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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Upper atmospheric probing by resonance fluorescence excited by tunable laser radiation.

Consideration of the application of the measurement of resonance fluorescence radiation excited by tunable laser radiation to the detection of atomic, molecular, and ionic species in the upper atmosphere. The species considered are N2, N2(+), NO, NO(+), O2(+), CO, CO(+), CH, Na, K, and Ca. Calculations of the resonance scattering cross sections, photon returns, and signal-to-noise ratios are given for these species for a range of conditions. Based on a probing altitude of 100 km, the detections of N2, NO, CO, CH, O2, and the trace metals appear feasible with state-of-the-art systems and within the concentration range present in the atmosphere.

Saunders, A. R.↗
NASA NTRS1969

The use of high frequency infrared radiometry for remote atmospheric probing with high vertical resolution

The necessity of obtaining soundings of temperature and water vapor content of the lower troposphere with sufficient vertical resolution to determine the exchange of heat and moisture between the surface and the atmosphere is discussed. The means for solving the problem will be emission measurements in the high frequency end of the thermal infrared. The means for solving another problem is supplementary scanning with high area resolution.

Kaplan, L. D.↗
NASA NTRS1969

Remote atmospheric probing by ground to ground line of sight optical methods

The optical effects arising from refractive-index variations in the clear air are qualitatively described, and the possibilities are discussed of using those effects for remotely sensing the physical properties of the atmosphere. The effects include scintillations, path length fluctuations, spreading of a laser beam, deflection of the beam, and depolarization. The physical properties that may be measured include the average temperature along the path, the vertical temperature gradient, and the distribution along the path of the strength of turbulence and the transverse wind velocity. Line-of-sight laser beam methods are clearly effective in measuring the average properties, but less effective in measuring distributions along the path. Fundamental limitations to the resolution are pointed out and experiments are recommended to investigate the practicality of the methods.

Lawrence, R. S.↗
NASA NTRS1969

Experimental approaches to remote atmospheric probing in the infrared from satellites

Thirteen different types of radiometric instruments either were flown in orbit or are scheduled to fly on forthcoming satellites. A fourteenth type, a very high resolution radiometer for geosynchronous altitude, is among several of the others whose development was stressed for the Global Atmospheric Research Program. Characteristics of each radiometric instrument and some applications of the different types of data are discussed.

Bandeen, W. R.↗
NASA NTRS1969

some comments on the use of infrared radiometry for remote atmospheric probing

A critique is presented of the lead paper by L.D. Kaplan on infrared radiometry. The following topics are analyzed: the extent to which the desirable thermal resolution of the lower troposphere can be achieved, the effects of complex cloud structure on infrared data, the effective weighting function if linearization is possible, remote sounding from below the atmosphere, first-guess fields and operational techniques to blend satellite infrared data into a mix of data from various meteorological systems, a simple inversion procedure for thermal structure, and problems arising from cloud and haze layers of variable amount and emissivity.

Godson, W. L.↗
NASA NTRS1971

Probing atmospheric water vapor profiles via multiple scattering of electromagnetic waves

A theoretical analysis on the multiple scattering of electromagnetic waves propagating in a finite inhomogeneous medium is presented and applied to the study of wave propagation in a clear atmosphere (fine weather conditions). It is shown that the analysis offers a method of synthesizing the water vapor density profile in a clear atmosphere by measuring the resultant reflections from the density profile at several different frequencies. It is also shown that the resultant reflection emerges as the consequence of multiple scattering of partial reflections from various parts of the inhomogeneous medium. The solutions of the multiple scattering approach are shown to be more accurate than those of the WKB approach, which neglects the multiple scattering effects.

Tang, C. C. H.↗
NASA NTRS1969

Additional line of sight methodology to that presented by John W. Strohbehn in the use of line of sight microwave propagation in remote atmospheric probing

Some additional microwave and infrared techniques are reported which are being tested in line-of-sight tropospheric scattering. Newly measured parameters of the incoherent scattered microwave field are sensitive to wavefront sphericity, to wind speed, and to the eddy wavenumber spectrum. A recommendation for advancing the state of the art is given by a proposed experimental program.

Beard, C. I.↗
NASA NTRS1975

Pioneer Jupiter Orbiter/Probe mission. II - Atmospheric Probe design considerations

Probe design considerations for a 1981 Pioneer Jupiter Orbiter/Probe mission are summarized. Extensive engineering analysis, design, and proof-of-concept testing of a reference probe system developed during the past three years are reviewed. Mission compatibility, science measurements, environmental characteristics, spacecraft interfaces, subsystem constraints, technology development, and programmatic factors are reviewed and discussed. It is demonstrated that for a low-entry-angle, daylight mission to Jupiter a 150 kg semiautonomous entry probe system utilizing state of the art technology is compatible with all the requirements.

Bradley, F. E.↗
NASA NTRS1986

Study of new systems concepts for a Titan atmospheric probe

Results of a systems concepts study for a Titan Probe were examined. The key tradeoffs performed are described in detail. Mass breakdown of each Probe subsystem or major element were given. The mission analysis performed to determine compliance with the high altitude sampling and descent time requirements are described. The baseline Descent Module design was derived. The element of the Probe System left on the Carrier after separation were described.

Bernard, Doug↗
NASA NTRS1995

PATHFINDER: Probing Atmospheric Flows in an Integrated and Distributed Environment

PATHFINDER is a software effort to create a flexible, modular, collaborative, and distributed environment for studying atmospheric, astrophysical, and other fluid flows in the evolving networked metacomputer environment of the 1990s. It uses existing software, such as HDF (Hierarchical Data Format), DTM (Data Transfer Mechanism), GEMPAK (General Meteorological Package), AVS, SGI Explorer, and Inventor to provide the researcher with the ability to harness the latest in desktop to teraflop computing. Software modules developed during the project are available in the public domain via anonymous FTP from the National Center for Supercomputing Applications (NCSA). The address is ftp.ncsa.uiuc.edu, and the directory is /SGI/PATHFINDER.

Wilhelmson, R. B.↗
NASA NTRS2005

Benefits of Application of Advanced Technologies for a Neptune Orbiter, Atmospheric Probes and Triton Lander

Missions with planned launch dates several years from today pose significant design challenges in properly accounting for technology advances that may occur in the time leading up to actual spacecraft design, build, test and launch. Conceptual mission and spacecraft designs that rely solely on off the shelf technology will result in conservative estimates that may not be attractive or truly representative of the mission as it actually will be designed and built. This past summer, as part of one of NASA s Vision Mission Studies, a group of students at the Laboratory for Spacecraft and Mission Design (LSMD) have developed and analyzed different Neptune mission baselines, and determined the benefits of various assumed technology improvements. The baseline mission uses either a chemical propulsion system or a solar-electric system. Insertion into orbit around Neptune is achieved by means of aerocapture. Neptune s large moon Triton is used as a tour engine. With these technologies a comprehensive Cassini-class investigation of the Neptune system is possible. Technologies under investigation include the aerocapture heat shield and thermal protection system, both chemical and solar electric propulsion systems, spacecraft power, and energy storage systems.

Somers, Alan↗