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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

The last Balmer line and H gamma in model B stars

Profiles of the last few Balmer lines (H12-H27) and the full profiles of the H gamma line were computed for a grid of hydrogen line blanketed model atmospheres. The use of the last hydrogen line and the equivalent width of H gamma provide a quick means of estimating the effective temperature and surface gravity of B stars. Regression curves relating the quantum number of the last hydrogen line to the electron density in the model atmosphere are given. Futhermore, it is shown that the difference in the gravity determination deduced from H gamma equivalent widths using the Edmonds-Schuter-Wells formalism and the Griem wing formulae is, at worst, 0.18 in the common logarithm.

Fischel, D.↗
NASA NTRS1973

HEAO-B X-ray experiments. Non-dispersive spectroscopy

The scientific objectives of HEAO-B are presented. They include four X-ray and gamma ray experiments in addition to two charged cosmic ray experiments. The first X-ray experiment is one using standard proportional counters, mechanically collimated, and covers the region from 0.2 to 60 keV. It is being designed for the purpose of detecting small changes in the surface brightness of the X-ray sky over a very broad spectral range. The second X-ray experiment involves Bragg crystal spectrometers for the range 0.5 to 10 keV. In the low energy gamma ray experiment, which also extends into the X-ray region, a cooled germanium (lithium drifted) gamma-ray spectrometer was used.

Boldt, E. A.↗
NASA NTRS1973

Panoramic attitude sensor for Radio Astronomy Explorer B

An instrument system to acquire attitude determination data for the RAE-B spacecraft was designed and built. The system consists of an electronics module and two optical scanner heads. Each scanner head has an optical scanner with a field of view of 0.7 degrees diameter which scans the sky and measures the position of the moon, earth and sun relative to the spacecraft. This scanning is accomplished in either of two modes. When the spacecraft is spinning, the scanner operates in spherical mode, with the spacecraft spin providing the slow sweep of lattitude to scan the entire sky. After the spacecraft is placed in lunar orbit and despun, the scanner will operate in planar mode, advancing at a rate of 5.12 seconds per revolution in a fixed plane parallel to the spacecraft Z axis. This scan will cross and measure the moon horizons with every revolution. Each scanner head also has a sun slit which is aligned parallel to the spin axis of the spacecraft and which provides a sun pulse each revolution of the spacecraft. The electronics module provides the command and control, data processing and housekeeping functions.

Thomsen, R.↗
NASA NTRS1973

Delta-95, RAE-B operations summary

A systems analysis of the Radio Astronomy Explorer - B satellite is presented. The subjects discussed are: (1) mission objective, (2) launch vehicle and spacecraft configurations, (3) launch operations plan, (4) communications, and (5) test operations.

Source record↗
NASA NTRS1973

Ultraviolet observations of peculiar B and A stars from OAO-2

Plotted photometric data in two far-ultraviolet bandpasses at 1550 and 1430 A for both normal and peculiar stars are compared for flux distribution. It is shown that the ultraviolet flux distribution of an A sub p or B sub p star is consistent with its spectral class and is notably inconsistent with its UBV colors. It is assumed that the helium line strength suppression mechanism is related to an abnormal atmospheric structure in the peculiar stars.

Leckrone, D. S.↗
NASA NTRS1973

Isothermal and cyclic oxidation at 1000 and 1100 deg C of four nickel-base alloys: NASA-TRW VIA, B-1900, 713C, and 738X

The isothermal and cyclic oxidation resistance of four cast Ni-base gamma + gamma prime alloys, NASA-TRW Via, B-1900, 713C, and 738X, was determined in still air at 1000 and 1100 C. The oxidation process was evaluated by specific sample weight change with time, sample thickness change, X-ray diffraction of the scales, and sample metallography. The behavior is discussed in terms of the Cr, Al, and refractory metal contents of the alloys.

Barrett, C. A.↗
NASA NTRS1973

Radio astronomy Explorer-B in-flight mission control system development effort

A description is given of the development for the Mission Analysis Evaluation and Space Trajectory Operations (MAESTRO) program to be used for the in-flight decision making process during the translunar and lunar orbit adjustment phases of the flight of the Radio Astronomy Explorer-B. THe program serves two functions: performance and evaluation of preflight mission analysis, and in-flight support for the midcourse and lunar insertion command decisions that must be made by the flight director. The topics discussed include: analysis of program and midcourse guidance capabilities; methods for on-line control; printed displays of the MAESTRO program; and in-flight operational logistics and testing.

Lutsky, D. A.↗
NASA NTRS1974

Spacelab Phase B study environmental control system component handbook

Descriptions are given of candidate components for the Phase B Study of the Spacelab environmental control system. Most of the hardware was defined for the baseline ECS design concept. A low cost design approach was followed, with most of the components being selected from the Apollo and Skylab Programs.

Burns, R. A.↗
NASA NTRS1974

Spacelab data management subsystem phase B study

The Spacelab data management system is described. The data management subsystem (DMS) integrates the avionics equipment into an operational system by providing the computations, logic, signal flow, and interfaces needed to effectively command, control, monitor, and check out the experiment and subsystem hardware. Also, the DMS collects/retrieves experiment data and other information by recording and by command of the data relay link to ground. The major elements of the DMS are the computer subsystem, data acquisition and distribution subsystem, controls and display subsystem, onboard checkout subsystem, and software. The results of the DMS portion of the Spacelab Phase B Concept Definition Study are analyzed.

Source record↗
NASA NTRS1974

Reynolds number effects on hypersonic characteristics of a 0.010-scale model of the 139-B shuttle orbiter

Longitudinal and lateral-directional stability characteristics of the 139-B orbiter (model 32-0) were obtained in a continuous flow hypersonic tunnel at Mach 10.3. Tests were made at Reynolds numbers of 1.04 million and 2.17 million (based on body length) over an angle of attack range of 12 deg to 36 deg at sideslip angles of 0 deg and minus 5 deg. Data were obtained at three elevon/body flap settings.

Bernot, P. T.↗
NASA NTRS1974

Hypersonic stability and control characteristics of the Rockwell International 139-B space shuttle orbiter

The purpose of this study was to determine the hypersonic aerodynamic performance, longitudinal trim, static stability, and the extent of the center-of-gravity boundaries within the design control limits as well as to examine the effect of Reynolds number on the longitudinal stability of the 139-B space shuttle orbiter. A 0.004 scale model (34-0)was tested in helium over an angle-of-attack range of 18 deg to 54 deg at 0 deg and -minus 5 deg sideslip angles. The total pressure was varied for selected configurations to obtain a Reynolds number range, based on model length, from 0.51 million to 3.6 million at Mach numbers between 17.6 and 21.6 Surface oil-flow studies and electron-beam illuminated-flow studies were also conducted at angles-of-attack of 30 deg, 40 deg, and 50 deg for selected Reynolds numbers.

Stone, D. R.↗
NASA NTRS1974

Radio astronomy Explorer-B postlaunch attitude operations analysis

The attitude support activities of the Radio Astronomy Explorer-B are reported. The performance of the spacecraft hardware and software are discussed along with details of the mission events, from launch through main boom deployment. Reproductions of displays are presented which were used during support activities. The interactive graphics proved the support function by providing the quality control necessary to ensure mission success in an environment where flight simulated ground testing of spacecraft hardware cannot be performed.

Werking, R. D.↗
NASA NTRS1974

Classification by means of B-spline potential functions with applications to remote sensing

A method is presented for using B-splines as potential functions in the estimation of likelihood functions (probability density functions conditioned on pattern classes), or the resulting discriminant functions. The consistency of this technique is discussed. Experimental results of using the likelihood functions in the classification of remotely sensed data are given.

Bennett, J. O.↗
NASA NTRS1973

The relative abundance of the isotopes of Li, Be and B and the age of cosmic rays

Using a balloon borne double dE/dx total energy telescope, we have determined the isotopic composition of cosmic ray Li, Be and B nuclei in the energy range 100-250 MeV/nuc. The measured mass resolution for these nuclei is about 0.3 AMU. The observed isotopic composition is in agreement with that predicted on the basis of interstellar fragmentation with the exception of a deficiency of Be-10. If the low abundance of Be-10 is attributed to the decay of this radioactive isotope, we obtain a mean cosmic ray lifetime of 3.4 (plus 3.4 or minus 1.3) m.y.

Webber, W. R.↗
NASA NTRS1974

A wind-tunnel investigation of a B-52 model flutter suppression system

Flutter modeling techniques have been successfully extended to the difficult case of the active suppression of flutter. The demonstration was conducted in a transonic dynamics tunnel using a 1/30 scale, elastic, dynamic model of a Boeing B-52 control configured vehicle. The results from the study show that with the flutter suppression system operating there is a substantial increase in the damping associated with the critical flutter mode. The results also show good correlation between the damping characteristics of the model and the aircraft.

Redd, L. T.↗
NASA NTRS1974

Workmanship vibration test of the SAS-B spacecraft

The occurrence of a technical problem made it necessary to remove the transmitter from the SAS-B spacecraft. The transmitter was repaired and reinstalled in the spacecraft. After this operation it was necessary to test the mechanical properties of the reassembled spacecraft in a vibration test to be conducted near the spacecraft launching place on the San Marco Range in the Indian Ocean. A vibration system was, therefore, sent to San Marco. The design of the vibration system is discussed, giving attention also to alternative solutions for conducting the required tests.

Demas, L. J.↗
NASA NTRS1975

Secular variations of L, B-coordinates

The calculation results of L, B-coordinates for different years from 1957 to 1967 are given. Periodic calculations of the geomagnetic coordinates for different epochs are considered to be very urgent.

Getselev, I. V.↗