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At least 145 records · Page 8

Investigation of Ejection Releases of an MB-1 Rocket from a 0.04956-Scaled Model of the Convair F-106A Airplane at Several Mach Numbers and Simulated Altitudes

As a continuation of an investigation of the ejection release characteristics of an internally carried MB-1 rocket in the Convair F-106A airplane, fin modifications at additional Mach numbers and simulated altitudes have been studied in the 27- by 27-inch preflight jet of the Langley Pilotless Aircraft Research Station at Wallops Island, Va. The MB-1 rocket was ejected with fins open, fins closed, fins closed with a shroud around the fins, and fins folded with a "boattail" placed in between the fins. Dynamically scaled models (0.0^956 scale) were tested at simulated altitudes of 12,000, 18,850, and 27,500 feet at subsonic Mach numbers and at 18,850, 27,500, and 40,000 feet for Mach numbers of 1-39, 1-59, and 1.98. Successful ejections can be obtained for over 10 store diameters from release point by the use of a shroud around the folded fins with the proper ejection velocity and nose-down pitching moment at release. In one case investigated it was found desirable to close off the front one-third of the bomb bay. It appeared that the fins should be opened after release and within 5 "to 6 rocket diameters if no modifications are made on the rocket. An increase in fuselage angle of attack caused higher nose-up pitch rates after release.

Lee, J. B.↗

Radar derived spatial statistics of summer rain. Volume 1: Experiment description

An experiment was performed at Wallops Island, Virginia, to obtain a statistical description of summer rainstorms. Its purpose was to obtain information needed for design of earth and space communications systems in which precipitation in the earth's atmosphere scatters or attenuates the radio signal. Rainstorms were monitored with the high resolution SPANDAR radar and the 3-dimensional structures of the storms were recorded on digital tape. The equipment, the experiment, and tabulated data obtained during the experiment are described.

Katz, I.↗

Trilateration range and range rate system. Volume 1: CDA system manual

This document is one of a series of manuals designed to provide the information required to operate and maintain the Command and Data Acquisition (CDA) equipment of the Trilateration Range and Range Rate (TRRR) System. Information pertaining to the equipment in the Trilateration Range and Range Rate System which is designed to interface with existing NASA equipment located at Wallops Island, Virginia is presented.

Source record↗

Ion composition in a noctilucent cloud

Ion composition at mesospheric altitudes was measured and compared between high and mid-latitude sites under summer daytime conditions. Rocket-borne measurements were made with pumped quadrupole ion mass spectrometers. The mid-latitude data were obtained at Wallops Island, Virginia on June 30, 1973, at 1510 LMT. Large quantities of hydronium cluster ions were observed through 109+, with maximum concentrations at 55+ and 73+. Also, cluster ions of nitric oxide were observed through 84+. The high latitude launch occurred at Kiruna, Sweden on August 2, 1973, at 0700 LMT following visual sighting of a noctilucent cloud on the prior evening. The data near mesopause shows cluster ions, but also a preponderance of heavy ions between 90 and 145 AMU, with groupings 18 AMU apart but unrelated to the more typical cluster ions. One possible set of consistent identifications leads to iron and iron oxide hydrates. These results may suggest the presence of metallic particulates and ions which form hydrated clusters ions.

Goldberg, R. A.↗

Flight of a UV spectrophotometer aboard Galileo 2, the NASA Convair 990 aircraft

An ultraviolet interference-filter spectrophotometer (UVS) fabricated for aircraft-borne use on the DOT Climatic Impact Assessment Program (CIAP) has been successfully tested in a series of flights on the NASA Convair 990, Galileo II. UV flux data and the calculated total ozone above the flight path are reported for several of the flights. Good agreement is obtained with the total ozone as deducted by integration of an ozone sonde vertical profile obtained at Wallops Island, Virginia near the time of a CV-990 underpass. Possible advantages of use of the UVS in the NASA Global Atmospheric Sampling Program are discussed.

Sellers, B.↗

Compatibility of meteorological rocketsonde data as indicated by international comparison tests

Results of two experiments involving intercomparisons of rocketsonde measurements of temperature and wind data in the 25 to 80 km altitude region in the CIMO (Commission for Instruments and Methods of Observations) program during September 1973 are reported. Rocketsonde systems used by France, the USSR, the UK, the U.S., and Japan in the two parts of the program (one series of tests at Wallops Island, Va., the other in French Guiana) are described. Wind data were derived from radar tracking of retardation devices and payloads in descent. Day and night temperature differences were examined. The intercomparisons revealed excellent compatibility of the rocketsonde data up to 60 km in wind observations. Some outstanding problems are pointed out.

Finger, F. G.↗

Rain cell statistics experiment

Communication links suffer from interference caused by precipitation along the transmission path. Terminals established to take advantage of space diversity must be spaced in a manner dependent on rain intensities, rain cell sizes, and spacings. A NASA sponsored radar experiment was conducted at Wallops Island, Va. in 1972 and 1973 to provide statistical data on rain shower intensities and their geometrical properties. The objectives of the experiment were to determine the statistics of the field of rain cells in terms of cell size, intensity, spacing, number density, and altitude dependence, and to find the detailed structure of individual cells leading to a model of an individual cell. The experimental system is described, emphasizing the frequency diversity aspects, the computer control of the antenna, and the digital and analog video recording.

Katz, I.↗

Ionization by energetic electrons in the midlatitude nighttime E region

Observations of the electron density profile and flux of energetic electrons obtained in two rocket flights at Wallops Island near midnight are presented. The ionization rates of the upper E region deduced from the electron density profiles are found to support the dependence on Kp established in previous observation. Calculations of the ionization rates using the observed electron fluxes show agreement with the values derived from the electron density profiles.

Smith, L. G.↗

An operational video data compression system for ATS and ITOS

An operational data compression system has been developed and implemented for transmission of digitized ATS and ITOS-VHRR satellite video data over the wideband communication link between the Wallops Island, Va. Command and Data Acquisition Station and the National Environmental Satellite Service at Suitland, Md. This system uses minicomputers for the coding and decoding of the data to achieve maximum flexibility together with specially designed interface equipment for greater efficiency. No loss in data quality occurs due to the compression, and, in certain cases, data is transmitted which would be otherwise unavailable due to the limited channel capacity. This paper describes the method of compression, the equipment used, and the compression results attained.

Kutz, R. L.↗

Field support, data analysis and associated research for the acoustic grenade sounding program

Temperature and horizontal winds in the 30 to 90 km altitude range of the upper atmosphere, were determined by acoustic grenade soundings conducted at Wallops Island, Virginia and Kourou, French Guiana. Field support provided at these locations included deployment of the large area microphone system, supervision, maintenance and operation of sound ranging stations; and coordination of activities. Data analysis efforts included the analysis of field data to determine upper atmospheric meteorological parameters. Profiles for upper atmospheric temperature, wind and density are provided in plots and tables for each of the acoustic grenade soundings conducted during the contract period. Research efforts were directed toward a systematic comparison of temperature data from acoustic grenade with other meteorological sensor probes in the upper atmosphere.

Barnes, T. G.↗

Attenuation of propagation through rain for an earth-satellite path correlated with predicted values using radar

During the summer of 1974 and spring of 1975, measurements of attenuation of propagation through rain were made at Wallops Island, VA, using 13 and 18 GHz transmitters operating in the uplink mode toward the ATS-6 satellite. Simultaneously, rain reflectivity levels were measured along the earth-satellite path using a high resolution (0.4 deg beamwidth) S-band radar having a scanning antenna. Four rain-gages and two disdrometers were also located in the vicinity of the transmitters. The radar and disdrometer data were used in a modelling program to predict attenuation levels which were subsequently compared to the directly measured fades over nearly simultaneous time intervals. Predicted attenuation levels were obtained for three drop size distributions. Comparisons between predicted and measured attenuation levels showed the APL dropsize distribution gave the smallest rms difference of 1.3 dB at 13 and 18 GHz although the rms difference corresponding to Marshall-Palmer was close to this value. The good agreement suggests the validity of using radar to model path attenuation to obtain attenuation statistics.

Goldhirsh, J.↗

Ion composition in a noctilucent cloud region

Ion composition at mesospheric altitudes was measured at high-latitude (Kiruna, Sweden) and mid-latitude (Wallops Island, Virginia) sites under summer daytime conditions, using two sets of rocket measurements both made with pumped quadrupole ion mass spectrometers. Cluster ions of hydronium and of nitric oxide were observed at midlatitudes, while, in addition to these cluster ions, a preponderance of heavy ions between 90 and 145 amu, was observed at high latitudes. These latter results may suggest the presence of metallic particles and ions which form hydrated cluster ions within the noctilucent cloud region.

Goldberg, R. A.↗

Metal ions and isotopes in sporadic E-layers during the Perseid meteor shower

The electron density and positive-ion composition above Wallops Island were measured on August 12, 1976, about 12 hours after the maximum of the Perseid shower. At launch time, 4.5 MHz was recorded for fbEs, corresponding to an electron density of 2.4 x 10 to the 5th power per cu cm. Electron profile and ion composition measurements confirmed the presence of a sporadic E-layer with two maxima at 101.3 and 105.4 km. The electron density was measured with a pair of boom-mounted probes at fixed potential. The positive ion composition above 77 km was measured with a magnetic mass spectrometer employing a liquid He cryopump. Some of the salient results of the (still incomplete) analysis are discussed.

Herrmann, U.↗

An evaluation of in situ ozone sensor performance during a cold frontal passage

The capabilities of the electrochemical concentration cell ozonesonde for measuring the vertical profile of atmospheric ozone were studied during a three day experiment at Wallops Island, Virginia, and Norfolk, Virginia. Using ancillary measurements at the surface and the spectrophotometer, it was concluded that the ozonesonde measures the total ozone overburden to within 10% of the real value. By releasing the balloon-borne instruments at a rate of four per day at each of the two sites, an indication was obtained of the temporal and spatial scales of atmospheric ozone variability. No significant effects of a weak cold front passage or of the loss of insolation at night were seen. An isolated incident of anomalously high ozone concentration at the peak of the profile was attributed to sporadic instrument performance effects. The data base currently available is not adequate for determining an exact cause of the anomaly.

Parsons, C. L.↗

GEOS-2 refraction program summary document

Data from an extensive array of collocated instrumentation at the Wallops Island test facility were intercompared in order to (1) determine the practical achievable accuracy limitations of various tropospheric and ionospheric correction techniques; (2) examine the theoretical bases and derivation of improved refraction correction techniques; and (3) estimate internal systematic and random error levels of the various tracking stations. The GEOS 2 satellite was used as the target vehicle. Data were obtained regarding the ionospheric and tropospheric propagation errors, the theoretical and data analysis of which was documented in some 30 separate reports over the last 6 years. An overview of project results is presented.

Mallinckrodt, A. J.↗

Mesospheric heating due to intense tropospheric convection

A series of rocket measurements made twice daily at Wallops Island, Va., revealed a rapid heating of the mesosphere on the order of 10 K on days when thunderstorms or squall lines were in the area. This heating is explained as the result of frictional dissipation of vertically propagating internal gravity waves generated by intense tropospheric convection. Ray-tracing theory is used to determine the spectrum of gravity wave groups that actually reach mesospheric heights. This knowledge is used in an equation describing the spectral energy density of a penetrative convective element to calculate the fraction of the total energy initially available to excite those waves that do reach the level of heating. This value, converted into a vertical velocity, is used as the lower boundary condition for a multilayer model used to determine the detailed structure of the vertically propagating waves. The amount of frictional dissipation produced by the waves is calculated from the solutions of the frictionless model by use of a vertically varying eddy viscosity coefficient. The heating produced by the dissipation is then calculated from the thermodynamic equation.

Taylor, L. L.↗

A rocket-borne data-manipulation experiment using a microprocessor

The development of a data-manipulation experiment using a Z-80 microprocessor is described. The instrumentation is included in the payloads of two Nike Apache sounding rockets used in an investigation of energetic particle fluxes. The data from an array of solid-state detectors and an electrostatic analyzer is processed to give the energy spectrum as a function of pitch angle. The experiment performed well in its first flight test: Nike Apache 14.543 was launched from Wallops Island at 2315 EST on 19 June 1978. The system was designed to be easily adaptable to other data-manipulation requirements and some suggestions for further development are included.

Davis, L. L.↗

Total ozone determination by spectroradiometry in the middle ultraviolet

A method has been developed to determine total ozone from multispectral measurements of the direct solar irradiance. The total ozone is determined by a least squares fit to the spectrum between 290 nm and 380 nm. The aerosol extinction is accounted for by expanding it in a power series in wavelength; use of the linear term proved adequate. A mobile laboratory incorporating a sky scanner has been developed and used to obtain data to verify the method. Sun tracking, wavelength setting of the double monochromator, and data acquisition are under control of a minicomputer. Results obtained at Wallops Island, Virginia, and Palestine, Texas, agree well with simultaneous Dobson and Canterbury spectrometer and balloon ECC ozonesonde values. The wavelength calibration of the monochromator and the values for the normalized ozone absorption are the most important factors in an accurate determination of total ozone.

Garrison, L. M.↗