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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 91 records · Page 5
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NASA NTRS1989

Concentrations and size distributions of Antarctic stratospheric aerosols

Particle Measuring Systems laser particle spectrometer (ASAS-X and FSSP) probes were used to measure aerosol particle concentrations and size distributions during 11 ER-2 flights between Punta Arenas (53 deg S) and Antarctica (up to 72 deg S) from August 17 to September 22, 1987. The time resolution was 10 s, corresponding to a spatial resolution of 2 km. The data were divided into two size classes (0.05-0.25 and 0.53-5.5 micron radius) to separate the small particle from the coarse particle populations. Results show that the small-particle concentrations are typical for a background aerosol during volcanic quiescence. This concentration is generally constant along a flight track; in only one instance a depletion of small particles during a polar stratospheric cloud (PSC) encounter was measured, suggesting a nucleation of type I PSC particles on background aerosols. Temporary increases of the coarse particle concentrations indicated the presence of tenuous polar stratospheric clouds that were encountered most frequently at the southernmost portion of a flight track and when the aircraft descended to lower altitudes. During 'particle events', particle modes were found at 0.6-micron radius, corresponding to type I PSCs, and occasionally, at 2.0-micron radius corresponding to type II PSCs.

Ferry, G. V.↗
NASA NTRS1989

In situ observations of BrO over Antarctica - ER-2 aircraft results from 54 deg S to 72 deg S latitude

Bromine monoxide was observed in situ during nine flights of the NASA ER-2 aircraft from Punta Arenas, Chile (54 deg S latitude), to 72 deg S latitude over the Palmer Peninsula, Antarctica. The first flight for the BrO detection system was on August 28. The distribution of BrO inside the chemically perturbed region defined by greatly elevated ClO abundances was different from that found just outside. Inside, the BrO mixing ratio was 6.1 + or - 1.1 pptv above the 440 K potential temperature surface, 4.7 + or - 2.0 pptv between the 400 and 440 K surfaces, and less than 4 pptv below the 400 K surface. At high latitudes outside the chemically perturbed region, the BrO mixing ratio was 5.4 + or - 1.4 pptv near the 450 K surface, but decreased to 2.9 + or - 1.2 pptv at the 420 K surface. The abundance of BrO showed no discernible temporal trend during the course of the nine flights. Away from the south polar region, at latitudes between 47 deg S and 37 deg N and potential temperatures between 435 and 500 K (18.5- to 20.7-km altitude), the BrO mixing ratio was 0.5-3.0 pptv.

Brune, W. H.↗
NASA NTRS1990

Ice saturation at the tropopause observed from the ER-2 aircraft

Ice saturation at or just above the tropopause was frequently observed during the ER-2 vertical profiles over Stavanger (59 deg N) during the Airborne Arctic Stratospheric Expedition (AASE). On occasion, ice saturation extended as much as 500 m above the tropopause. Saturation was not observed over Punta Arenas (53 deg S) during the Airborne Antarctic Ozone Experiment. Saturation extending just above the tropopause was observed at Moffett Field (38 deg N) in winter but not in summer. The top of a thick cirrus layer at the tropopause will be very strongly cooled, and a thin cloud layer at the tropopause will either be strongly heated or cooled depending on the presence of lower level clouds. Some ER-2 data suggests removal of water and nitrogen species from the tropopause.

Murphy, D. M.↗
NASA NTRS1990

A comparison of ER-2 measurements of stratospheric water vapor between the 1987 Antarctic and 1989 Arctic Airborne missions

Vertical profiles of water vapor inside the Antarctic vortex have been compared with those taken outside it over Punta Arenas (53 deg S, 71 deg W). A similar exercise was performed with Arctic vortex profiles and those taken over Stavanger (59 deg N, 6 deg E). Residual water, defined as the stratospheric water vapor mixing ratio with the contribution from methane oxidation subtracted, is also shown as profiles inside and outside the vortex for both missions. The Arctic and Antarctic profiles of water vapor and residual water are compared. Locally dehydrated air was evident both inside and outside the Antarctic vortex, but such dehydration was not evident in and around the Arctic vortex. Arctic profiles of residual water are consistent with nontropical entry for some air.

Kelly, K. K.↗
NASA NTRS1990

Bio-optical profile data report coastal transition zone program, R/V Thomas Washington, June 24 - July 21, 1988

Twenty-three vertical profiles of the bio-optical properties of the ocean were made during a research cruise on the R/V Thomas Washington, June 24 to July 21, 1988, as part of the Coastal Transition Zone Program off Point Arena, California. A summary is given, to provide investigators with an overview of the data collected. The entire data set is available in digital form for interested researchers.

Davis, Curtiss O.↗
NASA NTRS1990

Bio-optical profile data report coastal transition zone program, R/V Point Sur, June 15-28, 1987

Twenty vertical profiles of the bio-optical properties of the ocean were made during a research cruise on the R/V Point Sur, June 15 to 28, 1987, as part of the Coastal Transition Zone Program off Point Arena, California. Extracted chlorophyll values were also measured at some stations to provide calibration data for the in situ fluorometer. This summary provides investigators with an overview of the data collected. The entire data set is available in digital form.

Davis, Curtiss O.↗
NASA NTRS1991

Surface heating and patchiness in the coastal ocean off central California during a wind relaxation event

The difference between the temperature of the ocean at 4-cm and 2-m depth was continuously monitored during a cruise to the coastal transition zone off Point Arena, California, during June 1987. The two temperatures were coincident most of the time but diverged during one nearshore leg of the cruise where large temperature differences of up to 4.7 C were observed between the 4-cm and 2-m sensors, in areas which were separated by regions where the two temperatures were coincident as usual. The spatial scale of this 'patchy' thermal structure was about 5-10 km. A mixed layer model (Garwood, 1977) was used to simulate the near surface stratification when forced by the observed wind stress, surface heating, and optical clarity of the water. The model produced a thin strongly stratified surface layer at stations where exceptionally high turbidity was observed but did not produce such features otherwise. This simple model could not explain the horizontal patchiness in the thermal structure, which was likely due to patchiness in the near-surface chlorophyll distributions or to submesoscale variability of the surface wind stress.

Ramp, Steven R.↗
NASA NTRS1991

George M. Low Trophy: NASA's quality and excellence award

NASA's major goal is the preservation of America's position as a leader in the aerospace industry. To maintain that status, it is crucial that the products and services we depend upon from NASA contractors, subcontractors, and suppliers meet the highest quality standards to ensure the space program's success. The George M. Low Trophy: NASA's Quality and Excellence Award is the result of NASA's desire to encourage continuous improvement and Total Quality Management (TQM) in the aerospace industry and is awarded to members of NASA's contractor community that have demonstrated sustained excellence, customer orientation, and outstanding achievements in a Total Quality Management (TQM) environment. The purpose in presenting this award is to increase public awareness of the importance of quality and productivity to the nation's aerospace industry and the nation's leadership position overall; encourage domestic business to continuously pursue efforts that enhance quality and increase productivity which will strengthen the nation's competitiveness in the international arena; and provide a forum for sharing the successful techniques and strategies used by applicants with other American organizations. Awards to Rockwell International and Marotta Scientific Controls, Inc. are announced and discussed.

Source record↗
NASA NTRS1991

Neural network technologies

A whole new arena of computer technologies is now beginning to form. Still in its infancy, neural network technology is a biologically inspired methodology which draws on nature's own cognitive processes. The Software Technology Branch has provided a software tool, Neural Execution and Training System (NETS), to industry, government, and academia to facilitate and expedite the use of this technology. NETS is written in the C programming language and can be executed on a variety of machines. Once a network has been debugged, NETS can produce a C source code which implements the network. This code can then be incorporated into other software systems. Described here are various software projects currently under development with NETS and the anticipated future enhancements to NETS and the technology.

Villarreal, James A.↗
NASA NTRS1992

Intelligent Processing Equipment Research Supported by the National Science Foundation

The research in progress on processes, workstations, and systems has the goal of developing a high level of understanding of the issues involved. This will enable the incorporation of a level of intelligence that will allow the creation of autonomous manufacturing systems that operate in an optimum manner, under a wide range of conditions. The emphasis of the research has been on the development of highly productive and flexible techniques to address current and future problems in manufacturing and processing. Several of these projects have resulted in well-defined and established models that can now be implemented in the application arena in the next few years.

Rao, Suren B.↗
NASA NTRS1991

The role of reliability graph models in assuring dependable operation of complex hardware/software systems

The complexity of computer systems currently being designed for critical applications in the scientific, commercial, and military arenas requires the development of new techniques for utilizing models of system behavior in order to assure 'ultra-dependability'. The complexity of these systems, such as Space Station Freedom and the Air Traffic Control System, stems from their highly integrated designs containing both hardware and software as critical components. Reliability graph models, such as fault trees and digraphs, are used frequently to model hardware systems. Their applicability for software systems has also been demonstrated for software safety analysis and the analysis of software fault tolerance. This paper discusses further uses of graph models in the design and implementation of fault management systems for safety critical applications.

Patterson-Hine, F. A.↗
NASA NTRS1992

Planetary protection policy (U.S.A.)

Through existing treaty obligations of the United States, NASA is committed to exploring space while avoiding biological contamination of the planets, and to the protection of the earth against harm from materials returned from space. Because of the similarities between Mars and earth, plans for the exploration of Mars evoke discussions of these Planetary Protection issues. U.S. Planetary Protection Policy will be focused on the preservation of these goals in an arena that will change with the growth of scientific knowledge about the Martian environment. Early opportunities to gain the appropriate data will be used to guide later policy implementation. Because human presence on Mars will result in the end of earth's separation from the Martian environment, it is expected that precursor robotic missions will address critical planetary protection concerns before humans arrive.

Rummel, John D.↗
NASA NTRS1992

CONE - An STS-based cryogenic fluid management experiment

An overview of the CONE program is presented which includes a definition of the technology addressed by CONE and a baseline experiment set, a description of the experimental and support subsystems, interface requirements between the STS and the experiment carrier (Hitchhiker M), and the reusability and expansion capacity for additional experiment flights. CONE evaluates three primary technologies: the active thermodynamic vent system, the passive thermodynamic vent system, and liquid acquisition device performance. The cryogenic fluid management technology database that the system offers will allow for efficient subcritical cryogenic system designs for operation in a low-gravity environment. This system maximizes the balance between existing component technology and the need for the development of a cryogenic-fluid-management (CFM) test bed to investigate and demonstrate methods of storage and handling arenas.

Bell, R. S.↗
NASA NTRS1991

NASA's Office of Aeronautics and Exploration Technology space power flight projects

NASA created a program called In-STEP (in-space technology experiments program) to give the aerospace community an opportunity to validate advanced technologies in space. In-STEP has funded feasibility studies for the following experiments in the power technology arena: a microsphere insulation investigation, a utilized regenerative fuel cell experiment, an inflatable solar collector experiment, a moving belt radiator experiment, and a liquid drop radiator experiment. The following experiments are currently in the experiment definition phase: an integrated two-phase thermal experiment, an electrolysis performance experiment, and a sodium sulfur battery experiment. Three In-STEP experiments are entering the hardware fabrication phase: thermal energy storage technology, solar array module plasma interaction, and heat pipe performance experiments. Each of these experiments is described, with an emphasis on the benefits of technology validation.

Chmielewski, Art B.↗
NASA NTRS1992

Pressure vessel burst test program - Progress paper No. 3

An updated progress report is provided on a program developed to study through test and analysis, the characteristics of blast waves and fragmentation generated by ruptured gas filled pressure vessels. Prior papers on this USAF/NASA/General Physics program were presented to the AIAA in July 1990 and June 1991. Ten pressure vessels have been burst using pneumatic pressure. Tests were designed to explore burst characteristics and used an instrumented arena. Data trends for current experiments are presented. This paper is the third progress report on the program and addresses: (1) a brief review of current methods for assessing vessel safety and burst parameters, (2) a review of pneumatic burst testing operations and testing results, including a comparison to current methods for burst assessment, and (3) a review of the basis for the current test program including planned testing.

Cain, Maurice R.↗
NASA NTRS1992

An international approach to Mission to Planet Earth

The new international political constellation resulting from the disintegration of the Soviet Union opens up unique opportunities for cooperation in the space arena. Precedents since 1955 indicate a pervasive interest in mutual cooperation to use military reconnaissance and surveillance satellites for space observations to enforce treaty verification and compliance. One of the avenues that offer immediate prospects for fruitful cooperation is the incorporation of the military reconnaissance and surveillance satellite capabilities of both U.S. and Russia into the Mission to Planet Earth. Formation of a United Nations Satellite (UNSAT) fleet drawn from the American and Russian space assets is proposed. The role of UNSAT is to provide world wide monitoring of both military and enviromental activities under the umbrella of the Mission to Planet Earth.

Lawrence, Robert M.↗
NASA NTRS1992

A waning of technocratic faith - NASA and the politics of the Space Shuttle decision, 1967-1972

This paper analyzes the decision to build the Space Shuttle as part of a broader public policy trend away from a deference to technical experts and toward greater politicization of traditionally apolitical issues. At the beginning of the 1960s U.S. leaders had a strong faith in the ability of technology to solve most problems. By 1970 this commitment to technological answers had waned and a resurgence of the right of elected officials to control technical matters was gaining currency. The lengthy and bitter Shuttle decision-making process was part of a much broader shift in the formation of public policy, played out in other arenas as well, aimed at the reemergence of direct political management of technological and scientific affairs by politicians.

Launius, R. D.↗
NASA NTRS1991

The NASA/National Space Science Data Center trapped radiation environment model program, 1964 - 1991

The major effort that NASA, initially with the help of the United States Air Force (USAF), carried out for 27 years to synthesize the experimental and theoretical results of space research related to energetic charged particles into a quantitative description of the terrestrial trapped radiation environment in the form of model environments is detailed. The effort is called the Trapped Radiation Environment Modeling Program (TREMP). In chapter 2 the historical background leading to the establishment of this program is given. Also, the purpose of this modeling program as established by the founders of the program is discussed. This is followed in chapter 3 by the philosophy and approach that was applied in this program throughout its lifetime. As will be seen, this philosophy led to the continuation of the program long after it would have expired. The highlights of the accomplishments are presented in chapter 4. A view to future possible efforts in this arena is given in chapter 5, mainly to pass on to future workers the differences that are perceived from these many years of experience. Chapter 6 is an appendix that details the chronology of the development of TREMP. Finally, the references, which document the work accomplished over these years, are presented in chapter 7.

Vette, James I.↗