Search NASA⌕ Search

SEARCH · Search NASA

Results for “ASTRONOMY”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
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 NTRS1971

A Saturn launched X-ray astronomy experiment. Volume 1: S-027

The S-027 X-Ray Astronomy Experiment originally proposed in early 1966, was developed to detect X-rays in the 2 keV to 10 keV range. Both a prototype unit and flight unit were constructed with the prototype unit also serving as the engineering model, the qualification test unit, and after refurbishment, as the back-up flight unit. Two Ground Support Equipment consoles were built to verify the experiment operation. A photograph of one experiment package with its Ground Support Equipment is shown. The S-027 experiment was scheduled for launch in 1968/69 and although both units were completed and tested to the extent that either would be ready for the scheduled launch, delays in the space program resulted in a launch date slip of several years. When the 1968/69 launch delay became official, provisions were made for storage of the two experiment packages at SCI Electronics in Huntsville, Alabama until a new launch date could be established.

Source record↗
NASA NTRS1974

Development and evaluation of television tubes for space astronomy

An improved vidicon image sensor for space astronomy applications is developed that features reliably sealed ultraviolet transmitting windows and achieves acceptable photocathode quantum efficiency on these MgF2 windows. New preamplifier designs improve the dynamic range by reduction of the readout noise.

Spitzer, L.↗
NASA NTRS1974

The standardized functional support sectional for the Small Astronomy Satellite (SAS)

The standardized functional support section for the improved Small Astronomy Satellite (SAS) spacecraft, which can be used virtually without change for a wide variety of experimental packages and missions, is described. This functional support section makes the spacecraft remarkably flexible for a small satellite. Able to point its thrust axis to any direction in space, it can also spin or slow its outer body rotation to zero for star- or earth-locked pointing of side-viewing experiments. It features a reprogrammable telemetry system, a delayed command system, and an improved control system. Experiments can be built independently and attached to the SAS spacecraft just prior to final acceptance testing and launch. The spacecraft subsystems are described in detail. Included are a summary of the spacecraft characteristics, special design considerations, project reliability requirements, and environmental test conditions. It is intended that this new functional support section afford virtual off-the-shelf availability of the SAS spacecraft to independently built experiments, thus providing quick response time and minimum cost in meeting a wide variety of experimenter needs.

Townsend, M. R.↗
NASA NTRS1974

Processings of the Workshop on Electron Contamination in X-Ray Astronomy Experiments

The proceedings of a conference to investigate the effects of extraterrestrial radiation and particle contamination of X-ray astronomical data are presented. The subjects discussed include the following: (1) electrons at low altitudes which affect soft X-ray astronomy, (2) the geographical distribution of 100 keV electrons above the earth's atmosphere, (3) midlatitude electron precipitation, (4) particle background observed by X-ray detectors on board Copernicus satellite, and (5) a survey of trapped low energy electrons near the inner boundary of the inner radiation zone as determined by OSO-7.

Holt, S. S.↗
NASA NTRS1974

Electrons at low altitudes: A difficult background problem for soft X-ray astronomy

Quasi-trapped and precipitating electrons have been observed with rocket-borne X-ray astronomy detectors in the altitude range 150 to 500 km. Because the flights occured at low magnetic latitudes the electrons were unexpected. Data from many flights are combined to derive altitude dependence, an average electron spectrum, and variation with solar activity. Development of electron-rejecting collimators is discussed, and laboratory and flight data on these collimators are presented.

Seward, F. D.↗
NASA NTRS1974

Post-flight differential correction analysis using Vinti's spheroidal method for the small astronomy satellite orbit

The results of an intensive analysis of a differential orbit improvement method utilizing observational data for a 550-kilometer altitude, near-circular, near-equatorial satellite orbit are presented. Observations of the Small Astronomy Satellite (SAS-1) are in the form of direction cosines as measured at two ground interferometer tracking stations near the Equator during the first 22 orbital revolutions (approximately 37 hours) after launch of the spacecraft. Numerical results, in both tabular and graphical form, are displayed for numerous iterated fittings of various observational arcs by differential correction of the orbital elements. Parameters varied in these comparative cases include the time duration of the observational data block, the number of pairs of direction cosine data and the number of tracking station passes included in the solution, the distribution of such passes between the two available tracking stations, and the acceptance criterion for the observational residuals in the least squares fitting procedure. It was found that three observational pairs of direction cosine data, the minimum number possible for a uniquely determined solution in theory, are sufficient to promote covergence to an accurate solution, if properly selected.

Walden, H.↗
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 NTRS1973

Multidisciplinary research in the space sciences. Scope B: Experimental X-ray astronomy

A research program to design and develop instruments suitable for rocket-borne X-ray astronomy experiments is discussed. Successful designs that were implemented are summarized. The designs include the following: (1) a large area modular X-ray focusing system, (2) incoherent scattering polarimeters, (3) Bragg crystal spectrometers and polarimeters, and (4) a focusing collector for long wavelength. The applications of these instruments to the observation of X-ray sources in rocket-borne experiments are analyzed.

Novick, R.↗
NASA NTRS1974

The liquid-xenon Compton telescope - A new technique for gamma-ray astronomy

We propose a new technique for gamma-ray astronomy in the difficult but important energy decade from 0.3 to 3.0 MeV. Cosmic gamma rays Compton scatter in a liquid-xenon wire proportional chamber recently developed at Lawrence Berkeley Laboratory (Derenzo, et al., 1972; Muller, et al., 1971) and then are totally absorbed in a second chamber. The energy and position of each interaction is recorded for each gamma ray. This information determines a circle on the celestial sphere which must intersect the source position. A localized source of gamma-rays would show itself as the intersection of many such circles. We expect to locate sources to a fraction of a square degree in a balloon-borne sky survey experiment using an instrument with a one steradian acceptance.

Dauber, P. M.↗
NASA NTRS1973

Spacecraft control section for the improved Small Astronomy Satellite /SAS-C/

The upgraded spacecraft control section for the Small Astronomy Satellite (SAS-C) incorporates a remarkable amount of flexibility for a small satellite. Able to point its thrust axis to any direction in space, it can also spin or slow its outer body rotation to zero for star-locked pointing of side viewing experiments. A programmable telemetry system and delayed command system enhance the inherent capability of a spacecraft designed to be used for a variety of experiments, each of which can be built independently and attached just prior to final acceptance testing and launch. The design of this new spacecraft, whose first launch is scheduled for 1975, is provided in sufficient detail to permit the reader to ascertain its suitability for specific experiments.

Townsend, J. R.↗
NASA NTRS1974

Infrared astronomy and the Shuttle

The infrared spectral range extends approximately from 1 micron to 1000 microns. Observations in infrared astronomy are made with the aid of ground-based telescopes and telescopes flown in aircraft, balloons, or rockets. Advantages and drawbacks of infrared studies conducted by different approaches are discussed. Infrared astronomers are looking forward to observations made from orbiting spacecraft. Present plans call for placing a large telescope aboard the Space Shuttle Orbiter for short missions lasting from seven days to three weeks several times a year. However, the occurrence of a pollution of the spacecraft environment by dust particles and gases coming from the spacecraft might present a problem for the observations. Possible approaches for solving this problem are discussed.

Harwit, M.↗
NASA NTRS1974

A balloon-borne 1 meter telescope for far-infrared astronomy

The flight of a balloon-borne one-meter telescope for infrared astronomy in the wavelength interval of 40 to 240 microns is discussed. The gyro-stabilized telescope mapped the intensity of the far infrared radiation from NGC 7538, Mars, the Orion Nebula, and W3 with a resolution of one minute and from selected regions of these sources with a resolution of 30 seconds. The infrared detection is described and its capabilities are analyzed. The instrumentation, orientation system, and modes of observation of the telescope are defined.

Fazio, G. G.↗
NASA NTRS1975

X-ray and gamma-ray astronomy

Accomplishments in the fields of X-ray and gamma ray astronomy are discussed. Data obtained from IMP and OGO satellites are analyzed to determine the sources of interplanetary radiation bursts. The energy spectrum of cosmic gamma ray bursts as observed by IMP-6 is described. The application of cooling blackbody techniques as a method for examining cosmic gamma ray bursts is reported. The experimental results and theoretical interpretation of high energy diffuse gamma rays are investigated. The structure of the SAS-2 satellite is depicted and the accomplishments are examined. Other sources of gamma radiation to include galactic fermi, Cygnus X-1, supernovae, and the planet Jupiter are proposed. Data obtained from the Pioneer 10 space probe are presented in graph form.

Source record↗
NASA NTRS1974

Thunderstorms observed by radio astronomy Explorer 1 over regions of low man made noise

Radio Astronomy Explorer (RAE) I observations of thunderstorms over regions of low man-made noise levels are analyzed to assess the satellite's capability for noise source differentiation. The investigation of storms over Australia indicates that RAE can resolve noise generation due to thunderstorms from the general noise background over areas of low man-made noise activity. Noise temperatures observed by RAE over stormy regions are on the average 10DB higher than noise temperatures over the same regions in the absence of thunderstorms. In order to determine the extent of noise contamination due to distant transmitters comprehensive three dimensional computer ray tracings were generated. The results indicate that generally, distant transmitters contribute negligibly to the total noise power, being 30DB or more below contributions arriving from an area immediately below the satellite.

Caruso, J. A.↗
NASA NTRS1974

MSFC Skylab ground-based astronomy program

The Skylab Ground-Based Astronomy Program (SGAP) was conducted to enhance the data base of solar physics obtained during the Apollo Telescope Mount (ATM) mission flown in conjunction with the Skylab orbital station. Leading solar physicists from various observatories obtained data from the ground at the same time that orbital data were being acquired by ATM. The acquisition of corollary solar data from the ground simultaneously with the ATM orbital observations helped to provide a broader basis for understanding solar physics by increasing spectral coverage and by the use of additional sophisticated instruments of various types. This report briefly describes the individual tasks and the associated instrumentation selected for this ground-based program and contains as appendices, the final reports from the Principal Investigators.

Duncan, B. J.↗
NASA NTRS1975

A timeline algorithm for astronomy missions

An algorithm is presented for generating viewing timelines for orbital astronomy missions of the pointing (nonsurvey/scan) type. The algorithm establishes a target sequence from a list of candidate targets in a way which maximizes total viewing time. Two special cases are treated. One concerns dim targets which, due to lighting constraints, are scheduled only during the antipolar portion of each orbit. They normally require long observation times extending over several revolutions. A minimum slew heuristic is employed to select the sequence of dim targets. The other case deals with bright, or short duration, targets, which have less restrictive lighting constraints and are scheduled during the portion of each orbit when dim targets cannot be viewed. Since this process moves much more rapidly than the dim path, an enumeration algorithm is used to select the sequence that maximizes total viewing time.

Moore, J. E.↗