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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

The design, fabrication and delivery of a spacelab neutral buoyancy Instrument Pointing System (IPS) mockup

Underwater simulations of EVA contingency operations such as manual jettison, payload disconnect, and payload clamp actuation were used to define crew aid needs and mockup pecularities and characteristics to verify the validity of simulation using the trainer. A set of mockup instrument pointing system tests was conducted and minor modifications and refinements were made. Flight configuration struts were tested and verified to be operable by the flight crew. Tasks involved in developing the following end items are described: IPS gimbal system, payload, and payload clamp assembly; the igloos (volumetric); spacelab pallets, experiments, and hardware; experiment, and hardware; experiment 7; and EVA hand tools, support hardware (handrails and foot restraints). The test plan preparation and test support are also covered.

Vanvalkenburgh, C. N.↗
NASA NTRS1988

Expected IPS variations due to a disturbance described by a 3-D MHD model

The variations of interplanetary scintillation due to a disturbance described by a three-dimensional, time-dependent, MHD model of the interplanetary medium are calculated. The resulting simulated IPS maps are compared with observations of real disturbances and it is found that there is some qualitative agreement. It is concluded that the MHD model with a more realistic choice of input conditions would probably provide a useful description of many interplanetary disturbances.

Tappin, S. J.↗
NASA NTRS1995

Synoptic IPS and Yohkoh soft X-ray observations

Interplanetary scintillation measurements of the disturbance factor, g, from October 1991 to October 1992 are used to construct synoptic Carrington maps. These maps, which show the structure of the quiet solar wind, are compared with X-ray Carrington maps from the Yohkoh Soft X-ray Telescope (SXT) instrument. For the period studied the global structure outlined by (weakly) enhanced g-values apparent in the interplanetary scintillation (IPS) maps tend to match the active regions (as shown in the X-ray maps) significantly better than the heliospheric current sheet. Contrary to traditional opinion, which views active regions as magnetically closed structures that do not have any significant impact on the solar wind flow, our results suggest that density fluctuations in the solar wind are significantly enhanced over active regions. These results support the suggestion by Uchida et al. (1992), based on Yohkoh observations of expanding active regions, that active regions play a role in feeding mass into the quiet solar wind.

Hick, P.↗
NASA NTRS1996

IPS observations of heliospheric density structures associated with active regions

Interplanetary scintillation (IPS) measurements of the 'disturbance factor' g, obtained with the Cambridge (UK) array can be used to explore the heliospheric density structure. We have used these data to construct synoptic (Carrington) maps, representing the large-scale enhancements of the g-factor in the inner heliosphere. These maps emphasize the stable corotating, rather than the transient heliospheric density enhancements. We have compared these maps with Carrington maps of Fe XIV observations National Solar Observatory ((NSO), Sacramento Peak) and maps based on Yohkoh Soft X-Ray Telescope (SXT) X-ray observations. Our results indicate that the regions of enhanced g tend to map to active regions rather than the current sheet. The implication is that act ve regions are the dominant source of the small-scale (approximately equal 200 km) density variations present in the quiet solar wind.

Hick, P.↗
NASA NTRS1999

Energetic Neutral Atom Imaging with the POLAR CEPPAD/ IPS Instrument : Initial Forward Modeling Results

Although the primary function of the CEPPAD/IPS instrument on Polar is the measurement of energetic ions in-situ, it has also proven to be a very capable Energetic Neutral Atom (ENA) imager. Raw ENA images are currently being constructed on a routine basis with a temporal resolution of minutes during both active and quiet times. However, while analyses of these images by themselves provide much information on the spatial distribution and dynamics of the energetic ion population in the ring current. detailed modeling is required to extract the actual ion distributions. In this paper. we present the initial results of forward modeling an IPS ENA image obtained during a small geo-magnetic storm on June 9, 1997. The equatorial ion distribution inferred with this technique reproduces the expected large noon/midnight and dawn/dusk asymmetries. The limitations of the model are discussed and a number of modifications to the basic forward modeling technique are proposed which should significantly improve its performance in future studies.

Henderson, M. G.↗
NASA NTRS2007

Space-Based Voice over IP Networks

In human space exploration missions (e.g. a return to the Moon and for future missions to Mars), there will be a need to provide voice communications services. In this work we focus on the performance of Voice over IP (VoIP) techniques applied to space networks, where long range latencies, simplex links, and significant bit error rates occur. Link layer and network layer overhead issues are examined. Finally, we provide some discussion on issues related to voice conferencing in the space network environment.

voice conferencing↗
NASA NTRS2011

Telemetry and Communication IP Video Player

Aegis Video Player is the name of the video over IP system for the Telemetry and Communications group of the Launch Services Program. Aegis' purpose is to display video streamed over a network connection to be viewed during launches. To accomplish this task, a VLC ActiveX plug-in was used in C# to provide the basic capabilities of video streaming. The program was then customized to be used during launches. The VLC plug-in can be configured programmatically to display a single stream, but for this project multiple streams needed to be accessed. To accomplish this, an easy to use, informative menu system was added to the program to enable users to quickly switch between videos. Other features were added to make the player more useful, such as watching multiple videos and watching a video in full screen.

OFarrell, Zachary L.↗
NASA NTRS2020

Plasma environment effects on K lines of astrophysical interest IV. IPs, K thresholds, radiative rates, and Auger widths in Fe ii–Fe viii

Aims. Within the framework of compact-object accretion disks, we calculate plasma environment e ects on the atomic structure and decay parameters used in the modeling of K lines in lowly charged iron ions, namely Fe ii–Fe viii. Methods. For this study, we used the fully relativistic multiconfiguration Dirac–Fock method approximating the plasma electron–nucleus and electron-electron screenings with a time-averaged Debye-Hückel potential. Results. We report modified ionization potentials, K-threshold energies, wavelengths, radiative emission rates, and Auger widths for plasmas characterized by electron temperatures and densities in the ranges 10(exp 5)-10(exp 7) K and 10(exp 18)-10(exp 22) per cu.cm. In addition, we propose two universal fitting formulae to predict the IP and K-threshold lowerings in any elemental ion. Conclusions. We conclude that the high-resolution X-ray spectrometers onboard the future XRISM and ATHENA space missions will be able to detect the lowering of the K edges of these Fe ions due to the extreme plasma conditions occurring in the accretion disks around compact objects.

J. Deprince↗
DOE OSTI2025

Rescue of Unique Liquid IP-2 Portable Tanks at Savannah River Site – 25078

Westinghouse Savannah River Company, the SRS Management and Operations Contractor at the time, procured six large IP-2 portable tanks capable of transporting liquids in 2003 to support the layup of the F Canyon at SRS. F Canyon was one of two full-scale hardened radiochemical separations facilities built at SRS in the 1950s as part of the initial construction of the Site. F Canyon and H Canyon provided actinide separations capabilities for SRS through the end of the Cold War. Following the end of the Cold War era, the decision was eventually made that only one of these radiochemical separations facilities at SRS would still be needed moving forward. As H Canyon was considered better suited for ongoing SRS missions, F Canyon was placed into a layup state in the first decade of the 21st Century, with F Area deactivation completing in 2006. This process resulted in the creation of excess, radioactively contaminated solutions, which required disposition. These solutions included contaminated organic solutions as well as DU-bearing aqueous solutions. The six portable tanks were procured to support the transportation of these solutions.

Fee, Nathaniel C. [Savannah River Nuclear Solution↗
DOE OSTI2025

Simulating Charm Quarks in IP-Glasma Initial Stage and Quark-Gluon Plasma: A Hybrid Approach for charm quark phenomenology

We present phenomenological findings on charm quark transport while including its energy loss in both pre-equilibrium and hydrodynamic stages of the evolution. We employed the MARTINI event generator for the production and evolution of heavy quarks in the relativistic heavy-ion collisions. The sensitivity of the heavy meson nuclear modification factor and flow coeffcient to the early stage of heavy-ion collisions and bulk medium evolution is analyzed for Pb+Pb collisions at 5.02 TeV. Our study provides insights into the interaction strength of charm quarks during the early phase and within the quark-gluon plasma.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1974

An assessment of the Instrument Pointing Subsystems (IPS) requirements for spacelab missions

Instrument Pointing Subsystem requirements for Spacelab missions in solar physics, stellar astronomy, and earth observation are analyzed and design guidelines for fine pointing instrument platforms are presented. The requirements for the platforms are time-phased based on NASA projections of flight mission models and payload scheduling. The experiments used for these projections are to be viewed as representative payloads. Other experiments or experiment groupings within any one discipline may be accommodated by an Instrument Pointing Subsystem that meets these requirements.

Nein, M. E.↗
NASA NTRS1976

IPS observations of the solar wind speed out of the ecliptic

Interplanetary scintillation observations from 1971-1975 show that the average solar wind speed increases away from the solar equator, with a mean gradient of 2.1 km/s per degree. These results are compared with spacecraft observations over the + or - 7 deg attainable in the ecliptic and with those deduced from comet tails. The role of temporal variations, especially those caused by latitude dependent solar wind streams, is emphasized, and this points to the need for extensive ecliptic and ground-based observations during an out-of-the-ecliptic spacecraft mission.

Coles, W. A.↗
NASA NTRS1990

IPS limits on very low frequency VLBI

The ability of a space-based radio interferometer array to make high resolution images at frequencies of only a few MHz will be limited by interplanetary scintillation. Numerical simulations have been used to study the severity of interferometer phase fluctuations caused by the density fluctuations in the solar wind over a range of frequencies and solar elongation angles. The impact of these fluctuations on the quality of radio images produced has also been investigated. The results show that, for baselines up to 100 km, accurate imaging should be possible when nu sin (epsilon/2) is equal to or greater than 2.5, where nu is the observing frequency in MHz and epsilon is the solar elongation angle.

Jones, Dayton L.↗
NASA NTRS2002

Operational Limitations of the High Rate Frame Multiplexer (HRFM) Onboard the International Space Station(ISS)-and How These Limitations Affect Payload Developers (PDs) and International Partners (IPs)

The data system onboard the United States Operating Segment (USOS) of the ISS is currently used to capture, route, record and downlink high-rate science data from experiments inside the US Lab. Once NASDA's Japanese Experiment Module (JEM) and ESA's Attached Pressurized Module (APM) are launched - in the 2004 to 2005 timeframe - data from these facilities will also be routed to the ground using the USOS data system. A critical component of the USOS data system is the High Rate Frame Multiplexer (HRFM). The HRFM combines multiple data/video inputs and combines them into one data stream. This Ku-band data stream is then routed through the Tracking and Data Relay Satellite (TDRS) system to the ground. The Data Management Coordinator (DMC) - located at the Marshall Space Flight Center's Payload Operations Center (POC) - is responsible for commanding and controlling the HRFM. The HRFM can multiplex a maximum of eight digital data sources and four digital video sources. Thus far, this limitation has not been constraining to operations. However, once the JEM and APM are integrated, the HRFM limitations will become a major constraint to science operations onboard. The purpose of this paper is to characterize the limitations of the HRFM and to explain how these limitations can be successfully managed. With this information, Payload Developers and International Partners will be able to more effectively utilize the data systems onboard the ISS. Ultimately, more science data can be captured and downlinked to Flight Controllers and Scientists on the ground.

Mixson, Charles D.↗