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Swenson, G. R.

Publications and source records attributed to Swenson, G. R..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

A Global Upper Atmosphere Observatory Using of Lidar on the International Space Station

A concept for hosting a lidar facility for the upper atmosphere on the International Space Station (ISS) is presented and discussed. The concept is based on utilizing an existing Large Space Optics mirror having a 2.37-m aperture as the primary mirror in its receiver. This large aperture provides for hosting several transmitter systems to retrieve density, temperature, and wind measurements for several upper atmospheric species. Thus the concept provides for measurements over a wide altitude range (80-600 km), at various time and spatial resolutions, and hosting on the ISS provides nearly global coverage. The baseline concept includes transmitters and receivers for atomic oxygen (80-500 km), metastable helium (400-600 km), and sodium (80-110 km). The facility is conceived as being flexible such that other transmitter/receiver systems could be added to allow the possibility of other species to be studied, such as iron. The presentation discusses the transformative science that would be gained by such an observatory by combining the nearly global coverage afforded by the ISS orbit with the extension of powerful lidar techniques to high altitudes. The challenges in realizing such an observatory are discussed, as are current plans and partnerships to meet those challenges. The presentation also reports on the development status of several components, primarily various independent transmitter/receiver systems, that are under consideration for the baseline observatory. Several institutions are performing these developments.

Clemmons, J. H.↗
NASA NTRS1994

Topside observation of gravity waves

The AEPI (Atmospheric Emissions Photometric Imager) experiment on the ATLAS-1 shuttle mission (launched March 24, 1992) imaged the earth night airglow emission in O2 Atmospheric (0,0) bands, at 762.0 nm. Earthward views of O2 A bands show structure from gravity waves which exhibit extended horizontal structure with horizontal wavelenghts on the order of 50-100 km. These observations of the O2 A (0,0) bands are particularly interesting since in this wavelength the lower atmosphere absorbs all the earth-reflected emissions and most of the spectrally diffuse backgrounds. Herein we present observations of gravity waves using a topside airglow imaging technique.

Mende, S. B.↗
NASA NTRS1994

Excitation of the low lying vibrational levels of H2O by O(3P) as measured on Spacelab 2

The data from the infrared telescope (IRT), which was flown on space shuttle Challenger Spacelab 2 mission (July 1985), were originally reported by Koch et al. (1987) as originating from near orbital emissions, primarily H2O. In this study, analysis of this data was extended to determine the collisional cross sections for the excitation of the low lying vibrational levels of H2O, present in the orbiter cloud, by atmospheric O(3P). The evaluation of the contribution to the measured signal from solar excitation and ram O excitation of outgassing H2O permits the determination of the H2O column density and the excitation cross section of the (101) level at an O(3P) velocity of approximately 7.75 km/s. Contributions to the radiation in the 1.7-3.0 micron band by transitions from the (100), (001), and multiquantum excited levels are discussed. The findings of the study are (1) the IRT data for the 4.5-9.5 micron and the nighttime data for the 1.7-3.0 micron sensors are consistent with being explained by collision excitation of H2O by O(3P), (2) diurnal variations of 4.5-9.5 micron intensities follow the model predicted O density for a full orbit, (3) daytime increases in the H2O cloud density were not evident, (4) the cross sections for the collisional excitation process are derived and compared to values computated by Johnson (1986) and Redmon et al. (1986), (5) theoretical investigation suggests greater than 60% of the radiation from H2O is a result of multiphoton emission resulting from collisional multiquanta excitation, and (6) the large daytime increase in the 1.7-3.0 micron intensity data suggests that O(+) may likely be instrumental in producing excited H2O(+) through charge exchange.

Meyerott, R. E.↗
NASA NTRS1993

Artificial auroras in the upper atmosphere. I - Electron beam injections

The Atlas-1 Spacelab payload's Space Experiments with Particle Accelerators generated artificial electron beams for the stimulation of auroral emissions at southern auroral latitudes. Optical measurements were made by the Shuttle Orbiter's onboard TV cameras, as well as by the Atmospheric Emissions Photometric Imager (in both white light and the 427.8 nm N2(+) emission line). Shuttle-based auroral imaging furnished a novel perspective on the artificial auroras; the emissions were traced from 295 km to the 110 km level along the curved magnetic-field lines.

Burch, J. L.↗
NASA NTRS1993

Artificial auroras in the upper atmosphere. II - Imaging results

On the ATLAS 1 mission (STS-45, launched March 24, 1992) two experiments, AEPI (Atmospheric Emissions Photometric Imaging) and SEPAC (Space Experiments with Particle Accelerators) performed the first of a series of active experiments intended to probe the atmosphere, ionosphere and magnetosphere with electron beams. The luminous artificial aurora generated by the electron beam interaction was detected and measured by AEPI both in white light and in a narrow wavelength band at 427.8 nm (peak intensity 5 kR). Modelling calculation showed that there was a significant contribution from emissions originating near the spacecraft. The spatial intensity distribution of the observed auroral patch is consistent with emission contribution from both high and low altitude regions. An extended tail in the direction of the shuttle wake was observed in the 427.8 nm channel, consistent with a decay time associated with the dissipation of the hot electron plasma.

Mende, S. B.↗
NASA NTRS1992

Spectral characteristics of Shuttle glow

The glowing cloud near the ram surfaces of the Space Shuttle was observed with a hand-held, intensified spectrograph operated by the astronauts from the aft-flight-deck of the Space Shuttle. The spectral measurements were made between 400 and 800 nm with a resolution of 3 nm. Analysis of the spectral response of the instrument and the transmission of the Shuttle window was performed on orbit using earth-airglow OH Meinel bands. This analysis resulted in a correction of the Shuttle glow intensity in the spectral region between 700 and 800 nm. The data presented in this report is in better agreement with laboratory measurements of the NO2 continuum.

Viereck, R. A.↗
NASA NTRS1992

Medium resolution spectra of the shuttle glow in the visible region of the spectrum

Recent spectral measurements of the visible shuttle glow (lambda = 400 - 800 nm) at medium resolution (1 nm) reveal the same featureless continuum with a maximum near 680 nm that was reported previously. This is also in good agreement with recent laboratory experiments that attribute the glow to the emissions of NO2 formed by the recombination of O + NO. The data that are presented were taken from the aft flight deck with a hand-held spectrograph and from the shuttle bay with a low-light-level television camera. Shuttle glow images and spectra are presented and compared with laboratory data and theory.

Viereck, R. A.↗
NASA NTRS1991

Charge exchange contamination of CRIT-II barium CIV experiment

Experiments have been recently performed which attempted to confirm critical ionization velocity (CIV) ionization by deploying chemicals at high velocity in the ionosphere. Specifically, the CRIT-II rocket performed a barium release in the ionosphere, where observations of Ba(+) resonant emissions following the release are believed to have resulted from the CIV process. Calculations are presented which suggest a significant fraction (if not all) of the Ba(+) observed likely resulted from charge exchange with the thermosphere ions and not through CIV processes. The results presented here are pertinent to other CIV experiments performed in the ionosphere. It is recommended that laboratory measurements should be made of the charge exchange cross section between O(+) and Ba as well as other metal vapors used in CIV experiments.

Swenson, G. R.↗
NASA NTRS1991

Laboratory investigation of visible shuttle glow mechanisms

Laboratory experiments designed to uncover mechanistic information about the spectral and spatial characteristics of shuttle glow were conducted. The luminescence was created when a pulse of O atoms traveling at orbital velocities was directed toward NO molecules previously adsorbed to aluminum, nickel, and Z306 Chemglaz (a common baffle black) coated surfaces held at various temperatures. Spectral and spatial measurements were made using a CCD imaging spectrometer. Corroborative spectral information was recorded in separate measurements using a scanning monochromator and gated photomultiplier arrangement. The e-folding distance at several temperatures was calculated from images of the surface glow using the photometrics image processing capability of the imaging spectrometer. The e-folding distance was not altered as a function of incoming O beam velocity. The results are presented and the observations provide direct evidence that the visible shuttle glow results from recombination of oxygen atoms and surface bound NO.

Leone, A.↗
NASA NTRS1989

Dynamics of a barium release in the magnetospheric tail

The late time behavior of the May 13, 1985 magnetotail barium cloud is examined. The bulk dynamics of the cloud are studied based on triangulated data and data from Fabry-Perot Doppler velocity measurements. The changes in cloud morphology in relation to the in situ measurements made by the Ion Release Module satellite are discussed.

Mende, S. B.↗
NASA NTRS1989

Imaging observations of lower thermospheric O(1S) and O2 airglow emissions from STS 9 - Implications of height variations

The lower thermospheric nightglow in the Southern Hemisphere was observed with the Atmospheric Emissions Photometric Imager during the Spacelab 1 mission in December, 1983. Observations of emission from O(1S) at 2972 and 5577A, O2 at 7620 A, OH near 6300 A, and the combined emission from the three upper states of O2 which lead to the Herzberg I and II and Chamberlain band emissions in B and near UV are discussed. The altitudes of peak emission heights are determined, showing that the peak heights are not constant with latitude. It is found that airglow heights varied with latitude by as much as 8 km. The observed airglow height pattern near the equator is similar to that of Wasser and Donahue (1979).

Swenson, G. R.↗
NASA NTRS1987

Spacecraft ram glow and surface temperature

Space shuttle glow intensity measurements show large differences when the data from different missions are compared. In particular, on the 41-G mission the space shuttle ram glow was observed to display an unusually low intensity. Subsequent investigation of this measurement and earlier measurements suggest that there was a significant difference in temperature of the glow producing ram surfaces. The highly insulating properties coupled with the high emissivity of the shuttle tile results in surfaces that cool quickly when exposed to deep space on the night side of the orbit. The increased glow intensity is consistent with the hypothesis that the glow is emitted from excited NO2. The excited NO2 is likely formed through three body recombination (OI + NO + M = NO2*) where ramming of OI interacts with weakly surface bound NO. The NO is formed from atmospheric OI and NI which is scavenged by the spacecraft moving through the atmosphere. It is postulated that the colder surfaces retain a thicker layer of NO thereby increasing the probability of the reaction. It has been found from the glow intensity/temperature data that the bond energy of the surface bound precursor, leading to the chemical recombination producing the glow, is approximately 0.14 eV. A thermal analysis of material samples of STS-8 was made and the postulated temperature change of individual material samples prior to the time of glow measurements above respective samples are consistent with the thermal effect on glow found for the orbiter surface.

Swenson, G. R.↗
NASA NTRS1986

The effect of temperature on Shuttle glow

The glow on ram surfaces of the Space Shuttle has been reported from a series of photographic observations made during several orbiter missions. These measurements have shown that the spectrum of the glow is a continuum, has a spectral peak at 680 nm, and the brightness decreases with altitude. The spectrum has been tentatively identified as the nitrogen dioxide continuum and follows the interaction of adsorbed nitric oxide with ramming atmospheric oxygen. In this paper the variation of the glow brightness among several different Shuttle flights is reexamined and it is shown that a major contributing factor to glow brightness is probably the temperature of the rammed surface. The derived temperature dependence is also consistent with the Atmospheric Explorer-C satellite 'red' glow intensity data.

Swenson, G. R.↗
NASA NTRS1986

Spectral measurement of the Space Shuttle leeside shock layer and wake

Leeside shock layer and wake spectral radiation measured during the high altitude portion of the reentry of Space Shuttle Orbiter STS 51-D are presented and are compared with similar measurements obtained in an arc jet tunnel. The spectra, measured with a low-resolution spectral camera, are compared in order to identify the radiating species in a wavelength range from 4000 to 8000 angstroms. Emissions identified are: N2 first positive and N2 second positive systems, the N2(+) first negative system, and the sodium-D lines. No atomic air species or CN are observed. The spectra and procedure will be of use in comparison of flight flowfield properties with computational predictions and for guidance in developing future flight experiments.

Blackwell, H. E.↗
NASA NTRS1986

STS-9 Shuttle grow - Ram angle effect and absolute intensities

Visible imagery from Space Shuttle mission STS-9 (Spacelab 1) has been analyzed for the ram angle effect and the absolute intensity of glow. The data are compared with earlier measurements and the anomalous high intensities at large ram angles are confirmed. Absolute intensities of the ram glow on the shuttle tile, at 6563 A, are observed to be about 20 times more intense than those measured on the AE-E spacecraft. Implications of these observations for an existing theory of glow involving NO2 are presented.

Swenson, G. R.↗
NASA NTRS1985

Auroral thermosphere temperatures from observations of 6300 A emissions

Doppler temperatures determined from observations of the atomic oxygen OI 6300 A line during March 1984 at the University of Alaska/Fairbanks are presented. Temperatures are obtained from Fabry-Perot Interferometer pressure scans using a Fourier transform smoothing and fitting technique; this technique is presented in detail. The temperatures and the spread in the temperatures are consistent from day to day. On the clear nights of March 10 to 13, the temperatures were 800, 750, 750 and 800 K, respectively, with a spread of + or - 100 K. These temperatures are compared to the MSIS (84) model atmosphere for similar geomagnetic conditions and found to be in general agreement; they are also consistent with results obtained by other investigators.

Bird, J. C.↗
NASA NTRS1985

Vehicle glow measurements on the space shuttle

From the combined data set of glow observations on shuttle flight STS-3, STS-4, STS-5, STS-8, STS-9, 41-E, and 41-G some of the properties of the shuttle glow are discussed. Comparison of the STS-3 and STS-5 (240 and 305 km altitude, respectively) photographs shows that the intensity of the glow is about a factor of 3.5 brighter on the low-altitude (STS-3) flight. In an experiment to observe the dependence of the intensity on the ram angle, the angle of incidence between the spacecraft surface normal and the velocity vector, the Orbiter was purposely rotated about the x axis on the STS-5 mission. For a relatively large angle between the velocity vector and the surface normal there is an appreciable glow, provided the surface is not shadowed by some other spacecraft structure. As the angle becomes less the glow intensifies. Material samples were also exposed in the ram direction during nightside orbits and the glow surrounding the samples was photographed.

Mende, S. B.↗