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The ice crystal forming nuclei (IN) measured in solid rocket motor (SRM) exhaust products is discussed in relation to space shuttle exhaust. Preliminary results from laboratory investigations and flight preparations for March 1978 Titan launch are discussed. The work necessary to provide adequate measurements of IN and cloud condensation nuclei (CCN) in the stabilized ground clouds from SRM's is studied.
Atmospheric measurements between 30 and 90 km using two rocket-borne techniques - the inflatable falling sphere and the acoustic grenade - are compared in order to determine temperature measurement compatibility. The falling sphere, deployed at 115 km, is tracked by precision radar to determine winds as well as accurate drag parameters needed to deduce density from which temperatures are derived. The acoustic grenade technique uses sound arrivals at the ground from grenades ejected at 2-km intervals to determine temperature and wind between 40 and 90 km. The available data were obtained during an in-situ techniques-comparison with the remote sounders aboard Nimbus 6 during the summer and winter of 1975.
Transient pressure measurements in rocket thrust chambers used in propulsion systems research
Ground based and sounding rocket measurements of interplanetary dust particle flux
Far ultraviolet polarization analyzer for rocket measurement of resonantly scattered sunlight
In this paper, Solar Backscatter Ultraviolet (SBUV) measurements of solar irradiance and predictions from the Mg 280-nm index are compared with each other and with coincident Solar Mesosphere Explorer (SME) and rocket measurements. The SBUV irradiances show a systematic decrease with time not seen in the rocket measurements; a correction for this decrease is introduced. The scatter and overall structure in the SME spectra is 3-5 percent, of the order of or larger than most of the changes predicted by the Mg index. The corrected SBUV ratio and the Mg index prediction for it agree to within 1 percent. Such agreement supports a common origin for variations between solar maximum and minimum and those for individual rotations: the degree to which active regions cover the visible hemisphere of the sun.
Results of two types of measurements made at a site in the center of the eclipse track during the total eclipse of Mar. 7, 1970. The O I forbidden 5577-A and 6300-A lines were measured looking vertically through the eclipse shadow. The intensities were approximately 1 kR, essentially the values obtained in recent rocket measurements of normal day airglow at altitudes above 100 km. This is consistent with the hypothesis that these lines originate primarily at altitudes well above the shadow from mechanisms which are not appreciably perturbed by the approaching shadow. Measurements were also made of the time variation of intensity of incident light during the shadow-band period before second contact. There are saw-tooth fluctuations with steep leading edges, as well as many high-frequency components of smaller amplitude. This time variation does not appear to be obviously related in a simple way to current theories of their production mechanisms, or to the visual appearance of shadow bands.
Boeing Rocketdyne is pursuing the development of Rocket Based Combined Cycle (RBCC), propulsion systems as demonstrated by significant contract work in the hypersonic arena (ART, NASP, SCT, system studies) and over 12 years of steady company discretionary investment. The Rocketdyne concept is a fixed geometry integrated rocket, ramjet, scramjet which is hydrogen fueled and uses hydrogen regenerative cooling. The baseline engine structural configuration uses an integral structure that eliminates panel seals. seal purge gas, and closeout side attachments. Rocketdyne's experimental RBCC engine (Engine A5) was constructed under contract with the NASA Marshall Space Flight Center. Engine A5 models the complete flight engine flowpath consisting of an inlet, isolator, airbreathing combustor and nozzle. High performance rocket thrusters are integrated into the engine to enable both air-augmented rocket (AAR) and pure rocket operation. Engine A5 was tested in CASL's new FAST facility as an air-augmented rocket, a ramjet and a pure rocket. Measured performance demonstrated vision vehicle performance levels for Mach 3 AAR operation and ramjet operation from Mach 3 to 4. Rocket mode performance was above predictions. For the first time. testing also demonstrated transition from AAR operation to ramjet operation. This baseline configuration has also been shown, in previous testing, to perform well in the scramjet mode.
An analysis of long baseline NIMBUS 7 SBUV (Solar Backscatter UV Spectrometer) observations of the latitudinal variation of the noontime vertical Mg' content above approx. 70 km have revealed seasonal, solar activity and magnetic activity dependencies in the Mg+ content. The distributions were categorized in terms of magnetic coordinates partially because transport processes lifting metallic ions from the main meteor ionization layer below 100 km up into the F- region and down again are controlled by electrodynamical processes. Alternatively, the Nimbus Mg+ distributions may simply be a result of ion/neutral chemistry changes resulting from atmospheric changes and not dynamics. In such a case magnetic control would not dominate the distributions. Using in situ satellite measurements of metal ions from the Atmosphere Explorer satellites in the region above the main meteor layer and published sounding rocket measurements of the main metallic ion layers, the effects of the dynamics on the vertical content are delineated. The consequences of atmospheric changes on the vertical content are explored by separating the Nimbus measurements in a geodetic frame of reference.
The NASA Upper Atmosphere Research Program organized a Stratospheric Ozone Intercomparison Campaign (STOIC) held in July-August 1989 at the Table Mountain Facility (TMF) of the Jet Propulsion Laboratory (JPL). The primary instruments participating in this campaign were several that had been developed by NASA for the Network for the Detection of Stratospheric Change: the JPL ozone lidar at TMF, the Goddard Space Flight Center trailer-mounted ozone lidar which was moved to TMF for this comparison, and the Millitech/LaRC microwave radiometer. To assess the performance of these new instruments, a validation/intercomparison campaign was undertaken using established techniques: balloon ozonesondes launched by personnel from the Wallops Flight Facility and from NOAA Geophysical Monitoring for Climate Change (GMCC) (now Climate Monitoring and Diagnostics Laboratory), a NOAA GMCC Dobson spectrophotometer, and a Brewer spectrometer from the Atmospheric Environment Service of Canada, both being used for column as well as Umkehr profile retrievals. All of these instruments were located at TMF and measurements were made as close together in time as possible to minimize atmospheric variability as a factor in the comparisons. Daytime rocket measurements of ozone were made by Wallops Flight Facility personnel using ROCOZ-A instruments launched from San Nicholas Island. The entire campaign was conducted as a blind intercomparison, with the investigators not seeing each others data until all data had been submitted to a referee and archived at the end of the 2-week period (July 20 to August 2, 1989). Satellite data were also obtained from the Stratospheric Aerosol and Gas Experiment (SAGE 2) aboard the Earth Radiation Budget Satellite and the Total Ozone Mapping Spectrometer (TOMS) aboard Nimbus 7. An examination of the data has found excellent agreement among the techniques, especially in the 20- to 40-km range. As expected, there was little atmospheric variability during the intercomparison, allowing for detailed statistical comparisons at a high level of precision. This overview paper summarizes the campaign and provides a 'road map' to subsequent papers in this issue by the individual instrument teams which will present more detailed analysis of the data and conclusions.
An instrument (eroding potentionmeter) has been designed to measure real-time case wall and inhibitor insulation char depth within a rocket motor during firing. Thus measurement can be close to the real-time recession of the insulation surface. The eroding potentionmeter consists of two small (3 mils 9in diameter) twisted resistive wires that are polyimide insulated. The wire pair form an electrical circuit and will recede with the erosion of the rocket motor internal insulation. A constant current applied along the wires will detect the resistance change via a voltage drop across the wires as the wire pair recedes with the decomposition fo the insulation. The eroding potentionmeter, as presently designed, can be an effective tool for real time measurement of internal insulation recession of a solid rocket motor. This tool will provide a way to accurately measure inhibitor performance or to measure flight effects of insulation erosion on a flight test. The eroding potentiometer has been verified on a plasma torch test and two static tests of a small solid rocket motor. There are some irregularities in the measured date, but the data remains useful in determining the real-time performance of internal insulation during a motor firing.
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.
The O I 'green line' (1S-1D) at 5577 A and the O2 (0,0) atmosphere band at 7620 A were measured in a steady IBC II(plus) aurora simultaneously with N2 emissions and the auroral electron flux. An empirical model based on these rocket measurements shows that the principal excitation source of O2(b 1 Sigma g plus) is energy transfer from O(1D), with direct electron impact of O2 contributing less than 5 percent. While the altitude profile of the green line emission resembles that which would be produced by electron impact excitation of O2, a dissociative excitation cross section of 10 to the minus 16th power is required for this interpretation. None of the other known O(1S) excitation mechanisms are thought capable of producing the observed emission rate.
A program is described for obtaining a reliable, parametric set of measurements in the exhaust plumes of solid propellant rocket motors. Plume measurements included pressures, temperatures, forces, heat transfer rates, particle sampling, and high-speed movies. Approximately 210,000 digital data points and 15,000 movie frames were acquired. Measurements were made at points in the plumes via rake-mounted probes, and on the surface of a large plate impinged by the exhaust plume. Parametric variations were made in pressure altitude, propellant aluminum loading, impinged plate incidence angle and distance from nozzle exit to plate or rake. Reliability was incorporated by continual use of repeat runs. The test setup of the various hardware items is described along with an account of test procedures. Test results and data accuracy are discussed. Format of the data presentation is detailed. Complete data are included in the appendix.
This study assesses the impact of new O((sup 3)P) photoionization and N2 photoabsorption cross sections, and O(+) oscillator strengths and transition probabilities, on O II 834-A airglow calculations. The 834-A intensities computed using the new emission parameters are in good agreement with rocket measurements obtained in 1978 and 1980. The present study does not support a suggested reduction in the N2 photoabsorption cross section based on an earlier analysis of the rocket data. This study also explores the problem of determining F region electron densities from satellite limb scans of the O(+) 834-A emission. Our results indicate that electron density profiles inferred from limb scans are not necessarily unique; estimates of N(sub m)F(sub 2) and h(sub m)F(sub 2) can vary by at least a factor of 2 and 50 km, respectively.
Simultaneous rocket measurements of electric field and optical aurora during a weak PCA event are presented. The aurora consisted of faint structures superposed on a homogeneous glow, and on-board photometers showed that the rocket passed through two discrete auroral forms. These enhanced auroral emissions coincided with variations in the dc electric field and an increase in the ac field. A detailed comparison between electric fields and optical emissions shows that the relation is quite complex. The results are compared with earlier electric field and optical auroral measurements.
Results of a coordinated auroral experiment involving the Atmosphere Explorer C satellite and a sounding rocket are reported. Auroral primary electron fluxes and neutral gas densities measured by instruments on the satellite are used in a model calculation of the thermospheric manifestation of the aurora. There is encouraging agreement between the calculated and measured electron density, electron temperature, secondary electron flux, and O I emissions at 5577 and 6300 A. A discrepancy between the calculated and the rocket-measured 3914-A emission profile is discussed in terms of experiment geometry and auroral physics. The coordinated measurements are used to infer vertical fluxes of ionization and of electron thermal energy at high altitudes
An analysis of the acoustical and flowfield environment for the scaled 1-pound-force (lbf) thrust tabletop motor was performed. The jet characterization is based on computational fluid dynamics (CFD) in conjunction with Kirchhoff surface integral formulation and compared with correlations developed for measured rocket noise and a pressure fluctuation scaling (PFS) method. Comparisons are made for the overall sound pressure levels (OASPL's) and spectral dependence of sound pressure level (SPL).