Detection of celestial sources at far-infrared wavelengths
Celestial sources far IR radiation detection using balloon-borne telescope
Friedlander, M. W.↗
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Sensitivity analyses for several celestial and satellite navigation schemes
Celestial and satellite navigation sensitivity for Lunar roving vehicle /LRV/ position fix
Chen, C.↗
Linear and regular celestial mechanics- Perturbed two-body motion, numerical methods, canonical theory
Book on linear and ordinary celestial mechanics covering perturbed two body motion, numerical methods, canonical theory and initial value problems
Scheifele, G.↗
Automated algebraic manipulation in celestial mechanics
Automated algebraic manipulation in celestial mechanics, discussing use of Poisson series in perturbation theory problem
Jefferys, W. H.↗
Experiments D004 and D007: Celestial radiometry and space object radiometry
Two interferometer spectrometers and a multichannel spectroradiometer were used as sensing instruments during the Gemini 5 and 7 missions. The selection of the instruments and of the particular detectors in the instruments was based upon the spectral bands to be investigated in each flight and upon the nature of the intended measurements. The instrument characteristics were a compromise among optimization for a particular type of measurement, a need for a broad selection of spectral information, and performance and other pertinent characteristics of the spacecraft. Data were collected on earth background, sky background, rocket exhaust plumes, celestial bodies, man made objects in space, weather phenomena, and spectral calibrations.
Lovett, J.↗
Feasibility study of scanning celestial Attitude System (SCADS) for Earth Resources Technology Satellite (ERTS)
The feasibility of using the Scanning Celestial Attitude Determination System (SCADS) during Earth Resources Technology Satellite (ERTS) missions to compute an accurate spacecraft attitude by use of stellar measurements is considered. The spacecraft is local-vertical-stabilized. A heuristic discussion of the SCADS concept is first given. Two concepts are introduced: a passive system which contains no moving parts, and an active system in which the reticle is caused to rotate about the sensor's axis. A quite complete development of the equations of attitude motions is then given. These equations are used to generate the true attitude which in turn is used to compute the transit times of detectable stars and to determine the errors associated with the SCADS attitude. A more complete discussion of the analytical foundation of SCADS concept and its use for the geometries particular to this study, as well as salient design parameters for the passive and active systems are included.
Source record↗
Experiment to measure hard solar and celestial X-rays from the fifth Orbiting Solar Observatory.
In this paper we describe an experiment designed to measure solar and celestial X-rays in the energy range between 15 to 250 keV. The experiment was flown on the fifth Orbiting Solar Observatory which was launched on Jan. 22, 1969. Up to the time of this writing the instrument continues to operate satisfactorily.
Frost, K. J.↗
Surface photometry of celestial sources from a space vehicle - Introduction and observational procedures.
Consideration of the possibility of studying diffuse celestial sources of relatively low surface brightness such as the Milky Way, zodiacal light, and gegenschein from above the earth's atmosphere with equipment flown in artificial satellites. The techniques used for this purpose are reviewed, and some of the difficulties encountered in daytime observations from satellites by the use of a special photometer and polarimeter flown in the orbiting skylab observatory, OSO-6, are cited.
Roach, F. E.↗
Encounter trajectory design for SEP rendezvous with low mass celestial bodies.
This paper shows the considerations which precede and affect encounter trajectory design and the impact of this design on propulsion system performance requirements and interplanetary trajectory design. Representative missions selected to illustrate the problems and characteristics of encounter trajectory design are a Mercury Orbiter, Eros Rendezvous, Encke Rendezvous, and Ceres Orbiter. The paper shows that for SEP missions, particularly for low mass celestial bodies, the encounter trajectory may be freely specified to a large extent to satisfy mission goals rather than being dictated by a rigid interplanetary trajectory design.
Driver, J. M.↗
Design of a celestial Thomson-scattering X-ray polarimeter.
A general discussion of the scientific importance and status of stellar X-ray polarimetry is presented. A stellar X-ray polarimeter designed to fit into the bottom half of the NASA OSO-1 wheel compartment or other similar spacecraft is described. In this design, the linear polarization is obtained as a function of energy. The sensitivity of the polarimeter in the 4-24 keV energy range was optimized with the aid of a Monte Carlo simulation computer program and is given for several important celestial X-ray sources. Estimates of sensitivity thresholds for a much larger polarimeter, suitable for flight in the NASA High-Energy Astronomy Observatory (HEAO), are also given. The minimum detectable polarization for several X-ray sources is given.
Landecker, P. B.↗
Refraction effects of atmosphere on geodetic measurements to celestial bodies
The problem is considered of obtaining accurate values of refraction corrections for geodetic measurements of celestial bodies. The basic principles of optics governing the phenomenon of refraction are defined, and differential equations are derived for the refraction corrections. The corrections fall into two main categories: (1) refraction effects due to change in the direction of propagation, and (2) refraction effects mainly due to change in the velocity of propagation. The various assumptions made by earlier investigators are reviewed along with the basic principles of improved models designed by investigators of the twentieth century. The accuracy problem for various quantities is discussed, and the conclusions and recommendations are summarized.
Joshi, C. S.↗
Device for determining relative angular position between a spacecraft and a radiation emitting celestial body
Signals indicative of the relative angular position between a spin stabilized spacecraft, probe, or sounding rocket and a radiation emitting celestial body are derived with a detector including four electrodes for deriving indications of the centroid of the radiation image on the detector. During each spin of the satellite each electrode derives a signal having a first non-zero level while the detector is not illuminated by the radiation, and a sound non-zero level while it is illuminated by the radiation.
Farthing, W. H.↗
Celestial diffuse gamma radiation above 30 MeV observed by SAS-2
The Small Astronomy Satellite (SAS)-2, launched on November 15, 1972, carried into orbit a 32-deck magnetic-core digitized spark chamber gamma ray telescope to study celestial gamma radiation in the energy range above 30 MeV. In the study of several regions with b sub 2 15 deg, a finite, diffuse flux of gamma rays with a steep energy spectrum in the energy region from 35 to 200 MeV is observed. Representing the energy spectrum by a power law of the form dJ/dE = AE to - alpha power over this energy range, alpha is found along with the integral flux above 100 MeV. Combining this result with existing low energy gamma ray data yields an energy spectrum which is not a simple power law in energy, as in the X-ray region, but which demonstrates first an increase and then a decrease in slope, consistent within uncertainties with that predicted by cosmological theories, including the continuous production of high energy gamma rays primarily from neutral pi mesons throughout the history of the universe.
Fichtel, C. E.↗
X-ray pulse profile and celestial position of Hercules X-1.
The celestial position of the binary X-ray source Her X-1 has been measured with a precision of 30 sec and, within the uncertainties, agrees with the position of the optical variable HZ Herculis. An average light curve for the 1.24-sec periodicity has been obtained with about 10-msec resolution. The average pulse is a double-peaked structure which shows significant intensity changes in time scales down to 30 msec.
Doxsey, R.↗
Mariner 9 celestial mechanics experiment - A status report.
There are two basic efforts in the Mariner 9 celestial mechanics experiment: the determination of the gravity field of Mars and the performance of a very precise test of the theory of general relativity. In addition, there are a number of astrodynamic constants that are being determined. All the analyses are based on the Mariner 9 radio tracking data.
Lorell, J.↗
Observation of celestial high energy gamma rays from SAS-II
The Small Astronomy Satellite (SAS)-II, launched on Nov. 15, 1973, carried into orbit a 32-deck magnetic-core digitized-spark-chamber gamma-ray telescope to study celestial gamma radiation in the energy range above 30 MeV. As of May 21, 1973, SAS-II had viewed approximately half the sky, including the galactic center region, the galactic anti-center, and several regions off the galactic plane, and about one-third of the data from eight weeks of viewing has been analyzed. A finite diffuse flux for regions with galactic latitudes greater than 20 deg has been detected with a very steep energy spectrum. Combining this result with low-energy gamma-ray data yields a picture suggesting a cosmological origin for this radiation.
Fichtel, C. E.↗
SAS-2 observations of celestial diffuse gamma radiation above 30 MeV
The small astronomy satellite, SAS-2, used a 32-deck magnetic core digitized spark chamber to study gamma rays with energies above 30 MeV. Data for four regions of the sky away from the galactic plane were analyzed. These regions show a finite, diffuse flux of gamma rays with a steep energy spectrum, and the flux is uniform over all the regions. Represented by a power law, the differential energy spectrum shows an index of 2.5 + or - 0.4. The steep SAS-2 spectrum and the lower energy data are reasonably consistent with a neutral pion gamma-ray spectrum which was red-shifted (such as that proposed by some cosmological theories). It is concluded that the diffuse celestial gamma ray spectrum observed presents the possibility of cosmological studies and possible evidence for a residual cosmic ray density, and supports the galactic superclusters of matter and antimatter remaining from baryon-symmetric big bang.
Thompson, D. J.↗
Application of MACSYMA to first order perturbation theory in celestial mechanics
The application of MACSYMA to general first order perturbation theory in celestial mechanics is explored. Methods of derivation of small variations in the Keplerian orbital elements are developed. As an example of the methods, the small general relativistic perturbations on the two-body Newtonian motion, resulting from the rotation of the central body, are developed in detail.
Anderson, J. D.↗