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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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At least 1,135 records · Page 63
All sourcesNASA NTRSDOE OSTI
NASA NTRS1963

THE ENGINEERING DESIGN OF THE ORBITING ASTRONOMICAL OBSERVATORY

The Orbiting Astronomical Observatory (OAO) is designed to provide an accurately stabilized, unmanned platform for astronomical observations from well above the earth's atmosphere. Of primary immediate interest is the observation of stellar radiation in the ultraviolet range, which is severely limited even in balloon experiments because of absorption in the ozone layers. The OAO is a 3600-pound spacecraft that will be placed in orbit by an Atlas Agena D. It can handle optical systems up to 48 inches in diameter, 10 feet in length, weighing 1000 pounds. The key design requirements of the spacecraft are discussed. The reasons behind the configuration are then explained, followed by a discussion of the major subsystems showing how they have been designed to meet the exacting requirements astronomical observation.

SATELLITE INSTRUMENTATION↗
NASA NTRS1960

Vacancy-Vacancy Interaction in Copper

The binding energy of two vacancies in a static lattice as a function of their separation and the positions of their displaced neighboring atoms has been calculated using a Morse potential function model for copper. It was found that two vacancies attract one another at separation less than about 7 A. At separations greater than 7 A the vacancies do not interact appreciably. The most stable separation was found to be the first nearest- neighbor separation or the divacancy configuration, for which the binding energy was found to be 0.64 ev. Based on these calculations, it is shown that third-stage annealing in irradiated copper may be accounted for by divacancy migration. The role of the divacancy in copper self-diffusion is also explained.

Girifalco, L. A.↗
NASA NTRS1963

Space Flight Handbooks. Volume 3 - Planetary Flight Handbook: Speed Contours & Auxiliary Graphs for Manned Missions to Mars and Venus - Part 1

This Handbook contains a series of maps, graphs, and tables which will be of use to the preliminary design analyst in scheduling round-trip interplanetary missions to Mars and Venus in the time period 1965-1999. It constitutes the third in a series of space flight manuals prepared for the George C. Marshall Space Flight Center, NASA. The present Handbook, denoted as Volume 3 of this series, is divided into three Parts. Part 3-1 presents maps for obtaining departure and arrival speeds for trips to these planets, a listing of useful constants, planetary ephemerides, tables of important occurrences, and a number of auxiliary graphs. Although most of the basic calculations were performed for the period 1965 -1980, much of the information is also applicable to the years 1980- 1999, as is explained in the text.

VENUS↗
NASA NTRS1965

A Method of Implementing Cutoff Conditions for Saturn V Lunar Missions Out of Earth Parking Orbit Assuming a Continuous Ground Launch Window

A method of implementing Saturn V lunar missions from an earth parking orbit is presented. The ground launch window is assumed continuous over a four and one-half hour period. The iterative guidance scheme combined with a set of auxiliary equations that define suitable S-IVB cutoff conditions, is the approach taken. The four inputs to the equations that define cutoff conditions are represented as simple third-degree polynomials as a function of ignition time. Errors at lunar arrival caused by the separate and combined effects of the guidance equations, cutoff conditions, hypersurface errors, and input representations are shown. Vehicle performance variations and parking orbit injection errors are included as perturbations. Appendix I explains how aim vectors were computed for the cutoff equations. Appendix II presents all guidance equations and related implementation procedures. Appendix III gives the derivation of the auxiliary cutoff equations. No error at lunar arrival was large enough to require a midcourse correction greater than one meter per second assuming a transfer time of three days and the midcourse correction occurs five hours after injection. Since this result is insignificant when compared to expected hardware errors, the implementation procedures presented are adequate to define cutoff conditions for Saturn V lunar missions.

PARKING ORBIT↗
NASA NTRS1964

Radio Noise Problems in Arctic Regions

Three main types of radio noise should be considered when establishing noise levels for communication purposes or in experiments utilizing radio techniques in Arctic regions. These are atmospheric and man-made noise, and precipitation static. National Bureau of Standards radio noise data obtained hourly at Arctic and Antarctic stations on eight .fixed frequencies between 51 kc and 20 Mc/s are analyzed to show the characteristics of the three types. The diurnal and seasonal variations of atmospheric radio noise at high latitudes are explainable in terms of changes in propagation factors and in the distribution of world thunderstorm activity. In both northern and southern Arctic regions atmospheric noise decreases during polar cap absorption (PCA), most markedly in the h.f. band. The probable magnitude of man-made noise in the h.f. band is estimated from data taken during PCA, when atmospheric noise is absent. At Thule man-made noise on 2.5 and 5 Mc/s appears to be 57 and 49 dB above kTB (where kTB is antenna thermal noise power), respectively, while at Byrd Station the values are about 20 and 12 dB respectively. Precipitation static is generated on exposed antennas during periods of blowing snow (blizzards). The noise power magnitude can be at least 50 dB above man-made and atmospheric levels, but the maximum enhancement cannot be ascertained because of missing data. In winter and spring months at Byrd Station radio data dependent upon exposed antennas may be lost 10-30 per cent of the time due to precipitation static alone.

Radio Noise↗
NASA NTRS1965

An interpretation of epsilon aurigae.

Rotating opaque gaseous disk model to explain contradictory behavior of binary Epsilon Aurigae found in photometric and spectroscopic observations

ROTATING DISK↗
NASA NTRS1965

The rotation of the planet Mercury

Rotation of planet Mercury from radar observation explained by solar gravitational torque on tidal deformation and equatorial plane asymmetry

RADAR OBSERVATION↗
NASA NTRS1966

Some unique applications of intense magnetic fields

A brief history of our knowledge of ordinary magnetism and electromagnetism is given, from the time of the Roman poet, Lucretius Carus, to the present. Practical examples of magnetic field strength associated with objects familiar to all are discussed, and a frame of reference regarding magnetic field strength is thereby established. The earliest known investigators of intense transient magnetic field manipulation of solid conductor materials are mentioned, and the phenomena described. Systems, apparatus, and basic theory of operation are detailed. The importance of adequate diagnostics is discussed, and some techniques employed are illustrated. The "magnetic sawing" phenomenon is described, and implications explained. Typical applications are shown, including swaging, sizing, sealing. clamping, forming, and other unique neoterisms. A particularly successful application, the magnetomotive sizer, is described in detail, and beneficial application in the Saturn V program is described. Potential industrial applications are prognosticated, and developmental trends are indicated.

Electromagnetic field↗