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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Measurements of carbon monoxide, condensation nuclei, and ozone on a B 747SP aircraft flight around the world

Measurements of carbon monoxide, condensation nuclei, and ozone concentrations were obtained during a 54 hour polar flight around the world by an automated instrument package carried by a B-747SP commercial aircraft. These and other data were obtained as part of the NASA Global Atmospheric Sampling Program. All data exhibited longitudinal and hemispheric differences. Analysis of the data indicate increased concentrations of carbon monoxide and condensation nuclei at flight levels in the troposphere over tropical land masses. A background concentration for condensation nuclei was found to be 200 per cu cm for tropical tropospheric maritime air.

Gauntner, D. J.↗
NASA NTRS1979

Lightning location and lower-ionospheric height determination from two-station magnetic field measurements

Wide band magnetic direction finding from two stations is used to determine lightning locations and ionospheric height during two nocturnal maritime thunderstorms near Florida. A comparison of calculated lightning locations with radar reflectivity data of the two storms indicates systematic direction-finding errors to be on the order of 1 deg. From the lightning locations and measured arrival times of the first and second sky waves, ionospheric reflecting heights for both sky waves were determined. The effective heights for the first and second sky waves may differ, leading to large errors in single-station determinations of ionospheric height, such as in the method described by Kinzer (1974). The distribution of peak electric fields for the strokes studied is shown to be in reasonable agreement with other determinations, indicating the reliability of the present measurements.

Mcdonald, T. B., III↗
NASA NTRS1980

Ice nucleus concentrations measured during the 1975 Florida Area Cumulus Experiment /FACE/

Ice nuclei measurements were made aboard a cloud-base aircraft during the 1975 Florida Area Cumulus Experiment. Two techniques were used to obtain the ice nuclei concentrations; membranes were collected and analyzed using the NCAR membrane development chamber and continuous ice nuclei concentrations were obtained using the NCAR acoustical counter. Results showed that the membrane technique failed to effectively detect ice nuclei in this maritime tropical area. However, the concentrations recorded by the acoustical counter showed natural afternoon diurnal increases which may have ramifications on cloud development and seeding potential within the particular study area.

Wisniewski, J.↗
NASA NTRS1980

Position surveillance using one active ranging satellite and time-of-arrival of a signal from an independent satellite

Position surveillance using one active ranging/communication satellite and the time-of-arrival of signals from an independent satellite was shown to be feasible and practical. A towboat on the Mississippi River was equipped with a tone-code ranging transponder and a receiver tuned to the timing signals of the GOES satellite. A similar transponder was located at the office of the towing company. Tone-code ranging interrogations were transmitted from the General Electric Earth Station Laboratory through ATS-6 to the towboat and to the ground truth transponder office. Their automatic responses included digital transmissions of time-of-arrival measurements derived from the GOES signals. The Earth Station Laboratory determined ranges from the satellites to the towboat and computed position fixes. The ATS-6 lines-of-position were more precise than 0.1 NMi, 1 sigma, and the GOES lines-of-position were more precise than 1.6 NMi, 1 sigma. High quality voice communications were accomplished with the transponders using a nondirectional antenna on the towboat. The simple and effective surveillance technique merits further evaluation using operational maritime satellites.

Anderson, R. E.↗
NASA NTRS1981

Ambient ammonia measurements using laser photo-acoustic spectroscopy

Ammonia concentrations reached minimal levels (approximately 0.1 ppb) in early winter, followed by a sudden later winter increase. A direct relationship between ambient ammonia levels and air temperature was inferred from the data (linear correlation coefficient r=0.53). Ammonia concentrations were determined to be directly related to the absolute humidity of the air (r=0.72); a weaker relationship between ammonia concentrations and relative humidity was discovered (r=0.37). The data also indicated that ammonia levels were generally higher within continental air masses than those of maritime origin. Soil parameters such as pH and moisture content were found to have a major bearing on the release of gaseous ammonia from soils in the region.

Aldridge, M. D., III↗
NASA NTRS1980

Electronic search and rescue aids

There are two elements to the basic electronic search and rescue problem: a means for immediately alerting potential rescuers and an effective method to guide the rescue forces to the scene of the emergency. An Emergency Locator Transmitter (ELT) used by aircraft or an Emergency Position Indicating Radio Beacon (EPIRB) used by maritime vessels has the capability of providing for both an immediate alert and a homing signal to assist rescue forces in locating the site of the distress. This paper describes the development of ELT/EPIRB systems. Emphasis is placed on the SARSAT project, the COSPAS/SARSAT project, and an experimental 406 MHz ELT/EPIRB system.

Trudell, B. J.↗
NASA NTRS1980

Satellite-aided mobile communications, experiments, applications and prospects

NASA's ATS-series of satellites were used in a series of communications and position fixing experiments with automotive vehicles, ships and aircraft. Applications of the communications were demonstrated and evaluated for public services including law enforcement, search and rescue, and medical emergency, and for commercial uses in the land and maritime transportation industries. The technical success of the experiments and the demonstrated potential value of the communications prompted a study that concluded an operational satellite-aided system would be a valuable augmentation of planned trunking or cellular type terrestrial mobile radio telephone systems.

Anderson, R. E.↗
NASA NTRS1981

Current LTA technology developments

Lighter-than-air aircraft (LTA) developments and research in the United States and other countries are reviewed. The emphasis in the U.S. is on VTOL airships capable of heavy lift, and on long endurance types for coastal maritime patrol. Design concepts include hybrids which combine heavier-than-air and LTA components and characteristics. Research programs are concentrated on aerodynamics, flight dynamics, and control of hybrid types.

Mayer, N. J.↗
NASA NTRS1981

A theory of human error

Human errors tend to be treated in terms of clinical and anecdotal descriptions, from which remedial measures are difficult to derive. Correction of the sources of human error requires an attempt to reconstruct underlying and contributing causes of error from the circumstantial causes cited in official investigative reports. A comprehensive analytical theory of the cause-effect relationships governing propagation of human error is indispensable to a reconstruction of the underlying and contributing causes. A validated analytical theory of the input-output behavior of human operators involving manual control, communication, supervisory, and monitoring tasks which are relevant to aviation, maritime, automotive, and process control operations is highlighted. This theory of behavior, both appropriate and inappropriate, provides an insightful basis for investigating, classifying, and quantifying the needed cause-effect relationships governing propagation of human error.

Mcruer, D. T.↗
NASA NTRS1982

Legal education at sea via ATS-1. An evaluation of the T/S Golden Bear experiment

A course in maritime law was provided via ATS satellite to law students onboard ship. Classes were received while the ship was on the open seas and in the various ports visited. A half duplex audio channel provided the primary communication mode. All participants judged this pilot study to be extremely useful. Students were able to pursue their course work and to have the benefits of research guidance from academic advisors, while gaining practical, hands on experience at sea.

Connors, M. M.↗
NASA NTRS1982

The geophysical importance of bubbles in the sea

Present knowledge of the mechanisms for production and enrichment and film drops by bursting bubbles is summarized, with particular emphasis on the unsolved problems. Sea salt is by far the major constituent cycled through the Earth's atmosphere each year. Bursting bubbles in the oceans appear to be primarily responsible. These salt particles play a role in the formation of maritime clouds, which in turn affect the Earth's radiation budget. Along with the salt are carried various chemical pollutants and potentially pathogenic microorganisms, often in highly enriched form.

Cirpriano, R. J.↗
NASA NTRS1981

Current developments lighter than air systems

Lighter than air aircraft (LTA) developments and research in the United States and other countries are reviewed. The emphasis in the U.S. is on VTOL airships capable of heavy lift, and on long endurance types for coastal maritime patrol. Design concepts include hybrids which combine heavier than air and LTA components and characteristics. Research programs are concentrated on aerodynamics, flight dynamics, and control of hybrid types.

Mayer, N. J.↗
NASA NTRS1982

Passive microwave measurements of temperature and salinity in coastal zones

Experimental methods and results from the maritime remote sensing (MARSEN) experiments using dual frequency microwave radiometer detecting systems on board aircraft are described. The radiometers were operated at 1.43 and 2.65 GHz and flown above U.S. Atlantic coastal areas, Chesapeake Bay, around Puerto Rico, and over the German Bight. The advanced switched radiometers used were configured to be independent of gain variations and errors originating from front-end losses and determined the absolute brightness temperatures to within a few tenths Kelvin. Corrections to the observed brightness temperature of the ocean are analytically defined, including accounts made for roughness, the cosmic background radiation, and the solar radio source. The coastal flight data for salinity gradients and surface temperatures were compared with sea truth measured from ships and found to be accurate to within 1 C and 1 pph.

Blume, H.-J. C.↗
NASA NTRS1982

Short-term planetary-scale interactions over the tropics and midlatitudes during northern winter. I - Contrasts between active and inactive periods

Objectively analyzed 200 mb winds of four winters are used to study the short-term (several days) teleconnections between planetary-scale circulation components over the monsoon region. The composited structures suggest that during very actively northeasterly monsoon (surge) periods, the midlatitude and tropical circulation components vary in a coherent way. The jet streak and local Hadley circulation over East Asia, the divergent flow over the maritime continent, and the equatorial Walker circulations over the Pacific and Indian Oceans all strengthen steadily, while the secondary jet streak over West Asia weakens. During inactive (break) periods the midlatitude circulation components all exhibit reversed changes, while the variations in the tropics are less coherent, although still showing reversed tendencies. The results basically verify the short-term teleconnection model proposed by Chang and Lau (1980), but more complex processes in the acceleration of the midlatitude jet streaks are indicated. In addition, the contrast between the very active and break monsoon periods suggests the relative importance of tropical versus midlatitudinal forcings in different regions of the monsoon circulation.

Chang, C.-P.↗
NASA NTRS1981

Two-frequency /Delta k/ microwave scatterometer measurements of ocean wave spectra from an aircraft

A technique for remotely sensing the large-scale gravity wave spectrum on the ocean surface using a two frequency (Delta k) microwave scatterometer has been demonstrated from stationary platforms and proposed from moving platforms. This measurement takes advantage of Bragg type resonance matching between the electromagnetic wavelength at the difference frequency and the length of the large-scale surface waves. A prominent resonance appears in the cross product power spectral density (PSD) of the two backscattered signals. Ku-Band aircraft scatterometer measurements were conducted by NASA in the North Sea during the 1979 Maritime Remote Sensing (MARSEN) experiment. Typical examples of cross product PSD's computed from the MARSEN data are presented. They demonstrate strong resonances whose frequency and bandwidth agree with the surface characteristics and the theory. Directional modulation spectra of the surface reflectivity are compared to the gravity wave spectrum derived from surface truth measurements.

Johnson, J. W.↗
NASA NTRS1983

Intelsat communications satellite scheduled for launch

To be placed into a highly elliptical transfer orbit by the Atlas Centaur (AC-61) launch vehicle, the INTELSAT V-F satellite has 12,000 voice circuits and 2 color television channels and incorporates a maritime communication system for ship to shore communications. The stages of the launch vehicle and the launch operations are described. A table shows the launch sequence.

Source record↗
NASA NTRS1982

Measurements of ocean surface spectrum from an aircraft using the two-frequency microwave resonance technique

The present investigation is concerned with the results of a two-frequency (Delta k) microwave radar experiment conducted from an aircraft and aimed primarily at the development of remote sensing techniques to measure ocean surface wave spectral characteristics. The experiment was conducted as part of the Maritime Remote Sensing (MARSEN) project in the North Sea during the autumn of 1979. The objective was to demonstrate the feasibility of and study the performance of the Delta k technique from a higher altitude platform, at shallower incidence angles, and at higher Doppler velocities than earlier stationary platform experiments allowed. A quantitative engineering evaluation of the results of two comprehensive flights is provided, and the qualitative significance of the results is discussed from a geophysical point of view in terms of the existing theory.

Johnson, J. W.↗
NASA NTRS1983

1983 LTA technology assessment

Several aspects of LTA (lighter-than-air) technology development are reviewed. Technological developments of classical airships through 1974 are examined. A brief historical and technological summary of five specialized LTA equipment concepts is presented: metal-clad airships, free balloons, semibuoyant vehicles, high-altitude platforms, and tethered aerostats. Current LTA technology developments are reviewed with particular emphasis on VTOL airships capable of heavy lift and on long endurance types for coastal maritime patrol. Finally, the future prospects of LTA system development are considered with attention given to manned conventional and hybrid vehicles, tethered vehicles, and RPVs.

Ashford, R. L.↗