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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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Progress in the development and operations of the Deep Space Network is reported. Developments in Earth-based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are included.
Using the Very Large Array with a spatial resolution of 3 arcsec, two-dimensional, 10-second synthesis maps are produced of four 6-cm lambda bursts associated with multiply spiked hard X-ray bursts (20-300 keV). The positional, structural, and polarization characteristics are investigated. It is noted that three of the four burst sources are rather compact (less than approximately 10 arcsec). It is found that the positions of the individual peaks or spikes within a single burst are the same within plus or minus 2 arcsec. Interpreting these different peaks as separate electron acceleration events, the results suggest repeated acceleration of electrons within the same magnetic trap. The trap situation is found to be consistent with the bipolar nature of the burst sources except in one case.
An investigation was made to assess the effect of wing-mounted nacelles on a supercritical wing configuration at near-sonic Mach numbers. The investigation was made by utilizing the Cornell Aeronautical Laboratory 8-foot transonic tunnel and covered a Mach number range from 0.90 to 0.99. Force data and pressure measurements at selected locations were obtained. The investigation with the nacelles on included the effect of spanwise location of the nacelle (semispan locations of 35 and 70 percent) and the effect of area ruling for the nacelles located at the 35 percent semispan station. Tests were also made with the outboard nacelle extended forward so that it was directly adjacent to the inboard nacelle location. These tests provided a direct assessment of the extent of the nacelle interference flow field in a lateral direction.
Activities in space communication, radio navigation, radio science, and ground-based astronomy are reported. Advanced systems for the Deep Space Network and its Ground-Communications Facility are discussed including station control and system technology. Network sustaining as well as data and information systems are covered. Studies of geodynamics, investigations of the microwave spectrum, and the search for extraterrestrial intelligence are reported.
This quarterly publication provides archival reports on developments in programs managed by JPL's Office Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, in supporting research and technology, in implementation, and in operations. Also included is standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The preceding work is all performed for NASA's Office of Space Operations (OSO). The TDA Office also performs work funded by two other NASA program offices through and with the cooperation of the OSO. These are the Orbital Debris Radar Program and 21st Century Communication Studies.
Abstracts are provided for 174 patents and patent applications entered into the NASA scientific and technical information system during the period July 1992 through December 1992. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application.
A subject index is provided for over 4900 patents and patent applications for the period May 1969 through December 1992. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers.
We report on the evolution in the X-ray spectrum of the transient X-ray pulsar EXO 2030 + 375 during part of an outburst in 1985 May-August. The overall continuum spectral shape is similar to that of other accreting pulsars and can be represented by a power-law spectrum modified at low energies by significant absorption and at high energies either by an exponential cutoff or by the effects of cyclotron scattering. As the luminosity decreased by a factor of about 100, the X-ray spectrum became harder with the photon index decreasing from 1.83 +/- 0.01 to 1.29 +/- 0.01. In addition, the high-energy cutoff energy decreased from 20 to 10 keV during the same interval. If the cutoff is interpreted in terms of cyclotron resonance scattering, then this variation implies a magnetic field strength that decreased from 2.6 x 10 exp 12 to 1.3 x 10 exp 12. This variation implies that the cutoff energy does not provide a reliable measure of the surface magnetic field strength in this system.
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