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  • 1
    Publication Date: 2018-06-11
    Description: We wish to point out that a secular change in the Earth's atmospheric neutral density alters charged-particle lifetime in the inner trapped radiation belts, in addition to the changes recently reported as produced by greenhouse gases. Heretofore, changes in neutral density have been of interest primarily because of their effect on the orbital drag of satellites. We extend this to include the orbital lifetime of charged particles in the lower radiation belts. It is known that the charged-belt population is coupled to the neutral density of the atmosphere through changes induced by solar activity, an effect produced by multiple scattering off neutral and ionized atoms along with ionization loss in the thermosphere where charged and neutral populations interact. It will be shown here that trapped-belt flux J is bivariant in energy E and thermospheric neutral density , as J(E,rho). One can conclude that proton lifetimes in these belts are also directly affected by secular changes in the neutral species populating the Earth s thermosphere. This result is a consequence of an intrinsic property of charged-particle flux, that flux is not merely a function of E but is dependent upon density rho when a background of neutrals is present.
    Keywords: Space Sciences (General)
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  • 2
    Publication Date: 2018-06-06
    Description: An analysis of the effects of low energy proton irradiation on the electrical performance of triple junction (3J) InGaP2/GaAs/Ge solar cells is presented. The Monte Carlo ion transport code (SRIM) is used to simulate the damage profile induced in a 3J solar cell under the conditions of typical ground testing and that of the space environment. The results are used to present a quantitative analysis of the defect, and hence damage, distribution induced in the cell active region by the different radiation conditions. The modelling results show that, in the space environment, the solar cell will experience a uniform damage distribution through the active region of the cell. Through an application of the displacement damage dose analysis methodology, the implications of this result on mission performance predictions are investigated.
    Keywords: Space Sciences (General)
    Type: Proceedings of the 19th Space Photovoltaic Research and Technology Conference; 8-17; NASA/CP-2007-214494
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  • 3
    Publication Date: 2019-07-18
    Description: Brown dwarfs and low-mass stars show evidence of complicated atmospheres, including a variety of molecular species and clouds. Infrared observations are one of the best probes of the physics of these objects, but up until recently these observations have been limited in studies from ground-based telescopes by atmospheric absorption and insufficient sensitivity. With the launch of the Spitzer Space Telescope with its Infrared Spectrograph (IRS) instrument we now have the capability to undertake a systematic study of the atmospheric structure and chemistry in these cool objects. The IRS Dim Suns team has compiled spectra from objects ranging from M1 dwarfs with effective temperatures 3,800K of down to T8 dwarfs with effective temperatures of 700. This talk will present these results and discuss their implications for our understanding of cool dwarf atmospheric physics and structure.
    Keywords: Space Sciences (General)
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  • 4
    Publication Date: 2019-07-19
    Description: The Stratospheric Observatory for Infrared Astronomy (SOFIA) is nearing its first light obsetvations while in flight. This talk will present the current development status of the aircraft and its telescope, together with the plans for conducting its first science flights beginning in late spring, 2009. This presentation will also address the ongoing activities for SOFIA science outreach and will outline the different opportunities for participation in the Early Science program.
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN-195 , 40th Annual Meeting of the Division for Planetary Sciences of the American Astronomical Society; Oct 10, 2008 - Oct 15, 2008; Ithaca, NY; United States
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  • 5
    Publication Date: 2019-07-12
    Description: These lessons learned are part of a suite of hardware, software, test results, designs, knowledge base, and documentation that comprises the legacy of the Constellation Program. The context, summary information, and lessons learned are presented in a factual format, as known and described at the time. While our opinions might be discernable in the context, we have avoided all but factually sustainable statements. Statements should not be viewed as being either positive or negative; their value lies in what we did and what we learned that is worthy of passing on. The lessons include both "dos" and "don ts." In many cases, one person s "do" can be viewed as another person s "don t"; therefore, we have attempted to capture both perspectives when applicable and useful. While Volume I summarizes the views of those who managed the program, this Volume II encompasses the views at the working level, describing how the program challenges manifested in day-to-day activities. Here we see themes that were perhaps hinted at, but not completely addressed, in Volume I: unintended consequences of policies that worked well at higher levels but lacked proper implementation at the working level; long-term effects of the "generation gap" in human space flight development, the need to demonstrate early successes at the expense of thorough planning, and the consequences of problems and challenges not yet addressed because other problems and challenges were more immediate or manifest. Not all lessons learned have the benefit of being operationally vetted, since the program was cancelled shortly after Preliminary Design Review. We avoid making statements about operational consequences (with the exception of testing and test flights that did occur), but we do attempt to provide insight into how operational thinking influenced design and testing. The lessons have been formatted with a description, along with supporting information, a succinct statement of the lesson learned, and recommendations for future programs and projects that may be placed in similar circumstances.
    Keywords: Space Sciences (General)
    Type: NASA/SP-2011-6127-VOL-2 , JSC-CN-24727
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  • 6
    Publication Date: 2019-07-13
    Description: This paper describes the guiding vision, progress to date and the plan forward for development of the Marshall Space Flight Center (MSFC) Systems Engineering Guide (SEG), a virtual systems engineering handbook and archive that describes the system engineering processes used by MSFC in the development of ongoing complex space systems such as the Ares launch vehicle and forthcoming ones as well. It is the intent of this website to be a "One Stop Shop' for MSFC systems engineers that will provide tutorial information, an overview of processes and procedures and links to assist system engineering with guidance and references, and provide an archive of relevant systems engineering artifacts produced by the many NASA projects developed and managed by MSFC over the years.
    Keywords: Space Sciences (General)
    Type: IAC-07-D1.5.01 , International Astronautical Federation; Sep 24, 2007 - Sep 28, 2007; Hyderabad; India
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  • 7
    Publication Date: 2019-07-19
    Description: The Stratospheric Observatory for Infrared Astronomy comprises a 2.7m diameter telescope mounted in a heavily modified B747SP aircraft. The SOFIA program is a joint US NASA and German DLR program, with the development and operations costs split roughly 80%:20%, respectively. Although the observatory is funded by these two nations, its observing time is open to proposals from astronomers of any nationality. The observatory has been flying and taking scientific data since 2010 and currently observes astronomical targets from the stratosphere for approximately 800 research flight hours per year. Seven science instruments (with an eighth coming online in 2020) cover the visible to sub-millimeter wavelengths with a variety of spectral resolutions ranging up to 1e8. The AKARI Archive with its 1.7 to 180 micron wavelength coverage is a natural complementary source for follow-up observations with SOFIA. This presentation will cover the current SOFIA technical capabilities and will present a few recent science highlights that demonstrate the SOFIA/AKARI complementarity. The presentation will also cover the SOFIA proposal process and will summarize other partnership opportunities for additional observing time on SOFIA.
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN43899 , The AKARI International Conference; Oct 17, 2017 - Oct 20, 2017; Tokyo; Japan
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