NASA Scientific and Technical Aerospace Reports

to Measure the Mass of Stars; Flexibly Fueled Storage Tank Brings Hydrogen-Powered Cars Closers to Reality; The
Laboratory in the News; Patents and Awards and Abstracts.
NTIS
Research and Development; Supercomputers; Chromosomes
20040068308 National Centers for Environmental Prediction, Silver Spring, MD
Intense Space Weather Storms, October 19-November 07, 2003: Service Assessment
Mar. 2004; In English
Report No.(s): PB2004-105255; No Copyright; Avail: National Technical Information Service (NTIS)
The October-November 2003 solar storms rank as one of the largest outbreaks of solar activity in recent history. The
global effects were wide-ranging, impacting power grids, airline flights, spacecraft operations, and much more. Media interest
and public awareness of this activity was at the highest levels ever. Due to the magnitude of this space weather event, a service
assessment team was formed to examine the space environment warning and forecast services provided by the NOAA Space
Environment Center. Service assessments provide a valuable contribution to our ongoing efforts to improve the quality and
timelessness of our products and services for the protection of life and property. Findings and recommendations from this
assessment will help to improve techniques, products, services, and the information provided to the American public and
citizens around the world.
NTIS
Aerospace Environments; Meteorological Services; Space Weather
20040068393 NASA Ames Research Center, Moffett Field, CA, USA
Disk Dispersal Around Young Stars
Hollenbach, David; [2004]; 1 pp.; In English; Modeling the Structure, Chemistry and Appearance of Protopnaetary Disks,
13-17 Apr. 2004, Bavaria, Germany
Contract(s)/Grant(s): 21-344-53-00; No Copyright; Avail: Other Sources; Abstract Only
We first review the evidence pertaining to the lifetimes of planet-forming disks of gas and dust around young stars and
discuss possible disk dispersal mechanisms: 1) viscous accretion of material onto the central source, 2) close stellar
encounters, 3) stellar winds, and 4) photoevaporation caused by the heating of the disk surface by ultraviolet radiation.
Photoevaporation is likely the most important dispersal mechanism for the outer regions of disks, and this talk focuses on the
evaporation caused by the presence of a nearby, luminous star rather than the central star itself. We also focus on disks around
low-mass stars like the Sun rather than high-mass stars, which we have treated previously. Stars often form in clusters and
the ultraviolet flux from the most luminous star in the cluster can have a dramatic effect on the disk orbiting a nearby low-mass
star. We apply our theoretical models to the evaporating protoplanetary disks (or "proplyds") in the Trapezium
cluster in Orion, to the formation of gas giant planets like Jupiter around Sun-like stars in the Galaxy, and to the formation
of Kuiper belts around low mass stars. We find a possible explanation for the differences between Neptune and Jupiter, and
make a prediction concerning recent searches for giant planets in large clusters. We discuss recent models of the infrared
spectra from gaseous disks around young stars.
Author
Planetary Evolution; Protoplanetary Disks; Gas Giant Planets; Dispersing; Dust; Radiant Heating
20040068394 NASA Ames Research Center, Moffett Field, CA, USA
A Technical Overview and Description of SOFIA (Stratospheric Observatory for Infrared Astronomy)
Kunz, Nans; November 23, 2003; 2 pp.; In English; No Copyright; Avail: Other Sources; Abstract Only
This paper provides a technical overview of SOFIA, a unique airborne observatory, from an engineering perspective. It
will do this by describing several of the systems of this observatory that are common with mountain top ground based
observatories but mostly emphasize those more unique features and systems that are required to facilitate world class
astronomy from a highly modified Boeing 747-SP flying at Mach 0.84 in the Stratosphere. This paper provides a technical
overview of SOFIA by reviewing each of the performance specifications (the level one requirements for development) and
describing some of the technical advancements for the telescope as well as the platform required to achieve these performance
specifications. The technical advancements involved include mirror technologies, control system features, the telescope
suspension system, and the aircraft open port cavity with associated cavity door that opens in flight and tracks the telescope
elevation angle. For background this paper will provide a brief programmatic overview of the SOFIA project including the
joint project arrangement between the US and Germany (NASA and DLR). Additionally, this paper will describe the up to date
292