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TECHNOLOGY UTILIZATION AND SURFACE TRANSPORTATION
Includes aerospace technology transfer; urban technology; surface and mass transportation. For related information see also 03 Air
Transportation and Safety, 16 Space Transportation and Safety, and 44 Energy Production and Conversion. For specific technology
transfer applications see also the category where the subject is treated.
20030025367 NASA Goddard Space Flight Center, Greenbelt, MD, USA
The Nature of the UV/X-ray Absorber In PG 2302+029
Sabra, Bassem M.; Hamann, Fred; Jannuzi, Buell T.; George, Ian M.; Shields, Joseph C.; [2003]; 12 pp.; In English; Original
document is cut off on top of several pages.
Contract(s)/Grant(s): NAS5-26555; GO-07348.01-A; GO-0-1123X; GO-0-1157X; Copyright; Avail: CASI; A03, Hardcopy
We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029. This quasar has a rare system of ultra-high
velocity (-56,000 km s(exp -1) UV absorption lines that form in an outflow from the active nucleus. The Chandra data indicate
that soft X-ray absorption is also present. We perform a joint UV and X-ray analysis, using photoionization calculations, to
determine the nature of the absorbing gas. The UV and X-ray datasets were not obtained simultaneously. Nonetheless, our
analysis suggests that the X-ray absorption occurs at high velocities in the same general region as the UV absorber. There are
not enough constraints to rule out multi-zone models. In fact, the distinct broad and narrow UV line profiles clearly indicate
that multiple zones are present. Our preferred estimates of the ionization and total column density in the X-ray absorber (logU
= 1.6, N(sub eta) = 10(exp 22.4) cm (exp -2) over predict the O VI lambda lambda1032,1038 absorption unless the X-ray
absorber is also outflowing at approximately 56,000 km s(exp-l), but they over predict the Ne VIII lambda lambda 770,780
absorption at all velocities. If we assume that the X-ray absorbing gas is outflowing at the same velocity of the UV-absorbing
wind and that the wind is radiatively accelerated, then the outflow must be launched at a radius of less than or equal to 10(exp
15) cm from the central continuum source. The smallness of this radius casts doubts on the assumption of radiative
acceleration.
Author
X Ray Absorption; Ultraviolet Absorption; Quasars; Absorption Spectra; Active Galaxies; X Ray Analysis; Stellar Structure
88
SPACE SCIENCES (GENERAL)
Includes general research topics related to the natural space sciences. For specific topics in space sciences see categories 89 through
93.
20030021664 NASA Ames Research Center, Moffett Field, CA, USA Research Inst. for Advanced Computer Science,
Moffett Field, CA, USA
Modeling and Simulation for Mission Operations Work System Design
Sierhuis, Maarten; Clancey, William J.; Seah, Chin; Trimble, Jay P.; Sims, Michael H.; January 2003; 78 pp.; In English
Contract(s)/Grant(s): NCC2-1006; No Copyright; Avail: CASI; A05, Hardcopy
Work System analysis and design is complex and non-deterministic. In this paper we describe Brahms, a multiagent
modeling and simulation environment for designing complex interactions in human-machine systems. Brahms was originally
conceived as a business process design tool that simulates work practices, including social systems of work. We describe our
modeling and simulation method for mission operations work systems design, based on a research case study in which we used
Brahms to design mission operations for a proposed discovery mission to the Moon. We then describe the results of an actual
method application project-the Brahms Mars Exploration Rover. Space mission operations are similar to operations of
traditional organizations; we show that the application of Brahms for space mission operations design is relevant and
transferable to other types of business processes in organizations.
Author
Systems Engineering; Mathematical Models; Space Missions; Environment Simulation; Man Machine Systems
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