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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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At least 1,711 records · Page 95
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Docking and retrieval mechanism

An engineering prototype docking and retrieval mechanism (DRM) which enables two spacecraft to dock and be structurally joined on-orbit is described. The joining of two spacecraft or payloads on-orbit supports future planned space activities such as payload servicing, deployment and retrieval, and assembly or large space systems. Advantages of the DRM include: it is a nonimpact docking mechanism; does not require impact absorbing mechanisms or attitude stabilization on the target spacecraft; is capable of docking to a spinning spacecraft; and can spin up and deploy a spinning spacecraft or payload.

Tewell, J. R.↗
NASA NTRS1977

Docking and retrieval mechanism

An engineering prototype docking and retrieval mechanism (DRM) is described which enables two spacecraft to dock and be structurally joined on-orbit. The joining of two spacecraft or payloads on-orbit supports future planned space activities such as payload servicing, deployment and retrieval, and assembly of large space systems. The DRM, as developed, provides advantages over prior approaches because it is a nonimpact docking mechanism, does not require impact absorbing mechanisms or attitude stabilization on the target spacecraft, is capable of docking to a spinning spacecraft, and can spin up and deploy a spinning spacecraft or payload.

Tewell, J. R.↗
NASA NTRS1979

NASA research on general aviation power plants

Research activities within NASA to support general aviation industry in improving propulsion engines are described. Near-term objectives include improvements of gasoline piston engines to achieve fuel savings and reduce emissions well below EPA levels. To meet the longer term goals, advanced combustion research has been considered as essential in obtaining further improvements in BSFC (break specific fuel consumption). Modifications of an aircraft rotary engine were tested and it was found that by increasing the compression ratio and other refinements the BSFC was improved by 15%. The applicability of available large turbofan engine technology to small engines in order to obtain significant reductions in noise and pollutant emissions is being tested. Studies have been conducted at exploring the possibility of achieving high improvements in cost and performance for turboprop engines of less than 1000 horsepower.

Stewart, W. L.↗
NASA NTRS1979

Meteorological image processing applications

Meteorologists at NASA's Goddard Space Flight Center are conducting an extensive program of research in weather and climate related phenomena. This paper focuses on meteorological image processing applications directed toward gaining a detailed understanding of severe weather phenomena. In addition, the paper discusses the ground data handling and image processing systems used at the Goddard Space Flight Center to support severe weather research activities and describes three specific meteorological studies which utilized these facilities.

Bracken, P. A.↗
NASA NTRS1981

Technical communication: Notes toward defining discipline

In the field of technical communication, definitions posited in virtually any major text violate every major rule of definitions. The most popular method for defining the field is to state that technical writing is any writing that supports technology or technological activities. There is a need for a nice yardstick for measuring what "technology" is. Some ways in which the field can be defined in a tightly structured empirical way and some implications of technical communication for a humanistic education in a technological age are suggested.

Rubens, P. M.↗
NASA NTRS1981

Space tracking and data systems; Proceedings of the Symposium, Arlington, VA, June 16-18, 1981

The AIAA/NASA Symposium on Space Tracking and Data Systems, held in Pentagon City, Virginia, on June 16-18, 1981, had the purpose of reviewing international activities in space tracking and data systems for civil use in the 1980-2000 time frame. Participants included 225 representatives from industrial and government organizations in eight nations. The nations represented include the United States, France, Germany, India, Japan, Norway, Spain, and Sweden. The major functions of the systems described at the Symposium are related to the initial downlink of telemetry and spacecraft status data, attendant tracking activities, and uplink of spacecraft commands; communication between the associated acquisition sites and central processing and control stations; formulation and implementation of commands that control the spacecraft and its payload; and processing of spacecraft data needed to make command decisions. Attention is given to an overview of current activities and plans, and supporting developments, taking into account the time from 1980 to 1990. New developments are also considered.

Grey, J.↗
NASA NTRS1982

Economic and technical aspects of repair, servicing, and retrieval of low earth orbit free flying spacecraft

The economic and technical aspects of the Solar Maximum Observatory Repair Mission at NASA are presented, in an effort to demonstrate the Space Shuttle capability to rendezvous with and repair on-orbit the Solar Maximum Observatory (SMM). A failure in the Attitude Control Subsystem (ACS) after 10 months of operation caused a loss in precision pointing capability. The Multimission Modular Spacecraft (MMS) used for the mission, was designed with on-orbit repairability, and to correct various instrument anomalies, repiar kits such as an electronics box, a thermal aperture closure, and a high energy particle reflection baffle will be used. In addition, a flight support system will be used to berth, electrically safe, and support all the repair activities. A two year effort is foreseen, and the economic return on SMM will be $176 M, in addition to two to three years of solar observation. The mission will eventually conduct studies on flare as a function of solar cycle.

Cepollina, F. J.↗
NASA NTRS1982

The intercrater plains of Mercury and the Moon: Their nature, origin and role in terrestrial planet evolution. Alternative thermal histories

Interpretations supporting a differentiated, once active Mercury are listed. Alternative scenarios of the planet's thermal history involve: different distributions of accreted materials, including uranium and thorium-rich materials; variations of early melting; and different modes of plains and scarp formation. Arguments are advanced which strongly favor plains formation by volcanism, lack of a primordial surface, and possible identification of remnant tensional features. Studies of remotely sensed data which strongly suggest a modestly homogeneous surface of silicates imply core separation. Reasons for accepting or rejecting various hypotheses for thermal histories of the planet are mentioned.

Leake, M. A.↗
NASA NTRS1984

Spacecraft control research at NASA

Future missions is space will require controlling spacecraft which are both large and flexible. The limited inherent damping and the uncertain and changing dynamic characteristics of many of these vehicles, such as manned space stations and large antennas, will revolutionize spacecraft control requirements. In preparation for the time that such control systems are required, considerable research and technology development is necessary. A program is in place at NASA for the development of active control technology to support major initiatives for space station and advanced spacecraft. A number of key control technology program needs are cited in the paper as required for these and other future NASA missions together with an integrated controls/structures technology flight experiment to demonstrate and validate technology for large flexible structures.

Dahlgren, J. B.↗
NASA NTRS1984

Thermal analysis of cryogenic wind tunnel models

This paper summarizes the thermal analysis activity being performed in support of the design of wind tunnel models for the National Transonic Facility (NTF) at the NASA Langley Research Center. The goal of the analysis effort has been to address model design difficulties associated with the severe thermal environment of this cryogenic wind tunnel. The unique characteristics of this environment are discussed for various phases of tunnel operation. The methods used to calculate temperatures and thermal stresses in the models are also described. The results indicate that thermal considerations do not drive the design to the extent originally envisioned. In general, the problems identified are localized and associated with thermal mismatch between components. Several specific examples of thermal design problems and proposed solutions are given.

Carlson, A. B.↗
NASA NTRS1985

Investigation of Low-temperature Solders for Cryogenic Wind Tunnel Models

The advent of high Reynolds number cryogenic wind tunnels has forced alteration of manufacturing and assembly techniques and eliminated usage of many materials associated with conventional wind tunnel models. One of the techniques affected is soldering. Solder alloys commonly used for wind tunnel models are susceptible to low-temperature embrittlement and phase transformation. The low-temperature performance of several solder alloys is being examined during research and development activities being conducted in support of design and fabrication of cryogenic wind tunnel models. Among the properties examined during these tests are shear strength, surface quality, joint stability, and durability when subjected to dynamic loading. Results of these tests and experiences with recent models are summarized.

Firth, G. C.↗
NASA NTRS1986

Density and pressure variability in the mesosphere and thermosphere

In an effort to isolate the essential physics of the mesosphere and the thermosphere, a steady one-dimensional density and pressure model has been developed in support of related NASA activities, i.e., projects such as the AOTV and the Space Station. The model incorporates a zeroth order basic state including both the three-dimensional wind field and its associated shear structure, etc. A first order wave field is also incorporated in period bands ranging from about one second to one day. Both basic state and perturbation quantities satsify the combined constraints of mass, linear momentum and energy conservation on the midlatitude beta plane. A numerical (iterative) technique is used to solve for the vertical wind which is coupled to the density and pressure fields. The temperature structure from 1 to 1000 km and the lower boundary conditions are specified using the U.S. Standard Atmosphere 1976. Vertical winds are initialized at the top of the Planetary Boundary Layer using Ekman pumping values over flat terrain. The model also allows for the generation of waves during the geostrophic adjustment process and incorporates wave nonlinearity effects.

Davis, T. M.↗
NASA NTRS1985

Space Station power system issues

Issues governing the selection of power systems for long-term manned Space Stations intended solely for earth orbital missions are covered briefly, drawing on trade study results from both in-house and contracted studies that have been conducted over nearly two decades. An involvement, from the Program Development Office at MSFC, with current Space Station concepts began in late 1982 with the NASA-wide Systems Definition Working Group and continued throughout 1984 in support of various planning activities. The premise for this discussion is that, within the confines of the current Space Station concept, there is good reason to consider photovoltaic power systems to be a venerable technology option for both the initial 75 kW and 300 kW (or much greater) growth stations. The issue of large physical size required by photovoltaic power systems is presented considering mass, atmospheric drag, launch packaging and power transmission voltage as being possible practicality limitations. The validity of searching for a cross-over point necessitating the introduction of solar thermal or nuclear power system options as enabling technologies is considered with reference to programs ranging from the 4.8 kW Skylab to the 9.5 gW Space Power Satellite.

Giudici, R. J.↗
NASA NTRS1986

An overview of the NSCAT/N-ROSS program

The NASA Scatterometer (NSCAT) to fly on the U.S. Navy Remote Ocean Sensing System (N-ROSS) mission is presented. The overall N-ROSS mission, the NSCAT flight instrument and groundbased data processing/distribution system, and NASA-supported science and verification activities are described. The N-ROSS system is designed to provide measurements of near-surface wind, ocean topography, wave height, sea-surface temperature, and atmospheric water content over the global oceans. The NSCAT is an improved version of the Seasat scatterometer. It will measure near surface vector winds.

Martin, B. D.↗
NASA NTRS1987

Microgravity Fluid Management Symposium

The NASA Microgravity Fluid Management Symposium, held at the NASA Lewis Research Center, September 9 to 10, 1986, focused on future research in the microgravity fluid management field. The symposium allowed researchers and managers to review space applications that require fluid management technology, to present the current status of technology development, and to identify the technology developments required for future missions. The 19 papers covered three major categories: (1) fluid storage, acquisition, and transfer; (2) fluid management applications, i.e., space power and thermal management systems, and environmental control and life support systems; (3) project activities and insights including two descriptions of previous flight experiments and a summary of typical activities required during development of a shuttle flight experiment.

Source record↗
NASA NTRS1986

Submillimeter and millimeter observations of Uranus and Neptune

Neptune and Uranus were studied at submillimeter and millimeter wavelengths for 2 yr using the UK IR telescope and the NASA IR telescope at Mauna Kea and the 12 dish at Kitt Peak, AZ. The brightness temperatures of both planets are provided at various wavelengths over the 0.35-3.3 mm interval scanned in the study. The present data, in combination with data from the 17 microns-3 mm interval scanned in the study. The present data, in combination with data from the 17 microns-3 mm interval taken during previous campaigns, are employed to model the temperature structures in the atmospheres of the two planets over the vertical range 100 mbar-8 bar. The data support the presence of active convection processes at the 1 bar level and deeper in both atmospheres. A static equilibrium however, exists between para-H2 and ortho-H2, along with a constant CH4 fraction of 2 percent. Deficiencies in the current database are detailed.

Orton, G. S.↗
NASA NTRS1989

Unified Engineering Software System

Collection of computer programs performs diverse functions in prototype engineering. NEXUS, NASA Engineering Extendible Unified Software system, is research set of computer programs designed to support full sequence of activities encountered in NASA engineering projects. Sequence spans preliminary design, design analysis, detailed design, manufacturing, assembly, and testing. Primarily addresses process of prototype engineering, task of getting single or small number of copies of product to work. Written in FORTRAN 77 and PROLOG.

Purves, L. R.↗
NASA NTRS1989

Methods and decision making on a Mars rover for identification of fossils

A system for automated fusion and interpretation of image data from multiple sensors, including multispectral data from an imaging spectrometer is being developed. Classical artificial intelligence techniques and artificial neural networks are employed to make real time decision based on current input and known scientific goals. Emphasis is placed on identifying minerals which could indicate past life activity or an environment supportive of life. Multispectral data can be used for geological analysis because different minerals have characteristic spectral reflectance in the visible and near infrared range. Classification of each spectrum into a broad class, based on overall spectral shape and locations of absorption bands is possible in real time using artificial neural networks. The goal of the system is twofold: multisensor and multispectral data must be interpreted in real time so that potentially interesting sites can be flagged and investigated in more detail while the rover is near those sites; and the sensed data must be reduced to the most compact form possible without loss of crucial information. Autonomous decision making will allow a rover to achieve maximum scientific benefit from a mission. Both a classical rule based approach and a decision neural network for making real time choices are being considered. Neural nets may work well for adaptive decision making. A neural net can be trained to work in two steps. First, the actual input state is mapped to the closest of a number of memorized states. After weighing the importance of various input parameters, the net produces an output decision based on the matched memory state. Real time, autonomous image data analysis and decision making capabilities are required for achieving maximum scientific benefit from a rover mission. The system under development will enhance the chances of identifying fossils or environments capable of supporting life on Mars

Eberlein, Susan↗