UPPER ATMOSPHERIC WIND PROFILES DETERMINED FROM THREE ROCKET EXPERIMENTS
Rocket determination of upper atmospheric wind profiles at 80-200 km altitude for twilight conditions
WIND PROFILE↗
SEARCH · Search NASA
Results for “TWILIGHT”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Geo-astronomical observations
Gemini IV photographic data on zodiacal light, meteors, auroras, nightglow, and twilight horizon blue bands
GEMINI SPACECRAFT↗
Diurnal variations in helium emission
Graphic method for reducing spectrophotoelectric data of twilight helium emission
Taranova, O. G.↗
Latitude dependence of 6300 angstrom units
Latitude dependence of 6300 A /O I/ twilight airglow enhancement attributable to conjugate photoelectrons
Bennett, R. T.↗
Rocket measurement of nitric oxide between 60 and 96 kilometers.
Evening twilight nitric oxide density profile in gamma bands deduced from rocket measurements
Pearce, J. B.↗
Experiment S011: Airglow horizon photography
The night airglow, which lies in a thin layer 70 to 100 kilometers above the earth, was studied. Although the surface brightness is low when observed through this layer from below, brightness of the airglow is augmented by a factor of approximately 35 when the airglow is viewed tangentially from the vantage point of the Gemini orbit. This augmentation phenomenon is an effective means of synoptic airglow study. The objective was to extend and refine the photographic method. The following techniques were used to achieve this goal: (1) The camera was equipped with a filter to photograph the two prominent line emissions at 5577 and 5893 A; (2) An illuminated camera sight and an aiming camera mount were used in an attempt to reduce the number of blurred photographs; (3) The number of photographs taken and the amount of the earth photographed were as large as possible; and (4) The photograph of the twilight horizon revealed a sunlit dayglow layer.
Koomen, M. J.↗
Infrared studies of the circumsolar and night sky, April 1968 - 30 November 1971
A program is summarized of infrared studies of the circumsolar and night sky conducted between April, 1968, and November 30, 1971, at the University of New Mexico. In addition to observations performed at Capillo Peak Observatory in New Mexico, airborne observations from the Ames Research Center's CV990 were performed in 1968, and eclipses in Siberia (1968) and southern Mexico (1970) were observed. Two dual-channel filter photometers covering wavelengths in the 0.8 to 4.8 micron range were constructed for the aircraft and eclipse observations. A single channel differential photometer was constructed for daytime circumsolar observations. Two large-aperture (12 inch and 24 inch) photometers have been constructed for twilight and night sky photometry. Finally, a small spectrograph for eclipse work has been constructed. It has been used for airglow observations also. Other specialized instrumentation include a four-axis mounting for radial scanning with the eclipse photometers and a 14-inch diameter collimator for use with a black body in calibration of the photometers. The observations performed are included.
Peterson, A. W.↗
Rocket measurements of ion and electron densities in the D-region during sunrise.
Results from two rockets launched near sunrise at White Sands, N. Mex., when positive ion and electron densities were measured in the D-region for solar zenith angles of 91 and 79 deg. The measurements cover the height range 80 to 110 km and complement previous vlf observations and rocket measurements of electron density. It is shown that the majority of negative ions in this height range are detached near to after ground sunrise. On the basis of these measurements it is possible to discuss electron affinity of negative ions and ion production functions during twilight.
Pedersen, A.↗
The possibility of supersonic plasma flow in a collapsing post-sunset ionosphere.
As a result of the rapidly decreasing pressure in the topside ionosphere during twilight hours, a rapid downward flow of hydrogen plasma from the protonosphere takes place. In the case of steady state, isothermal, frictionless flow, the criterion for the existence of a critical point (transition to supersonic flow) above 1000 km is that the plasma temperature be lower than a certain limiting temperature which is a function of the field line considered. In the latitude region between 40 and 70 deg, this upper temperature limit varies from 963 to 1066 K. Since these temperatures are considerably lower than the observed temperatures, it follows that in the case of steady state, isothermal flow the velocities will always remain subsonic. When the effect of the neglected terms is examined, the temperature gradient is shown to exert the strongest influence on the nature of the flow. It is concluded that there is a definite possibility that supersonic downward flows in a post-sunset topside ionosphere may occur.
Fontheim, E. G.↗
Heavy ions from interplanetary dust.
Most atoms that are evaporated from interplanetary dust near the sun are quickly ionized and are probably carried away by the interplanetary magnetic field and the solar wind. The contribution of these heavy ions to the solar-wind flux has been estimated by using estimates of the mass required to maintain the zodiacal cloud. This contribution appears to be small compared with the heavy-ion flux of coronal origin. Many ions from dust remain singly ionized; some of these, such as Ca(+), can resonantly scatter solar radiation. The contribution of this interplanetary glow to the background of twilight glow has been estimated. Interplanetary glow may be detectable. Some atoms from dust may be accelerated by radiation pressure before being ionized. Estimates of velocities and fluxes for Fe indicate that this acceleration is not very effective.
Nakada, M. P.↗
Auroral data from Michigan airglow payload launch
Auroral studies are presented of flight data analysis from the Michigan airglow payload. Analysis of the stellar occultation data and results from the twilight flight are reported. Optical emissions from bottled aurora and an electron analyzer for measurement of distributions in energy of electrons along a beam are also presented. A list of related publications is included.
Hays, P. B.↗
Thermal electron energy distribution measurements in the ionosphere.
A recoverable payload instrumented for twilight airglow studies was launched by an Aerobee 150 from the White Sands Test Range on Feb. 8, 1971 at 13.56 UT. The payload included a low energy electron spectrometer (HARP) and a cylindrical Langmuir probe. The HARP electron spectrometer is a new device designed to make high resolution differential electron flux measurements. Measurements of ionospheric electron energy distribution in the range from about 0.2 to 4.0 eV are presented.
Hays, P. B.↗
Investigation of mid-latitude ionospheric currents by combined rocket techniques.
A comprehensive range of neutral atmospheric and simultaneous ionospheric structure measurements were obtained from a Skylark rocket launched at Woomera during evening twilight on a quiet magnetic day. Above 150 km, good agreement was found between the results obtained from three different methods of electric field measurement despite the low field strength (about 1.5 mV/m). In the immediate vicinity of an intense sporadic E layer, the probe measurements indicated large excursions of the electrostatic field amounting to 6.5 mV/m at 105.3 km and 2.7 mV/m at 104.8 km. The calculated ionospheric current system in the vicinity of the rocket trajectory was of similar magnitude to that indicated by local ground-based magnetometers, but was diametrically opposed in direction.
Rees, D.↗
Satellite ultraviolet measurements of nitric oxide fluorescence with a diffusive transport model.
Twilight measurements of fluorescence in the (1, 0) gamma band of nitric oxide were made from June 1967 to January 1969 by an ultraviolet scanning spectrometer on board the polar orbiting satellite Ogo 4. Nitric oxide vertical column emission rates were measured between solar zenith angles of 93 and 98 deg. Seasonal and latitudinal variations were found to be less than a factor of 1.3, the scatter and uncertainty in the data prohibiting more precise determinations from being made. Time independent chemical diffusion models for the vertical distribution of nitric oxide agree well with profiles measured from sounding rockets. The column emission rates calculated from the theoretical models are larger than the satellite measurements by a factor of 3.
Rusch, D. W.↗
Radiative transfer in realistic planetary atmospheres
The research accomplished during this period is briefly summarized. The interior radiances within an optically deep absorbing medium scattering according to the Haze L phase function is discussed along with a method for calculating the radiance and color of the twilight sky. The application of the matrix operator method to calculations of radiance, polarization, and ellipticity of the radiation scattered from homogeneous layers scattering is reported. Reports, and publications are listed.
Plass, G. N.↗
Photoelectric photometry of comet Kohoutek (1973f)
Comet Kohoutek was observed with the 50 cm (f/15) reflecting telescope of the European Southern Observatory, La Silla, Chile, on fourteen nights between January 16 and 30, when the heliocentric and geocentric distances of the comet were r=0.66 - 1.00 A.U. and delta=0.81 - 0.96 A.U., respectively. The 40 inch and 80 inch diaphragms were used for the photometry of the cometary head in the UBV system and with six interference filters. The atmospheric conditions were good but the accuracy of observations was low due to large extinction and twilight. The mean error of one measurement of log F in all but Na 5893 A filters can be estimated at plus or minus 0.02, whereas the accuracy through the Na filter was substantially lower.
Kohoutek, L.↗
Skylab explores the earth
During the third manned mission on Skylab, an experiment was conducted by the crewmen to determine what type of earth survey information man could obtain through visual observations and by handheld cameras. More than 850 observations and 2000 photographs were taken for 16 different scientific disciplines. Observations and photographs were taken over the entire range of possible sun angles (twilight to local noon) and viewing angles (high oblique to vertical). Results of the experiment confirm that man's ability to recognize objects and patterns, to integrate his observations over a range of aspects and lighting angles, to reason, and to make selective observations, can bring another dimension to the study of the earth.
Wilmarth, V. R.↗