Language) test programming language was developed for use in ground checkout operations in a space vehicle launch environment. To insure compatibility with a maximum number of applications, a systematic and error-free method of referencing command/response (analog and digital) hardware measurements is a principle feature of the language. Central to the concept of requiring the test language to be independent of launch complex equipment and terminology is that of addressing measurements via symbolic names that have meaning directly in the hardware units being tested. To form the link from test program through test system interfaces to the units being tested the concept of a data bank has been introduced. The data bank is actually a large cross-reference table that provides pertinent hardware data such as interface unit addresses, data bus routings, or any other system values required to locate and access measurements.
The following areas were discussed in relation to a study of the commonality of space vehicle applications to future national needs: (1) index of initiatives (civilian observation, communication, support), brief illustrated description of each initiative, time periods (from 1980 to 2000+) for implementation of these initiatives; (2) data bank of functional system options, presented in the form of data sheets, one for each of the major functions, with the system option for near-term, midterm, and far-term space projects applicable to each subcategory of functions to be fulfilled; (3) table relating initiatives and desired goals (public service and humanistic, materialistic, scientific and intellectual); and (4) data on size, weight and cost estimations.
The paper attempts to define a desirable and reachable goal for a second generation SST. Justifications for the need of an SST are considered as is the ecological impact of a second generation SST project. Required technology advances to reach the range of 6500 nautical miles are examined along with structural weight reduction and drag reduction. Possible performance improvements due to design modifications are discussed, and environmental problems are discussed in detail with emphasis on sonic booms.
The socio-economic benefits to be derived from system applications of space technology goals developed by NASA were assessed. Specific studies include: electronic mail; personal telephone communications; weather and climate monitoring, prediction, and control; crop production forecasting and water availability; planetary engineering of the planet Venus; and planetary exploration.
An analysis and evaluation of the social value of the SST project are presented. It is emphasized that the means of civil mass transportation reaching the same range available to military decrease the tension among neighboring nations and reduce human fatigue. The present status of the SST in the United States, together with the future goals, are described.
A joint NASA/industry project called Integrated Programs for Aerospace-vehicle Design (IPAD) is described, which has the goal of raising aerospace-industry productivity through the application of computers to integrate company-wide management of engineering data. Basically a general-purpose interactive computing system developed to support engineering design processes, the IPAD design is composed of three major software components: the executive, data management, and geometry and graphics software. Results of IPAD activities include a comprehensive description of a future representative aerospace vehicle design process and its interface to manufacturing, and requirements and preliminary design of a future IPAD software system to integrate engineering activities of an aerospace company having several products under simultaneous development.
The paper discusses the concept of the Space Operations Center, a Shuttle-serviced permanent manned LEO space station. The SOC has the mission-oriented role of construction, assembly, and servicing of space systems and spacecraft. Previous space-station concepts are reviewed; future space goals are compared; and objectives for the future Space Operations Center and its initial analysis are described.
The objectives of the Seasat mission, which was dedicated to establishing the utility of microwave sensors for the remote sensing of the earth's oceans, and data collected during some three months of orbital operations are briefly reviewed. In particular, consideration is given to the Seasat sensors and measurement goals, surface and in situ observations, evaluation organization, and current status of geophysical evaluation for each sensor (altimeter, Seasat-A scatterometer system, scanning multichannel microwave radiometer, visible and infrared radiometer, and synthetic aperture radar). Finally, future plans related to the Seasat project are discussed.
Thermo-structural performance of the Space Shuttle orbiter Columbia's leading-edge structural subsystem for the first five (5) flights is compared with the design goals. Lessons learned from thse initial flights of the first reusable manned spacecraft are discussed in order to assess design maturity, deficiencies, and modifications required to rectify the design deficiencies. Flight data and post-flight inspections support the conclusion that the leading-edge structural subsystem hardware performance was outstanding for the initial five (5) flights.
Robotic systems will play an increasingly important role in space operations. This paper describes the objective and design of a proposed goal-oriented telerobotic system for space operations. This design effort encompasses the elements of the system executive and user interface, and the distribution and general structure of the knowledge bases, the displays, and the task sequencing. The objective of the design effort is to provide an evolutionary structure for a telerobotic system, i.e., one that can progress from strictly teleoperated through phases of serving as an assistant, a colleague, and an expert, to eventually serve as a truly autonomous unit, requiring only minimal supervision. A preliminary design for such a system involving 'mixed initiative', or the flexible shared control between the human operator and the software system, is complete and described in this paper.
Flexible arms offer a great degree of flexibility in maneuvering in the space environment. The problem of transporting an astronaut for extra-vehicular activity using a space station based flexible arm robot was studied. Inverse kinematic solutions of the multilink structure were developed. The technique is goal driven and can support decision making for configuration selection as required for stability and obstacle avoidance. Details of this technique and results are given.
Recent studies of impulsive hard x ray and microwave bursts suggest that a propagating causative agent with a characteristic velocity of the order of 1000 km/s is responsible for these bursts. The results of these studies are summarized and observable distinguishing characteristics of the various possible agents are highlighted, with emphasis on key observational goals for the Max '91 campaigns. The most likely causative agents suggested by the evidence are shocks, thermal conduction fronts, and propagating modes of magnetic reconnection in flare plasmas. With new instrumentation planned for Max '91, high spatial resolution observations of hard x ray sources have the potential to identify the agent by revealing detailed features of source spatial evolution. Observations with the Very Large Array and other radio imaging instruments are of great importance, as well as detailed modeling of coronal loop structures to place limits on their density and temperature profiles. With the combined hard x ray and microwave imaging observations, aided by loop model results, the simplest causative agent to rule out would be the propagating modes of magnetic reconnection. To fit the observational evidence, reconnection modes would need to travel at approximately the same velocity (the Alfven velocity) in different coronal structures that vary in length by a factor of 10(exp 3). Over such a vast range in loop lengths, it is difficult to believe that the Alfven velocity is constant. Thermal conduction fronts would be suggested by sources that expand along the direction of B and exhibit relatively little particle precipitation. Particle acceleration due to shocks could produce more diverse radially expanding source geometries with precipitation at loop footprints.
This document is part of the Final Report performed under contract NASW-3864, titled "NASA's Long-Range Technology Goals". The objectives of the effort were: To identify technologies whose development falls within NASA's capability and purview, and which have high potential for leapfrog advances in the national industrial posture in the 2005-2010 era. To define which of these technologies can also enable quantum jumps in the national space program. To assess mechanisms of interaction between NASA and industry constituencies for realizing the leapfrog technologies. This Volume details the findings pertaining to the advanced space-enabling technologies.
Space transportation propulsion systems symposium is discussed. The following subject areas are covered: overall goals; main issues; materials characterization; reduction of manufacturing defects; standards and certification; advanced NDE techniques; designing for inspectability; candidate programs/milestones; and NDE technology potentials.
Realistic production systems require an integrated combination of forward and backward reasoning to reflect appropriately the processes of natural human expert reasoning. A control mechanism that consists solely of forward reasoning is not an effective way to promptly focus the system's attention as calculation proceeds. Often, expert system programmers will attempt to compensate for this lack by using data to enforce the desired goal directed control structure. This approach is inherently flawed in that it is attempting to use data to fulfill the role of control. This paper will describe our implementation of backward chaining in C Language Integrated Production System (CLIPS), and show how this has shortened and simplified various CLIPS programs. This work was done at the Aerospace Corporation, and has general applicability.
Summarized here are the activities of a one-day workshop convened to assess the effectiveness and priority setting mechanisms used by NASA's Office of Space Science and Applications in carrying out its diverse scientific programs. Among the topics discussed were strategic planning, decision making, and goal setting.