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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 127 records · Page 7
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NASA NTRS1977

Thermospheric meridional winds and atomic oxygen depletion at high latitudes

Rocket vapor trail measurements of the properties of the high latitude wind system are compared with Ogo 6 measurements, the atomic densities being studied as a function of geomagnetic local time at three seasons for three ranges of magnetic activity. It is found that the atomic oxygen densities at altitudes in the region of 120 km are about 35% lower in the post-midnight sector than in the afternoon and evening sectors, decrease with increasing magnetic activity, and are lower in summer than in winter. The variations are related to vertical velocities in the 95-150 km altitude range and to the meridional fluxes at 70 deg geomagnetic latitude. The upward average vertical velocity of atomic oxygen in the region poleward of 70 deg is calculated to be of the order of 0.3 m/s at 120 km and the energy transported by the winds out of this region is calculated to be of the order of 10 to the 10th W for Kp levels of 2.

Nisbet, J. S.↗
NASA NTRS1977

Solar mesosphere explorer: Experiment description

The Solar Mesosphere Explorer (SME) satellite experiments will provide a comprehensive study of atmospheric ozone and the processes which form and destroy it. Five instruments to be carried on the spacecraft will measure the ozone density and altitude distribution, monitor the incoming solar radiation, and measure other atmospheric constituents which affect ozone. The investigative approach concept, methods and procedures, preflight studies, and orbits and mission lifetime are presented. Descriptions of the instruments are also presented.

Source record↗
NASA NTRS1979

Description and charging results from the RSPM

Representative satellite materials, to be flown on STP-78-2 in 1979 on the SSPM instruments, were included as part of the AFGL Rocket payload flown from White Sands Missile Range on January 21, 1978. Potentials as high as + 1100 volts on the conductor and + or - 400 volts on the insulator were recorded by the RSPM near the minimum in the electron density vs altitude profile. In addition to the charging potentials measured during ion gun operation, sample charging currents also were recorded with time resolutions near 30 milliseconds. These results demonstrate the validity of the experiment concept of the SSPM on SCATHA.

Mizera, P. F.↗
NASA NTRS1979

Solar-induced variations of environment affecting manned space flight and spacecraft operations

Estimates of short and long term solar activity are required for calculating variations in the environment with regard to spacecraft charging, radiation effects, and orbital lifetime. Correlations appear to exist between the time of solar activity and the time of operational anomalies due to electrical discharges when the dielectric surfaces of geosynchronous spacecraft are charged by interaction with the ambient plasma to levels above breakdown voltage. An ability to predict the solar induced variation variability of the plasmas could permit refinement of design criteria. The influence of the radiation on spacecraft materials, systems, and manned operations is summarized. Solar radition effects on the orbital altitude atmospheric density environment and spacecraft lifetimes are also considered.

Johnson, W. G.↗
NASA NTRS1981

Lidar observation of the mesospheric sodium layer over Urbana, Illinois

Atmospheric sodium has been observed over Urbana (40 deg 10 min N, 88 deg 10 min W) using a monostatic lidar tuned to 589.0 nm. The photocount data are processed using ditital smoothing filters to obtain continuous estimates of the sodium density versus altitude. The filter cutoff frequency is related to the height resolution and accuracy of the estimated profile. Wavelike structures in the sodium layer have been observed with typical wavelengths of 3-15 km and phase velocities of 1-3 m/s. The layer is characterized by a sharp falloff on the bottomside and often an undulatory motion of the bottomside of the layer accompanies the wave motion. The topside gradient of the layer is frequently observed to decrease through the night.

Richter, E. S.↗
NASA NTRS1981

The development of cryogenic wind tunnels and their application to maneuvering aircraft technology

Cryogenic wind tunnels are considered as a means of studying high Reynolds number (Re) complicated flows encountered by high maneuvering lift and high angles of attack characteristic of modern fighter aircraft. Large decreases in the viscous force while the inertial force remains constant are provided by the use of cryogenic facilities. A 2.5 m square tunnel is nearing completion at the National Transonic Facility (NTF), and will be driven by synchronous motors having a total power of 120,000 hp. The tunnel, using N2 as the cryogenic fluid, will allow large Re sweeps at constant dynamic pressure and dynamic pressure, and aeroelastic sweeps at constant Re; full altitude (air density) and acceleration force simulation will also be possible. Advances in model and strain gage balance technologies for use at the NTF are outlined, and experiments with buffet are described.

Polhamus, E. C.↗
NASA NTRS1984

Analytical characterization of AOTV perigee aerothermodynamic regime

In preliminary design studies of AOTV (Aeroassisted Orbital Transfer Vehicle) configurations, it is desirable to have a simple analytical method for characterizing the aerothermodynamic regime at skip trajectory perigee as a function of vehicle L/D and m/CDA (ballistic coefficient). The present study derives an approximate perigee solution from the generalized equations of motion. For a prescribed entry velocity vector, the solution determines a Zeta function (proportional to density divided by m/CDA) at perigee as a parametric function of the exit velocity vector and (constant) L/D. The perigee Zeta function then determines perigee density (or altitude) as a parametric function of m/CDA. The solution allows the following classic aerothermodynamic parameters to be determined at perigee as parametric functions of m/CDA, L/D, and the exit velocity vector: Reynolds Number (viscous effects), Mach Number (compressibility effects), Knudsen Number (rarefaction effects), sphere and disk bow shock standoff distance, Damkohler Number (relaxation effects), viscous correlation parameter (viscid-inviscid interactions), and Stanton Number (convective heat transfer). Results of the analysis are given for low L/D and mid L/D AOTV configurations on return from geosynchronous and L5 orbits. It is concluded the method successfully provides preliminary estimates of the aerothermodynamic parameters through the use of simple algebraic equations and plots.

Desautel, D.↗
NASA NTRS1985

Ozone intercomparisons from the Balloon Intercomparison Campaign

Intercomparisons of remote and in-situ techniques used to measure stratospheric ozone are made using results obtained on the Balloon Intercomparison Campaign of 1982 and 1983. Two in-situ and four remote instruments participated. These included ECC ozonesondes, a UV absorption photometer, and microwave emission, IR emission, and absorption spectrometers. Differences are generally less than 15 percent, and are within the quoted error bars. Flights which involved different sets of instruments were made on four separate days, and results are intercompared in plots of ozone density versus altitude. A careful assessment of errors was made for each instrument, and a plot of absolute errors versus altitude is given.

Robbins, D.↗
NASA NTRS1987

Residual motions caused by micro-gravitational accelerations

It is shown here that, under certain conditions, the low-frequency accelerations on experiments being performed aboard orbiting spacecraft due to gravity gradient, atmospheric drag, and spacecraft attitude or orientation can cause sustained fluid motions which require correction by advanced mass compensation techniques. The gravity gradient tensor is derived, and an expression for the difference between the absolute accelerations of a free particle and the mass center of the spacecraft is obtained. A model for the variation of atmospheric density with altitude is discussed, the equations governing the relative motion of a drag-free particle with respect to the mass center of the spacecraft are presented, and analytical and numerical solutions are obtained. Two possible spacecraft altitudes are considered. The problem of the Stokes motion of a sphere immersed in a viscous fluid is examined. Results are presented for the motion of a steel ball in water and for a triglycine sulfate crystal freely suspended in solution.

Alexander, J. Iwan D.↗
NASA NTRS1990

Response of nightside ionosphere and ionotail of Venus to variations in solar EUV and solar wind dynamic pressure

Pioneer Venus in situ measurements of N(e), total solar EUV flux, and solar wind dynamic pressure P(sw) are used to investigate the solar cycle and orbit-to-orbit variations of the Venus nightside ionosphere. It is found that the density of the main body of the nightside ionosphere below 600 km responds to the solar wind dynamic pressure variations in much the same way that the density of the ionotail does: both regions are depleted at times of high P(sw). Solar cycle variations in the EUV flux near solar minimum produce very large changes in the electron density in ionotail, changes that are consistent with the ionotail being supplied by nightward ion flow. However, short-term variations in the EUV flux produce a weak negative response in the density at altitudes between 150 and 600 km, at least at solar maximum. The nightside variations are consistent with enhanced solar wind scavenging of plasma from the nightside ionosphere during periods of higher P(sw).

Brace, L. H.↗
NASA NTRS1990

Hydrometeor development in cold clouds in FIRE

The role of cirrus clouds, particularly in weather and climate processes, has been increasingly investigated. Numerical models have demonstrated the importance of the solar reflectivity and infrared radiation of cirrus clouds in the Earth's radiation budget and climate. These properties depend upon the cloud microphysical characteristics, density, and altitude and hence justify investigation. The results reported were obtained from cold clouds (-20 to -46 C) in the mid to upper troposphere during ten flights of the NCAR King Air as part of the First ISCCP Research Experiment (FIRE) in Wisconsin.

Heymsfield, Andrew J.↗
NASA NTRS1992

Shuttle entry aerothermodynamic flight research - The Orbiter Experiments (OEX) Program

Results of the OEX program are summarized with emphasis on the information on entry aerothermodynamic phenomena derived from Space Shuttle operations. The discussion focuses on OEX experiment complement and operational history, freestream environment and vehicle attitude data, aerodynamic force and moment data, aerodynamic surface data, and vehicle configuration data. Attention is also given to orbiter aerodynamic performance, stability and control, high-altitude atmospheric density variability, direct simulation Monte Carlo validation, orbital drag variation, and computational fluid dynamic technique validation.

Throckmorton, David A.↗
NASA NTRS1991

Analysis of atmospheric trace constituents from high resolution infrared balloon-borne and ground-based solar absorption spectra

Results of ongoing studies of high-resolution solar absorption spectra aimed at the identification and quantification of trace constituents of importance in the chemistry of the stratosphere and upper troposphere are presented. An analysis of balloon-borne and ground-based spectra obtained at 0.0025/cm covering the 700-2200/cm interval is presented. The 0.0025/cm spectra, along with corresponding laboratory spectra, improves the spectral line parameters, and thus the accuracy of quantifying trace constituents. Results for COF2, F22, SF6, and other species are presented. The retrieval methods used for total column density and altitude distribution for both ground-based and balloon-borne spectra are also discussed.

Goldman, A.↗
NASA NTRS1993

The AFP-675 Far Ultraviolet Cameras experiment - Observations of the far-UV space environment

The NRL's Far UV Cameras experiment flew aboard the Shuttle Orbiter on STS-39, in 1991: obtaining 105-200 nm measurements of the upper atmosphere, astronomical targets, and the Shuttle environment. Attention is presently given to observations of O2 density vs altitude in the nighttime atmosphere, the nocturnal ionosphere, Space Shuttle FUV glow, and photometry for both the stars and diffuse sources of 12 star fields at high and low galactic latitudes. The first FUV observations of the extended region of reflection nebulosity in Scorpius are included.

Carruthers, George R.↗
NASA NTRS1922

Notes on the Standard Atmosphere

This report contains the derivation of a series of relations between temperature, pressure, density, and altitude in a standard atmosphere which assumes a uniform decrease of temperature with altitude.

Diehl, Walter S↗
NASA NTRS1994

Mesospheric and lower thermospheric winds, temperatures densities, and volume emission rates

This memo has been written to report on the progress made under grant NAG1-1315 and to request a continuation of funding for this work. Our proposal involved a plan to utilize an existing ground-based chain of optical and radar facilities to assemble a comprehensive, long-term, multi-station base of upper-mesospheric and lower thermospheric measurements of neutral winds, temperatures, and volume emission rates that can be used to make comparisons with data from the HRDI and WINDII instruments that are flying aboard the UARS spacecraft. The ground-based, optical data were to be obtained on a routine basis from five geographically separated observatories at: Thule, Greenland; Sondrestrom, Greenland; Watson Lake, Yukon (replacing Calgary, Alberta); Ann Arbor, Michigan; and Maynooth, Eire. Several different optical instruments are present at these sites: the total array of instruments is comprised of five Fabry-Perot interferometers, two half meter Ebert-Fastie spectrometers, one all-sky CCD imager, and a near infra-red Michelson Fourier transform spectrometer. In addition to these optical instruments, data were to be obtained from the incoherent scatter radar at Sondrestrom, Greenland. These radar measurements are comprised of neutral winds, temperatures, and densities from altitudes between approximately 70 - 120 km. The optical measurements are obtained locally from specific altitudes depending on the emission line studied. For example, red line optical data come from about 220 km. In this report we summarize the progress made in obtaining these data and relate it to the specific tasks outlined in the original grant application. These tasks are discussed in the next section. Progress towards their completion is discussed in section three, while future plans and summary are described in section four.

Killeen, Timothy L.↗
NASA NTRS1963

Planetary Aeronomy: NO2 In the Martian Atmosphere - 2

The transmission curve of the Martian atmosphere derived by Opik is compared with transmission curves of an atmosphere containing various amounts of nitrogen dioxide. It is found that the amount of 6 x l0(exp 18) sq cm column NO2 (or even less) given by Sinton as an upper limit for the Martian NO2 content could adequately explain the phenomenon of the blue haze. This finding made it worthwhile to investigate the effect of the temperature and pressure sensitive equilibrium 2 NO2 reversibly yields N204 upon the total NO2 content and the altitude-number density distributions of NO2 and N204. Computations were carried out for surface temperatures of 273 K, 243 K, 213 K, and 183 K and for three different temperature distributions. The discussion of the results leads to the suggestion of several important new experiments.

Warneck, P.↗
NASA NTRS1991

Analysis of Atmospheric Trace Constituents from High Resolution Infrared Balloon-Borne and Ground-Based Solar Absorption Spectra

Recent results and ongoing studies of high resolution solar absorption spectra will be presented. The analysis of these spectra is aimed at the identification and quantification of trace constituents important in atmospheric chemistry of the stratosphere and upper troposphere. Analysis of balloon-borne and ground-based spectra obtained at 0.0025/ cm covering the 700-2200/ cm interval will be presented. Results from ground-based 0.02/ cm solar spectra, from several locations such as Denver, South Pole, M. Loa, and New Zealand will also be shown. The 0.0025/ cm spectra show many new spectroscopic features. The analysis of these spectra, along with corresponding laboratory spectra, improves the spectral line parameters, and thus the accuracy of trace constituents quantification. The combination of the recent balloon flights, with earlier flights data since 1978 at 0.02/ cm resolution, provides trends analysis of several stratospheric trace species. Results for COF2, F22, SF6, and other species will be presented. Analysis of several ground-based solar spectra provides trends for HCl, HF and other species. The retrieval methods used for total column density and altitude distribution for both ground-based and balloon-borne spectra will be presented. These are extended for the analysis of the ground-based spectra to be obtained by the high resolution interferometers of the Network for Detection of Stratospheric Change (NDSC). Progress or the University of Denver studies for the NDSC will be presented. This will include intercomparison of solar spectra and trace gases retrievals obtained from simultaneous scans by the high resolution (0.0025/ cm) interferometers of BRUKER and BOMEM.

Goldman, A.↗