Technology and Advanced Development for a Non-Toxic Orbital Maneuvering System and Reaction Control System for Orbiter Upgrade

NASA intends to pursue technology applications to upgrade the Space Shuttle Orbiter OMS and RCS systems with non-toxic propellants. The primary objectives of an upgraded OMS/RCS are improved safety and reliability, reduced operations and maintenance costs while meeting basic OMS/RCS operational and performance requirements. The OMS/RCS has a high degree of direct interaction with the crew and requires subsystem and components that are compatible with integration into the orbiter vehicle with regard to external mold-line, power and thermal control The non-toxic propulsion technology is also applicable to future Human Exploration and Development of Space (HEDS) missions. The HEDS missions have similar requirements for attitude control and lander descent/ascent propulsion and which will emphasize the use of In-Situ Resource for propellants. When used as a regenerative coolant as in the Shuttle Orbiter OMS combustion chamber, non-toxic fuels such as ethanol are limited in their cooling capacity by the bulk temperature rise permitted to prevent film boiling or possible coking. Typical regeneratively cooled chambers are constructed from highly conductive copper, which maximizes heat transfer, or from low conductivity materials like stainless steel that can also exacerbate cooling problems. For an ethanol cooled application the heat transfer into the fluid must be controlled to reduce the fuel coolant bulk temperature rise. An approach to provide this control is the subject of this report. This report is being issued to document work done by Aerojet on NASA contract NAS 8-98042. Specifically, this project investigates of the use of ethanol, a designated non-toxic fuel, as a coolant for the Space Shuttle Orbital Maneuvering System Engine combustion chamber. The project also addresses a cost reducing fabrication technique for construction of such a combustion chamber. The study contained three major sub-tasks: an analytical investigation and trade study which included layout of a flight type chamber concept, the fabrication and evaluation of formed platelet liner panels and the preparation and testing of mechanical properties specimens representative of a novel hot gas wall concept

Meaurement of Cosmic Ray elemental composition from the CAKE balloon experiment

CAKE (Cosmic Abundances below Knee Energies) was a prototype balloon experiment for the determination of the charge spectra and of abundances of the primary cosmic-rays (CR) with Z$>$10. It was a passive instrument made of layers of CR39 and Lexan nuclear track detectors; it had a geometric acceptance of $\sim$0.7 m$^2$sr for Fe nuclei. Here, the scanning and analysis strategies, the algorithms used for the off-line filtering and for the tracking in automated mode of the primary cosmic rays are presented, together with the resulting CR charge distribution and their abundances.Comment: 5 pages, 8 figure

Qualitative evaluation of a preventive intervention for the offspring of parents with a history of depression

Background: Meta-analyses of randomised controlled trials suggest that psychological interventions to reduce children’s risk of depression are effective. Nevertheless, these effects are modest and diminish over time. The Medical Research Council recommends a mixed-methods approach to the evaluation of complex interventions. By gaining a more thorough understanding of participants’ perspectives, qualitative evaluations of preventive interventions could improve their efficacy, longevity and transfer into clinical practice. Methods: 18 parents and 22 children who had received a 12-session family- and group-based cognitivebehavioural intervention to prevent youth depression as part of a randomised controlled trial took part in semistructured interviews or a focus group about aspects which had been perceived as helpful, elements they were still using after the intervention had ended, and suggestions they had for improving the intervention. Results: The chance to openly share and discuss their experiences of depression within and between families was considered helpful by both children and parents. Children benefitted the most from learning coping strategies for dealing with stress and many still used them in everyday life. Parents profited mostly from increasing positive family time, but noted that maintaining new routines after the end of the intervention proved difficult. Participants were generally content with the intervention but commented on how tiring and time consuming it was. Conclusions: Managing parents’ expectations of family-based interventions in terms of their own mental health needs (versus those of their children) and leaving more room for open discussions may result in interventions which are more appealing to participating families. Increasing intervals between sessions may be one means of improving the longevity of interventions. Trial registration: The original RCT this evaluation is a part of was registered under NCT02115880

Galactic Cosmic Rays from Supernova Remnants: II Shock Acceleration of Gas and Dust

This is the second paper (the first was astro-ph/9704267) of a series analysing the Galactic Cosmic Ray (GCR) composition and origin. In this we present a quantitative model of GCR origin and acceleration based on the acceleration of a mixture of interstellar and/or circumstellar gas and dust by supernova remnant blast waves. We present results from a nonlinear shock model which includes (i) the direct acceleration of interstellar gas-phase ions, (ii) a simplified model for the direct acceleration of weakly charged dust grains to energies of order 100keV/amu simultaneously with the gas ions, (iii) frictional energy losses of the grains colliding with the gas, (iv) sputtering of ions of refractory elements from the accelerated grains and (v) the further shock acceleration of the sputtered ions to cosmic ray energies. The calculated GCR composition and spectra are in good agreement with observations.Comment: to appear in ApJ, 51 pages, LaTeX with AAS macros, 9 postscript figures, also available from ftp://wonka.physics.ncsu.edu/pub/elliso

Energy dependence of Ti/Fe ratio in the Galactic cosmic rays measured by the ATIC-2 experiment

Titanium is a rare, secondary nucleus among Galactic cosmic rays. Using the Silicon matrix in the ATIC experiment, Titanium has been separated. The energy dependence of the Ti to Fe flux ratio in the energy region from 5 GeV per nucleon to about 500 GeV per nucleon is presented.Comment: 8 pages, 4 figures, accepted for publication in Astronomy Letter

Cosmic ray neon, Wolf-Rayet stars, and the superbubble origin of galactic cosmic rays

The abundances of neon isotopes in the galactic cosmic rays (GCRs) are reported using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). We compare our ACE-CRIS data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (WR) models. The three largest deviations of GCR isotope ratios from solar-system ratios predicted by these models are indeed present in the GCRs. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with WR models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.Comment: 22 pages, 6 figures Accepted for publication by Ap