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  • NASA Technical Reports  (39)
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  • 2012  (39)
  • 1
    Publikationsdatum: 2018-06-11
    Beschreibung: Heritage is important for both cost and risk related issues and as such, it is heavily discussed in NASA proposal evaluations. If used and communicated efficiently, heritage can lower both the perception of risk and the associated costs. Definitions of heritage vary between engineering, cost, and scientific communities, but when applied appropriately, heritage provides a benefit to the proposed mission. By making an instrument at least once before, the cost of producing it again can be reduced. The time and effort needed to develop the instrument concept and test the product represent an expense that can be lowered through the use of a previously built and developed instrument. This same thought can be applied when using a flight spare or build-to-print model of the heritage instrument. The lowered perception of risk is a result of the confidence gained in the instrument through successful use in the target environment. This is extremely important in early mission development to the evaluation board. This analysis will use JPL-managed proposals from 2003 to 2011, including Discovery, New Frontiers, and Mars Scout missions. Through the examination of these proposals and their associated debriefs, a set of guidelines have been created for successful use and communication of instrument heritage in early mission development
    Schlagwort(e): Administration and Management; Instrumentation and Photography
    Format: text
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  • 2
    Publikationsdatum: 2019-07-27
    Beschreibung: This paper will give an overview of the unique mechanical and optical design of the DVA-1 telescope. The rim supported carbon fibre reflector surfaces are designed to be both low cost and have high performance under wind, gravity, and thermal loads. The shaped offset Gregorian optics offer low and stable side lobes along with a large area at the secondary focus for multiple feeds with no aperture blockage. Telescope performance under ideal conditions as well as performance under gravity, wind, and thermal loads will be compared directly using calculated radiation patterns for each of these operating conditions.
    Schlagwort(e): Optics
    Materialart: International Conference on Electromagnetics in Advanced Applications; 2-7 Sept. 2012; Cape Town; South Africa
    Format: text
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  • 3
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    In:  CASI
    Publikationsdatum: 2019-07-19
    Beschreibung: It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -〉 IR-excess quasar -〉 optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.
    Schlagwort(e): Astrophysics
    Materialart: GSFC.ABS.6691.2012
    Format: application/pdf
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  • 4
    Publikationsdatum: 2019-07-19
    Beschreibung: Thoroughly studied classic space-based gravitational-wave missions concepts such as the Laser Interferometer Space Antenna (LISA) are based on laser-interferometry techniques. Ongoing developments in atom-interferometry techniques have spurred recently proposed alternative mission concepts. These different approaches can be understood on a common footing. We present an comparative analysis of how each type of instrument responds to some of the noise sources which may limiting gravitational-wave mission concepts. Sensitivity to laser frequency instability is essentially the same for either approach. Spacecraft acceleration reference stability sensitivities are different, allowing smaller spacecraft separations in the atom interferometry approach, but acceleration noise requirements are nonetheless similar. Each approach has distinct additional measurement noise issues.
    Schlagwort(e): Instrumentation and Photography
    Materialart: GSFC.ABS.00201.2012 , LISA Symposium; May 21, 2012 - May 25, 2012; Paris; France
    Format: application/pdf
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  • 5
    Publikationsdatum: 2019-07-13
    Beschreibung: The human exploration of Mars represents one of civilizations next major challenges and is an enterprise that would confirm the potential of humans to leave our home planet system and make our way outward into the cosmos. As exploration endeavors begin to set sights beyond low-Earth orbit, exploration of the surface of Mars continues to serve as the horizon destination to help focus technology development and research efforts. Recent thoughts on exploration follow a flexible path approach beginning with missions which do not extend down into planetary gravity wells including surface exploration. Consistent with that flexible path strategy is the notion of exploring the moons of Mars, namely Phobos and Deimos, prior to exploring the surface. The premise behind this thought is that exploring Mars moons would be less costly and risky since these missions would avoid the difficulties associated with landing on the surface and subsequent ascent back to orbit. A complete assessment of this strategy has not been performed in the context of the flexible path approach and is needed to clearly understand all of the advantages and disadvantages. This paper examines the strategic implications of human exploration of the moons of Mars as a potential prelude to surface exploration. Various operational concepts for Phobos and Deimos exploration that include the infusion of different propulsion technologies are assessed in terms of mission duration, technologies required, overall risk and difficulty, and operational construct. Finally, the strategic implications of each concept are assessed to determine the overall key challenges and strategic links to other key flexible path destinations.
    Schlagwort(e): Lunar and Planetary Science and Exploration
    Materialart: JSC-CN-26485 , JSC-CN-26361 , Global Space Exploration Conference; May 22, 2012 - May 24, 2012; Washington, DC; United States
    Format: application/pdf
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  • 6
    Publikationsdatum: 2019-07-13
    Beschreibung: The possible human exploration of Mars represents one of civilization s next major challenges and is an enterprise that would confirm the potential of humans to leave our home planet system and make our way outward into the cosmos. As exploration endeavors begin to set sights beyond low Earth orbit, potential exploration of the surface of Mars continues to serve as the horizon destination to help focus technology development and research efforts. Recent thoughts on exploration follow a flexible path approach beginning with missions that do not extend down into planetary gravity wells including surface exploration. Consistent with that flexible path strategy is the notion of exploring the moons of Mars, namely Phobos and Deimos, prior to exploring the surface. The premise behind this thought is that exploring Mars moons would be less costly and risky since these missions would avoid the difficulties associated with landing on the surface and subsequent ascent back to orbit. A complete assessment of this strategy has not been performed in the context of the flexible path approach and is needed to clearly understand all of the advantages and disadvantages. This paper examines the strategic implications of possible human exploration of the moons of Mars as a potential prelude to surface exploration. Various operational concepts for Phobos and Deimos exploration that include the infusion of different propulsion technologies are assessed in terms of mission duration, technologies required, overall risk and difficulty, and operational construct. Finally, the strategic implications of each concept are assessed to determine the overall key challenges and strategic links to other key flexible path destinations.
    Schlagwort(e): Lunar and Planetary Science and Exploration
    Materialart: GLEX-2012.08.2.2x12575 , JSC-CN-26381 , Global Space Exploration Conference; May 22, 2012 - May 24, 2012; Washington, DC; United States
    Format: text
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  • 7
    Publikationsdatum: 2019-07-13
    Beschreibung: In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic ray induced muons recorded by the partially deployed IceCube observatory between May 2009 and May 2010. The data include a total of 33 x 10(exp 9) muon events with a median angular resolution of approx. 3 degrees. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high energy skymap shows a different anisotropy structure including a deficit with a post-trial significance of -6.3 sigma. This anisotropy reveals a new feature of the Galactic cosmic ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.
    Schlagwort(e): Astronomy
    Materialart: GSFC.ABS..5857.2012 , The Astrophysical Journal; 746; 1
    Format: text
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  • 8
    Publikationsdatum: 2019-07-13
    Beschreibung: The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method. to measure the flux of cosmogenic neutrinos expected on Earth. The energy threshold for this process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS). deployed in the upper part of four boreholes of the IceCube Neutrino Observatory, has monitored the noise in Antarctic ice at the geographic South Pole for more than two years down to 500 m depth. The noise is very stable and Gaussian distributed, Lacking an in situ calibration up to now, laboratory measurements have been used to estimate the absolute noise level in the 10-50 kHz frequency range to be smaller than 20 mPa. Using a threshold trigger. sensors of the South Pole Acoustic Test Setup registered acoustic events in the IceCube detector volume and its vicinity. Acoustic signals from refreezing IceCube holes and from anthropogenic sources have been used to test the localization of acoustic events. An upper limit on the neutrino flux at energies E(sub v) 〉 10(exp 11) GeV is derived from acoustic data taken over eight months.
    Schlagwort(e): Acoustics
    Materialart: GSFC.JA.7117.2012 , Astroparticle Physics; 35; 6; 312-324
    Format: text
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  • 9
    Publikationsdatum: 2019-07-13
    Beschreibung: Phobos Surveyor Mission concept provides an innovative low cost, highly reliable approach to exploring the inner solar system 1/16/2013 3 Dual manifest launch. Use only flight proven, well characterize commercial off-the-shelf components. Flexible mission architecture allows for a slew of unique measurements.
    Schlagwort(e): Spacecraft Design, Testing and Performance
    Materialart: Global Space Exploration Conference; May 22, 2012 - May 24, 2012; Washington, DC; United States
    Format: text
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  • 10
    Publikationsdatum: 2019-07-13
    Beschreibung: Primitive bodies are exciting targets for exploration as they provide clues to the early Solar system conditions and dynamical evolution. The two moons of Mars are particularly interesting because of their proximity to an astrobiological target. However, after four decades of Mars exploration, their origin and nature remain enigmatic. In addition, when considering the long-term objectives of the flexible path for the potential human exploration to Mars, Phobos and Deimos present exciting intermediate opportunities without the complication and expense of landing and ascending from the surface. As interest in these targets for the next frontier of human exploration grows, characterization missions designed specifically to examine surface properties, landing environments, and surface mapping prior to human exploration are becoming increasingly important. A precursor mission concept of this sort has been developed using two identical spacecraft designed from low cost, flight proven and certified off-the-shelf component and utilizing Solar Electric Propulsion (SEP) to orbit both targets as secondary payloads launched aboard any NASA or GTO launch. This precursor mission has the potential to address both precursor measurements that are strategic knowledge gaps and decadal science, including soil physical properties at the global and local (human) scale and the search for in situ resources.
    Schlagwort(e): Lunar and Planetary Science and Exploration
    Materialart: GLEX-2012.03.2.4x12737 , Global Space Exploration Conference; May 22, 2012 - May 24, 2012; Washington, DC; United States
    Format: text
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