Sonic radiation from a circular piston with impulse excitation
Sonic pressure as function of space and time calculated for radiation from circular piston with impulse excitation
Bess, L.↗
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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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Solid state sequencer system
Development and characteristics of solid state sequencer system to perform abort and separation functions on space shuttle
Leck, D. E.↗
An efficient method of energy projection
Nucleus energy spectra projection from Hartree- Fock intrinsic wave functions model space, using coupled orbital matrix elements
Braley, R. C.↗
Encoding of a counting rate source with orthogonal functions
Counting rate source encoding algorithm with orthogonal functions in space experiment data processing before telemetering to ground
Algazi, V. R.↗
Survey of auxiliary-propulsion systems for communications satellites.
In order to provide insight for the selection of attitude- and stationkeeping propulsion systems for future communications satellites, current auxiliary-propulsion systems are surveyed. Thruster systems specifically considered are stored gas, vaporizing ammonia/electrothermal, catalytic monopropellant hydrazine, electrothermal monopropellant hydrazine, plenum monopropellant hydrazine, ion, colloid, and pulsed plasma. Each of the thruster types is discussed in three sections: (1) description of thruster system and how it functions, (2) space flight experience, and (3) survey of state-of-the-art thrusters. In addition, a qualitative tabulation of thruster characteristics is included.
Holcomb, L. B.↗
Field line motion in the presence of finite conductivity.
The relation of plasma motion to field line motion is determined in the case where the conductivity is imperfect. The imperfect conductivity may result from collisions between plasma particles and neutrals, as in the case of the earth's ionosphere, or from the scattering of charged particles by the enhanced field fluctuations which characterize a turbulent plasma. A magnetic field is assumed which is a given, known function of space and time, and it is further assumed that all field lines intersect an ideally conducting surface and are identified by their points of intersection. It is shown that the relative displacement between drifting particles and moving field lines has significance only when compared with some other pertinent length such as the total particle drift distance. In such a comparison, when the latter quantity is much larger than the first, the particles can be followed by tracing field lines.
Birmingham, T. J.↗
Spacecraft boost and abort guidance and control systems requirement study, boost dynamics and control analysis study. Exhibit A: Boost dynamics and control anlaysis
The simulation developments for use in dynamics and control analysis during boost from liftoff to orbit insertion are reported. Also included are wind response studies of the NR-GD 161B/B9T delta wing booster/delta wing orbiter configuration, the MSC 036B/280 inch solid rocket motor configuration, the MSC 040A/L0X-propane liquid injection TVC configuration, the MSC 040C/dual solid rocket motor configuration, and the MSC 049/solid rocket motor configuration. All of the latest math models (rigid and flexible body) developed for the MSC/GD Space Shuttle Functional Simulator, are included.
Williams, F. E.↗
Structure of the star field in the direction of the cluster NGC 6913. 2: Spatial distribution of stars
The space density function for the stars was determined in the Mikly Way field around NGC 6913 in the direction l = 76.9 deg, b = + 0.6 deg (along the local spiral arm toward Cygnus) by means of BV-photometry and spectral classification. O-B3 stars are concentrated at distances of 1 - 2 kpc, the density shows maximum at a distance of 1.6 kpc. There are also concentrations of O-B3 stars at distances of 1.9 and 2.5 kpc. The density for classes AV - FV shows maximum between 400 and 500 pc.
Kolesnik, L. N.↗
Monte Carlo investigation of transient acoustic fields in partially or completely bounded medium
A simple repetitive calculation was used to investigate what happens to the field in terms of the signal paths of disturbances originating from the energy source. The computation allowed the field to be reconstructed as a function of space and time on a statistical basis. The suggested Monte Carlo method is in response to the need for a numerical method to supplement analytical methods of solution which are only valid when the boundaries have simple shapes, rather than for a medium that is bounded. For the analysis, a suitable model was created from which was developed an algorithm for the estimation of acoustic pressure variations in the region under investigation. The validity of the technique was demonstrated by analysis of simple physical models with the aid of a digital computer. The Monte Carlo method is applicable to a medium which is homogeneous and is enclosed by either rectangular or curved boundaries.
Thanedar, B. D.↗
Asymmetrical booster ascent guidance and control system design study. Volume 2: SSFS math models - Ascent
The engineering equations and mathematical models developed for use in the space shuttle functional simulator (SSFS) are presented, and include extensive revisions and additions to earlier documentation. Definitions of coordinate systems used by the SSFS models and coordinate tranformations are given, along with documentation of the flexible body mathematical models. The models were incorporated in the SSFS and are in the checkout stage.
Williams, F. E.↗
Analysis of impingement heat transfer for two parallel liquid-metal slot jets
An analytical method is developed for determining heat transfer by impinging liquid-metal slot jets. The method involves mapping the jet flow region, which is bounded by free streamlines, into a potential plane where it becomes a uniform flow in a channel of constant width. The energy equation is transformed into potential plane coordinates and is solved in the channel flow region. Conformal mapping is then used to transform the solution back into the physical plane and obtain the desired heat-transfer characteristics. The analysis given here determines the heat-transfer characteristics for two parallel liquid-metal slot jets impinging normally against a uniformly heated flat plate. The liquid-metal assumptions are made that the jets are inviscid and that molecular conduction is dominating heat diffusion. Wall temperature distributions along the heated plate are obtained as a function of spacing between the jets and the jet Peclet number.
Siegel, R.↗
Research and applications modules /RAM/
RAM, a family of payload carriers that operate in conjunction with the Space Shuttle, is shown to provide flexible and economical laboratories and facilities for the conduct of manned and man-tended scientific and applications investigations in near-earth orbit. Two primary mission modes of RAM are discussed in terms of capability provided, and major advantages and constraints. The Sortie mission mode uses the Shuttle orbiter as the space platform and RAM as the scientific equipment carrier to provide a flexible and economical means for conducting short-duration manned investigations. The man-tended observatory mode uses Shuttle for delivery, periodic on-orbit update and service, and retrieval of the observatory, with RAM providing the interface with the Shuttle for servicing and the space platform functions for operation.
Macdonald, J. M.↗
Radiation effects
The effects of cosmic radiation and radiation from solar flares on space probe functions are investigated. Long life batteries for probe use were also investigated.
Thayne, L.↗
The effect of adiabatic focusing upon charged particle propagation in random magnetic fields
Charged particles propagating along the diverging lines of force of a spatially inhomogeneous guiding field were considered as they are scattered by random fields. Their longitudinal transport is described in terms of the eigenfunctions of a Sturm-Liouville operator incorporating the effect of adiabatic focussing along with that of scattering. The relaxation times and characteristic velocities are graphed and tabulated. The particle density is evaluated as a function of space and time for two different regimes. In the first regime (relatively weak focussing), a diffusive mode of propagation is dominant but coherent modes are also dominant. In the second regime (strong focussing), diffusion does not occur and the propagation is purely coherent. This supercoherent mode corresponds exactly to the so-called scatter-free propagation of kilovolt solar flare electrons. On a larger scale, focussed transport provides an interpretation of many observed characteristics of extragalactic radio sources.
Earl, J. A.↗
Apu/hydraulic/actuator Subsystem Computer Simulation. Space Shuttle Engineering and Operation Support, Engineering Systems Analysis
Major developments are examined which have taken place to date in the analysis of the power and energy demands on the APU/Hydraulic/Actuator Subsystem for space shuttle during the entry-to-touchdown (not including rollout) flight regime. These developments are given in the form of two subroutines which were written for use with the Space Shuttle Functional Simulator. The first subroutine calculates the power and energy demand on each of the three hydraulic systems due to control surface (inboard/outboard elevons, rudder, speedbrake, and body flap) activity. The second subroutine incorporates the R. I. priority rate limiting logic which limits control surface deflection rates as a function of the number of failed hydraulic. Typical results of this analysis are included, and listings of the subroutines are presented in appendicies.
Source record↗
Dispersion of ensembles of non-interacting particles
The dynamics of an ensemble of noninteracting particles dispersing from a common origin and moving in a common force field with an initial distribution of momenta is analyzed using an approach where the particles are considered as a continuum described by a phase-space distribution function. General solutions are obtained for both the distribution function and the associated spatial density function. The linear case of small departures from circular orbits in an axisymmetric gravitational field is treated along with the specific case of particle dispersion from an object in a circular orbit in the same type of field. Numerical results are presented for the latter case, and consideration is given to the inverse problem of determining the initial time and velocity distribution from knowledge of the ensemble structure at a later time. Explicit results are provided for the case of an ellipsoidal distribution of initial momenta, and a numerical procedure is indicated for treating more general cases.
Heard, W. B.↗
A simulation of air pollution model parameter estimation using data from a ground-based LIDAR remote sensor
One way to obtain estimates of the unknown parameters in a pollution dispersion model is to compare the model predictions with remotely sensed air quality data. A ground-based LIDAR sensor provides relative pollution concentration measurements as a function of space and time. The measured sensor data are compared with the dispersion model output through a numerical estimation procedure to yield parameter estimates which best fit the data. This overall process is tested in a computer simulation to study the effects of various measurement strategies. Such a simulation is useful prior to a field measurement exercise to maximize the information content in the collected data. Parametric studies of simulated data matched to a Gaussian plume dispersion model indicate the trade offs available between estimation accuracy and data acquisition strategy.
Kibler, J. F.↗
Theory on acoustic sources
A theory is described for the radiation emission emission from acoustic multipole sources. The sources can be stationary or moving at speeds including supersonic and experience stationary or moving disturbances. The effect of finite source distributions and disturbances is investigated as well as the manner in which they interact. Distinction is made between source distributions that responsed as a function of time and those that respond as a function of space.
Wright, S. E.↗