Low-Earth-Orbit and Geosynchronous-Earth-Orbit Testing of 80 Ah Batteries under Real-time Profiles

NASA Technical Reports Server (NTRS)

Staniewicz, Robert J.; Willson, John; Briscoe, J. Douglas; Rao, Gopalakrishna M.

2004-01-01

This viewgraph presentation gives an update on test results from two 16 cell batteries, one in a simulated Low Earth Orbit (LEO) environment and the other in simulated Geosynchronous Earth Orbit (GEO) environment. The tests measured how voltage and capacity are affected over time by thermal cycling.

Electrostatic protection of the Solar Power Satellite and rectenna

NASA Technical Reports Server (NTRS)

Freeman, J. W.; Few, A. A., Jr.; Reiff, P. H.; Cooke, D.; Bohannon, J.; Haymes, B.

1979-01-01

Several features of the interactions of the solar power satellite (SPS) with its space environment were examined theoretically. The voltages produced at various surfaces due to space plasmas and the plasma leakage currents through the kapton and sapphire solar cell blankets were calculated. At geosynchronous orbit, this parasitic power loss is only 0.7%, and is easily compensated by oversizing. At low-Earth orbit, the power loss is potentially much larger (3%), and anomalous arcing is expected for the EOTV high voltage negative surfaces. Preliminary results of a three dimensional self-consistent plasma and electric field computer program are presented, confirming the validity of the predictions made from the one dimensional models. Magnetic shielding of the satellite, to reduce the power drain and to protect the solar cells from energetic electron and plasma ion bombardment is considered. It is concluded that minor modifications can allow the SPS to operate safely and efficiently in its space environment. The SPS design employed in this study is the 1978 MSFC baseline design utilizing GaAs solar cells at CR-2 and an aluminum structure.

Protecting the GEO Environment: Policies and Practices

NASA Technical Reports Server (NTRS)

Johnson, Nicholas L.; McKay, Gordon A. (Technical Monitor)

1999-01-01

The geosynchronous orbital regime has long been recognized as a unique space resource, dictating special measures to ensure its continuing use for future generations. During the past 20 years a variety of national and international policies have been developed to preserve this environment. A review of current practices involving the deployment and disposal of geosynchronous spacecraft, associated upper stages and apogee kick motors, and geosynchronous orbit transfer objects indicates both positive and negative trends. Most spacecraft operators are indeed performing end-of-mission maneuvers, but the boost altitudes normally fall short of policy guidelines. Russia, a major operator in geosynchronous orbit, maneuvers only 1 in 3 spacecraft out of the region, while China has never refired a spacecraft above GEO. The viability of voluntary protection measures for this regime depends upon the responsible actions of the aerospace community as a whole.

An empirical model of electron and ion fluxes derived from observations at geosynchronous orbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denton, M. H.; Thomsen, M. F.; Jordanova, V. K.

Knowledge of the plasma fluxes at geosynchronous orbit is important to both scientific and operational investigations. We present a new empirical model of the ion flux and the electron flux at geosynchronous orbit (GEO) in the energy range ~1 eV to ~40 keV. The model is based on a total of 82 satellite-years of observations from the Magnetospheric Plasma Analyzer instruments on Los Alamos National Laboratory satellites at GEO. These data are assigned to a fixed grid of 24 local-times and 40 energies, at all possible values of Kp. Bi-linear interpolation is used between grid points to provide the ionmore » flux and the electron flux values at any energy and local-time, and for given values of geomagnetic activity (proxied by the 3-hour Kp index), and also for given values of solar activity (proxied by the daily F10.7 index). Initial comparison of the electron flux from the model with data from a Compact Environmental Anomaly Sensor II (CEASE-II), also located at geosynchronous orbit, indicate a good match during both quiet and disturbed periods. The model is available for distribution as a FORTRAN code that can be modified to suit user-requirements.« less

An empirical model of electron and ion fluxes derived from observations at geosynchronous orbit

DOE PAGES

Denton, M. H.; Thomsen, M. F.; Jordanova, V. K.; ...

2015-04-01

Knowledge of the plasma fluxes at geosynchronous orbit is important to both scientific and operational investigations. We present a new empirical model of the ion flux and the electron flux at geosynchronous orbit (GEO) in the energy range ~1 eV to ~40 keV. The model is based on a total of 82 satellite-years of observations from the Magnetospheric Plasma Analyzer instruments on Los Alamos National Laboratory satellites at GEO. These data are assigned to a fixed grid of 24 local-times and 40 energies, at all possible values of Kp. Bi-linear interpolation is used between grid points to provide the ionmore » flux and the electron flux values at any energy and local-time, and for given values of geomagnetic activity (proxied by the 3-hour Kp index), and also for given values of solar activity (proxied by the daily F10.7 index). Initial comparison of the electron flux from the model with data from a Compact Environmental Anomaly Sensor II (CEASE-II), also located at geosynchronous orbit, indicate a good match during both quiet and disturbed periods. The model is available for distribution as a FORTRAN code that can be modified to suit user-requirements.« less

NASCAP programmer's reference manual

NASA Astrophysics Data System (ADS)

Mandell, M. J.; Stannard, P. R.; Katz, I.

1993-05-01

The NASA Charging Analyzer Program (NASCAP) is a computer program designed to model the electrostatic charging of complicated three-dimensional objects, both in a test tank and at geosynchronous altitudes. This document is a programmer's reference manual and user's guide. It is designed as a reference to experienced users of the code, as well as an introduction to its use for beginners. All of the many capabilities of NASCAP are covered in detail, together with examples of their use. These include the definition of objects, plasma environments, potential calculations, particle emission and detection simulations, and charging analysis.

NASCAP programmer's reference manual

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Stannard, P. R.; Katz, I.

1993-01-01

The NASA Charging Analyzer Program (NASCAP) is a computer program designed to model the electrostatic charging of complicated three-dimensional objects, both in a test tank and at geosynchronous altitudes. This document is a programmer's reference manual and user's guide. It is designed as a reference to experienced users of the code, as well as an introduction to its use for beginners. All of the many capabilities of NASCAP are covered in detail, together with examples of their use. These include the definition of objects, plasma environments, potential calculations, particle emission and detection simulations, and charging analysis.

Effective Coulomb force modeling for spacecraft in Earth orbit plasmas

NASA Astrophysics Data System (ADS)

Seubert, Carl R.; Stiles, Laura A.; Schaub, Hanspeter

2014-07-01

Coulomb formation flight is a concept that utilizes electrostatic forces to control the separations of close proximity spacecraft. The Coulomb force between charged bodies is a product of their size, separation, potential and interaction with the local plasma environment. A fast and accurate analytic method of capturing the interaction of a charged body in a plasma is shown. The Debye-Hückel analytic model of the electrostatic field about a charged sphere in a plasma is expanded to analytically compute the forces. This model is fitted to numerical simulations with representative geosynchronous and low Earth orbit (GEO and LEO) plasma environments using an effective Debye length. This effective Debye length, which more accurately captures the charge partial shielding, can be up to 7 times larger at GEO, and as great as 100 times larger at LEO. The force between a sphere and point charge is accurately captured with the effective Debye length, as opposed to the electron Debye length solutions that have errors exceeding 50%. One notable finding is that the effective Debye lengths in LEO plasmas about a charged body are increased from centimeters to meters. This is a promising outcome, as the reduced shielding at increased potentials provides sufficient force levels for operating the electrostatically inflated membrane structures concept at these dense plasma altitudes.

Natural orbital environment definition guidelines for use in aerospace vehicle development

NASA Technical Reports Server (NTRS)

Anderson, B. Jeffrey (Editor); Smith, Robert E. (Compiler)

1994-01-01

This document provides definitions of the natural near-Earth space environment suitable for use in the initial development/design phase of any space vehicle. The natural environment includes the neutral atmosphere, plasma, charged particle radiation, electromagnetic radiation (EMR), meteoroids, orbital debris, magnetic field, physical and thermal constants, and gravitational field. Communications and other unmanned satellites operate in geosynchronous-Earth orbit (GEO); therefore, some data are given for GEO, but emphasis is on altitudes from 200 km to 1000 km (low-Earth orbit (LEO)). This document does not cover the induced environment of other effects resulting from presence of the space vehicle. Manmade factors are included as part of the ambient natural environment; i.e., orbital debris and radio frequency (RF) noise generated on Earth, because they are not caused by the presence of the space vehicle but form part of the ambient environment that the space vehicle experiences.

Experimental Tests of UltraFlex Array Designs in Low Earth Orbital and Geosynchronous Charging Environments

NASA Technical Reports Server (NTRS)

Galofaro, Joel T.; Vayner, Boris V.; Hillard, Grover B.

2011-01-01

The present ground based investigations give the first definitive look describing the expected on-orbit charging behavior of Orion UltraFlex array coupons in the Low Earth Orbital and Geosynchronous Environments. Furthermore, it is important to note that the LEO charging environment also applies to the International Space Station as well as to the lunar mission charging environments. The GEO charging environment includes the bounding case for all lunar orbital and lunar surface mission environments. The UltraFlex thin film photovoltaic array technology has been targeted to become the sole power system for life support and on-orbit power for the manned Aires Crew Exploration Vehicle. It is therefore, crucial to gain an understanding of the complex charging behavior to answer some of the basic performance and survivability issues in an attempt to ascertain that a single UltraFlex array design will be able to cope with the projected worst case LEO and GEO charging environments. Testing was limited to four array coupons, two coupons each from two different array manufactures, Emcore and Spectrolab. The layout of each array design is identical and varies only in the actual cell technology used. The individual array cells from each manufacturer have an antireflection layered coating and come in two different varieties either uncoated (only AR coating) or coated with a thin conducting ITO layer. The LEO Plasma tests revealed that all four coupons passed the arc threshold -120 V bias tests. GEO electron gun charging tests revealed that only front side area of ITO coated coupons passed tests. Only the Emcore AR array passed backside Stage 2 GEO Tests.

Simulation of external and internal electrostatic discharges at the spacecraft system test level

NASA Technical Reports Server (NTRS)

Whittlesey, A.; Leung, P.

1984-01-01

Environmental test activities concerned with space plasma-caused charging and discharing phenomena are discussed. It is pointed out that the origin of such an electrostatic discharge (ESD) is charging of spacecraft dielectrics by an energetic plasma in geosynchronous orbit, Jupiter's magnetosphere, or other similar space environments. In dealing with environmental testing problems, it is necessary to define the location and magnitude of any ESD's in preparation for a subsequent simulation of the given conditions. Questions of external and internal charging are discussed separately. The environmental hazard from an external discharge can be assessed by viewing the dielectric surface as one side of a parallel plate capacitor. In the case of internal charging, the level of environmental concern depends on the higher energy spectrum of the ambient electrons.

Solar cycle variation of geosynchronous plasma mass density derived from the frequency of standing Alfvén waves

NASA Astrophysics Data System (ADS)

Takahashi, Kazue; Denton, Richard E.; Singer, Howard J.

2010-07-01

We have studied the solar cycle variation of equatorial plasma mass density ρeq in the plasma trough at geosynchronous altitude. The density was indirectly determined from the frequency, fT3, of the third harmonic of toroidal standing Alfvén waves detected over a 12 year period from 1980 to 1991 with magnetometers on five Geostationary Operational Environmental Satellites (GOES). Realistic models of the ambient magnetic field and field line mass distribution were used in numerically solving the wave equation to relate fT3 to ρeq. Scanning the magnetometer data in a 30 min time window that moved forward in 10 min steps, we obtained 228,382 fT3 samples equivalent to 1586 days of data. The detection rate of fT3 is highest (˜50%) in the prenoon sector, and fT3 and ρeq samples from this sector were used to examine their dependence on F10.7, Kp, and Dst. Overall, F10.7 exhibits the highest correlation with fT3 and ρeq, implying that the solar UV/EUV control of ion production at the ionospheric height is strongly reflected in mass density variations at geosynchronous orbit. Using 27 day medians computed excluding periods of plasmasphere expansion to geosynchronous orbit and geomagnetic storm, we obtained the empirical formula fT3 (mHz) = 38 - 0.097F10.7 and logρeq (amu cm-3) = 0.42 + 0.0039F10.7, where F10.7 is given in the solar flux units 10-22 W · m-2 · Hz-1. This last formula means that with the 27 day F10.7 in the range of 68-255 in the selected solar cycle, the mass density varied by a factor of ˜5 from ˜5 to ˜26 amu cm-3. During extremely quiet times (Kp averaged using a 3 day time scale <1), for which the plasmasphere may extend out to geosynchronous orbit, and during storm periods (Dst < -50 nT), the mass density may be enhanced beyond these values.

Multi-Sensor Image Fusion for Target Recognition in the Environment of Network Decision Support Systems

DTIC Science & Technology

2015-12-01

FOV Field of view GEO Geosynchronous, or geostationary , earth orbit HEO Highly elliptical earth orbit HTTP Hypertext transfer protocol HTTPS...orbit (MEO), geosynchronous or geostationary earth orbit (GEO), and highly elliptical earth orbit (HEO) [38]. Furthermore, if we consider the actual

Thermal blanket metallic film groundstrap and second surface mirror vulnerability to arc discharges

NASA Technical Reports Server (NTRS)

Inouye, G. T.; Sanders, N. L.; Komatsu, G. K.; Valles, J. R.; Sellen, J. M., Jr.

1979-01-01

Available data on the geosynchronous orbit energetic plasma environment were examined, and a crude model was generated to permit an estimation to be made of the number of arc discharges per year to which a thermal blanket groundstrap would be subjected. Laboratory experiments and a survey of the literature on arc discharge characteristics were performed to define typical and worst case arc discharge current waveforms. In-air tests of different groundstrap configurations to a standardized test pulse were performed and a wide variability of durability values were found. A groundstrap technique, not used thus far, was found to be far superior than the others.

Calculation of current collected in a dilute plasma through a pinhole in the insulation covering a high-voltage surface

NASA Technical Reports Server (NTRS)

Fralick, G. C.

1975-01-01

A procedure is described for calculating the current collected by a pinhole defect in the insulation covering a high voltage surface. The results apply to a satellite at geosynchronous altitude where the effects of satellite motion and collective plasma effects on the collected current may be ignored.

Representation of the Geosynchronous Plasma Environment in Spacecraft Charging Calculations

NASA Technical Reports Server (NTRS)

Davis, V. A.; Mandell, M. J.; Thomsen, M. F.

2006-01-01

Historically, our ability to predict and postdict spacecraft surface charging has been limited by the characterization of the plasma environment. One difficulty lies in the common practice of fitting the plasma data to a Maxwellian or Double Maxwellian distribution function, which may not represent the data well for charging purposes. We use electron and ion flux spectra measured by the Los Alamos National Laboratory (LANL) Magnetospheric Plasma Analyzer (MPA) to examine how the use of different spectral representations of the charged particle environment in computations of spacecraft potentials during magnetospheric substorms affects the accuracy of the results. We calculate the spacecraft potential using both the measured fluxes and several different fits to these fluxes. These measured fluxes have been corrected for the difference between the measured and calculated potential. The potential computed using the measured fluxes and the best available material properties of graphite carbon, with a secondary electron escape fraction of 81%, is within a factor of three of the measured potential for 87% of the data. Potentials calculated using a Kappa function fit to the incident electron flux distribution function and a Maxwellian function fit to the incident ion flux distribution function agree with measured potentials nearly as well as do potentials calculated using the measured fluxes. Alternative spectral representations gave less accurate estimates of potential. The use of all the components of the net flux, along with spacecraft specific average material properties, gives a better estimate of the spacecraft potential than the high energy flux alone.

Physical Modeling for Processing Geosynchronous Imaging Fourier Transform Spectrometer-Indian Ocean METOC Imager (GIFTS-IOMI) Hyperspectral Data

DTIC Science & Technology

2002-09-30

Physical Modeling for Processing Geosynchronous Imaging Fourier Transform Spectrometer-Indian Ocean METOC Imager ( GIFTS -IOMI) Hyperspectral Data...water quality assessment. OBJECTIVES The objective of this DoD research effort is to develop and demonstrate a fully functional GIFTS - IOMI...environment once GIFTS -IOMI is stationed over the Indian Ocean. The system will provide specialized methods for the characterization of the atmospheric

Spacecraft-plasma interaction codes: NASCAP/GEO, NASCAP/LEO, POLAR, DynaPAC, and EPSAT

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Jongeward, G. A.; Cooke, D. L.

1992-01-01

Development of a computer code to simulate interactions between the surfaces of a geometrically complex spacecraft and the space plasma environment involves: (1) defining the relevant physical phenomena and formulating them in appropriate levels of approximation; (2) defining a representation for the 3-D space external to the spacecraft and a means for defining the spacecraft surface geometry and embedding it in the surrounding space; (3) packaging the code so that it is easy and practical to use, interpret, and present the results; and (4) validating the code by continual comparison with theoretical models, ground test data, and spaceflight experiments. The physical content, geometrical capabilities, and application of five S-CUBED developed spacecraft plasma interaction codes are discussed. The NASA Charging Analyzer Program/geosynchronous earth orbit (NASCAP/GEO) is used to illustrate the role of electrostatic barrier formation in daylight spacecraft charging. NASCAP/low Earth orbit (LEO) applications to the CHARGE-2 and Space Power Experiment Aboard Rockets (SPEAR)-1 rocket payloads are shown. DynaPAC application to the SPEAR-2 rocket payloads is described. Environment Power System Analysis Tool (EPSAT) is illustrated by application to Tethered Satellite System 1 (TSS-1), SPEAR-3, and Sundance. A detailed description and application of the Potentials of Large Objects in the Auroral Region (POLAR) Code are presented.

Time-Integral Correlations of Multiple Variables With the Relativistic-Electron Flux at Geosynchronous Orbit: The Strong Roles of Substorm-Injected Electrons and the Ion Plasma Sheet

NASA Astrophysics Data System (ADS)

Borovsky, Joseph E.

2017-12-01

Time-integral correlations are examined between the geosynchronous relativistic electron flux index Fe1.2 and 31 variables of the solar wind and magnetosphere. An "evolutionary algorithm" is used to maximize correlations. Time integrations (into the past) of the variables are found to be superior to time-lagged variables for maximizing correlations with the radiation belt. Physical arguments are given as to why. Dominant correlations are found for the substorm-injected electron flux at geosynchronous orbit and for the pressure of the ion plasma sheet. Different sets of variables are constructed and correlated with Fe1.2: some sets maximize the correlations, and some sets are based on purely solar wind variables. Examining known physical mechanisms that act on the radiation belt, sets of correlations are constructed (1) using magnetospheric variables that control those physical mechanisms and (2) using the solar wind variables that control those magnetospheric variables. Fe1.2-increasing intervals are correlated separately from Fe1.2-decreasing intervals, and the introduction of autoregression into the time-integral correlations is explored. A great impediment to discerning physical cause and effect from the correlations is the fact that all solar wind variables are intercorrelated and carry much of the same information about the time sequence of the solar wind that drives the time sequence of the magnetosphere.

Experimental Charging Behavior of Orion UltraFlex Array Designs

NASA Technical Reports Server (NTRS)

Golofaro, Joel T.; Vayner, Boris V.; Hillard, Grover B.

2010-01-01

The present ground based investigations give the first definitive look describing the charging behavior of Orion UltraFlex arrays in both the Low Earth Orbital (LEO) and geosynchronous (GEO) environments. Note the LEO charging environment also applies to the International Space Station (ISS). The GEO charging environment includes the bounding case for all lunar mission environments. The UltraFlex photovoltaic array technology is targeted to become the sole power system for life support and on-orbit power for the manned Orion Crew Exploration Vehicle (CEV). The purpose of the experimental tests is to gain an understanding of the complex charging behavior to answer some of the basic performance and survivability issues to ascertain if a single UltraFlex array design will be able to cope with the projected worst case LEO and GEO charging environments. Stage 1 LEO plasma testing revealed that all four arrays successfully passed arc threshold bias tests down to -240 V. Stage 2 GEO electron gun charging tests revealed that only the front side area of indium tin oxide coated array designs successfully passed the arc frequency tests

Global Geospace Science (GGS)/POLAR Thermal Ion Dynamics Experiments (TIDE) Co-Investigator Program: Mission Operations and Data Analysis (MO/DA)

NASA Technical Reports Server (NTRS)

Nagy, Andrew; Liemohn, M.

2004-01-01

We have pursued several investigations using the Polar/TIDE data set. The first was a comparison of TIDE high-altitude observations with similar ion flux signatures in the Los Alamos National Laboratory (LANL) magnetospheric plasma analyzer (MPA) data. There are several geosynchronously orbiting satellites with LANL MPA instruments onboard. When the satellite is immersed in fresh plasma sheet electrons, the spacecraft voltage drops to several hundred volts negative, and cold ions are accelerated in to the detector. In the LANL MPA spectrograms, the accelerated cold ions appear as a bright, narrow line, following the voltage of the spacecraft. This "ion line" is seen regularly on the nightside, but has not received much attention. The Polar TIDE observations indicated a ubiquitous "lobal wind" in the near-- magnetotail, a field-aligned stream of approx. 100 eV ions flowing out of both polar ionospheres. The interesting result of this research is that the MPA ion line is also peaked in the field-aligned direction, even though the potential well should be uniform in all directions. It is believed that this is evidence that the lobal winds not only populate the high-latitude lobes, but fill the lobes all the way in to the near-Earth plasma sheet (the location of geosynchronous orbit). This activity developed into a full-scale survey of the lobal wind observations in the TIDE database. The universality of these observations with respect to local time and solar wind conditions implies that the ionospheric outflow is supplying the near-Earth plasma sheet at all times, regardless of magnetic activity. We have conducted a statistical study of the characteristics of the lobal wind in these two data sets FIDE and LANL MPA), finding much similarity between them. Using these characteristics as input conditions to our inner magnetosphere ion transport model, we have conducted simulations of the flow of these particles inside of geosynchronous orbit to show the impact these particles will have on the near-Earth space environment. As the study has progressed, these results have been presented several times to the TIDE team during teleconferences. It is planned to present this survey at the GEM 2004 Summer Workshop, and hopefully at additional conferences in the near future. We are presently writing a paper on the lobal wind occurrence statistics, which should be submitted in April or May to the Journal of Geophysical Research for publication. An undergraduate student at the University of Alabama in Huntsville, Will Maddox, working at NASA MSFC with Dr. Paul Craven, is presently creating a database of the values TIDE moments for the lobal wind (under Dr. Liemohn's guidance), and this will be the focus of a follow-on paper.

Natural environment design requirements for the Solar Electric Propulsion Stage (SEPS)

NASA Technical Reports Server (NTRS)

Andrews, L. E.

1973-01-01

The natural environment design requirements for the solar electric propulsion stage are presented. Environment criteria for the SEP stage will cover earth orbital operations out to geosynchronous altitudes and also interplanetary missions including comet and asteroid missions.

Specification of the Surface Charging Environment with SHIELDS

NASA Astrophysics Data System (ADS)

Jordanova, V.; Delzanno, G. L.; Henderson, M. G.; Godinez, H. C.; Jeffery, C. A.; Lawrence, E. C.; Meierbachtol, C.; Moulton, J. D.; Vernon, L.; Woodroffe, J. R.; Brito, T.; Toth, G.; Welling, D. T.; Yu, Y.; Albert, J.; Birn, J.; Borovsky, J.; Denton, M.; Horne, R. B.; Lemon, C.; Markidis, S.; Thomsen, M. F.; Young, S. L.

2016-12-01

Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure, i.e. "space weather", remains a big space physics challenge. A recently funded project through the Los Alamos National Laboratory (LANL) Directed Research and Development (LDRD) program aims at developing a new capability to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. The project goals are to understand the dynamics of the surface charging environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro- and microscale. Important physics questions related to rapid particle injection and acceleration associated with magnetospheric storms and substorms as well as plasma waves are investigated. These challenging problems are addressed using a team of world-class experts in the fields of space science and computational plasma physics, and state-of-the-art models and computational facilities. In addition to physics-based models (like RAM-SCB, BATS-R-US, and iPIC3D), new data assimilation techniques employing data from LANL instruments on the Van Allen Probes and geosynchronous satellites are developed. Simulations with the SHIELDS framework of the near-Earth space environment where operational satellites reside are presented. Further model development and the organization of a "Spacecraft Charging Environment Challenge" by the SHIELDS project at LANL in collaboration with the NSF Geospace Environment Modeling (GEM) Workshop and the multi-agency Community Coordinated Modeling Center (CCMC) to assess the accuracy of SCE predictions are discussed.

Numerical Analysis of Neutral Entrainment Effect on Field-Reversed Configuration Thruster Efficiency

DTIC Science & Technology

2014-12-01

and acceleration. Whereas such a high Isp may be highly desirable for deep space missions, the low - Earth - orbit and geosynchronous- Earth - orbit ...Due to the aforementioned factors, the optimal conditions are achieved for low -Z plasma at high (∼50 eV) temperature and in strong magnetic fields...cannot capture strongly nonequilibrium velocity distributions of charged and neutral species typical for high-energy plasma –neutral interaction . A

DMSP Spacecraft Charging in Auroral Environments

NASA Technical Reports Server (NTRS)

Colson, Andrew; Minow, Joseph

2011-01-01

The Defense Meteorological Satellite Program (DMSP) spacecraft are a series of low-earth orbit (LEO) satellites whose mission is to observe the space environment using the precipitating energetic particle spectrometer (SSJ/4-5). DMSP satellites fly in a geosynchronous orbit at approx.840 km altitude which passes through Earth s ionosphere. The ionosphere is a region of partially ionized gas (plasma) formed by the photoionization of neutral atoms and molecules in the upper atmosphere of Earth. For satellites in LEO, such as DMSP, the plasma density is usually high and the main contributors to the currents to the spacecraft are the precipitating auroral electrons and ions from the magnetosphere as well as the cold plasma that constitutes the ionosphere. It is important to understand how the ionosphere and auroral electrons can accumulate surface charges on satellites because spacecraft charging has been the cause of a number of significant anomalies for on-board instrumentation on high altitude spacecraft. These range from limiting the sensitivity of measurements to instrument malfunction depending on the magnitude of the potential difference over the spacecraft surface. Interactive Data Language (IDL) software was developed to process SSJ/4-5 electron and ion data and to create a spectrogram of the particles number and energy fluxes. The purpose of this study is to identify DMSP spacecraft charging events and to present a preliminary statistical analysis. Nomenclature

Investigation of beam-plasma interactions

NASA Technical Reports Server (NTRS)

Olsen, Richard C.

1987-01-01

Data from the SCATHA satellite was analyzed to solve the problems of establishing electrical contact between a satellite and the ambient plasma. The original focus of the work was the electron gun experiments conducted near the geosynchronous orbit, which resulted in observations which bore a startling similarity to observations of the SEPAC experiments on SPACELAB 1. The study has evolved to include the ion gun experiments on SCATHA, a modest laboratory effort in hollow cathode performance, and preparation for flight experiments pertinent to tether technology. These areas are addressed separately.

Active control of spacecraft potentials at geosynchronous orbit

NASA Technical Reports Server (NTRS)

Goldstein, R.; Deforest, S. E.

1976-01-01

Tests have been conducted concerning the active control of the potentials of the geosynchronous satellites ATS-5 and ATS-6. The ATS-5 tests show that a simple electron emitter can be used to reduce the magnitude of the potential of a spacecraft which has been charged negatively by the environment. The ATS-6 ion thruster had also a pronounced effect on the potential barrier. In this case, the flux of high-energy primary ions and of low-charge exchange ions produces a space-charge neutralization effect which the electron gun alone cannot achieve.

MHD simulation of the shock wave event on October 24, 2003

NASA Astrophysics Data System (ADS)

Ogino, T.; Kajiwara, Y.; Nakao, M.; Park, K. S.; Fukazawa, K.; Yi, Y.

2007-11-01

A three-dimensional global MHD simulation of the interaction between the solar wind and the Earth's magnetosphere has been executed to study the shock wave event on space weather problem on October 24, 2003, when an abnormal operation happened in a satellite for Environment Observation Technology, ADEOS-II (Midori-II). Characteristic features of the event are the long duration of southward IMF, arrival of a strong shock wave, then large variation of IMF By from negative to positive for about 15 min duration. In the simulation, the shock wave compresses the magnetosphere for southward IMF and a hot plasma was injected around the geosynchronous orbit from plasma sheet. During the interval when IMF By changes from negative to positive, the magnitude of IMF extremely decreases to bring attenuation of magnetic reconnection. The open-closed boundary shrinks in the polar cap and the transient expansion of the magnetic field lines occurs to imply enhancement of particle precipitation. The reconnection site moves from dawn to dusk in the dayside magnetopause and a narrow cockscomb closed field region is formed in the high latitude tail.

Highly efficient, very low-thrust transfer to geosynchronous orbit - Exact and approximate solutions

NASA Astrophysics Data System (ADS)

Redding, D. C.

1984-04-01

An overview is provided of the preflight, postflight, and accuracy analysis of the Titan IIIC launch vehicle that injects payloads into geosynchronous orbits. The postflight trajectory reconstruction plays an important role in determining payload injection accuracy. Furthermore, the postflight analysis provides useful information about the characteristics of measuring instruments subjected to a flight environment. Suitable approaches for meeting mission specifications, trajectory requirements, and instrument constraints are considered, taking into account the importance of preflight trajectory analysis activities. Gimbal flip avoidance algorithms in the flight software, and considerable beta gimbal analysis ensures a singularity-free trajectory.

Dosimeter Design Program

DTIC Science & Technology

2015-01-05

monitor the radiation environment in a geosynchronous satellite. 15. SUBJECT TERMS Radiation testing, Cobalt, Microcontroller 16. SECURITY...electronics including: an Aeroflex 8051 microcontroller , a Maxwell Electrically Erasable Programmable Read-Only Memory (EEPROM), Texas Instrument analog

A predictive model of geosynchronous magnetopause crossings

NASA Astrophysics Data System (ADS)

Dmitriev, A.; Suvorova, A.; Chao, J.-K.

2011-05-01

We have developed a model predicting whether or not the magnetopause crosses geosynchronous orbit at a given location for given solar wind pressure Psw, Bz component of the interplanetary magnetic field (IMF), and geomagnetic conditions characterized by 1 min SYM-H index. The model is based on more than 300 geosynchronous magnetopause crossings (GMCs) and about 6000 min when geosynchronous satellites of GOES and Los Alamos National Laboratory (LANL) series are located in the magnetosheath (so-called MSh intervals) in 1994-2001. Minimizing of the Psw required for GMCs and MSh intervals at various locations, Bz, and SYM-H allows describing both an effect of magnetopause dawn-dusk asymmetry and saturation of Bz influence for very large southward IMF. The asymmetry is strong for large negative Bz and almost disappears when Bz is positive. We found that the larger the amplitude of negative SYM-H, the lower the solar wind pressure required for GMCs. We attribute this effect to a depletion of the dayside magnetic field by a storm time intensification of the cross-tail current. It is also found that the magnitude of threshold for Bz saturation increases with SYM-H index such that for small negative and positive SYM-H the effect of saturation diminishes. This supports an idea that enhanced thermal pressure of the magnetospheric plasma and ring current particles during magnetic storms results in the saturation of magnetic effect of the IMF Bz at the dayside magnetopause. A noticeable advantage of the model's prediction capabilities in comparison with other magnetopause models makes the model useful for space weather predictions.

Particle tracing modeling of ion fluxes at geosynchronous orbit during substorms

NASA Astrophysics Data System (ADS)

Brito, T. V.; Jordanova, V.; Woodroffe, J. R.; Henderson, M. G.; Morley, S.; Birn, J.

2016-12-01

The SHIELDS project aims to couple a host of different models for different regions of the magnetosphere using different numerical methods such as MHD, PIC and particle tracing, with the ultimate goal of having a more realistic model of the whole magnetospheric environment capturing, as much as possible, the different physics of the various plasma populations. In that context, we present a modeling framework that can be coupled with a global MHD model to calculate particle fluxes in the inner magnetosphere, which can in turn be used to constantly update the input for a ring current model. In that regard, one advantage of that approach over using spacecraft data is that it produces a much better spatial and temporal coverage of the nightside geosynchronous region and thus a possibly more complete input for the ring current model, which will likely produce more accurate global results for the ring current population. In this presentation, we will describe the particle tracing method in more detail, describe the method used to couple it to the BATS-R-US 3D global MHD code, and the method used to update the flux results to the RAM-SCB ring current model. We will also present the simulation results for the July 18, 2013 period, which showed significant substorm activity. We will compare simulated ion fluxes on the nightside magnetosphere with spacecraft observations to gauge how well our simulations are capturing substorm dynamics.

Disposal strategy for the geosynchronous orbits of the Beidou Navigation Satellite System

NASA Astrophysics Data System (ADS)

Tang, Jingshi; Liu, Lin

Beidou Navigation Satellite System (BDS) is China's navigation satelite system. It is now operational for navigation service in China and Asia-Pacific region and is due to be fully operational as a global navigation system by 2020. Unlike other navigation satellite systems, BDS consists of both 12-hour medium Earth orbit and 24-hour geosynchronous orbit. To sustain a safe environment for the navigation satellites, the end-of-life satellites must be disposed appropriately so they do not pose potential dangers to the operational satellites. There are currently two strategies for the disposal orbit. One is to put the disposed satellite in a graveyard orbit that has a safe distance from the operational satellites. It is often applied in geosynchronous orbits and such graveyard orbit can always maintain a safe distance even for a few centuries. This strategy is also currently adopted by GPS, yet recent researches show a re-entry orbit can sometimes be a better alternative. The interaction of Earth oblateness and lunisolar gravitation can lead to a rapid increase in the orbit eccentricity such that by proper design the disposed GPS satellite can be cleared out by re-entry into the atmosphere. In this work we focus on the disposal strategy for BDS geosynchronous orbit, which consists of the equatorial stationary orbit (GEO) and the inclined orbit (IGSO). We show that these two orbits are essentially in two different dynamical environments and evolve quite distinctly over a long period of time. Taking advantage of the dynamic nature, we apply the graveyard orbit and the re-entry orbit to GEO and IGSO respectively and propose appropriate disposal strategies accordingly.

The effects of the geosynchronous energetic particle radiation environment on spacecraft charging phenomena

NASA Technical Reports Server (NTRS)

Reagan, J. B.; Imhof, W. L.; Gaines, E. E.

1977-01-01

The energetic electron environment at the geosynchronous orbit is responsible for a variety of adverse charging effects on spacecraft components. The most serious of these is the degradation and failure of a complementary-metal-oxide-semiconductor (CMOS) electronic components as a result of internal charge-buildup induced by the energetic electrons. Efforts to accurately determine the expected lifetime of these components in this orbit are hampered by the lack of detailed knowledge of the electron spectrum and intensity, particularly of the more penetrating energies greater than 1.5 MeV. This problem is illustrated through the calculation of the dose received by a CMOS device from the energetic electrons and associated bremsstrahlung as a function of aluminum shielding thickness using the NASA AE-6 and the Aerospace measured electron environments. Two computational codes which were found to be in good agreement were used to perform the calculations. For a given shielding thickness the dose received with the two radiation environments differ by as much as a factor of seven with a corresponding variation in lifetime of the CMOS.

Charged Coupled Device Debris Telescope Observations of the Geosynchronous Orbital Debris Environment - Observing Year: 1998

NASA Technical Reports Server (NTRS)

Jarvis, K. S.; Thumm, T. L.; Matney, M. J.; Jorgensen, K.; Stansbery, E. G.; Africano, J. L.; Sydney, P. F.; Mulrooney, M. K.

2002-01-01

NASA has been using the charged coupled device (CCD) debris telescope (CDT)--a transportable 32-cm Schmidt telescope located near Cloudcroft, New Mexico-to help characterize the debris environment in geosynchronous Earth orbit (GEO). The CDT is equipped with a SITe 512 x 512 CCD camera whose 24 m2 (12.5 arc sec) pixels produce a 1.7 x 1.7-deg field of view. The CDT system can therefore detect l7th-magnitude objects in a 20-sec integration corresponding to an approx. 0.6-m diameter, 0.20 albedo object at 36,000 km. The telescope pointing and CCD operation are computer controlled to collect data automatically for an entire night. The CDT has collected more than 1500 hrs of data since November 1997. This report describes the collection and analysis of 58 nights (approx. 420 hrs) of data acquired in 1998.

AOTV Low L/D Preliminary Aeroheating Design Environment

NASA Technical Reports Server (NTRS)

Engel, C. D.

1983-01-01

The aerothermal environment to a configuration with a brake face which exhibits a low lift to drag ratio (L/D) of below 0.75 is emphasized. The five times geosynchronous (5 x Geo) orbit entry was selected as the design trajectory. The available data base and math model is discussed. The resulting preliminary design environment is documented. Recommendations as to how the design environment may be improved through technological advances are given.

Life Modeling for Nickel-Hydrogen Batteries in Geosynchronous Satellite Operation

DTIC Science & Technology

2005-03-25

aerothermodynamics; chemical and electric propulsion; environmental chemistry; combustion processes; space environment effects on materials, hardening and...intelligent microinstruments for monitoring space and launch system environments . Space Science Applications Laboratory: Magnetospheric, auroral and cosmic-ray...hyperspectral imagery to defense, civil space, commercial, and environmental missions; effects of solar activity, magnetic storms and nuclear explosions on the

Superposed Epoch Analysis of Ring Current Geoeffectiveness Related to Solar Wind and Plasma Sheet Drivers

NASA Technical Reports Server (NTRS)

Liemohm, M. W.; Kozyra, J. U.; Thomsen, M. F.; Borovsky, J. E.; Gahurthakurta, Madulika (Technical Monitor)

2004-01-01

The goal of that proposal was to examine the relationship between solar wind drivers and ring current dynamics through data analysis and numerical simulations. The data analysis study was a statistical examination (via superposed epoch analyses) of a solar cycle's worth of storm data. Solar wind data, geophysical indices, and geosynchronous plasma data were collected for every time period with Dst< -50 nT from 1989 through 2002, and the storm list now exceeds 400 entries. This work was first conducted by a summer undergraduate student, Mr. John Vann (University of Kansas), with funding from the NSF Research Experience for Undergraduates program. It was then continued by a University of Michigan graduate student, Mr. Jichun Zhang. Mr. Zhang is now in his fourth year at U-M and is progressing very well toward a PhD in space science. His dissertation will be based on his data analysis and modeling efforts using this geomagnetic storm database. The results of the data analysis study have been the focus of several conference presentations, and the first manuscript has just been published. Two additional papers are presently being prepared, one on average (superposed) solar wind features for various storm subsets (e.g., intense storms at solar maximum), and another on geosynchronous plasma features for these same storm subsets. The latter result was highlighted by the TR&T program director in his presentation at the COSPAR meeting this summer.

High voltage space plasma interactions. [charging the solar power satellites

NASA Technical Reports Server (NTRS)

Mccoy, J. E.

1980-01-01

Two primary problems resulted from plasma interactions; one of concern to operations in geosynchronous orbit (GEO), the other in low orbits (LEO). The two problems are not the same. Spacecraft charging has become widely recognized as a problem, particularly for communications satellites operating in GEO. The very thin thermal plasmas at GEO are insufficient to bleed off voltage buildups due to higher energy charged particle radiation collected on outer surfaces. Resulting differential charging/discharging causes electrical transients, spurious command signals and possible direct overload damage. An extensive NASA/Air Force program has been underway for several years to address this problem. At lower altitudes, the denser plasmas of the plasmasphere/ionosphere provide sufficient thermal current to limit such charging to a few volts or less. Unfortunately, these thermal plasma currents which solve the GEO spacecraft charging problem can become large enough to cause just the opposite problem in LEO.

Overview of the SHIELDS Project at LANL

NASA Astrophysics Data System (ADS)

Jordanova, V.; Delzanno, G. L.; Henderson, M. G.; Godinez, H. C.; Jeffery, C. A.; Lawrence, E. C.; Meierbachtol, C.; Moulton, D.; Vernon, L.; Woodroffe, J. R.; Toth, G.; Welling, D. T.; Yu, Y.; Birn, J.; Thomsen, M. F.; Borovsky, J.; Denton, M.; Albert, J.; Horne, R. B.; Lemon, C. L.; Markidis, S.; Young, S. L.

2015-12-01

The near-Earth space environment is a highly dynamic and coupled system through a complex set of physical processes over a large range of scales, which responds nonlinearly to driving by the time-varying solar wind. Predicting variations in this environment that can affect technologies in space and on Earth, i.e. "space weather", remains a big space physics challenge. We present a recently funded project through the Los Alamos National Laboratory (LANL) Directed Research and Development (LDRD) program that is developing a new capability to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. The project goals are to specify the dynamics of the hot (keV) particles (the seed population for the radiation belts) on both macro- and micro-scale, including important physics of rapid particle injection and acceleration associated with magnetospheric storms/substorms and plasma waves. This challenging problem is addressed using a team of world-class experts in the fields of space science and computational plasma physics and state-of-the-art models and computational facilities. New data assimilation techniques employing data from LANL instruments on the Van Allen Probes and geosynchronous satellites are developed in addition to physics-based models. This research will provide a framework for understanding of key radiation belt drivers that may accelerate particles to relativistic energies and lead to spacecraft damage and failure. The ability to reliably distinguish between various modes of failure is critically important in anomaly resolution and forensics. SHIELDS will enhance our capability to accurately specify and predict the near-Earth space environment where operational satellites reside.

NASCAP modelling computations on large optics spacecraft in geosynchronous substorm environments

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Purvis, C. K.

1980-01-01

Satellites in geosynchronous orbits have been found to be charged to significant negative voltages during encounters with geomagnetic substorms. When satellite surfaces are charged, there is a probability of enhanced contamination from charged particles attracted back to the satellite by electrostatic forces. This could be particularly disturbing to large satellites using sensitive optical systems. In this study the NASA Charging Analyzer Program (NASCAP) is used to evaluate qualitatively the possibility of such enhanced contamination on a conceptual version of a large satellite. The evaluation is made by computing surface voltages on the satellite due to encounters with substorm environments and then computing charged-particle trajectories in the electric fields around the satellite. Particular attention is paid to the possibility of contaminants reaching a mirror surface inside a dielectric tube because this mirror represents a shielded optical surface in the satellite model used. Deposition of low energy charged particles from other parts of the spacecraft onto the mirror was found to be possible in the assumed moderate substorm environment condition. In the assumed severe substorm environment condition, however, voltage build up on the inside and edges of the dielectric tube in which the mirror is located prevents contaminants from reaching the mirror surface.

Modulation of auroras by Pc5 pulsations in the dawn sector in association with reappearance of energetic particles at geosynchronous orbit

NASA Astrophysics Data System (ADS)

Saka, O.; Hayashi, K.; Klimushkin, D. Yu.; Mager, P. N.

2014-04-01

Geomagnetic Pc5 pulsations were observed in the dawn sector of the auroral zone on 17 January 1994 in association with increased energetic ion fluxes at geosynchronous orbit 10 min after the Pi2 onset. The characteristic properties of auroras associated with these pulsations were studied using movies taken by an all-sky imager. It was found that a pulsating aurora (PA) can be an optical manifestation of the Pc5 waves by a strong poloidal component observed with ground-based magnetometers. Goes7 observations showed compressional pulsations with the same period which can be attributed to the influence of the finite pressure of plasma and field line curvature on the poloidally polarized Alfvén waves. These poloidal pulsations may be generated by the ion injection observed with the LANL 1989-046 satellite. Two auroral arcs were observed north of the PA with optical features characteristic for the toroidal field line resonances: strong localization across L-shells, 180° phase change across the resonance, poleward phase propagation. Thus the Pc5 oscillations split into the toroidal and poloidal mode and oscillated coherently at latitudes from 62°N to 70°N. This study provides observational evidence of polarization splitting of the Alfven oscillation spectrum. Such a polarization splitting would occur in association with the reappearance of the energetic particles at geosynchronous orbit.

Ideas for a future earth observing system from geosynchronous orbit

NASA Technical Reports Server (NTRS)

Shenk, William E.; Hall, Forrest; Esaias, Wayne; Maxwell, Marvin; Suomi, Verner E.; Von Bun, Fritz

1986-01-01

Uses for the proposed geosynchronous platform are described. The geosynchronous satellite could provide good spatial and temporal resolution, a large field-of-view, easier calibration, stereography, and data relay. The limitations of the platform are discussed. The applications of the geosynchronous platform to meteorology, earth surveying, and oceanography are examined.

Nonadiabatic heating of the central plasma sheet at substorm onset

NASA Technical Reports Server (NTRS)

Huang, C. Y.; Frank, L. A.; Rostoker, G.; Fennell, J.; Mitchell, D. G.

1992-01-01

Heating events in the plasma sheet boundary layer and central plasma sheet are found to occur at the onset of expansive phase activity. The main effect is a dramatic increase in plasma temperature, coincident with a partial dipolarization of the magnetic field. Fluxes of energetic particles increase without dispersion during these events which occur at all radial distances up to 23 RE, the apogee of the ISEE spacecraft. A major difference between these heating events and those observed at geosynchronous distances lies in the heating mechanism which is nonadiabatic beyond 10 RE but may be adiabatic closer to earth. The energy required to account for the increase in plasma thermal energy is comparable with that required for Joule heating of the ionosphere. The plasma sheet must be considered as a major sink in the energy balance of a substorm. Lobe magnetic pressures during these events are estimated. Change in lobe pressure are generally not correlated with onsets or intensifications of expansive phase activity.

Preliminary analysis of accelerated space flight ionizing radiation testing

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Stock, L. V.; Carter, D. J.; Chang, C. K.

1982-01-01

A preliminary analysis shows that radiation dose equivalent to 30 years in the geosynchronous environment can be accumulated in a typical composite material exposed to space for 2 years or less onboard a spacecraft orbiting from perigee of 300 km out to the peak of the inner electron belt (approximately 2750 km). Future work to determine spacecraft orbits better tailored to materials accelerated testing is indicated. It is predicted that a range of 10 to the 9th power to 10 to the 10th power rads would be accumulated in 3-6 mil thick epoxy/graphite exposed by a test spacecraft orbiting in the inner electron belt. This dose is equivalent to the accumulated dose that this material would be expected to have after 30 years in a geosynchronous orbit. It is anticipated that material specimens would be brought back to Earth after 2 years in the radiation environment so that space radiation effects on materials could be analyzed by laboratory methods.

Characterizing the Survey Strategy and Initial Orbit Determination Abilities of the NASA MCAT Telescope for Geosynchronous Orbital Debris Environmental Studies

NASA Technical Reports Server (NTRS)

Frith, James; Barker, Ed; Cowardin, Heather; Buckalew, Brent; Anz-Meado, Phillip; Lederer, Susan

2017-01-01

The NASA Orbital Debris Program Office (ODPO) recently commissioned the Meter Class Autonomous Telescope (MCAT) on Ascension Island with the primary goal of obtaining population statistics of the geosynchronous (GEO) orbital debris environment. To help facilitate this, studies have been conducted using MCAT's known and projected capabilities to estimate the accuracy and timeliness in which it can survey the GEO environment. A simulated GEO debris population is created and sampled at various cadences and run through the Constrained Admissible Region Multi Hypotheses Filter (CAR-MHF). The orbits computed from the results are then compared to the simulated data to assess MCAT's ability to determine accurately the orbits of debris at various sample rates. Additionally, estimates of the rate at which MCAT will be able produce a complete GEO survey are presented using collected weather data and the proposed observation data collection cadence. The specific methods and results are presented here.

Estimation of Untracked Geosynchronous Population from Short-Arc Angles-Only Observations

NASA Technical Reports Server (NTRS)

Healy, Liam; Matney, Mark

2017-01-01

Telescope observations of the geosynchronous regime will observe two basic types of objects --- objects related to geosynchronous earth orbit (GEO) satellites, and objects in highly elliptical geosynchronous transfer orbits (GTO). Because telescopes only measure angular rates, the GTO can occasionally mimic the motion of GEO objects over short arcs. A GEO census based solely on short arc telescope observations may be affected by these ``interlopers''. A census that includes multiple angular rates can get an accurate statistical estimate of the GTO population, and that then can be used to correct the estimate of the geosynchronous earth orbit population.

Statistical Investigations on Solar Wind Dynamic Pressure Pulses:Basic features and Their Impacts on Geosynchronous Magnetic Fields

NASA Astrophysics Data System (ADS)

Zuo, Pingbing; Feng, Xueshang

2016-07-01

Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. Recently we have developed a novel procedure that is able to rapidly identify the DPPs from the plasma data stream, and simultaneously define the transition region and smartly select the upstream and downstream region for analysis. The plasma data with high time-resolution from 3DP instrument on board the WIND spacecraft are inspected with this automatic DPP-searching code, and a complete list of solar wind DPPs of historic WIND observations are built up. We perform a statistical survey on the properties of DPPs near 1 AU based on this event list. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, being stronger at the noon sector.

Theoretical studies of radiation effects in composite materials for space use. [graphite-epoxy composites

NASA Technical Reports Server (NTRS)

Chang, C. K.; Kamaratos, E.

1982-01-01

Tetraglycidyl 4,4'-diamino diphenyl methane epoxy cured with diamino diphenyl sulfone was used as a model compound. Computer programs were developed to calculate (1) energy deposition coefficients of protons and electrons of various energies at different depths of the material; (2) ranges of protons and electrons of various energies in the material; and (3) cumulative doses received by the composite in different geometric shapes placed in orbits of various altitudes and inclination. A preliminary study on accelerated testing was conducted and it was found that an elliptical equitorial orbit of 300 km perigee by 2750 km apogee can accumulate, in 2 years or less, enough radiation dose comparable to geosynchronous environment for 30 years. The local plasma model calculated the mean excitation energies for covalent and ionic compounds. Longitudinal and lateral distributions of excited species by electron and proton impact as well as the probability of overlapping of two tracks due to two charged particles within various time intervals were studied.

Active space debris charging for contactless electrostatic disposal maneuvers

NASA Astrophysics Data System (ADS)

Schaub, Hanspeter; Sternovsky, Zoltán

2014-01-01

The remote charging of a passive object using an electron beam enables touchless re-orbiting of large space debris from geosynchronous orbit (GEO) using electrostatic forces. The advantage of this method is that it can operate with a separation distance of multiple craft radii, thus reducing the risk of collision. The charging of the tug-debris system to high potentials is achieved by active charge transfer using a directed electron beam. Optimal potential distributions using isolated- and coupled-sphere models are discussed. A simple charging model takes into account the primary electron beam current, ultra-violet radiation induced photoelectron emission, collection of plasma particles, secondary electron emission and the recapture of emitted particles. The results show that through active charging in a GEO space environment high potentials can be both achieved and maintained with about a 75% transfer efficiency. Further, the maximum electrostatic tractor force is shown to be insensitive to beam current levels. This latter later result is important when considering debris with unknown properties.

Mission analysis data for inclined geosynchronous orbits, part 1

NASA Technical Reports Server (NTRS)

Graf, O. F., Jr.; Wang, K. C.

1980-01-01

Data needed for preliminary design of inclined geosynchronous missions are provided. The inertial and Earth fixed coordinate systems are described, as well as orbit parameters and elements. The complete family of geosynchronous orbits is discussed. It is shown that circular inclined geosynchronous orbits comprise only one set in this family. The major orbit perturbation and their separate effects on the geosynchronous orbit are discussed. Detailed information on the orbit perturbation of inclined circular geosynchronous orbits is given, with emphasis on time history data of certain orbital elements. Orbit maintenance delta velocity (V) requirements to counteract the major orbit perturbations are determined in order to provide order of magnitude estimates and to show the effects of orbit inclination on delta V. Some of the considerations in mission design for a multisatellite system, such as a halo orbit constellation, are discussed.

Space simulation test for thermal control materials

NASA Technical Reports Server (NTRS)

Hardgrove, W. R.

1990-01-01

Tests were run in TRW's Combined Environment Facility to examine the degradation of thermal control materials in a simulated space environment. Thermal control materials selected for the test were those presently being used on spacecraft or predicted to be used within the next few years. The geosynchronous orbit environment was selected as the most interesting. One of the goals was to match degradation of those materials with available flight data. Another aim was to determine if degradation can adequately be determined with accelerated or short term ground tests.

Comparison of high-energy trapped particle environments at the Earth and Jupiter.

PubMed

Jun, Insoo; Garrett, Henry B

2005-01-01

The 'Van Allen belts' of the trapped energetic particles in the Earth's magnetosphere were discovered by the Explorer I satellite in 1958. In addition, in 1959, it was observed that UHF radio emissions from Jupiter probably had a similar source--the Jovian radiation belts. In this paper, the global characteristics of these two planets' trapped radiation environments and respective magnetospheres are compared and state-of-the-art models used to generate estimates of the high-energy electron (> or = 100 keV) and proton (> or = 1 MeV) populations--the dominant radiation particles in these environments. The models used are the AP8/AE8 series for the Earth and the Divine-Garrett/GIRE model for Jupiter. To illustrate the relative magnitude of radiation effects at each planet, radiation transport calculations were performed to compute the total ionising dose levels at the geosynchronous orbit for the Earth and at Europa (Jupiter's 4th largest moon) for Jupiter. The results show that the dose rates are -0.1 krad(Si) d(-1) at the geosynchronous orbit and -30 krad(Si) d((-1) at Europa for a 2.5 mm spherical shell aluminium shield--a factor of -300 between the two planets.

A threshold effect for spacecraft charging

NASA Technical Reports Server (NTRS)

Olsen, R. C.

1983-01-01

The borderline case between no charging and large (kV) negative potentials for eclipse charging events on geosynchronous satellites is investigated, and the dependence of this transition on a threshold energy in the ambient plasma is examined. Data from the Applied Technology Satellite 6 and P78-2 (SCATHA) show that plasma sheet fluxes must extend above 10 keV for these satellites to charge in eclipse. The threshold effect is a result of the shape of the normal secondary yield curve, in particular the high energy crossover, where the secondary yield drops below 1. It is found that a large portion of the ambient electron flux must exceed this energy for a negative current to exist.

Radiation protection design considerations for man in geosynchronous orbits

NASA Technical Reports Server (NTRS)

Rossi, M. L.; Stauber, M. C.

1977-01-01

A description is presented of preliminary studies which have been carried out to identify design requirements and mission constraints imposed by the geosynchronous radiation environment. The radiation species of dominant impact are the trapped electrons and solar flare particles. The criterion used in the conducted shielding design analysis has been to limit the skin dose to 100 rems for 3 months. The analysis included the optimization of an electron/bremsstrahlung shield for residence within the vehicle, the minimization of the dose received in extravehicular activity, and the calculation of special shield requirements for solar flares. An investigation was conducted of the potential benefits accruing from a three-layered composite shield with part of the aluminum layer replaced with a lower atomic number material. The materials considered were polyethylene, carbon, beryllium, and lithium hydride.

Geosynchronous platform definition study. Volume 3: Geosynchronous mission characteristics

NASA Technical Reports Server (NTRS)

1973-01-01

The objectives of the study were to examine the nature of currently planned and new evolutionary geosynchronous programs, to analyze alternative ways of conducting missions, to establish concepts for new systems to support geosynchronous programs in an effective and economical manner, and to define the logistic support to carry out these programs. In order to meet these objectives, it was necessary to define and examine general geosynchronous mission characteristics and the potentially applicable electromagnetic spectrum characteristics. An organized compilation of these data is given with emphasis on the development and use of the data. Fundamental geosynchronous orbit time histories, mission profile characteristics, and delivery system characteristics are presented. In addition, electromagnetic spectrum utilization is discussed in terms of the usable frequency spectrum, the spectrum potentially available considering established frequency allocations, and the technology status as it affects the ability to operate within specific frequency bands.

Spacecraft Charging at Geosynchronous Orbit and Large Scale Electric Fields in the High Latitude Ionosphere.

DTIC Science & Technology

1981-09-30

changes are not inductive in nature. San Diego (UCSD), Group and co-workers. We wish to focus ’Dynamic’ injections of plasma are characterized by a...549, 1971. 4555, 1981. Ulmatead, D., On the recent secular period of the King, J. H., Solar cycle variations in the IMF aurora borealis , Smithson...photoemission for the different materials suggest the University of California at San Diego (UCSD) differences exist with regards to the relative impor

Space Tug Aerobraking Study. Volume 2: Technical

NASA Technical Reports Server (NTRS)

Corso, C. J.; Eyer, C. L.

1972-01-01

The feasibility and practicality of employing an aerobraking trajectory for return of the reusable Space Tug from geosynchronous and other high energy missions was investigated. The aerobraking return trajectory modes from high orbits employ transfer ellipses which have low perigee altitudes wherein the earth's sensible atmosphere provides drag to reduce the Tug descent delta velocity requirements and thus decrease the required return trip propulsive energy. An aerobraked Space Tug, sized to the Space Shuttle payload capability and dimensional constraints, can accomplish 95 percent of the geosynchronous missions with a single Shuttle/Tug launch per mission. Aerodynamics, aerothermodynamics, trajectory, quidance and control, configuration concepts, materials, weights and performance parameters were identified. Sensitivities to trajectory uncertainties, atmospheric anomalies and re-entry environments were determined. New technology requirements and future studies required to further enhance the aerobraking potential were identified.

Ring/Shell Ion Distributions at Geosynchronous Orbit

NASA Astrophysics Data System (ADS)

Thomsen, M. F.; Denton, M. H.; Gary, S. P.; Liu, Kaijun; Min, Kyungguk

2017-12-01

One year's worth of plasma observations from geosynchronous orbit is examined for ion distributions that may simultaneously be subject to the ion Bernstein (IB) instability (generating fast magnetosonic waves) and the Alfvén cyclotron (AC) instability (generating electromagnetic ion cyclotron waves). Confirming past analyses, distributions with robust ∂fp(v⊥)/∂v⊥ > 0 near v|| = 0, which we denote as "ring/shell" distributions, are commonly found primarily on the dayside of the magnetosphere. A new approach to high-fidelity representation of the observed ring/shell distribution functions in a form readily suited to both analytical moment calculation and linear dispersion analysis is presented, which allows statistical analysis of the ring/shell properties. The ring/shell temperature anisotropy is found to have a clear upper limit that depends on the parallel beta of the ring/shell (β||r) in a manner that is diagnostic of the operation of the AC instability. This upper limit is only reached in the postnoon events, which are primarily produced by the energy- and pitch angle-dependent magnetic drifts of substorm-injected ions. Further, it is primarily the leading edge of such injections, where the distribution is strongly ring-like, that the AC instability appears to be operating. By contrast, the ratio of the ring energy to the Alfvén energy remains well within the range of 0.25-4.0 suitable for IB instability throughout essentially all of the events, except those that occur in denser cold plasma of the outer plasmasphere.

Geosynchronous earth orbit/low earth orbit space object inspection and debris disposal: A preliminary analysis using a carrier satellite with deployable small satellites

NASA Astrophysics Data System (ADS)

Crockett, Derick

Detailed observations of geosynchronous satellites from earth are very limited. To better inspect these high altitude satellites, the use of small, refuelable satellites is proposed. The small satellites are stationed on a carrier platform in an orbit near the population of geosynchronous satellites. A carrier platform equipped with deployable, refuelable SmallSats is a viable option to inspect geosynchronous satellites. The propellant requirement to transfer to a targeted geosynchronous satellite, perform a proximity inspection mission, and transfer back to the carrier platform in a nearby orbit is determined. Convex optimization and traditional optimization techniques are explored, determining minimum propellant trajectories. Propellant is measured by the total required change in velocity, delta-v. The trajectories were modeled in a relative reference frame using the Clohessy-Wiltshire equations. Mass estimations for the carrier platform and the SmallSat were determined by using the rocket equation. The mass estimates were compared to the mass of a single, non-refuelable satellite performing the same geosynchronous satellite inspection missions. From the minimum delta-v trajectories and the mass analysis, it is determined that using refuelable SmallSats and a carrier platform in a nearby orbit can be more efficient than using a single non-refuelable satellite to perform multiple geosynchronous satellite inspections.

Space Weathering Experiments on Spacecraft Materials

NASA Technical Reports Server (NTRS)

Engelhart, D. P.; Cooper, R.; Cowardin, H.; Maxwell, J.; Plis, E.; Ferguson, D.; Barton, D.; Schiefer, S.; Hoffmann, R.

2017-01-01

A project to investigate space environment effects on specific materials with interest to remote sensing was initiated in 2016. The goal of the project is to better characterize changes in the optical properties of polymers found in multi-layered spacecraft insulation (MLI) induced by electron bombardment. Previous analysis shows that chemical bonds break and potentially reform when exposed to high energy electrons like those seen in orbit. These chemical changes have been shown to alter a material's optical reflectance, among other material properties. This paper presents the initial experimental results of MLI materials exposed to various fluences of high energy electrons, designed to simulate a portion of the geosynchronous Earth orbit (GEO) space environment. It is shown that the spectral reflectance of some of the tested materials changes as a function of electron dose. These results provide an experimental benchmark for analysis of aging effects on satellite systems which can be used to improve remote sensing and space situational awareness. They also provide preliminary analysis on those materials that are most likely to comprise the high area-to-mass ratio (HAMR) population of space debris in the geosynchronous orbit environment. Finally, the results presented in this paper serve as a proof of concept for simulated environmental aging of spacecraft polymers that should lead to more experiments using a larger subset of spacecraft materials.

Space Weathering Experiments on Spacecraft Materials

NASA Technical Reports Server (NTRS)

Cooper, R.; Cowardin, H.; Engelhar, D.; Plis, Elena; Hoffman, R.

2017-01-01

A project to investigate space environment effects on specific materials with interest to remote sensing was initiated in 2016. The goal of the project is to better characterize changes in the optical properties of polymers and Mylar, specifically those found in multi-layered spacecraft insulation, due to electron bombardment. Previous analysis shows that chemical bonds break and potentially reform when exposed to high energy electrons. Among other properties these chemical changes altered the optical reflectance as documented in laboratory analysis. This paper presents results of the initial experiment results focused on the exposure of materials to various fluences of high energy electrons, used to simulate a portion of the geosynchronous space environment. The paper illustrates how the spectral reflectance changes as a function of time on orbit with respect to GEO environmental factors and investigates the survivability of the material after multiple electron doses. These results provide a baseline for analysis of aging effects on satellite systems used for remote sensing. They also provide preliminary analysis on what materials are most likely to encompass the high area-to-mass population of space debris in the geosynchronous environment. Lastly, the paper provides the results of the initial experimentation as a proof of concept for space aging on polymers and Mylar for conducting more experiments with a larger subset of spacecraft materials.

First geosynchronous weather satellite prepared for launch

NASA Technical Reports Server (NTRS)

1974-01-01

The Synchronous Meteorological Satellite (SMS), which is scheduled for launch 16 May 1974 is described along with the data transmission system. The Carrier Balloon System is discussed. The primary type of data to be obtained in conjunction with SMS and Nimbus F are meteorological, oceanographic, seismic, and tsunami information. The Space Environment Monitoring System is also described.

Geosynchronous platform definition study. Volume 6: Geosynchronous program evaluation and recommendations

NASA Technical Reports Server (NTRS)

Myers, H. L.

1973-01-01

The programmatic analyses conducted to achieve the objectives of the study are presented. The characteristics are examined of alternate geosynchronous programs based on servicing concepts, geosynchronous platform configurations, and equipment definitions which have evolved during the study. The logistics support necessary to carry out programs using these systems is defined considering alternate approaches for on-orbit servicing. The costs of the resultant programs are then determined and the alternate program approaches compared. Conventional programs with expendable satellites are also defined to the extent necessary to permit comparison with on-orbit serviced platform programs.

An RCM-E simulation of a steady magnetospheric convection event

NASA Astrophysics Data System (ADS)

Yang, J.; Toffoletto, F.; Wolf, R.; Song, Y.

2009-12-01

We present simulation results of an idealized steady magnetospheric convection (SMC) event using the Rice Convection Model coupled with an equilibrium magnetic field solver (RCM-E). The event is modeled by placing a plasma distribution with substantially depleted entropy parameter PV5/3 on the RCM's high latitude boundary. The calculated magnetic field shows a highly depressed configuration due to the enhanced westward current around geosynchronous orbit where the resulting partial ring current is stronger and more symmetric than in a typical substorm growth phase. The magnitude of BZ component in the mid plasma sheet is large compared to empirical magnetic field models. Contrary to some previous results, there is no deep BZ minimum in the near-Earth plasma sheet. This suggests that the magnetosphere could transfer into a strong adiabatic earthward convection mode without significant stretching of the plasma-sheet magnetic field, when there are flux tubes with depleted plasma content continuously entering the inner magnetosphere from the mid-tail. Virtual AU/AL and Dst indices are also calculated using a synthetic magnetogram code and are compared to typical features in published observations.

A system for predicting close approaches and potential collisions in geosynchronous orbits

NASA Astrophysics Data System (ADS)

Beusch, J.; Abbot, R.; Sridharan, R.

The geosynchronous orbit is getting crowded with over 300 active, revenue producing large satellites and over 500 inactive dead resident space objects that pose a physical collision threat to the active satellites. The in situ demise of a particular satellite, Telstar 401, followed by a similar demise of SOLIDARIDAD 1, initiated a research and development effort at MIT Lincoln Laboratory to address this threat. This work with commercial satellite operators is accomplished using the mechanism of Cooperative Research and Development Agreements. Initial work to detect and warn of close approaches with these two failed satellites led to more extensive research on the collision threat over the entire geosynchronous belt. It is apparent that: a) There is a significant probability of collision; b) The probability has increased considerably in the last decade or so; c) The continuing failure of geosynchronous satellites and injection of rocket bodies into or near geosynchronous orbit will increase the threat; d) Debris in or near geosynchronous orbit poses another problem that has to be addressed. This paper surveys what has been achieved so far in predicting the threat and protecting satellites. An assessment of the probability of collision is presented as well as a description of the Geosynchronous Monitoring and Warning System. The operations of the GMWS are described as well as some of the results achieved so far. Areas of current research are mentioned.

Technology, design, simulation, and evaluation for SEP-hardened circuits

NASA Technical Reports Server (NTRS)

Adams, J. R.; Allred, D.; Barry, M.; Rudeck, P.; Woodruff, R.; Hoekstra, J.; Gardner, H.

1991-01-01

This paper describes the technology, design, simulation, and evaluation for improvement of the Single Event Phenomena (SEP) hardness of gate-array and SRAM cells. Through the use of design and processing techniques, it is possible to achieve an SEP error rate less than 1.0 x 10(exp -10) errors/bit-day for a 9O percent worst-case geosynchronous orbit environment.

Characterizing the Survey Strategy and Initial Orbit Determination Abilities of the NASA MCAT Telescope for Geosynchronous Orbital Debris Environmental Studies

NASA Astrophysics Data System (ADS)

Frith, J.; Barker, E.; Cowardin, H.; Buckalew, B.; Anz-Meador, P.; Lederer, S.

The National Aeronautics and Space Administration (NASA) Orbital Debris Program Office (ODPO) recently commissioned the Meter Class Autonomous Telescope (MCAT) on Ascension Island with the primary goal of obtaining population statistics of the geosynchronous (GEO) orbital debris environment. To help facilitate this, studies have been conducted using MCAT’s known and projected capabilities to estimate the accuracy and timeliness in which it can survey the GEO environment, including collected weather data and the proposed observational data collection cadence. To optimize observing cadences and probability of detection, on-going work using a simulated GEO debris population sampled at various cadences are run through the Constrained Admissible Region Multi Hypotheses Filter (CAR-MHF). The orbits computed from the results are then compared to the simulated data to assess MCAT’s ability to determine accurately the orbits of debris at various sample rates. The goal of this work is to discriminate GEO and near-GEO objects from GEO transfer orbit objects that can appear as GEO objects in the environmental models due to the short arc observation and an assumed circular orbit. The specific methods and results are presented here.

Data-constrained models of quiet and storm-time geosynchronous magnetic field based on observations in the near geospace

NASA Astrophysics Data System (ADS)

Andreeva, V. A.; Tsyganenko, N. A.

2017-12-01

The geosynchronous orbit is unique in that its nightside segment skims along the boundary, separating the inner magnetosphere with a predominantly dipolar configuration from the magnetotail, where the Earth's magnetic field becomes small relative to the contribution from external sources. The ability to accurately reconstruct the magnetospheric configuration at GEO is important to understand the behavior of plasma and energetic particles, which critically affect space weather in the area densely populated by a host of satellites. To that end, we have developed a dynamical empirical model of the geosynchronous magnetic field with forecasting capability, based on a multi-year set of data taken by THEMIS, Polar, Cluster, Geotail, and Van Allen missions. The model's mathematical structure is devised using a new approach [Andreeva and Tsyganenko, 2016, doi:10.1002/2015JA022242], in which the toroidal/poloidal components of the field are represented using the radial and azimuthal basis functions. The model describes the field as a function of solar-magnetic coordinates, geodipole tilt angle, solar wind pressure, and a set of dynamic variables, quantifying the magnetosphere's response to external driving/loading and internal relaxation/dissipation during the disturbance recovery. The response variables are introduced following the approach by Tsyganenko and Sitnov [2005, doi:10.1029/2004JA010798], in which the electric current dynamics was described as a result of competition between the external energy input and the subsequent internal losses of the injected energy. The model's applicability range extends from quiet to moderately disturbed conditions, with peak Sym-H values -150 nT. The obtained results have been validated using independent GOES magnetometer data, taken during the maximum of the 23rd solar cycle and its declining phase.

Discrimination of Closely-Spaced Geosynchronous Satellites - Phase Curve Analysis & New Small Business Innovative Research (SBIR) Efforts

DTIC Science & Technology

2010-09-01

Discrimination of Closely-Spaced Geosynchronous Satellites – Phase Curve Analysis & New Small Business Innovative Research (SBIR) Efforts...such objects from one time epoch to another showcases the deficiencies in associating individual objects before and after the configuration change...1]) have emphasized examples of multiple satellites occupying the same geosynchronous slot, with individual satellites maneuvering about one another

Long-lived plasmaspheric drainage plumes: Where does the plasma come from?

NASA Astrophysics Data System (ADS)

Borovsky, Joseph E.; Welling, Daniel T.; Thomsen, Michelle F.; Denton, Michael H.

2014-08-01

Long-lived (weeks) plasmaspheric drainage plumes are explored. The long-lived plumes occur during long-lived high-speed-stream-driven storms. Spacecraft in geosynchronous orbit see the plumes as dense plasmaspheric plasma advecting sunward toward the dayside magnetopause. The older plumes have the same densities and local time widths as younger plumes, and like younger plumes they are lumpy in density and they reside in a spatial gap in the electron plasma sheet (in sort of a drainage corridor). Magnetospheric-convection simulations indicate that drainage from a filled outer plasmasphere can only supply a plume for 1.5-2 days. The question arises for long-lived plumes (and for any plume older than about 2 days): Where is the plasma coming from? Three candidate sources appear promising: (1) substorm disruption of the nightside plasmasphere which may transport plasmaspheric plasma outward onto open drift orbits, (2) radial transport of plasmaspheric plasma in velocity-shear-driven instabilities near the duskside plasmapause, and (3) an anomalously high upflux of cold ionospheric protons from the tongue of ionization in the dayside ionosphere, which may directly supply ionospheric plasma into the plume. In the first two cases the plume is drainage of plasma from the magnetosphere; in the third case it is not. Where the plasma in long-lived plumes is coming from is a quandary: to fix this dilemma, further work and probably full-scale simulations are needed.

Measuring Geosynchronous Satellites from Stellar Appulses with AO

DTIC Science & Technology

2014-09-01

These stars provided reference positions and magnitudes for the satellites . Overall, we demonstrate that we can time appulses of stars and geosynchronous...provided reference positions and magnitudes for the satellites . Overall, we demonstrate that we can time appulses of stars and geosynchronous satellites to...with 20 ms exposure times . When we returned to the third set of images, we found another satellite in the field and followed them together on the third

Design Concept for a Reusable/Propellantless MXER Tether Space Transportation System

NASA Technical Reports Server (NTRS)

McCandless, B., II; Kustas, F. m.; Marshall, L. S.; Lytle, W. B.; Hansen, N. P.

2005-01-01

The Momentum Exchange/Electrodynamic Reboost (MXER) tether facility is a transformational concept that significantly reduces the fuel requirements (and associated costs) in transferring payloads above low earth orbit (LEO). Facility reboost is accomplished without propellant by driving current against a voltage created by a conducting tether's interaction with the Earth's magnetic field (electrodynamic reboost). This system can be used for transferring a variety of payloads (scientific, cargo, and human space vehicles) to multiple destinations including geosynchronous transfer orbit, the Moon or Mars. MXER technology advancement requires development in two key areas: survivable, high tensile strength non-conducting tethers and reliable, lightweight payload catch/release mechanisms. Fundamental requirements associated with the MXER non-conducting strength tether and catch mechanism designs will be presented. Key requirements for the tether design include high specific-strength (tensile strength/material density), material survivability to the space environment (atomic oxygen and ultraviolet radiation), and structural survivability to micrometeoroid/orbital debris (MM/OD) impacts. The driving mechanism key,gequirements include low mass-to-capture-volume ratio, positional and velocity error tolerance, and operational reliability. Preliminary tether and catch mechanism design criteria are presented, which have been used as guidelines to "screen" and down-select initial concepts. Candidate tether materials and protective coatings are summarized along with their performance in simulated space environments (e.g., oxygen plasma, thermal cycling). A candidate catch mechanism design concept is presented along with examples of demonstration hardware.

A Statistical Examination of Magnetic Field Model Accuracy for Mapping Geosynchronous Solar Energetic Particle Observations to Lower Earth Orbits

NASA Astrophysics Data System (ADS)

Young, S. L.; Kress, B. T.; Rodriguez, J. V.; McCollough, J. P.

2013-12-01

Operational specifications of space environmental hazards can be an important input used by decision makers. Ideally the specification would come from on-board sensors, but for satellites where that capability is not available another option is to map data from remote observations to the location of the satellite. This requires a model of the physical environment and an understanding of its accuracy for mapping applications. We present a statistical comparison between magnetic field model mappings of solar energetic particle observations made by NOAA's Geostationary Operational Environmental Satellites (GOES) to the location of the Combined Release and Radiation Effects Satellite (CRRES). Because CRRES followed a geosynchronous transfer orbit which precessed in local time this allows us to examine the model accuracy between LEO and GEO orbits across a range of local times. We examine the accuracy of multiple magnetic field models using a variety of statistics and examine their utility for operational purposes.

Participation in the scientific activities of the Waves in Space Plasma (WISP) project

NASA Technical Reports Server (NTRS)

Alpert, Yakov L.; Grossi, Mario D.

1994-01-01

This is the Final Report for Contract NAG5-1925, that consisted of experiment design, for possible use by the space science mission called WISP (Waves in Space Plasma). This mission is under study by the Canadian Space Agency and by NASA. Two WISP configurations are contemplated, under the name of BICEPS: one is called BOLAS, and the other WISPRS. Both these configurations are meant to perform bistatic sounding of the ionosphere, at a height close to F(sub 2) H(sub max) (about 350 Km), with a pair of satellites, either tethered or in free flight. Investigation A (with Y.L. Alpert as P.I.) addresses the subject of parametric decay effects, expected to arise in a magnetoplasma under the influence of high-intensity HF fields. Criteria were formulated that could be used in searching for parametric instabilities and of electric fields in the ionosphere and magnetosphere, by in-situ satellites, such as the BICEPS Pair. Investigation B (with M.D.Grossi as P.I.) addressed the bistatic measurement, by the BICEPS pair,of ionospheric features, such as large-scale and small-scale disturbances, travelling ionospheric disturbances, electron density irregularities, spread-F phenomena, etc. These measurements by BICEPS could be correlated with the waveform distortion and degradation experienced by microwave links from geosynchronous height to ground, such as the ACTS satellite, expected to radiate pulses as short as 1 nanosecond in the band 20 to 30 GHz. These links are transionospheric and propagate e.m. waves in the volume of the ionosphere where BICEPS operates. It will be possible, therefore, to correlate the two classes of measurements, and learn the causative mechanisms that are responsible for the time-spread and frequency-spread nature of communications waveforms at microwave, in geosynchronous height to ground paths.

Information services platforms at geosynchronous earth orbit: A requirements analysis

NASA Technical Reports Server (NTRS)

1978-01-01

The potential user requirements for Information Services Platforms at geosynchronous orbits were investigated. A rationale for identifying the corollary system requirements and supporting research and technology needs was provided.

The Role of Ionospheric Outflow Preconditioning in Determining Storm Geoeffectiveness

NASA Astrophysics Data System (ADS)

Welling, D. T.; Liemohn, M. W.; Ridley, A. J.

2012-12-01

It is now well accepted that ionospheric outflow plays an important role in the development of the plasma sheet and ring current during geomagnetic storms. Furthermore, even during quiet times, ionospheric plasma populates the magnetospheric lobes, producing a reservoir of hydrogen and oxygen ions. When the Interplanetary Magnetic Field (IMF) turns southward, this reservoir is connected to the plasma sheet and ring current through magnetospheric convection. Hence, the conditions of the ionosphere and magnetospheric lobes leading up to magnetospheric storm onset have important implications for storm development. Despite this, there has been little research on this preconditioning; most global simulations begin just before storm onset, neglecting preconditioning altogether. This work explores the role of preconditioning in determining the geoeffectiveness of storms using a coupled global model system. A model of ionospheric outflow (the Polar Wind Outflow Model, PWOM) is two-way coupled to a global magnetohydrodynamic model (the Block-Adaptive Tree Solar wind Roe-type Upwind Scheme, BATS-R-US), which in turn drives a ring current model (the Ring current Atmosphere interactions Model, RAM). This unique setup is used to simulate an idealized storm. The model is started at many different times, from 1 hour before storm onset to 12 hours before. The effects of storm preconditioning are examined by investigating the total ionospheric plasma content in the lobes just before onset, the total ionospheric contribution in the ring current just after onset, and the effects on Dst, magnetic elevation angle at geosynchronous, and total ring current energy density. This experiment is repeated for different solar activity levels as set by F10.7 flux. Finally, a synthetic double-dip storm is constructed to see how two closely spaced storms affect each other by changing the preconditioning environment. It is found that preconditioning of the magnetospheric lobes via ionospheric outflow greatly influences the geoeffectiveness of magnetospheric storms.

The 50 AMP-hour nickel cadmium battery manual

NASA Technical Reports Server (NTRS)

Webb, D. A.

1981-01-01

The battery is designed with a minimum battery to cell weight ratio consistent with adequate containment for operating conditions and dynamic environments and minimized weight. The battery is fully qualified and the environments to which it was successfully subjected were selected by NASA Goddard to cover a wide range of probable uses. The battery is suitable for either near-Earth geosynchronous missions, is compatible with passive or active thermal control systems and may be electrically controlled by a variety of changing routines. The initial application of the 50 A.H. Battery is a near-Earth mission aboard the LANDSAT D Satellite.

Long-lived plasmaspheric plumes: What is the source of the plasma?

NASA Astrophysics Data System (ADS)

Denton, M.; Borovsky, J.; Thomsen, M. F.; Welling, D. T.

2015-12-01

Magnetospheric Plasma Analyzer (MPA) instruments on-board Los Alamos National Laboratory (LANL) satellites regularly measures cold ions in the plasmasphere, and in plasmaspheric plumes. Following periods of calm geomagnetic conditions, the plasmasphere fills to ion number densities in excess of 100 cm-3 - these ions corotate with the Earth. During enhanced convection the outer plasmasphere is eroded - these ions are convected to the dayside magnetopause. LANL/MPA instruments regularly measure plumes which last for many days. On occasion, plumes can last more than two weeks. Such observations raise questions as to the production mechanisms that can continually supply high-number-density material to geosynchronous orbit, and onwards to the magnetopause. We will discuss the plume observations by LANL/MPA, improvements in theoretical modeling of the refilling process, and the need for in-situ observations (from TEC, satellites, etc.) required to address this problem.

Large space system: Charged particle environment interaction technology

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Roche, J. C.; Grier, N. T.

1979-01-01

Large, high voltage space power systems are proposed for future space missions. These systems must operate in the charged-particle environment of space and interactions between this environment and the high voltage surfaces are possible. Ground simulation testing indicated that dielectric surfaces that usually surround biased conductors can influence these interactions. For positive voltages greater than 100 volts, it has been found that the dielectrics contribute to the current collection area. For negative voltages greater than-500 volts, the data indicates that the dielectrics contribute to discharges. A large, high-voltage power system operating in geosynchronous orbit was analyzed. Results of this analysis indicate that very strong electric fields exist in these power systems.

Development of a continuous broad-energy-spectrum electron source

NASA Technical Reports Server (NTRS)

Adamo, R. C.; Nanevicz, J. E.

1985-01-01

The development of a practical prototype, large-area, continuous-spectrum, multienergy electron source to simulate the lower energy (approx = 1 to 30 keV) portion of the geosynchronous orbit electron environment was investigated. The results of future materials-charging tests using this multienergy source should significantly improve the understanding of actual in-orbit charging processes and should help to resolve some of the descrepancies between predicted and observed spacecraft materials performance.

Geosynchronous platform definition study. Volume 4, Part 1: Traffic analysis and system requirements for the baseline traffic model

NASA Technical Reports Server (NTRS)

1973-01-01

The traffic analyses and system requirements data generated in the study resulted in the development of two traffic models; the baseline traffic model and the new traffic model. The baseline traffic model provides traceability between the numbers and types of geosynchronous missions considered in the study and the entire spectrum of missions foreseen in the total national space program. The information presented pertaining to the baseline traffic model includes: (1) definition of the baseline traffic model, including identification of specific geosynchronous missions and their payload delivery schedules through 1990; (2) Satellite location criteria, including the resulting distribution of the satellite population; (3) Geosynchronous orbit saturation analyses, including the effects of satellite physical proximity and potential electromagnetic interference; and (4) Platform system requirements analyses, including satellite and mission equipment descriptions, the options and limitations in grouping satellites, and on-orbit servicing criteria (both remotely controlled and man-attended).

The magnetospheric lobe at geosynchronous orbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomsen, M.F.; Bame, S.J.; McComas, D.J.

1994-09-01

On rare occasions, satellites at geosynchronous altitude enter the magnetospheric lobe, characterized by extremely low ion fluxes between 1 eV and 40 keV and electron fluxes above a few hundred eV. One year of plasma observations from two simultaneously operating spacecraft at synchronous orbit is surveyed for lobe encounters. A total of 34 full encounters and 56 apparent near encounters are identified, corresponding to {approximately}0.06% of the total observation time. Unlike energetic particle (E>40 keV) dropouts studied earlier, there is a strong tendency for the lobe encounters to occur postmidnight, as late as 07 local time. The two spacecraft encountermore » the lobe with different rates and in different seasons. These occurrence properties are not simply explicable in terms of the orbital geometry in either the solar magnetic or the geocentric solar magnetospheric coordinate system. A composite coordinate system which previously organized more energetic particle dropouts is somewhat more successful in organizing the lobe encounters, suggesting that solar wind distortion of the magnetic equatorial plane away from the dipole location and toward the antisolar direction may be largely responsible for these dropouts. The authors results further suggest that this distortion persists even sunward of the dawn-dusk terminator. However, a simple dawn-dusk symmetric distortion does not fully account for all the seasonal and local time asymmetries in the occurrence of the lobe encounters; thus there is probably an additional dawn-dusk asymmetry in the distorted field. The lobe encounters are strongly associated with magnetospheric activity and tend to occur in association with rare magnetosheath encounters at synchronous orbit. It thus appears that the presence of the lobe at geosynchronous orbit is the result of major, probably asymmetric modifications of the magnetospheric field geometry in times of strong disturbance. 19 refs., 7 figs., 1 tab.« less

Mission analysis data for inclined geosynchronous orbits, part 2. Appendix A: Bibliography

NASA Technical Reports Server (NTRS)

1980-01-01

A bibliography of papers and reports on geosynchronous orbits, as well as background papers concerned with the fundamentals of orbital mechanics is presented. A listing of computer programs developed for this study is included.

Results from an experiment that collected visible-light polarization data using unresolved imagery for classification of geosynchronous satellites

NASA Astrophysics Data System (ADS)

Speicher, Andy; Matin, Mohammad; Tippets, Roger; Chun, Francis; Strong, David

2015-05-01

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. The objective of this study was to collect and analyze visible-spectrum polarization data from unresolved images of geosynchronous satellites taken over various solar phase angles. Different collection geometries were used to evaluate the polarization contribution of solar arrays, thermal control materials, antennas, and the satellite bus as the solar phase angle changed. Since materials on space objects age due to the space environment, their polarization signature may change enough to allow discrimination of identical satellites launched at different times. Preliminary data suggests this optical signature may lead to positive identification or classification of each satellite by an automated process on a shorter timeline. The instrumentation used in this experiment was a United States Air Force Academy (USAFA) Department of Physics system that consists of a 20-inch Ritchey-Chrétien telescope and a dual focal plane optical train fed with a polarizing beam splitter. Following a rigorous calibration, polarization data was collected during two nights on eight geosynchronous satellites built by various manufacturers and launched several years apart. When Stokes parameters were plotted against time and solar phase angle, the data indicates that a polarization signature from unresolved images may have promise in classifying specific satellites.

Electric fields in Earth orbital space

NASA Astrophysics Data System (ADS)

Olson, W. P.; Pfitzer, K. A.; Scotti, S. J.

1982-05-01

This is a report of progress during the past year. The work was performed in three areas with a long term goal understanding the formation and maintenance of electrostatic fields in the earth's magnetosphere. The entry of low energy charged particles into a magnetically closed magnetosphere has been examined in some detail. Entry is permitted because of the non-uniform nature of the magnetic field over the magnetopause surface. Electrostatic fields may be formed across the tail of the magnetosphere because fo the different 'entry efficiencies ' of protons and electrons. The consequences of this particle entry mechanism for the plasma sheet, plasma mantle, and boundary plasmas in the magnetosphere are examined. The mathematics of particle entry was investigated in a one-dimensional boundary using both kinetic theory and bulk MHD parameters. From our participation in the 6th Coordinated Data Analysis Workshop, we have determined that at least during disturbed magnetic conditions, currents persist near geosynchronous orbit in the nightime region which are presently not included in our dynamic magnetic field models. These currents are probably associated with the field aligned currents which close in the ionosphere near auroral latitudes.

Midtail plasma flows and the relationship to near-Earth substorm activity: A case study

NASA Technical Reports Server (NTRS)

Lopez, R. E.; Goodrich, C. C.; Reeves, G. D.; Belian, R. D.; Taktakishvili, A.

1994-01-01

Recent simulations of magnetotail reconnection have pointed to a link between plasma flows, dipolarization, and the substorm current wedge. In particular, Hesse and Birn (1991) have proposed that earthward jetting of plasma from the reconnection region transports flux into the near-Earth region. At the inner edge of the plasma sheet this flux piles up, producing a dipolarization of the magnetic field. The vorticity produced by the east-west deflection of the flow at the inner edge of the plasma sheet gives rise to field-aligned currents that have region 1 polarity. Thus in this scenario the earthward flow from the reconnection region produces the dipolarization ad the current wedge in a self-consistent fashion. In this study we examine observations made on April 8, 1985 by the Active Magnetospheric Particle Tracer Explorers (AMPTE)/Ion Release Module (IRM), the geosynchronous satellites 1979-053, 1983-019, and 1984-037, and Syowa station, as well as AE. This event is unique because IRM was located near the neutral sheet in the midnight sector for am extended period of time. Ground data show that there was ongoing activity in the IRM local time sector for several hours, beginning at 1800 UT and reaching a crescendo at 2300 UT. This activity was also accompanied by energetic particle variations, including injections, at geosynchronous orbit in the nighttime sector. Significantly, there were no fast flows at the neutral sheet until the great intensification of activity at 2300 UT. At that time, IRM recorded fast eartheard flow simultaneous with a dipolatization of the magetic field. We conclude that while the aforementioned scenario for the creation of the current wedge encounters serious problems explaining the earlier activity, the observations at 2300 UT are consistent with the scenario of Hesse and Birn (1191). On that basis it is argued that the physics of substorms is not exclusively rooted in the development of a global tearing mode. Processes at the inner edge of the cross-tail current that cause a disruption of the current and a consequent dipolarization and current wedge may be unrelated to the formation of a macroscale reconnection region. Thus the global evolution of a substorm is probably a complicated superposition of such processes operating on a very localized scale and a global macroscale process that allows for such things as releasing te energy stored in lobe flux and creation of plasmoids.

GIFTS EDU Ground-based Measurement Experiment

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Smith, W. L., Sr.; Zollinger, L. J.; Huppi, R. J.; Reisse, R. A.; Larar, A. M.; Liu, X.; Tansock, J. J., Jr.; Jensen, S. M.; Revercomb, H. E.;

Characteristics of Sudden Commencements Observed by Van Allen Probes in the Inner Magnetosphere

NASA Astrophysics Data System (ADS)

Fathy, A.; Kim, K.-H.; Park, J.-S.; Jin, H.; Kletzing, C.; Wygant, J. R.; Ghamry, E.

2018-02-01

We have statistically studied sudden commencement (SC) by using the data acquired from Van Allen Probes (VAP) in the inner magnetosphere (L = 3.0-6.5) and GOES spacecraft at geosynchronous orbit (L =˜ 6.7) from October 2012 to September 2017. During the time period, we identified 85 SCs in the inner magnetosphere and 90 SCs at geosynchronous orbit. Statistical results of the SC events reveal the following characteristics. (1) There is strong seasonal dependence of the geosynchronous SC amplitude in the radial BV component at all local times. However, BV shows weak seasonal variation on the dayside in the inner magnetosphere. (2) The local time dependence of the SC amplitude in the compressional BH component at geosynchronous orbit is similar to that in the inner magnetosphere. (3) In a nightside region of L = 5.0-6.5, ˜19% of BH events are negative, while ˜58% of BH events are negative at geosynchronous orbit. (4) The amplitude of the SC-associated Ey perturbations varies systematically with local time with a morning-afternoon asymmetry near noon. These observations can be explained by spatial and/or temporal changes in the magnetopause and cross-tail currents, which are caused by changes in the solar wind dynamic pressure, with respect to spacecraft positions.

The evolution of the storm-time ring current in response to different characteristics of the plasma source

NASA Astrophysics Data System (ADS)

Lemon, C.; Chen, M.; O'Brien, T. P.; Toffoletto, F.; Sazykin, S.; Wolf, R.; Kumar, V.

2006-12-01

We present simulation results of the Rice Convection Model-Equilibrium (RCM-E) that test and compare the effect on the storm time ring current of varying the plasma sheet source population characteristics at 6.6 Re during magnetic storms. Previous work has shown that direct injection of ionospheric plasma into the ring current is not a significant source of ring current plasma, suggesting that the plasma sheet is the only source. However, storm time processes in the plasma sheet and inner magnetosphere are very complex, due in large part to the feedback interactions between the plasma distribution, magnetic field, and electric field. We are particularly interested in understanding the role of the plasma sheet entropy parameter (PV^{5/3}, where V=\\int ds/B) in determining the strength and distribution of the ring current in both the main and recovery phases of a storm. Plasma temperature and density can be measured from geosynchrorous orbiting satellites, and these are often used to provide boundary conditions for ring current simulations. However, magnetic field measurements in this region are less commonly available, and there is a relatively poor understanding of the interplay between the plasma and the magnetic field during magnetic storms. The entropy parameter is a quantity that incorporates both the plasma and the magnetic field, and understanding its role in the ring current injection and recovery is essential to describing the processes that are occuring during magnetic storms. The RCM-E includes the physics of feedback between the plasma and both the electric and magnetic fields, and is therefore a valuable tool for understanding these complex storm-time processes. By contrasting the effects of different plasma boundary conditions at geosynchronous orbit, we shed light on the physical processes involved in ring current injection and recovery.

Space tug thermal control. [design criteria and specifications

NASA Technical Reports Server (NTRS)

1974-01-01

It was determined that space tug will require the capability to perform its mission within a broad range of thermal environments with currently planned mission durations of up to seven days, so an investigation was conducted to define a thermal design for the forward and intertank compartments and fuel cell heat rejection system that satisfies tug requirements for low inclination geosynchronous deploy and retrieve missions. Passive concepts were demonstrated analytically for both the forward and intertank compartments, and a worst case external heating environment was determined for use during the study. The thermal control system specifications and designs which resulted from the research are shown.

Removing the solar exclusion with high altitude satellites [Orbital strategies to mitigate the Solar Exclusion Effect on Space-Based Observation of the Geosynchronous Belt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vallado, David A.; Cefola, Paul J.; Kiziah, Rex R.

Here, observing geosynchronous satellites has numerous applications. Lighting conditions near the equinoxes routinely cause problems for traditional observations of sensors near the equator – the solar exclusion. We investigate using sensors on satellites (in polar and high- altitude orbits) to observe satellites that are in geosynchronous orbit. It is hoped that these satellite configurations will alleviate many of these problems. Assessing the orbit insertion and station-keeping requirements are important to understand. We summarize the literature to understand the relevant perturbing forces and assess the delta-v requirements.

Removing the solar exclusion with high altitude satellites [Orbital strategies to mitigate the Solar Exclusion Effect on Space-Based Observation of the Geosynchronous Belt

DOE PAGES

Vallado, David A.; Cefola, Paul J.; Kiziah, Rex R.; ...

2016-09-09

Here, observing geosynchronous satellites has numerous applications. Lighting conditions near the equinoxes routinely cause problems for traditional observations of sensors near the equator – the solar exclusion. We investigate using sensors on satellites (in polar and high- altitude orbits) to observe satellites that are in geosynchronous orbit. It is hoped that these satellite configurations will alleviate many of these problems. Assessing the orbit insertion and station-keeping requirements are important to understand. We summarize the literature to understand the relevant perturbing forces and assess the delta-v requirements.

Geosynchronous platform definition study. Volume 5: Geosynchronous platform synthesis

NASA Technical Reports Server (NTRS)

1973-01-01

The development is described of the platform configurations, support subsystems, mission equipment, and servicing concepts. A common support module is developed; subsystem concepts are traded off; data relay, TDRS, earth observational, astro-physics, and advanced navigation and traffic control mission equipment concepts are postulated; and ancillary equipment required for delivery and on-orbit servicing interfaces with geosynchronous platforms is grossly defined. The general approach was to develop a platform concept capable of evolving through three on-orbit servicing modes: remote, EVA, and shirtsleeve. The definition of the equipment is to the assembly level. Weight, power, and volumetric data are compiled for all the platforms.

Space Shuttle Projects

NASA Image and Video Library

1985-04-01

In this photograph the SYNCOM IV-3, also known as LEASAT 3, satellite moves away from the Space Shuttle Orbiter Discovery. SYNCOM (Hughes Geosynchronous Communication Satellite) provides communication services from geosynchronous orbit, principally to the U.S. Government. The satellite was launched on April 12, 1985, aboard the Space Shuttle Orbiter Discovery.

Spatial structure and temporal evolution of energetic particle injections in the inner magnetosphere during the 14 July 2013 substorm event

DOE PAGES

Gkioulidou, Matina; Ohtani, S.; Mitchell, D. G.; ...

2015-03-20

Recent results by the Van Allen Probes mission showed that the occurrence of energetic ion injections inside geosynchronous orbit could be very frequent throughout the main phase of a geomagnetic storm. Understanding, therefore, the formation and evolution of energetic particle injections is critical in order to quantify their effect in the inner magnetosphere. We present a case study of a substorm event that occurred during a weak storm (Dst ~ –40 nT) on 14 July 2013. Van Allen Probe B, inside geosynchronous orbit, observed two energetic proton injections within 10 min, with different dipolarization signatures and duration. The first onemore » is a dispersionless, short-timescale injection pulse accompanied by a sharp dipolarization signature, while the second one is a dispersed, longer-timescale injection pulse accompanied by a gradual dipolarization signature. We combined ground magnetometer data from various stations and in situ particle and magnetic field data from multiple satellites in the inner magnetosphere and near-Earth plasma sheet to determine the spatial extent of these injections, their temporal evolution, and their effects in the inner magnetosphere. Our results indicate that there are different spatial and temporal scales at which injections can occur in the inner magnetosphere and depict the necessity of multipoint observations of both particle and magnetic field data in order to determine these scales.« less

Orbital Debris: A Chronology

NASA Technical Reports Server (NTRS)

Portree, Davis S. F. (Editor); Loftus, Joseph P., Jr. (Editor)

1999-01-01

This chronology covers the 37-year history of orbital debris concerns. It tracks orbital debris hazard creation, research, observation, experimentation, management, mitigation, protection, and policy. Included are debris-producing, events; U.N. orbital debris treaties, Space Shuttle and space station orbital debris issues; ASAT tests; milestones in theory and modeling; uncontrolled reentries; detection system development; shielding development; geosynchronous debris issues, including reboost policies: returned surfaces studies, seminar papers reports, conferences, and studies; the increasing effect of space activities on astronomy; and growing international awareness of the near-Earth environment.

Age Induced Effects on ESD Characteristics of Solar Array Coupons After Combined Space Environmental Exposures

NASA Technical Reports Server (NTRS)

Wright, Kenneth H.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Funderburk, Victor V.; Wong, Frankie; Gardiner, George

2012-01-01

A set of multi-junction GaAs/Ge solar array test coupons provided by Space Systems/Loral were subjected to a sequence of 5-year increments of combined space environment exposure tests. The test coupons capture an integrated design intended for use in a geosynchronous (GEO) space environment. A key component of this test campaign is performing electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO standard for ESD testing on solar array panels [ISO-11221]. The test schematic in the ISO reference has been modified with Space System/Loral designed circuitry to better simulate the on-orbit operational conditions of its solar array design. Part of the modified circuitry is to simulate a solar array panel coverglass flashover discharge. All solar array coupons used in the test campaign consist of four cells constructed to form two strings. The ESD tests were performed at the beginning-of-life (BOL) and at each 5-year environment exposure point until end-of-life (EOL) at 15 years. The space environmental exposure sequence consisted of ultra-violet radiation, electron/proton particle radiation, thermal cycling, and Xenon ion thruster plume erosion. This paper describes the ESD test setup and the importance of the electrical test design in simulating the on-orbit operational conditions. Arc inception voltage results along with ESD test behavior from the BOL condition through the 15th year age condition are discussed. In addition, results from a Xenon plasma plume exposure test with an EOL coupon under the full ESD test condition will be discussed.

Comparison and evaluation of power plant options for geosynchronous power stations. Part 1: Synchronous solar power

NASA Technical Reports Server (NTRS)

Williams, J. R.

1973-01-01

The present state-of-the-art is described for the development of solar power generators in far out synchronous orbit for power generation. Concepts of geosynchronous solar power satellites are discussed including photovoltaic arrays for power satellites, solar-thermal power satellites, and power transmission to earth.

Geosynchronous Meteorological Satellite Data Seminar

NASA Technical Reports Server (NTRS)

1976-01-01

A seminar was organized by NASA to acquaint the meteorological community with data now available, and data scheduled to be available in the future, from geosynchronous meteorological satellites. The twenty-four papers were presented in three half-day sessions in addition to tours of the Image Display and LANDSAT Processing Facilities during the afternoon of the second day.

Solar power satellite: Analysis of alternatives for transporting material to geosynchronous orbit

NASA Technical Reports Server (NTRS)

Graff, W. J.; Huang, C. J.

1976-01-01

A systems design study of the alternative methods and relative merits of various approaches to transporting and assembling a solar power satellite in geosynchronous orbit was conducted. State of the art alternatives for chemical and electrical interorbital propulsion were studied, and several possible scenarios for construction were proposed.

Particle tracing modeling of ion fluxes at geosynchronous orbit

DOE PAGES

Brito, Thiago V.; Woodroffe, Jesse; Jordanova, Vania K.; ...

2017-10-31

The initial results of a coupled MHD/particle tracing method to evaluate particle fluxes in the inner magnetosphere are presented. This setup is capable of capturing the earthward particle acceleration process resulting from dipolarization events in the tail region of the magnetosphere. On the period of study, the MHD code was able to capture a dipolarization event and the particle tracing algorithm was able to capture our results of these disturbances and calculate proton fluxes in the night side geosynchronous orbit region. The simulation captured dispersionless injections as well as the energy dispersion signatures that are frequently observed by satellites atmore » geosynchronous orbit. Currently, ring current models rely on Maxwellian-type distributions based on either empirical flux values or sparse satellite data for their boundary conditions close to geosynchronous orbit. In spite of some differences in intensity and timing, the setup presented here is able to capture substorm injections, which represents an improvement regarding a reverse way of coupling these ring current models with MHD codes through the use of boundary conditions.« less

Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS): Imaging and Tracking Capability

NASA Technical Reports Server (NTRS)

Zhou, D. K.; Larar, A. M.; Liu, Xu; Reisse, R. A.; Smith, W. L.; Revercomb, H. E.; Bingham, G. E.; Zollinger, L. J.; Tansock, J. J.; Huppi, Ronald J.

2007-01-01

The geosynchronous-imaging Fourier transform spectrometer (GIFTS) engineering demonstration unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. It measures the infrared spectrum in two spectral bands (14.6 to 8.8 microns, 6.0 to 4.4 microns) using two 128 128 detector arrays with a spectral resolution of 0.57/cm with a scan duration of approx. 11 seconds. From a geosynchronous orbit, the instrument will have the capability of taking successive measurements of such data to scan desired regions of the globe, from which atmospheric status, cloud parameters, wind field profiles, and other derived products can be retrieved. The GIFTS EDU provides a flexible and accurate testbed for the new challenges of the emerging hyperspectral era. The EDU ground-based measurement experiment, held in Logan, Utah during September 2006, demonstrated its extensive capabilities and potential for geosynchronous and other applications (e.g., Earth observing environmental measurements). This paper addresses the experiment objectives and overall performance of the sensor system with a focus on the GIFTS EDU imaging capability and proof of the GIFTS measurement concept.

Ground-Based Measurement Experiment and First Results with Geosynchronous-Imaging Fourier Transform Spectrometer Engineering Demonstration Unit

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Smith, William L.; Bingham, Gail E.; Huppi, Ronald J.; Revercomb, Henry E.; Zollinger, Lori J.; Larar, Allen M.; Liu, Xu; Tansock, Joseph J.; Reisse, Robert A.;

Particle tracing modeling of ion fluxes at geosynchronous orbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brito, Thiago V.; Woodroffe, Jesse; Jordanova, Vania K.

The initial results of a coupled MHD/particle tracing method to evaluate particle fluxes in the inner magnetosphere are presented. This setup is capable of capturing the earthward particle acceleration process resulting from dipolarization events in the tail region of the magnetosphere. On the period of study, the MHD code was able to capture a dipolarization event and the particle tracing algorithm was able to capture our results of these disturbances and calculate proton fluxes in the night side geosynchronous orbit region. The simulation captured dispersionless injections as well as the energy dispersion signatures that are frequently observed by satellites atmore » geosynchronous orbit. Currently, ring current models rely on Maxwellian-type distributions based on either empirical flux values or sparse satellite data for their boundary conditions close to geosynchronous orbit. In spite of some differences in intensity and timing, the setup presented here is able to capture substorm injections, which represents an improvement regarding a reverse way of coupling these ring current models with MHD codes through the use of boundary conditions.« less

Statistical modeling of Earth's plasmasphere

NASA Astrophysics Data System (ADS)

Veibell, Victoir

The behavior of plasma near Earth's geosynchronous orbit is of vital importance to both satellite operators and magnetosphere modelers because it also has a significant influence on energy transport, ion composition, and induced currents. The system is highly complex in both time and space, making the forecasting of extreme space weather events difficult. This dissertation examines the behavior and statistical properties of plasma mass density near geosynchronous orbit by using both linear and nonlinear models, as well as epoch analyses, in an attempt to better understand the physical processes that precipitates and drives its variations. It is shown that while equatorial mass density does vary significantly on an hourly timescale when a drop in the disturbance time scale index ( Dst) was observed, it does not vary significantly between the day of a Dst event onset and the day immediately following. It is also shown that increases in equatorial mass density were not, on average, preceded or followed by any significant change in the examined solar wind or geomagnetic variables, including Dst, despite prior results that considered a few selected events and found a notable influence. It is verified that equatorial mass density and and solar activity via the F10.7 index have a strong correlation, which is stronger over longer timescales such as 27 days than it is over an hourly timescale. It is then shown that this connection seems to affect the behavior of equatorial mass density most during periods of strong solar activity leading to large mass density reactions to Dst drops for high values of F10.7. It is also shown that equatorial mass density behaves differently before and after events based on the value of F10.7 at the onset of an equatorial mass density event or a Dst event, and that a southward interplanetary magnetic field at onset leads to slowed mass density growth after event onset. These behavioral differences provide insight into how solar and geomagnetic conditions impact mass density at geosynchronous orbit, enabling operators to better anticipate the response to space weather events and magnetosphere models to include mass density effects in magnetosphere simulations. It is shown that it is possible to classify an equatorial mass density event onset as being distinct from the three hours preceding it, indicating that there are distinguishing characteristics of solar wind and geomagnetic conditions surrounding an event. It is also been shown that given four days of solar and geomagnetic conditions, an event can be forecasted a day in advance with reasonable accuracy, but also with a number of false positives. These false positives have similarly distributed values as the true positives, though, indicating more data are needed to distinguish impending events.

An improved empirical model of electron and ion fluxes at geosynchronous orbit based on upstream solar wind conditions

DOE PAGES

Denton, M. H.; Henderson, M. G.; Jordanova, V. K.; ...

2016-07-01

In this study, a new empirical model of the electron fluxes and ion fluxes at geosynchronous orbit (GEO) is introduced, based on observations by Los Alamos National Laboratory (LANL) satellites. The model provides flux predictions in the energy range ~1 eV to ~40 keV, as a function of local time, energy, and the strength of the solar wind electric field (the negative product of the solar wind speed and the z component of the magnetic field). Given appropriate upstream solar wind measurements, the model provides a forecast of the fluxes at GEO with a ~1 h lead time. Model predictionsmore » are tested against in-sample observations from LANL satellites and also against out-of-sample observations from the Compact Environmental Anomaly Sensor II detector on the AMC-12 satellite. The model does not reproduce all structure seen in the observations. However, for the intervals studied here (quiet and storm times) the normalized root-mean-square deviation < ~0.3. It is intended that the model will improve forecasting of the spacecraft environment at GEO and also provide improved boundary/input conditions for physical models of the magnetosphere.« less

Manned Orbital Transfer Vehicle (MOTV). Volume 3: Program requirements documents

NASA Technical Reports Server (NTRS)

Boyland, R. E.; Sherman, S. W.; Morfin, H. W.

1979-01-01

The requirements for geosynchronous orbit capability using the manned orbit transfer vehicle (MOTV) are defined. The program requirements, the mission requirements, and the system and subsystem requirements for the MOTV are discussed. The mission requirements include a geosynchronous Earth orbit vehicle for the construction, servicing, repair and operation of communications, solar power, and Earth observation satellites.

Multi-access laser communications transceiver system

NASA Technical Reports Server (NTRS)

Ross, Monte (Inventor); Lokerson, Donald C. (Inventor); Fitzmaurice, Michael W. (Inventor); Meyer, Daniel D. (Inventor)

1993-01-01

A satellite system for optical communications such as a multi-access laser transceiver system. Up to six low Earth orbiting satellites send satellite data to a geosynchronous satellite. The data is relayed to a ground station at the Earth's surface. The earth pointing geosynchronous satellite terminal has no gimbal but has a separate tracking mechanism for tracking each low Earth orbiting satellite. The tracking mechanism has a ring assembly rotatable about an axis coaxial with the axis of the field of view of the geosynchronous satellite and a pivotable arm mounted for pivotal movement on the ring assembly. An optical pickup mechanism at the end of each arm is positioned for optical communication with one of the orbiting satellites by rotation of the ring.

NASCAP modelling computations on large optics spacecraft in geosynchronous substorm environments

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Purvis, C. K.

1980-01-01

The NASA Charging Analyzer Program (NASCAP) is used to evaluate qualitatively the possibility of such enhanced spacecraft contamination on a conceptual version of a large satellite. The evaluation is made by computing surface voltages on the satellite due to encounters with substorm environments and then computing charged particle trajectories in the electric fields around the satellite. Particular attention is paid to the possibility of contaminants reaching a mirror surface inside a dielectric tube because this mirror represents a shielded optical surface in the satellite model used. Deposition of low energy charged particles from other parts of the spacecraft onto the mirror was found to be possible in the assumed moderate substorm environment condition. In the assumed severe substorm environment condition, however, voltage build up on the inside and edges of the dielectric tube in which the mirror is located prevents contaminants from reaching the mirror surface.

Solar Array at Very High Temperatures: Ground Tests

NASA Technical Reports Server (NTRS)

Vayner, Boris

2016-01-01

Solar array design for any spacecraft is determined by the orbit parameters. For example, operational voltage for spacecraft in Low Earth Orbit (LEO) is limited by significant differential charging due to interactions with low temperature plasma. In order to avoid arcing in LEO, solar array is designed to generate electrical power at comparatively low voltages (below 100 V) or to operate at higher voltages with encapsulated of all suspected discharge locations. In Geosynchronous Orbit (GEO) differential charging is caused by energetic electrons that produce differential potential between coverglass and conductive spacecraft body in a kilovolt range. In such a case, weakly conductive layer over coverglass (ITO) is one of possible measures to eliminate dangerous discharges on array surface. Temperature variations for solar arrays in both orbits are measured and documented within the range of -150 C +110 C. This wide interval of operational temperatures is regularly reproduced in ground tests with radiative heating and cooling inside shroud with flowing liquid nitrogen. The requirements to solar array design and tests turn out to be more complicated when planned trajectory crosses these two orbits and goes closer to Sun. Conductive layer over coverglass causes sharp increase in parasitic current collected from LEO plasma, high temperature may cause cracks in encapsulating material (RTV), radiative heating of coupon in vacuum chamber becomes practically impossible above 150 C, conductivities of glass and adhesive go up with temperature that decrease array efficiency, and mechanical stresses grow up to critical magnitudes. A few test arrangements and respective results are presented in current paper. Coupons were tested against arcing in simulated LEO and GEO environments under elevated temperatures up to 200 C. The dependence of leakage current on temperature was measured, and electrostatic cleanness was verified for coupons with antireflection (AR) coating over ITO layer.

Design of a laboratory study of contaminant film darkening in space

NASA Astrophysics Data System (ADS)

Judeikis, H. S.; Arnold, G. S.; Hill, M.; Young Owl, R. C.; Hall, D. F.

This paper reports the philosophy, design, and initial results of a program aimed at improving control of the optical effects of contamination in the design of a spacecraft. The types of basic data needed to produce criteria for the selection of spacecraft material based on the effects of the contaminant films they produce are discussed. The results of a spacecraft nonmetallic materials list analysis and radiation sensitivity estimates are presented. A rationale is given for simulation analysis of the potential effects of the geosynchronous environment on organic contaminant films.

Use and Protection of GPS Sidelobe Signals for Enhanced Navigation Performance in High Earth Orbit

NASA Technical Reports Server (NTRS)

Parker, Joel J. K.; Valdez, Jennifer E.; Bauer, Frank H.; Moreau, Michael C.

2016-01-01

GPS (Global Positioning System) Space Service Volume (SSV) signal environment is from 3,000-36,000 kilometers altitude. Current SSV specifications only capture performance provided by signals transmitted within 23.5(L1) or 26(L2-L5) off-nadir angle. Recent on-orbit data lessons learned show significant PNT (Positioning, Navigation and Timing) performance improvements when the full aggregate signal is used. Numerous military civil operational missions in High Geosynchronous Earth Orbit (HEOGEO) utilize the full signal to enhance vehicle PNT performance

Space Weather Workshop

NASA Technical Reports Server (NTRS)

Gallagher, D. L.

2004-01-01

This workshop will focus on what space weather is about and its impact on society. An overall picture will be "painted" describing the Sun's influence through the solar wind on the near-Earth space environment, including the aurora, killer electrons at geosynchronous orbit, million ampere electric currents through the ionosphere and along magnetic field lines, and the generation of giga-Watts of natural radio waves. Reference material in the form of Internet sites will be provided so that teachers can discuss space weather in the classroom and enable students to learn more about this topic.

DCS: A global satellite environmental data collection system study

NASA Technical Reports Server (NTRS)

1973-01-01

Cost analysis and technical feasibility data are presented on five medium orbiting and six geosynchronous satellite data collection systems with varying degrees of spacecraft and local user terminal complexity. Data are also provided on system approaches, user requirements, and user classes. Systems considered include orbiting ERTS and EOS type satellites and geosynchronous SmS and SEOS type data collectors.

The dynamic radiation environment assimilation model (DREAM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reeves, Geoffrey D; Koller, Josef; Tokar, Robert L

2010-01-01

The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate resultsmore » than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.« less

The life cycle of a tornadic cloud as seen from a geosynchronous satellite

NASA Technical Reports Server (NTRS)

Hung, R. J.; Dodge, J. C.; Smith, R. E.

1983-01-01

The life span of a severe storm is on the order of a few hours. Rapid-scan infrared and visible observations from geosynchronous satellites can be useful for studying the life cycle of a severe convective storm. By using artificial colors for pixels representing blackbody temperatures of the cloud top, convective storms can be observed throughout their life cycles. In this paper clouds associated with a tornadic storm, the Ringwood, OK tornado on May 29, 1977, are compared with those without a tornadic storm to illustrate how the infrared and visible observations from a geosynchronous satellite can be used to study the differences in their life cycles. The instability of the air mass and the meteorological background are discussed based on balloon observations.

Spacecraft attitude control for a solar electric geosynchronous transfer mission

NASA Technical Reports Server (NTRS)

Leroy, B. E.; Regetz, J. D., Jr.

1975-01-01

A study of the Attitude Control System (ACS) is made for a solar electric propulsion geosynchronous transfer mission. The basic mission considered is spacecraft injection into a low altitude, inclined orbit followed by low thrust orbit changing to achieve geosynchronous orbit. Because of the extended thrusting time, the mission performance is a strong function of the attitude control system. Two attitude control system design options for an example mission evolve from consideration of the spacecraft configuration, the environmental disturbances, and the probable ACS modes of operation. The impact of these design options on other spacecraft subsystems is discussed. The factors which must be considered in determining the ACS actuation and sensing subsystems are discussed. The effects of the actuation and sensing subsystems on the mission performance are also considered.

A Model for Plasma Transport in a Corotation-Dominated Magnetosphere.

NASA Astrophysics Data System (ADS)

Pontius, Duane Henry, Jr.

1988-06-01

The gross structures of the magnetospheres of the outer planets are decided by processes quite different from those predominant in that of the earth. The terrestrial plasmapause, the boundary beyond which plasma motion is principally determined by magnetospheric interaction with the solar wind, is typically inside geosynchronous orbit. Within the plasmasphere, rotational effects are present, but gravity exceeds the centrifugal force of corotation. In contrast, the Jovian plasmasphere extends to a distance at least twenty times farther than synchronous orbit, affording a large region where rotational effects are expected to he clearly manifest (Brice and Ioannidis, 1970). The goal of this thesis is to develop an appropriate theoretical model for treating the problem of plasma transport in a corotation dominated plasmasphere. The model presented here is intended to describe the radial transport of relatively cold plasma having an azimuthally uniform distribution in a dipolar magnetic field. The approach is conceptually similar to that of the radial diffusion model in that small scale motions are examined to infer global consequences, but the physical understanding of those small scale motions is quite different. In particular, discrete flux tubes of small cross section are assumed to move over distances large compared to their widths. The present model also differs from the corotating convection model by introducing a mechanism whereby the conservation of flux tube content along flowlines is violated. However, it is quite possible that a global convection pattern co -exists with the motions described here, leading to longitudinal asymmetries in the plasma distribution.

Noise and interference study for satellite lightning sensor

NASA Technical Reports Server (NTRS)

Herman, J. R.

1981-01-01

The use of radio frequency techniques for the detection and monitoring of terrestrial thunderstorms from space are discussed. Three major points are assessed: (1) lightning and noise source characteristics; (2) propagation effects imposed by the atmosphere and ionosphere; and (3) the electromagnetic environment in near space within which lightning RF signatures must be detected. A composite frequency spectrum of the peak of amplitude from lightning flashes is developed. Propagation effects (ionospheric cutoff, refraction, absorption, dispersion and scintillation) are considered to modify the lightning spectrum to the geosynchronous case. It is suggested that in comparing the modified spectrum with interfering noise source spectra RF lightning pulses on frequencies up to a few GHz are detectable above the natural noise environment in near space.

Changes to Electrical Conductivity in Irradiated Carbon-Nickel Nanocomposites

DTIC Science & Technology

2010-03-01

fluxes that geosynchronous satellites must withstand as established by MIL-STD-1809... Voltage keV Kilo Electron Volt [10 3 eV] LSU Louisiana State University LTAPCVD Low Temperature Atmospheric Pressure Chemical Vapor Decomposition...geosynchronous altitude energetic electron fluxes range up to 5 x 10 6 cm -2 sec -1 for electrons with energies 2 of 0.5 MeV or greater, while proton

Spectral Measurements of Geosynchronous Satellites During Glint Season

DTIC Science & Technology

2015-01-01

the satellite solar panels and has been observed in the past using broadband photometry techniques. In this paper, we present the first observations... photometry . We believe that these small-scale features can be exploited to discern satellite features such as solar panel orientation and secondary...Spectral Measurements of Geosynchronous Satellites During Glint Season Ryan M. Tucker, Evan M. Weld, Francis K. Chun, and Roger D. Tippets

Observations of field-aligned currents, waves, and electric fields at substorm onset

NASA Technical Reports Server (NTRS)

Smits, D. P.; Hughes, W. J.; Cattell, C. A.; Russell, C. T.

1986-01-01

Substorm onsets, identified Pi 2 pulsations observed on the Air Force Geophysics Laboratory Magnetometer Network, are studied using magnetometer and electric field data from ISEE 1 as well as magnetometer data from the geosynchronous satellites GOES 2 and 3. The mid-latitude magnetometer data provides the means of both timing and locating the substorm onset so that the spacecraft locations with respect to the substorm current systems are known. During two intervals, each containing several onsets or intensifications, ISEE 1 observed field-aligned current signatures beginning simultaneously with the mid-latitude Pi 2 pulsation. Close to the earth broadband bursts of wave noise were observed in the electric field data whenever field-aligned currents were detected. One onset occurred when ISEE 1 and GOES 2 were on the same field line but in opposite hemispheres. During this onset ISEE 1 and GOES 2 saw magnetic signatures which appear to be due to conjugate field-aligned currents flowing out of the western end of the westward auroral electrojets. The ISEE 1 signature is of a line current moving westward past the spacecraft. During the other interval, ISEE 1 was in the near-tail region near the midnight meridian. Plasma data confirms that the plasma sheet thinned and subsequently expanded at onset. Electric field data shows that the plasma moved in the opposite direction to the plasma sheet boundary as the boundary expanded which implies that there must have been an abundant source of hot plasma present. The plasma motion was towards the center of the plasma sheet and earthwards and consisted of a series of pulses rather than a steady flow.

Solar Radiation Pressure Binning for the Geosynchronous Orbit

NASA Technical Reports Server (NTRS)

Hejduk, M. D.; Ghrist, R. W.

2011-01-01

Orbital maintenance parameters for individual satellites or groups of satellites have traditionally been set by examining orbital parameters alone, such as through apogee and perigee height binning; this approach ignored the other factors that governed an individual satellite's susceptibility to non-conservative forces. In the atmospheric drag regime, this problem has been addressed by the introduction of the "energy dissipation rate," a quantity that represents the amount of energy being removed from the orbit; such an approach is able to consider both atmospheric density and satellite frontal area characteristics and thus serve as a mechanism for binning satellites of similar behavior. The geo-synchronous orbit (of broader definition than the geostationary orbit -- here taken to be from 1300 to 1800 minutes in orbital period) is not affected by drag; rather, its principal non-conservative force is that of solar radiation pressure -- the momentum imparted to the satellite by solar radiometric energy. While this perturbation is solved for as part of the orbit determination update, no binning or division scheme, analogous to the drag regime, has been developed for the geo-synchronous orbit. The present analysis has begun such an effort by examining the behavior of geosynchronous rocket bodies and non-stabilized payloads as a function of solar radiation pressure susceptibility. A preliminary examination of binning techniques used in the drag regime gives initial guidance regarding the criteria for useful bin divisions. Applying these criteria to the object type, solar radiation pressure, and resultant state vector accuracy for the analyzed dataset, a single division of "large" satellites into two bins for the purposes of setting related sensor tasking and orbit determination (OD) controls is suggested. When an accompanying analysis of high area-to-mass objects is complete, a full set of binning recommendations for the geosynchronous orbit will be available.

Operational Real-time Forecast of MeV Electrons at Geosynchronous Orbit Based on ACE and GOES-10 Measurements

NASA Astrophysics Data System (ADS)

Li, X.; Temerin, M. A.; Monk, S.; Baker, D. N.; Reeves, G. D.

2002-05-01

The MeV electrons, also known as `killer electrons', have a deleterious impact on satellites through deep dielectric charging and the bodies of astronauts through radiation damage during extravehicular activity. Using a recently developed model based on the standard radial diffusion equation [Li et al., 2001], we show that the intensity of these MeV electrons at geosynchronous orbit can be quantitatively predicted 1-2 days in advance given knowledge of the solar wind. Our current model is operating in real-time, using real-time data from ACE and GOES-10, to make forecast of >2 MeV eletrons at geosynchronous orbit up to 48 hours in advance, the results are available on the web, currently updated every two hours (http://lasp.colorado.edu/~monk/xlf2.html).

Rotation State Evolution of Retired Geosynchronous Satellites

NASA Astrophysics Data System (ADS)

Benson, C.; Scheeres, D. J.; Ryan, W. H.; Ryan, E. V.; Moskovitz, N.

Non-periodic light curve rotation state analysis is conducted for the retired geosynchronous satellite GOES 8. This particular satellite has been observed periodically at the Maui Research and Technology Center as well as Magdalena Ridge and Lowell Observatories since 2013. To extract tumbling periods from the light curves, twodimensional Fourier series fits were used. Torque-free dynamics and the satellite’s known mass properties were then leveraged to constrain the candidate periods. Finally, simulated light curves were generated using a representative shape model for further validation. Analysis of the light curves suggests that GOES 8 transitioned from uniform rotation in 2014 to continually evolving tumbling motion by 2016. These findings are consistent with previous dynamical simulations and support the hypothesis that the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect drives rotation state evolution of retired geosynchronous satellites.

Mission Advantages of Constant Power, Variable Isp Electrostatic Thrusters

NASA Technical Reports Server (NTRS)

Oleson, Steven R.

2000-01-01

Electric propulsion has moved from station-keeping capability for spacecraft to primary propulsion with the advent of both the Deep Space One asteroid flyby and geosynchronous spacecraft orbit insertion. In both cases notably more payload was delivered than would have been possible with chemical propulsion. To provide even greater improvements electrostatic thruster performance could be varied in specific impulse, but kept at constant power to provide better payload or trip time performance for different mission phases. Such variable specific impulse mission applications include geosynchronous and low earth orbit spacecraft stationkeeping and orbit insertion, geosynchronous reusable tug missions, and interplanetary probes. The application of variable specific impulse devices is shown to add from 5 to 15% payload for these missions. The challenges to building such devices include variable voltage power supplies and extending fuel throughput capabilities across the specific impulse range.

Flight evidence of spacecraft surface contamination rate enhancement by spacecraft charging obtained with a quartz crystal microbalance

NASA Technical Reports Server (NTRS)

Clark, D. M.; Hall, D. F.

1980-01-01

The significance of the fraction of the mass outgassed by a negatively charged space vehicle which is ionized within the vehicle plasma sheath and electrostatically reattracted to the space vehicle was determined. The ML-12 retarding potential analyzer/temperature controlled quartz crystal microbalances (RPA/TQCMs) distinguishes between charged and neutral molecules and investigates contamination mass transport mechanism. Two long term, quick look flight data sets indicate that on the average a significant fraction of mass arriving at one RPA/TQCM is ionized. It is assumed that vehicle frame charging during these periods was approximately uniformly distributed in degree and frequency. It is shown that electrostatic reattraction of ionized molecules is an important contamination mechanism at and near geosynchronous altitudes.

The All Seeing Eye: Space-Based Persistent Surveillance in 2030

DTIC Science & Technology

2009-04-01

and ORS cannot. A GEO-based system can potentially deliver the ability to continuously monitor a theater-sized area with no concern of over flight ...paper investigates a geosynchronous orbit based surveillance system . Such a system would be beyond the reach of current anti-satellite weapons. However...significant technical hurdles remain to make such a system a reality. Operating in geosynchronous orbit affords a system the ability to remain

Comparison of Low Earth Orbit and Geosynchronous Earth Orbits

NASA Technical Reports Server (NTRS)

Drummond, J. E.

1980-01-01

The technological, environmental, social, and political ramifications of low Earth orbits as compared to geosynchronous Earth orbits for the solar power satellite (SPS) are assessed. The capital cost of the transmitting facilities is dependent on the areas of the antenna and rectenna relative to the requirement of high efficiency power transmission. The salient features of a low orbit Earth orbits are discussed in terms of cost reduction efforts.

NASCAP modelling of high-voltage power system interactions with space charged-particle environments

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Roche, J. C.; Mandell, M. J.

1979-01-01

A simple space power system operating in geosynchronous orbit was analyzed. This system consisted of two solar array wings and a central body. Each solar array wing was considered to be divided into three regions operating at 2000 volts. The center body was considered to be an electrical ground with the array voltages both positive and negative relative to ground. The system was analyzed for both a normal environment and a moderate geomagnetic substorm environment. Initial results indicate a high probability of arcing at the interconnects on the negative operating voltage wing. The dielectric strength of the substrate may be exceeded giving rise to breakdown in the bulk of the material. The geomagnetic substorm did not seem to increase the electrical gradients at the interconnects on the negative operating voltage wing but did increase the gradients on the positive operating voltage wing which could result in increased coupling current losses.

Environet: An interactive space-environment information resource

NASA Astrophysics Data System (ADS)

Vampola, A. L.; Hall, William N.; Lauriente, Michael

1989-05-01

EnviroNET is an interactive menu-driven system set up as an information resource for experimenters, program managers, and design and test engineers who are involved in space missions. Its basic use is as a fundamental single-source of data for the environment encountered by Shuttle and Space Station payloads, but is also has wider applicability in that it includes information on environments encountered by other satellites in both low altitude and high altitude (including geosynchronous) orbits. It incorporates both a text-retrieval mode and an interactive modeling code mode. The system is maintained on the ENVNET and MicroVAX computer at NASA/Goddard. It's services are available at no cost to any user who has access to a terminal and a dial-up port. It is a tail-node on SPAN and so it is accessible either directly or through BITNET, ARPANET, and GTE/TELENET via NPSS.

Space Environmental Effects Testing and Characterization of the Candidate Solar Sail Material Aluminized Mylar

NASA Technical Reports Server (NTRS)

Edwards, D. L.; Hubbs, W. S.; Wertz, G. E.; Alstatt, R.; Munafo, Paul (Technical Monitor)

2001-01-01

The usage of solar sails as a propellantless propulsion system has been proposed for many years. The technical challenges associated with solar sails are fabrication of ultralightweight films, deploying the sails and controlling the spacecraft. Integral to all these challenges is the mechanical property integrity of the sail while exposed to the harsh environment of space. This paper describes testing and characterization of a candidate solar sail material, Aluminized Mylar. This material was exposed to a simulated Geosynchronous Transfer Orbit (GTO) and evaluated by measuring thermooptical and mechanical property changes. Testing procedures and results are presented.

Spacecraft Charging Calculations: NASCAP-2K and SEE Spacecraft Charging Handbook

NASA Technical Reports Server (NTRS)

Davis, V. A.; Neergaard, L. F.; Mandell, M. J.; Katz, I.; Gardner, B. M.; Hilton, J. M.; Minor, J.

2002-01-01

For fifteen years NASA and the Air Force Charging Analyzer Program for Geosynchronous Orbits (NASCAP/GEO) has been the workhorse of spacecraft charging calculations. Two new tools, the Space Environment and Effects (SEE) Spacecraft Charging Handbook (recently released), and Nascap-2K (under development), use improved numeric techniques and modern user interfaces to tackle the same problem. The SEE Spacecraft Charging Handbook provides first-order, lower-resolution solutions while Nascap-2K provides higher resolution results appropriate for detailed analysis. This paper illustrates how the improvements in the numeric techniques affect the results.

Evaluation of solar cells for potential space satellite power applications

NASA Technical Reports Server (NTRS)

1977-01-01

The evaluation focused on the following subjects: (1) the relative merits of alternative solar cell materials, based on performance and availability, (2) the best manufacturing methods for various solar cell options and the effects of extremely large production volumes on their ultimate costs and operational characteristics, (3) the areas of uncertainty in achieving large solar cell production volumes, (4) the effects of concentration ratios on solar array mass and system performance, (5) the factors influencing solar cell life in the radiation environment during transport to and in geosynchronous orbit, and (6) the merits of conducting solar cell manufacturing operations in space.

Equivalent electron fluence for space qualification of shallow junction heteroface GaAs solar cells

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Stock, L. V.

1984-01-01

It is desirable to perform qualification tests prior to deployment of solar cells in space power applications. Such test procedures are complicated by the complex mixture of differing radiation components in space which are difficult to simulate in ground test facilities. Although it has been shown that an equivalent electron fluence ratio cannot be uniquely defined for monoenergetic proton exposure of GaAs shallow junction cells, an equivalent electron fluence test can be defined for common spectral components of protons found in space. Equivalent electron fluence levels for the geosynchronous environment are presented.

Electrostatic Return of Contaminants

NASA Technical Reports Server (NTRS)

Rantanen, R.; Gordon, T.

2003-01-01

A Model has been developed capable of calculating the electrostatic return of spacecraft-emitted molecules that are ionized and attracted back to the spacecraft by the spacecraft electric potential on its surfaces. The return of ionized contaminant molecules to charged spacecraft surfaces is very important to all altitudes. It is especially important at geosynchronous and interplanetary environments, since it may be the only mechanism by which contaminants can degrade a surface. This model is applicable to all altitudes and spacecraft geometries. In addition to results of the model will be completed to cover a wide range of potential space systems.

Space tug aerobraking study. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Corso, C. J.; Eyer, C. L.

1972-01-01

The feasibility and practicality of employing an aerobraking trajectory for return of the reusable space tug from geosynchronous orbit was investigated. The aerobraking return trajectory modes employ transfer ellipses from high orbits which have low perigee altitudes wherein the earth's sensible atmosphere provides drag to reduce the tug return delta velocity requirements and thus decrease the required return trip propulsive energy. Aerodynamics, aerothermodynamics, trajectories, guidance and control, configuration concepts, materials, weights and performance were considered. Sensitivities to trajectory uncertainties, atmospheric anomalies and reentry environments were determined. New technology requirements and future studies required to further enhance the aerobraking potential were identified.

Assessment of VAS soundings in the analysis of a preconvective environment

NASA Technical Reports Server (NTRS)

Mostek, A.; Uccellini, L. W.; Petersen, R. A.; Chesters, D.

1985-01-01

Retrievals from the VISSR Atmospheric Sounder (VAS) are combined with conventional data to assess the impact of geosynchronous satellite soundings upon the analysis of a preconvective environment. VAS retrievals of temperature, dewpoint, equivalent potential temperature, precipitable water, and lifted index are derived with 60 km resolution at 3 hour intervals. When VAS fields are combined with analyses from conventional data sources, mesoscale regions with convective instability are more clearly delineated prior to the rapid development of the thunderstorms. The retrievals differentiate isolated areas in which air extends throughout the lower troposphere from those regions where moisture is confined to a thin layer near the Earth's surface. The analyses of the VAS retrievals identify significant spatial gradients and temporal changes in the thermal and moisture fields, especially in the regions between radiosonde observations.

Highlights of Recent Research Activities at the NASA Orbital Debris Program Office

NASA Technical Reports Server (NTRS)

Liou, J - C.

2017-01-01

The NASA Orbital Debris Program Office (ODPO) was established at the NASA Johnson Space Center in 1979. The ODPO has initiated and led major orbital debris research activities over the past 38 years, including developing the first set of the NASA orbital debris mitigation requirements in 1995 and supporting the establishment of the U.S. Government Orbital Debris Mitigation Standard Practices in 2001. This paper is an overview of the recent ODPO research activities, ranging from ground-based and in-situ measurements, to laboratory tests, and to engineering and long-term orbital debris environment modeling. These activities highlight the ODPO's commitment to continuously improve the orbital debris environment definition to better protect current and future space missions from the low Earth orbit to the geosynchronous Earth orbit regions.

Physical Modeling for Processing Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Hyperspectral Data

DTIC Science & Technology

2003-09-30

Physical Modeling for Processing Geosynchronous Imaging Fourier Transform Spectrometer ( GIFTS ) Hyperspectral Data Dr. Allen H.-L. Huang...ssec.wisc.edu Award Number: N000140110850 Grant Number: 144KE70 http://www.ssec.wisc.edu/ gifts /navy/ LONG-TERM GOALS This Office of Naval...objective of this DoD research effort is to develop and demonstrate a fully functional GIFTS hyperspectral data processing system with the potential for a

A CCD search for geosynchronous debris

NASA Technical Reports Server (NTRS)

Gehrels, Tom; Vilas, Faith

1986-01-01

Using the Spacewatch Camera, a search was conducted for objects in geosynchronous earth orbit. The system is equipped with a CCD camera cooled with dry ice; the image scale is 1.344 arcsec/pixel. The telescope drive was off so that during integrations the stars were trailed while geostationary objects appeared as round images. The technique should detect geostationary objects to a limiting apparent visual magnitude of 19. A sky area of 8.8 square degrees was searched for geostationary objects while geosynchronous debris passing through was 16.4 square degrees. Ten objects were found of which seven are probably geostationary satellites having apparent visual magnitudes brighter than 13.1. Three objects having magnitudes equal to or fainter than 13.7 showed motion in the north-south direction. The absence of fainter stationary objects suggests that a gap in debris size exists between satellites and particles having diameters in the millimeter range.

gLISA: geosynchronous laser interferometer space antenna concepts with off-the-shelf satellites.

PubMed

Tinto, M; DeBra, D; Buchman, S; Tilley, S

2015-01-01

We discuss two geosynchronous gravitational wave (GW) mission concepts, which we generically name gLISA. One relies on the science instrument hosting program onboard geostationary commercial satellites, while the other takes advantage of recent developments in the aerospace industry that result in dramatic satellite and launching vehicle cost reductions for a dedicated geosynchronous mission. To achieve the required level of disturbance free-fall onboard these large and heavy platforms, we propose a new drag-free system, which we have named "two-stage" drag-free. It incorporates the Modular Gravitational Reference Sensor (developed at Stanford University) and does not rely on the use of μN thrusters. Although both mission concepts are characterized by different technical and programmatic challenges, individually they could be flown and operated at a cost significantly lower than those of previously envisioned gravitational wave missions, and in the year 2015 we will perform at JPL a detailed selecting mission analysis.

Results in orbital evolution of objects in the geosynchronous region

NASA Technical Reports Server (NTRS)

Friesen, Larry Jay; Jackson, Albert A., IV; Zook, Herbert A.; Kessler, Donald J.

1990-01-01

The orbital evolution of objects at or near geosynchronous orbit (GEO) has been simulated to investigate possible hazards to working geosynchronous satellites. Orbits of both large satellites and small particles have been simulated, subject to perturbations by nonspherical geopotential terms, lunar and solar gravity, and solar radiation pressure. Large satellites in initially circular orbits show an expected cycle of inclination change driven by lunar and solar gravity, but very little altitude change. They thus have little chance of colliding with objects at other altitudes. However, if such a satellite is disrupted, debris can reach thousands of kilometers above or below the initial satellite altitude. Small particles in GEO experience two cycles driven by solar radiation: an expected eccentricity cycle and an inclination cycle not expected. Particles generated by GEO insertion stage solid rocket motors typically hit the earth or escape promptly; a small fraction appear to remain in persistent orbits.

The effects of simulated space environmental parameters on six commercially available composite materials

NASA Technical Reports Server (NTRS)

Funk, Joan G.; Sykes, George F., Jr.

1989-01-01

The effects of simulated space environmental parameters on microdamage induced by the environment in a series of commercially available graphite-fiber-reinforced composite materials were determined. Composites with both thermoset and thermoplastic resin systems were studied. Low-Earth-Orbit (LEO) exposures were simulated by thermal cycling; geosynchronous-orbit (GEO) exposures were simulated by electron irradiation plus thermal cycling. The thermal cycling temperature range was -250 F to either 200 F or 150 F. The upper limits of the thermal cycles were different to ensure that an individual composite material was not cycled above its glass transition temperature. Material response was characterized through assessment of the induced microcracking and its influence on mechanical property changes at both room temperature and -250 F. Microdamage was induced in both thermoset and thermoplastic advanced composite materials exposed to the simulated LEO environment. However, a 350 F cure single-phase toughened epoxy composite was not damaged during exposure to the LEO environment. The simuated GEO environment produced microdamage in all materials tested.

Second harmonic poloidal waves observed by Van Allen Probes in the dusk-midnight sector

DOE PAGES

Min, Kyungguk; Takahashi, Kazue; Ukhorskiy, Aleksandr Y.; ...

2017-02-24

This paper presents observations of ultralow-frequency (ULF) waves from Van Allen Probes. The event that generated the ULF waves occurred 2 days after a minor geomagnetic storm during a geomagnetically quiet time. Narrowband pulsations with a frequency of about 7 mHz with moderate amplitudes were registered in the premidnight sector when Probe A was passing through an enhanced density region near geosynchronous orbit. Probe B, which passed through the region earlier, did not detect the narrowband pulsations but only broadband noise. Despite the single-spacecraft measurements, we were able to determine various wave properties. We find that the observed waves aremore » a second harmonic poloidal mode propagating westward with an azimuthal wave number estimated to be ~100; the magnetic field fluctuations have a finite compressional component due to small but finite plasma beta (~0.1); the energetic proton fluxes in the energy ranging from above 10 keV to about 100 keV exhibit pulsations with the same frequency as the poloidal mode and energy-dependent phase delays relative to the azimuthal component of the electric field, providing evidence for drift-bounce resonance; and the second harmonic poloidal mode may have been excited via the drift-bounce resonance mechanism with free energy fed by the inward radial gradient of ~80 keV protons. Here, we show that the wave active region is where the plume overlaps the outer edge of ring current and suggest that this region can have a wide longitudinal extent near geosynchronous orbit.« less

Second harmonic poloidal waves observed by Van Allen Probes in the dusk-midnight sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Min, Kyungguk; Takahashi, Kazue; Ukhorskiy, Aleksandr Y.

This paper presents observations of ultralow-frequency (ULF) waves from Van Allen Probes. The event that generated the ULF waves occurred 2 days after a minor geomagnetic storm during a geomagnetically quiet time. Narrowband pulsations with a frequency of about 7 mHz with moderate amplitudes were registered in the premidnight sector when Probe A was passing through an enhanced density region near geosynchronous orbit. Probe B, which passed through the region earlier, did not detect the narrowband pulsations but only broadband noise. Despite the single-spacecraft measurements, we were able to determine various wave properties. We find that the observed waves aremore » a second harmonic poloidal mode propagating westward with an azimuthal wave number estimated to be ~100; the magnetic field fluctuations have a finite compressional component due to small but finite plasma beta (~0.1); the energetic proton fluxes in the energy ranging from above 10 keV to about 100 keV exhibit pulsations with the same frequency as the poloidal mode and energy-dependent phase delays relative to the azimuthal component of the electric field, providing evidence for drift-bounce resonance; and the second harmonic poloidal mode may have been excited via the drift-bounce resonance mechanism with free energy fed by the inward radial gradient of ~80 keV protons. Here, we show that the wave active region is where the plume overlaps the outer edge of ring current and suggest that this region can have a wide longitudinal extent near geosynchronous orbit.« less

Extravehicular activity at geosynchronous earth orbit

NASA Technical Reports Server (NTRS)

Shields, Nicholas, Jr.; Schulze, Arthur E.; Carr, Gerald P.; Pogue, William

1988-01-01

The basic contract to define the system requirements to support the Advanced Extravehicular Activity (EVA) has three phases: EVA in geosynchronous Earth orbit; EVA in lunar base operations; and EVA in manned Mars surface exploration. The three key areas to be addressed in each phase are: environmental/biomedical requirements; crew and mission requirements; and hardware requirements. The structure of the technical tasks closely follows the structure of the Advanced EVA studies for the Space Station completed in 1986.

On-line Flagging of Anomalies and Adaptive Sequential Hypothesis Testing for Fine-feature Characterization of Geosynchronous Satellites

DTIC Science & Technology

2015-10-18

statistical assessment of geosynchronous satellite status based on non- resolved photometry data,” AMOS Technical Conference, 2014 2. Wald, A...the seasonal changes. Its purpose is to enable an ongoing, automated assessment of satellite behavior through its life cycle using the photometry data...work on the decision to move the time slider [1], which is required in order to update the baseline signature (brightness) data for a satellite

Forecast the energetic electron flux on geosynchronous orbit with interplanetary parameters

NASA Astrophysics Data System (ADS)

Xue, B.; Ye, Z.

The high flux of energetic electron on geo-synchronous orbit can cause many kinds of malfunction of the satellite there, within which the bulk charging is the most significant that several broadcast satellite failures were confirmed to be due to this effect. The electron flux on geo-synchronous orbit varies in a large range even up to three orders accompanied the passage of interplanetary magnetic cloud and the following geomagnetic disturbances. Upon investigating electron flux, interplanetary solar wind data, and geomagnetic data as well, we found that: (1) The enhancement of energetic flux on the geo-synchronous orbit exhibits periodic recurrence of 27days. (2)Significant increase of electron flux relates to interplanetary index and characters of their distribution. (3)The electron flux also has relation to solar activity index. In our research work, artificial neural network was employed and constructed according to the job. The neural network, we call it full connecting network, was proved to be a sufficient tool to analyze the character of the evolving parameters, remember the omen of "electron storm", and establish the relationship between interplanetary parameters etc., and the fluence of high energetic electrons. The neural network was carefully constructed and trained to do the job mentioned above. Preliminary result showed that the accuracy forecast of electron flux 1 day ahead can reach 80%, and 70% for 2 days ahead.

The role of volume charging of dielectrics in the occurrence of electrostatic discharges on spacecraft

NASA Astrophysics Data System (ADS)

Chirskaia, Natalia; Novikov, Lev; Voronina, Ekaterina

2016-07-01

Most recent works consider the occurrence of electrostatic discharges (ESD) on the surface of the spacecraft due to spacecraft charging as a consequence of its surface interaction with the surrounding space plasma and solar radiation [1]. At the same time, low-orbit spacecraft are simultaneously exposed to the hot magnetospheric plasma with the typical energies of the particles ~ 0.1 - 50 keV and to the particles of the Earth radiation belts (ERB) with a typical energy in the range of 0.1-10 MeV. Electrons of ERB with these energies penetrate into spacecraft dielectrics on the order of a few millimeters in depth and create an embedded charge with their own electric field. It has been shown in a number of papers that exactly a volume charge of the electrons of ERB can be the cause of ESD on spacecraft [2,3]. In this work we present the results of calculation of the dose rate and, correspondingly, the radiation conductivity in a typical spacecraft dielectrics, arising under the action of the hot magnetospheric plasma and electrons of ERB. Using software packages based on Monte Carlo methods and on the solution of equations of charge transport in spacecraft dielectrics, it is shown that in a number of areas of the Earth's magnetosphere the ESD can occur under the action of the ERB electrons. The results of present work can provide a basis for creation of the standard, characterizing the emergence of ESR on spacecraft due to volume charging of dielectrics and describing the methods of laboratory tests of spacecraft dielectrics. L.S. Novikov, A.A. Makletsov, and V.V. Sinolits, Comparison of Coulomb-2, NASCAP-2K, MUSCAT and SPIS codes for geosynchronous spacecraft charging, Advances in Space Research, 2016, V. 57, Is. 2, pp. 671-680. Wrenn G.L., Smith R.J.K. The ESD Threat to GEO Satellites: Empirical Models for Observed Effects Due to Both Surface and Internal Charging. Proc. ESA Symp. "Environment Modelling for Space-based Applications", ESTEC Noordwijk, The Netherlands, 1996, pp. 121-124. Paulmier, T., Dirassen, B., Arnaout, M., Payan, D., Balcon, N., Radiation-Induced Conductivity of Space Used Polymers Under High Energy Electron Irradiation, Plasma Science, IEEE Transactions, 2015, V. 43, No. 9, pp.2907-2914.

Pressure balance inconsistency exhibited in a statistical model of magnetospheric plasma

NASA Astrophysics Data System (ADS)

Garner, T. W.; Wolf, R. A.; Spiro, R. W.; Thomsen, M. F.; Korth, H.

2003-08-01

While quantitative theories of plasma flow from the magnetotail to the inner magnetosphere typically assume adiabatic convection, it has long been understood that these convection models tend to overestimate the plasma pressure in the inner magnetosphere. This phenomenon is called the pressure crisis or the pressure balance inconsistency. In order to analyze it in a new and more detailed manner we utilize an empirical model of the proton and electron distribution functions in the near-Earth plasma sheet (-50 RE < X < -10 RE), which uses the [1989] magnetic field model and a plasma sheet representation based upon several previously published statistical studies. We compare our results to a statistically derived particle distribution function at geosynchronous orbit. In this analysis the particle distribution function is characterized by the isotropic energy invariant λ = EV2/3, where E is the particle's kinetic energy and V is the magnetic flux tube volume. The energy invariant is conserved in guiding center drift under the assumption of strong, elastic pitch angle scattering. If, in addition, loss is negligible, the phase space density f(λ) is also conserved along the same path. The statistical model indicates that f(λ, ?) is approximately independent of X for X ≤ -35 RE but decreases with increasing X for X ≥ -35 RE. The tailward gradient of f(λ, ?) might be attributed to gradient/curvature drift for large isotropic energy invariants but not for small invariants. The tailward gradient of the distribution function indicates a violation of the adiabatic drift condition in the plasma sheet. It also confirms the existence of a "number crisis" in addition to the pressure crisis. In addition, plasma sheet pressure gradients, when crossed with the gradient of flux tube volume computed from the [1989] magnetic field model, indicate Region 1 currents on the dawn and dusk sides of the outer plasma sheet.

End-of-Life Disposal of Satellites in Geosynchronous Altitude (Space and Missile Systems Center Standard)

DTIC Science & Technology

2010-03-19

developments. ’ This revised SMC standard comprises the text of The Aerospace Corporation report number TOR-2006( 8583 )-4474, Rev A (18 August 2009...Operating at Geosynchronous Altitude,” Aerospace TOR -2006( 8583 )- 4474, 3 November 2005 4. Campbell, W.S., “SMC Space Debris Mitigation Handbook...Revision 2.0,” Aerospace Report, TOR-2007(8506)-6693, 30 June 2007 5. ISO TC 20/SC 14 N, Space systems --- Disposal of satellites operating at

Joint search and sensor management for geosynchronous satellites

NASA Astrophysics Data System (ADS)

Zatezalo, A.; El-Fallah, A.; Mahler, R.; Mehra, R. K.; Pham, K.

2008-04-01

Joint search and sensor management for space situational awareness presents daunting scientific and practical challenges as it requires a simultaneous search for new, and the catalog update of the current space objects. We demonstrate a new approach to joint search and sensor management by utilizing the Posterior Expected Number of Targets (PENT) as the objective function, an observation model for a space-based EO/IR sensor, and a Probability Hypothesis Density Particle Filter (PHD-PF) tracker. Simulation and results using actual Geosynchronous Satellites are presented.

NASA Orbital Debris Baseline Populations

NASA Technical Reports Server (NTRS)

Krisko, Paula H.; Vavrin, A. B.

2013-01-01

The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.

Ion engine auxiliary propulsion applications and integration study

NASA Technical Reports Server (NTRS)

Zafran, S. (Editor)

1977-01-01

The benefits derived from application of the 8-cm mercury electron bombardment ion thruster were assessed. Two specific spacecraft missions were studied. A thruster was tested to provide additional needed information on its efflux characteristics and interactive effects. A Users Manual was then prepared describing how to integrate the thruster for auxiliary propulsion on geosynchronous satellites. By incorporating ion engines on an advanced communications mission, the weight available for added payload increases by about 82 kg (181 lb) for a 100 kg (2200 lb) satellite which otherwise uses electrothermal hydrazine. Ion engines can be integrated into a high performance propulsion module that is compatible with the multimission modular spacecraft and can be used for both geosynchronous and low earth orbit applications. The low disturbance torques introduced by the ion engines permit accurate spacecraft pointing with the payload in operation during thrusting periods. The feasibility of using the thruster's neutralizer assembly for neutralization of differentially charged spacecraft surfaces at geosynchronous altitude was demonstrated during the testing program.

Estimating GATE rainfall with geosynchronous satellite images

NASA Technical Reports Server (NTRS)

Stout, J. E.; Martin, D. W.; Sikdar, D. N.

1979-01-01

A method of estimating GATE rainfall from either visible or infrared images of geosynchronous satellites is described. Rain is estimated from cumulonimbus cloud area by the equation R = a sub 0 A + a sub 1 dA/dt, where R is volumetric rainfall, A cloud area, t time, and a sub 0 and a sub 1 are constants. Rainfall, calculated from 5.3 cm ship radar, and cloud area are measured from clouds in the tropical North Atlantic. The constants a sub 0 and a sub 1 are fit to these measurements by the least-squares method. Hourly estimates by the infrared version of this technique correlate well (correlation coefficient of 0.84) with rain totals derived from composited radar for an area of 100,000 sq km. The accuracy of this method is described and compared to that of another technique using geosynchronous satellite images. It is concluded that this technique provides useful estimates of tropical oceanic rainfall on a convective scale.

Dipolarizing flux bundles in the cis-geosynchronous magnetosphere: relationship between electric fields and energetic particle injections

NASA Astrophysics Data System (ADS)

Liu, J.; Angelopoulos, V.; Zhang, X. J.; Turner, D. L.; Gabrielse, C.; Runov, A.; Funsten, H. O.; Spence, H. E.

2015-12-01

Dipolarizing flux bundles (DFBs) are small flux tubes (typically < 3 RE in XGSM and YGSM) in the nightside magnetosphere that have magnetic field more dipolar than the background field. Although DFBs are known to accelerate particles to create energetic particle injections, their acceleration mechanism and importance in generating injections inside geosynchronous orbit remain open questions. To answer these questions, we investigate DFBs in the inner magnetosphere by conducting a statistical study with data from the Van Allen Probes. The results show that just like DFBs outside geosynchronous orbit, those inside that orbit occur most often in the pre-midnight sector. Half the DFBs are accompanied by energetic particle injection. Statistically, DFBs with injection have an electric field three times that of those without. All the injections accompanying DFBs appear dispersionless within the temporal and energy resolution considered. These findings suggest that the injections are ushered or locally produced by the DFB, and the DFB's strong electric field is an important aspect of the injection generation mechanism.

Examining Magnetotail Stretching and Substorm Onsets using GOES Satellite Data and Information Theory

NASA Astrophysics Data System (ADS)

Johnson, J.; Verrill, N.; Horton, D.; Wing, S.

2017-12-01

Since the beginning of NOAA and NASA's Geostationary Operational Environmental Satellite (GOES) program in 1975, GOES satellites have been monitoring the geomagnetic field at geosynchronous orbit with onboard magnetometers. Using this GOES magnetometer data, we develop a state variable which characterizes the stretching of the near-Earth magnetotail by mapping the data to a central location within the magnetotail at geosynchronous distance (≈6.6 RE). Because the stretching of the magnetotail is thought to be related to the occurrence of substorms, we then assess the transfer entropy between the measure of tail stretching and substorm onsets in order to quantify the information content of our state variable with regards to substorms. Our results support the idea that stretching in the magnetotail precedes substorms and that the relationship is causal, which can be useful for magnetospheric activity and substorm predictions. We are currently assessing how well magnetic field measurements at geosynchronous orbit characterize tail stretching and their usefulness for predictions.

Computerized ionospheric tomography based on geosynchronous SAR

NASA Astrophysics Data System (ADS)

Hu, Cheng; Tian, Ye; Dong, Xichao; Wang, Rui; Long, Teng

2017-02-01

Computerized ionospheric tomography (CIT) based on spaceborne synthetic aperture radar (SAR) is an emerging technique to construct the three-dimensional (3-D) image of ionosphere. The current studies are all based on the Low Earth Orbit synthetic aperture radar (LEO SAR) which is limited by long repeat period and small coverage. In this paper, a novel ionospheric 3-D CIT technique based on geosynchronous SAR (GEO SAR) is put forward. First, several influences of complex atmospheric environment on GEO SAR focusing are detailedly analyzed, including background ionosphere and multiple scattering effects (induced by turbulent ionosphere), tropospheric effects, and random noises. Then the corresponding GEO SAR signal model is constructed with consideration of the temporal-variant background ionosphere within the GEO SAR long integration time (typically 100 s to 1000 s level). Concurrently, an accurate total electron content (TEC) retrieval method based on GEO SAR data is put forward through subband division in range and subaperture division in azimuth, obtaining variant TEC value with respect to the azimuth time. The processing steps of GEO SAR CIT are given and discussed. Owing to the short repeat period and large coverage area, GEO SAR CIT has potentials of covering the specific space continuously and completely and resultantly has excellent real-time performance. Finally, the TEC retrieval and GEO SAR CIT construction are performed by employing a numerical study based on the meteorological data. The feasibility and correctness of the proposed methods are verified.

Crres Observations of Particle Flux Dropout Events

NASA Technical Reports Server (NTRS)

Fennell, J.; Roeder, J.; Spence, H.; Singer, H.; Korth, A.; Grande, M.; Vampola, A.

1999-01-01

The complete disappearance of energetic electrons was observed by CRRES in the near geosynchronous region in 7.5% of the orbits examined. These total flux dropouts were defined by the fluxes rapidly dropping to levels below the sensitivity of the MEA energetic electron spectrometer on the CRRES satellite. They were separated into those that were only energetic electron dropouts and those that were associated with energetic ion and plasma dropouts. Approximately 20% of the events showed dropouts of 0 particle fluxes, and these were usually coincident with large increases in the local magnetic intensity and signatures of strong current systems. The energetic particle instruments and magnetometer on CRRES provide a detailed picture of the particle and field responses to these unusual conditions. Both the local morning and dusk events were associated with strong azimuthal (eastward) and radial changes in the magnetic field indicative of a strong current system approaching and sometimes crossing the CRRES position at the time of the flux dropouts. The direction of the field changes and the details of particle observations are consistent with CRRES passing through the plasma sheet boundary layer and entering the tail lobe for a significant number of the events.

Use of Faraday-rotation data from beacon satellites to determine ionospheric corrections for interplanetary spacecraft navigation

NASA Technical Reports Server (NTRS)

Royden, H. N.; Green, D. W.; Walson, G. R.

1981-01-01

Faraday-rotation data from the linearly polarized 137-MHz beacons of the ATS-1, SIRIO, and Kiku-2 geosynchronous satellites are used to determine the ionospheric corrections to the range and Doppler data for interplanetary spacecraft navigation. The JPL operates the Deep Space Network of tracking stations for NASA; these stations monitor Faraday rotation with dual orthogonal, linearly polarized antennas, Teledyne polarization tracking receivers, analog-to-digital converter/scanners, and other support equipment. Computer software examines the Faraday data, resolves the pi ambiguities, constructs a continuous Faraday-rotation profile and converts the profile to columnar zenith total electron content at the ionospheric reference point; a second program computes the line-of-sight ionospheric correction for each pass of the spacecraft over each tracking complex. Line-of-sight ionospheric electron content using mapped Faraday-rotation data is compared with that using dispersive Doppler data from the Voyager spacecraft; a difference of about 0.4 meters, or 5 x 10 to the 16th electrons/sq m is obtained. The technique of determining the electron content of interplanetary plasma by subtraction of the ionospheric contribution is demonstrated on the plasma torus surrounding the orbit of Io.

Solar Array at Very High Temperatures: Ground Tests

NASA Technical Reports Server (NTRS)

Vayner, Boris

2016-01-01

Solar array design for any spacecraft is determined by the orbit parameters. For example, operational voltage for spacecraft in Low Earth Orbit (LEO) is limited by significant differential charging due to interactions with low temperature plasma. In order to avoid arcing in LEO, solar array is designed to generate electrical power at comparatively low voltages (below 100 volts) or to operate at higher voltages with encapsulation of all suspected discharge locations. In Geosynchronous Orbit (GEO) differential charging is caused by energetic electrons that produce differential potential between the coverglass and the conductive spacecraft body in a kilovolt range. In such a case, the weakly conductive layer over coverglass, indium tin oxide (ITO) is one of the possible measures to eliminate dangerous discharges on array surface. Temperature variations for solar arrays in both orbits are measured and documented within the range of minus150 degrees Centigrade to plus 1100 degrees Centigrade. This wide interval of operational temperatures is regularly reproduced in ground tests with radiative heating and cooling inside a shroud with flowing liquid nitrogen. The requirements to solar array design and tests turn out to be more complicated when planned trajectory crosses these two orbits and goes closer to the Sun. The conductive layer over coverglass causes a sharp increase in parasitic current collected from LEO plasma, high temperature may cause cracks in encapsulating (Room Temperature Vulcanizing (RTV) material; radiative heating of a coupon in vacuum chamber becomes practically impossible above 1500 degrees Centigrade; conductivities of glass and adhesive go up with temperature that decrease array efficiency; and mechanical stresses grow up to critical magnitudes. A few test arrangements and respective results are presented in current paper. Coupons were tested against arcing in simulated LEO and GEO environments under elevated temperatures up to 2000 degrees Centigrade. The dependence of leakage current on temperature was measured, and electrostatic cleanness was verified for coupons with antireflection (AR) coating over the indium tin oxide (ITO) layer.

Identification of geostationary satellites using polarization data from unresolved images

NASA Astrophysics Data System (ADS)

Speicher, Andy

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. Since resolved images of geosynchronous satellites are not technically feasible with current technology, another method of distinguishing space objects was explored that exploits the polarization signature from unresolved images. The objective of this study was to collect and analyze visible-spectrum polarization data from unresolved images of geosynchronous satellites taken over various solar phase angles. Different collection geometries were used to evaluate the polarization contribution of solar arrays, thermal control materials, antennas, and the satellite bus as the solar phase angle changed. Since materials on space objects age due to the space environment, it was postulated that their polarization signature may change enough to allow discrimination of identical satellites launched at different times. The instrumentation used in this experiment was a United States Air Force Academy (USAFA) Department of Physics system that consists of a 20-inch Ritchey-Chretien telescope and a dual focal plane optical train fed with a polarizing beam splitter. A rigorous calibration of the system was performed that included corrections for pixel bias, dark current, and response. Additionally, the two channel polarimeter was calibrated by experimentally determining the Mueller matrix for the system and relating image intensity at the two cameras to Stokes parameters S0 and S1. After the system calibration, polarization data was collected during three nights on eight geosynchronous satellites built by various manufacturers and launched several years apart. Three pairs of the eight satellites were identical buses to determine if identical buses could be correctly differentiated. When Stokes parameters were plotted against time and solar phase angle, the data indicates that there were distinguishing features in S0 (total intensity) and S1 (linear polarization) that may lead to positive identification or classification of each satellite.

The cycle life chemistry of ambient-temperature secondary lithium cells

NASA Technical Reports Server (NTRS)

Somoano, R.; Carter, B. J.; Subba Rao, S.; Shen, D.; Yen, S. P. S.

1985-01-01

The Jet Propulsion Laboratory is involved in a NASA-sponsored research program to demonstrate the feasibility of ambient-temperature secondary lithium batteries for geosynchronous space applications. Encouraging cycle life has been demonstrated in sealed, cathode-limited laboratory cells. However, the cell capacity declines with cycle life. The results of recent studies of the lithium electrode passivation chemistry, and of conductive diluents for TiS2 cathodes and their possible contribution to capacity decline, are here presented. Technical issues associated with the unique operational requirements of a geosynchronous mission are also described.

Japan's launch vehicle program update

NASA Astrophysics Data System (ADS)

Tadakawa, Tsuguo

1987-06-01

NASDA is actively engaged in the development of H-I and H-II launch vehicle performance capabilities in anticipation of future mission requirements. The H-I has both two-stage and three-stage versions for medium-altitude and geosynchronous orbits, respectively; the restart capability of the second stage affords considerable mission planning flexibility. The H-II vehicle is a two-stage liquid rocket primary propulsion design employing two solid rocket boosters for secondary power; it is capable of launching two-ton satellites into geosynchronous orbit, and reduces manufacture and launch costs by extensively employing off-the-shelf technology.

Space colonies and energy supply to the earth

NASA Technical Reports Server (NTRS)

Oneill, G. K.

1975-01-01

It is pointed out that a space manufacturing facility may be economically more effective than alternative industries on the earth for the construction of products which are to be used in geosynchronous or higher orbits. The suggestion is made to construct solar power stations at a space colony and relocate them in geosynchronous orbit to supply energy to the earth. Attention is given to energy problems and approaches for solving them, taking into account environmental effects and economic factors. Economic aspects of space manufacturing are discussed in some detail.

Charging/discharge events in coated spacecraft polymers during electron beam irradiation in a scanning electron microscope

NASA Astrophysics Data System (ADS)

Czeremuszkin, G.; Latrèche, M.; Wertheimer, M. R.

2001-12-01

Spacecraft, such as those operating in geosynchronous orbit (GEO), can be subjected to intense irradiation by charged particles, for example high-energy (e.g. 20 keV) electrons. The surfaces of dielectric materials (for example, polymers used as "thermal blankets") can therefore become potential sites for damaging electrostatic discharge (ESD) pulse events. We simulate these conditions by examining small specimens of three relevant polymers (polyimide, polyester and fluoropolymer), both bare and coated, in a scanning electron microscope (SEM). The coatings examined include commercial indium-tin oxide (ITO), and thin films of SiO 2 and a-Si:H deposited by plasma-enhanced chemical vapor deposition (PECVD). All coatings are found to greatly modify the observed ESD behavior, compared with that of the bare polymer counterparts. These observations are explained in terms of the model for ESD pulses proposed by Frederickson.

Azimuthal propagation and frequency characteristic of compressional Pc 5 waves observed at geostationary orbit

NASA Astrophysics Data System (ADS)

Takahashi, K.; Higbie, P. R.; Baker, D. N.

1985-02-01

Properties of compressional Pc 5 waves as deduced from multiple-satellite observations at geosynchronous orbit are presented. The occurrence characteristics of the waves are determined, and the relation between variations in particle fluxes and magnetic field is examined. The spatiotemporal structure of the waves is considered, including the propagation perpendicular to the ambient magnetic field and the relation of the frequency characteristics to harmonic waves. It is demonstrated that the waves have large azimuthal wave numbers from 40 to 120, westward propagation at a typical velocity of 10 km/s, frequency roughly 25 percent of the second harmonic of the poloidal wave, and phase lag of 180 deg between the parallel and radial components of the wave magnetic field and + or -90 deg between the parallel and azimuthal components. These features are discussed in the light of existing theories of instabilities in the ring current plasma.

Aerodynamic heating on AFE due to nonequilibrium flow with variable entropy at boundary layer edge

NASA Technical Reports Server (NTRS)

Ting, P. C.; Rochelle, W. C.; Bouslog, S. A.; Tam, L. T.; Scott, C. D.; Curry, D. M.

1991-01-01

A method of predicting the aerobrake aerothermodynamic environment on the NASA Aeroassist Flight Experiment (AFE) vehicle is described. Results of a three dimensional inviscid nonequilibrium solution are used as input to an axisymmetric nonequilibrium boundary layer program to predict AFE convective heating rates. Inviscid flow field properties are obtained from the Euler option of the Viscous Reacting Flow (VRFLO) code at the boundary layer edge. Heating rates on the AFE surface are generated with the Boundary Layer Integral Matrix Procedure (BLIMP) code for a partially catalytic surface composed of Reusable Surface Insulation (RSI) times. The 1864 kg AFE will fly an aerobraking trajectory, simulating return from geosynchronous Earth orbit, with a 75 km perigee and a 10 km/sec entry velocity. Results of this analysis will provide principal investigators and thermal analysts with aeroheating environments to perform experiment and thermal protection system design.

Rapid thermal cycling of new technology solar array blanket coupons

NASA Technical Reports Server (NTRS)

Scheiman, David A.; Smith, Bryan K.; Kurland, Richard M.; Mesch, Hans G.

1990-01-01

NASA Lewis Research Center is conducting thermal cycle testing of a new solar array blanket technologies. These technologies include test coupons for Space Station Freedom (SSF) and the advanced photovoltaic solar array (APSA). The objective of this testing is to demonstrate the durability or operational lifetime of the solar array interconnect design and blanket technology within a low earth orbit (LEO) or geosynchronous earth orbit (GEO) thermal cycling environment. Both the SSF and the APSA array survived all rapid thermal cycling with little or no degradation in peak performance. This testing includes an equivalent of 15 years in LEO for SSF test coupons and 30 years of GEO plus ten years of LEO for the APSA test coupon. It is concluded that both the parallel gap welding of the SSF interconnects and the soldering of the APSA interconnects are adequately designed to handle the thermal stresses of space environment temperature extremes.

Dipolarizing flux bundles in the cis-geosynchronous magnetosphere: Relationship between electric fields and energetic particle injections

NASA Astrophysics Data System (ADS)

Liu, Jiang; Angelopoulos, V.; Zhang, Xiao-Jia; Turner, D. L.; Gabrielse, C.; Runov, A.; Li, Jinxing; Funsten, H. O.; Spence, H. E.

2016-02-01

Dipolarizing flux bundles (DFBs) are small flux tubes (typically <3 RE in XGSM and YGSM) in the nightside magnetosphere that have magnetic field more dipolar than the background. Although DFBs are known to accelerate particles, creating energetic particle injections outside geosynchronous orbit (trans-GEO), the nature of the acceleration mechanism and the importance of DFBs in generating injections inside geosynchronous orbit (cis-GEO) are unclear. Our statistical study of cis-GEO DFBs using data from the Van Allen Probes reveals that just like trans-GEO DFBs, cis-GEO DFBs occur most often in the premidnight sector, but their occurrence rate is ~1/3 that of trans-GEO DFBs. Half the cis-GEO DFBs are accompanied by an energetic particle injection and have an electric field 3 times stronger than that of the injectionless half. All DFB injections are dispersionless within the temporal resolution considered (11 s). Our findings suggest that these injections are ushered or produced locally by the DFB, and the DFB's strong electric field is an important aspect of the injection generation mechanism.

Forecast and Specification of Radiation Belt Electrons Based on Solar Wind Measurements

NASA Astrophysics Data System (ADS)

Li, X.; Barker, A.; Burin Des Roziers, E.

2003-12-01

Relativistic electrons in the Earth's magnetosphere are of considerable practical importance because of their effect on spacecraft and because of their radiation hazard to astronauts who perform extravehicular activity. The good correlation between solar wind velocity and MeV electron fluxes at geosynchronous orbit has long been established. We have developed a radial diffusion model, using solar wind parameters as the only input, to reproduce the variation of the MeV electrons at geosynchronous orbit. Based on this model, we have constructed a real-time model that forecasts one to two days in advance the daily averaged >2 MeV electron flux at geosynchronous orbit using real-time solar wind data from ACE. The forecasts from this model are available on the web in real time. A natural extension of our current model is to create a system for making quantitative forecasts and specifications of radiation belt electrons at different radial distances and different local times based on the solar wind conditions. The successes and obstacles associated with this extension will be discussed in this presentation.

An Earth Orbiting Satellite Service and Repair Facility

NASA Technical Reports Server (NTRS)

Berndt, Andrew; Cardoza, Mike; Chen, John; Daley, Gunter; Frizzell, Andy; Linton, Richard; Rast, Wayne

1989-01-01

A conceptual design was produced for the Geosynchronous Satellite Servicing Platform (GSSP), an orbital facility capable of repairing and servicing satellites in geosynchronous orbit. The GSSP is a man-tended platform, which consists of a habitation module, operations module, service bay and truss assembly. This design review includes an analysis of life support systems, thermal and power requirements, robotic and automated systems, control methods and navigation, and communications systems. The GSSP will utilize existing technology available at the time of construction, focusing mainly on modifying and integrating existing systems. The entire facility, along with two satellite retrieval vehicles (SRV), will be placed in geosynchronous orbit by the Advanced Launch System. The SRV will be used to ferry satellites to and from the GSSP. Technicians will be transferred from Earth to the GSSP and back in an Apollo-derived Crew Transfer Capsule (CTC). These missions will use advanced telerobotic equipment to inspect and service satellites. Four of these missions are tentatively scheduled per year. At this rate, the GSSP will service over 650 satelites during the projected 25 year lifespan.

Thermal control design of the Lightning Mapper Sensor narrow-band spectral filter

NASA Technical Reports Server (NTRS)

Flannery, Martin R.; Potter, John; Raab, Jeff R.; Manlief, Scott K.

1992-01-01

The performance of the Lightning Mapper Sensor is dependent on the temperature shifts of its narrowband spectral filter. To perform over a 10 degree FOV with an 0.8 nm bandwidth, the filter must be 15 cm in diameter and mounted externally to the telescope optics. The filter thermal control required a filter design optimized for minimum bandpass shift with temperature, a thermal analysis of substrate materials for maximum temperature uniformity, and a thermal radiation analysis to determine the parameter sensitivity of the radiation shield for the filter, the filter thermal recovery time after occultation, and heater power to maintain filter performance in the earth-staring geosynchronous environment.

Weight optimization of ultra large space structures

NASA Technical Reports Server (NTRS)

Reinert, R. P.

1979-01-01

The paper describes the optimization of a solar power satellite structure for minimum mass and system cost. The solar power satellite is an ultra large low frequency and lightly damped space structure; derivation of its structural design requirements required accommodation of gravity gradient torques which impose primary loads, life up to 100 years in the rigorous geosynchronous orbit radiation environment, and prevention of continuous wave motion in a solar array blanket suspended from a huge, lightly damped structure subject to periodic excitations. The satellite structural design required a parametric study of structural configurations and consideration of the fabrication and assembly techniques, which resulted in a final structure which met all requirements at a structural mass fraction of 10%.

NASCAP modelling of environmental-charging-induced discharges in satellites

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Roche, J. C.

1979-01-01

The charging and discharging characteristics of a typical geosynchronous satellite experiencing time-varying geomagnetic substorms, in sunlight, were studied utilizing the NASA Charging Analyzer Program (NASCAP). An electric field criteria of 150,000 volts/cm to initiate discharges and transfer of 67 percent of the stored charge was used based on ground test results. The substorm characteristics were arbitrarily chosen to evaluate effects of electron temperature and particle density (which is equivalent to current density). It was found that while there is a minimum electron temperature for discharges to occur, the rate of discharges is dependent on particle density and duration times of the encounter. Hence, it is important to define the temporal variations in the substorm environments.

Analytical Study on Flight Performance of a RP Laser Launcher

NASA Astrophysics Data System (ADS)

Katsurayama, H.; Ushio, M.; Komurasaki, K.; Arakawa, Y.

2005-04-01

An air-breathing RP Laser Launcher has been proposed as the alternative to conventional chemical launch systems. This paper analytically examines the feasibility of SSTO system powered by RP lasers. The trajectory from the ground to the geosynchronous orbit is computed and the launch cost including laser-base development is estimated. The engine performance is evaluated by CFD computations and a cycle analysis. The results show that the beam power of 2.3MW per unit initial vehicle mass is optimum to reach a geo-synchronous transfer orbit, and 3,000 launches are necessary to redeem the cost for laser transmitter.

Four dimensional observations of clouds from geosynchronous orbit using stereo display and measurement techniques on an interactive information processing system

NASA Technical Reports Server (NTRS)

Hasler, A. F.; Desjardins, M.; Shenk, W. E.

1979-01-01

Simultaneous Geosynchronous Operational Environmental Satellite (GOES) 1 km resolution visible image pairs can provide quantitative three dimensional measurements of clouds. These data have great potential for severe storms research and as a basic parameter measurement source for other areas of meteorology (e.g. climate). These stereo cloud height measurements are not subject to the errors and ambiguities caused by unknown cloud emissivity and temperature profiles that are associated with infrared techniques. This effort describes the display and measurement of stereo data using digital processing techniques.

Performance of an electrically raised, synchronous satellite when subjected to radiation degradation effects

NASA Technical Reports Server (NTRS)

Cake, J. E.; Regetz, J. D., Jr.

1971-01-01

The use of solar electric propulsion to raise a high-power communication satellite from a low altitude, inclined circular orbit of the geosynchronous orbit is evaluated. Since the satellite ascends through the high intensity radiation belts, the power available from the solar array and therefore to the ion thrusters degrades. The performance of the solar electric stage in combination with the thrust augmented Thor/Delta launch vehicle is evaluated for two thrust steering programs. The transfer times and solar array requirements are presented for total geosynchronous payloads from 450 to 1100 kg.

Low-thrust trajectory analysis for the geosynchronous mission

NASA Technical Reports Server (NTRS)

Jasper, T. P.

1973-01-01

Methodology employed in development of a computer program designed to analyze optimal low-thrust trajectories is described, and application of the program to a Solar Electric Propulsion Stage (SEPS) geosynchronous mission is discussed. To avoid the zero inclination and eccentricity singularities which plague many small-force perturbation techniques, a special set of state variables (equinoctial) is used. Adjoint equations are derived for the minimum time problem and are also free from the singularities. Solutions to the state and adjoint equations are obtained by both orbit averaging and precision numerical integration; an evaluation of these approaches is made.

Solar electric propulsion and interorbital transportation

NASA Technical Reports Server (NTRS)

Austin, R. E.

1978-01-01

In-house MSFC and contracted systems studies have evaluated the requirements associated with candidate SEP missions and the results point to a standard system approach for both program flexibility and economy. The prospects for economical space transportation in the 1980s have already provided a stimulus for Space Industrialization (SI) planning. Two SI initiatives that are used as examples for interorbital transportation requirements are discussed - Public Service Platforms and Satellite Power System. The interorbital requirements for SI range from support of manned geosynchronous missions to transfers of bulk cargo and large-delicate space structures from low earth orbit to geosynchronous orbit.

KSC00pp0540

NASA Image and Video Library

2000-04-21

The GOES-L satellite arrives on pad 36A, Cape Canaveral Air Force Station. The Atlas IIA rocket is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC-00pp0540

NASA Image and Video Library

2000-04-21

The GOES-L satellite arrives on pad 36A, Cape Canaveral Air Force Station. The Atlas IIA rocket is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

Exhaustive Strategy for Optical Survey of Geosynchronous Region using TAROT Telescopes

NASA Astrophysics Data System (ADS)

Richard, P.; Yanez, C.; Morand, V.; Verzeni, A.; Boer, M.; Klotz, A.

CNES and CNRS has been working on Optical Space Surveillance and Tracking for many years using the TAROT telescopes network. The goal of the study presented here is to propose an exhaustive strategy for optical survey of geosynchronous region. First, constraints will be defined on perigee and apogee of the orbits for which we are looking for exhaustiveness and then solutions will be explored making the survey in one or several nights using one or several telescopes. The last part of the study proposes solutions to help maintaining exhaustiveness if some observations failed.

Selected tether applications in space: Phase 2

NASA Technical Reports Server (NTRS)

Thorsen, M. H.; Lippy, L. J.

1985-01-01

System characteristics and design requirements are assessed for tether deployment. Criteria are established for comparing alternate concepts for: (1) deployment of 220 klb space shuttle from the space station; (2) tether assisted launch of a 20,000 lb payload to geosynchronous orbit; (3) placement of the 20,000 lb AXAF into 320 nmi orbit via orbiter; (4) retrieval of 20,000 lb AXAF from 205 nmi circular orbit for maintenance and reboost to 320 nmi; and (5) tethered OMV rendezvous and retrieval of OTV returning from a geosynchronous mission. Tether deployment systems and technical issues are discussed.

Efficient structures for geosynchronous spacecraft solar arrays. Phase 1, 2 and 3

NASA Astrophysics Data System (ADS)

Adams, L. R.; Hedgepeth, J. M.

1981-09-01

Structural concepts for deploying and supporting lightweight solar-array blankets for geosynchronous electrical power are evaluated. It is recommended that the STACBEAM solar-array system should be the object of further study and detailed evaluation. The STACBEAM system provides high stiffness at low mass, and with the use of a low mass deployment mechanism, full structural properties can be maintained throughout deployment. The stowed volume of the STACBEAM is acceptably small, and its linear deployment characteristic allows periodic attachments to the solar-array blanket to be established in the stowed configuration and maintained during deployment.

Efficient structures for geosynchronous spacecraft solar arrays. Phase 1, 2 and 3

NASA Technical Reports Server (NTRS)

Adams, L. R.; Hedgepeth, J. M.

1981-01-01

Structural concepts for deploying and supporting lightweight solar-array blankets for geosynchronous electrical power are evaluated. It is recommended that the STACBEAM solar-array system should be the object of further study and detailed evaluation. The STACBEAM system provides high stiffness at low mass, and with the use of a low mass deployment mechanism, full structural properties can be maintained throughout deployment. The stowed volume of the STACBEAM is acceptably small, and its linear deployment characteristic allows periodic attachments to the solar-array blanket to be established in the stowed configuration and maintained during deployment.

Near Space Tracking of the EM Phenomena Associated with the Main Earthquakes

NASA Technical Reports Server (NTRS)

Ouzounov, Dimitar; Taylor, Patrick; Bryant, Nevin; Pulinets, Sergey; Liu, Jann-Yenq; Yang, Kwang-Su

2004-01-01

Searching for electromagnetic (EM) phenomena originating in the Earth's crust prior to major earthquakes (M>5) are the object of this exploratory study. We present the idea of a possible relationship between: (1) electro-chemical and thermodynamic processes in the Earth's crust and (2) ionic enhancement of the atmosphere/ionosphere with tectonic stress and earthquake activity. The major source of these signals are proposed to originate from electromagnetic phenomenon which are responsible for these observed pre-seismic processes, such as, enhanced IR emission, also born as thermal anomalies, generation of long wave radiation, light emission caused by ground-to-air electric discharges, Total Electron Content (TEC) ionospheric anomalies and ionospheric plasma variations. The source of these data will include: (i) ionospheric plasma perturbations data from the recently launched DEMETER mission and currently available TEC/GPS network data; (ii) geomagnetic data from ORSTED and CHAMP; (iii) Thermal infra-red (TIR) transients mapped by the polar orbiting (NOAA/AVHRR, MODIS) and (iv) geosynchronous weather satellites measurements of GOES, METEOSAT. This approach requires continues observations and data collecting, in addition to both ground and space based monitoring over selected regions in order to investigate the various techniques for recording possible anomalies. During the space campaign emphasis will be on IR emission, obtained from TIR (thermal infrared) satellites, that records land/sea surface temperature anomalies and changes in the plasma and total electron content (TEC) of the ionosphere that occur over areas of potential earthquake activity.

Enhancement of low energy particle flux around plasmapause under quiet geomagnetic condition

NASA Astrophysics Data System (ADS)

Lee, J.

2016-12-01

Plasmapause is the boundary of the plasmaspheric region where cold plasma is dominant. In this boundary, the plasma density shows depletion to 1 10 on direction from the plasmasphere to magnetosphere and changes composition of energy distribution of particle. Some previous study provides that the location of the plasmapause expand beyond geosynchronous orbit under the quiet geomagnetic conditions. In this work, we study the changed characteristic of particle flux around the plasmapause using measurement from Van Allen Probes. On 23 April 2013, the satellites observed simultaneously proton and electron fluxes enhancement with E > 100 eV. During 12 hours prior to this event, the geomagnetic conditions were very quiet, Kp < 1, and geomagnetic storm did not occur. This event maintain for 15 minutes and only proton flux decrease rapidly in the magnetosphere. In this period SYM-H index enhanced abruptly in response to the impact of the dynamic pressure enhancement and AE index increased gradually up to about 200 nT. Electric field started to perturb in coincidence with enhancement of particle flux from the plasmapause. To explain the variation of low energy particle flux we will compare kinetic property of low energy particle by using velocity space distribution function at region of inner and outer boundary of the plasmapause.

Simultaneous Traveling Convection Vortex (TCV) Events and Pc 1-2 Wave Bursts at Cusp/Cleft Latitudes observed in Arctic Canada and Svalbard

NASA Astrophysics Data System (ADS)

Posch, J. L.; Witte, A. J.; Engebretson, M. J.; Murr, D.; Lessard, M.; Raita, T.; Singer, H. J.

2010-12-01

Traveling convection vortices (TCVs), which appear in ground magnetometer records at near-cusp latitudes as solitary ~5 mHz pulses, are now known to originate in instabilities in the ion foreshock just upstream of Earth’s bow shock. They can also stimulate compressions or relaxations of the dayside magnetosphere (evident in geosynchronous satellite data). These transient compressions can in turn sharply increase the growth rate of electromagnetic ion cyclotron (EMIC) waves, which also appear in ground records at near-cusp latitudes as bursts of Pc 1-2 pulsations. In this study we have identified simultaneous TCV - Pc 1-2 burst events occurring from 2008 through the first 7 months of 2010 in Eastern Arctic Canada and Svalbard, using a combination of fluxgate magnetometers (MACCS and IMAGE) and search coil magnetometers in each region. Magnetometer observations at GOES 10 and 12, at longitudes near the MACCS sites, are also used to characterize the strength of the magnetic perturbations. There is no direct proportion between the amplitude of TCV and Pc 1-2 wave events in either region, consistent with the highly variable densities and pitch angle distributions of plasma of ring current / plasma sheet energies in the outer dayside magnetosphere.

Remote Spacecraft Attitude Control by Coulomb Charging

NASA Astrophysics Data System (ADS)

Stevenson, Daan

The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose orbits experience no natural means of decay. The ability to rendezvous with these derelict satellites would enable active debris removal by servicing or repositioning missions, but docking procedures are generally inhibited by the large rotational momenta of uncontrolled satellites. Therefore, a contactless means of reducing the rotation rate of objects in the space environment is desired. This dissertation investigates the viability of Coulomb charging to achieve such remote spacecraft attitude control. If a servicing craft imposes absolute electric potentials on a nearby nonspherical debris object, it will impart electrostatic torques that can be used to gradually arrest the object's rotation. In order to simulate the relative motion of charged spacecraft with complex geometries, accurate but rapid knowledge of the Coulomb interactions is required. To this end, a new electrostatic force model called the Multi-Sphere Method (MSM) is developed. All aspects of the Coulomb de-spin concept are extensively analyzed and simulated using a system with simplified geometries and one dimensional rotation. First, appropriate control algorithms are developed to ensure that the nonlinear Coulomb torques arrest the rotation with guaranteed stability. Moreover, the complex interaction of the spacecraft with the plasma environment and charge control beams is modeled to determine what hardware requirements are necessary to achieve the desired electric potential levels. Lastly, the attitude dynamics and feedback control development is validated experimentally using a scaled down terrestrial testbed. High voltage power supplies control the potential on two nearby conductors, a stationary sphere and a freely rotating cylinder. The nonlinear feedback control algorithms developed above are implemented to achieve rotation rate and absolute attitude control. Collectively, these studies decisively validate the feasibility of Coulomb charging for remote spacecraft attitude control.

On Possible Arc Inception on Low Voltage Solar Array

NASA Technical Reports Server (NTRS)

Vayner, Boris

2015-01-01

Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 of all registered failures and anomalies, and comprised the most costly losses (25) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over coverglass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in coverglass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent sustained discharges between adjacent strings, and many ground tests were performed to determine threshold parameters (voltage and current) for sustained arcs. And again, manufacturing defects and aging in space environments may result in considerable decrease of critical threshold parameters. This paper is devoted to the analysis of possible reasons behind arcing on spacecraft with low bus voltages.

On Possible Arc Inception on Low Voltage Solar Array

NASA Technical Reports Server (NTRS)

Vayner, Boris

2015-01-01

Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 percent of all registered failures and anomalies, and comprised the most costly losses (25 percent) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over cover-glass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in cover-glass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent sustained discharges between adjacent strings, and many ground tests were performed to determine threshold parameters (voltage and current) for sustained arcs. And again, manufacturing defects and aging in space environments may result in considerable decrease of critical threshold parameters. This paper is devoted to the analysis of possible reasons behind arcing on spacecraft with low bus voltages.

Boeing Low-Thrust Geosynchronous Transfer Mission Experience

NASA Technical Reports Server (NTRS)

Poole, Mark; Ho, Monte

2007-01-01

Since 2000, Boeing 702 satellites have used electric propulsion for transfer to geostationary orbits. The use of the 25cm Xenon Ion Propulsion System (25cm XIPS) results in more than a tenfold increase in specific impulse with the corresponding decrease in propellant mass needed to complete the mission when compared to chemical propulsion[1]. In addition to more favorable mass properties, with the use of XIPS, the 702 has been able to achieve orbit insertions with higher accuracy than it would have been possible with the use of chemical thrusters. This paper describes the experience attained by using the 702 XIPS ascent strategy to transfer satellite to geosynchronous orbits.

KSC00pp0421

NASA Image and Video Library

2000-03-29

The second stage of an Atlas II/Centaur rocket arrives on pad 36-A, Cape Canaveral Air Force Station, for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0412

NASA Image and Video Library

2000-03-27

Workers at Cape Canaveral Air Force Station prepare to erect the first stage of an Atlas II/Centaur rocket in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0417

NASA Image and Video Library

2000-03-27

The first stage of an Atlas II/Centaur rocket stands erect in the launch gantry on pad 36A, Cape Canaveral Air Force Station. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0421

NASA Image and Video Library

2000-03-29

The second stage of an Atlas II/Centaur rocket arrives on pad 36-A, Cape Canaveral Air Force Station, for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0416

NASA Image and Video Library

2000-03-27

At Cape Canaveral Air Force Station, the first stage of an Atlas II/Centaur rocket is nearing erection in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0415

NASA Image and Video Library

2000-03-27

At Cape Canaveral Air Force Station, the first stage of an Atlas II/Centaur rocket is slowly raised in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0417

NASA Image and Video Library

2000-03-27

The first stage of an Atlas II/Centaur rocket stands erect in the launch gantry on pad 36A, Cape Canaveral Air Force Station. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0541

NASA Image and Video Library

2000-04-21

The GOES-L satellite is lifted up the gantry on pad 36A, Cape Canaveral Air Force Station. the Atlas IIA is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC-00pp0416

NASA Image and Video Library

2000-03-27

At Cape Canaveral Air Force Station, the first stage of an Atlas II/Centaur rocket is nearing erection in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0414

NASA Image and Video Library

2000-03-27

At Cape Canaveral Air Force Station, the first stage of an Atlas II/Centaur rocket begins erection in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0412

NASA Image and Video Library

2000-03-27

Workers at Cape Canaveral Air Force Station prepare to erect the first stage of an Atlas II/Centaur rocket in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0541

NASA Image and Video Library

2000-04-21

The GOES-L satellite is lifted up the gantry on pad 36A, Cape Canaveral Air Force Station. the Atlas IIA is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC-00pp0543

NASA Image and Video Library

2000-04-23

The GOES-L satellite is about midway in its journey up the gantry on pad 36A, Cape Canaveral Air Force Station. The Atlas IIA rocket is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC00pp0415

NASA Image and Video Library

2000-03-27

At Cape Canaveral Air Force Station, the first stage of an Atlas II/Centaur rocket is slowly raised in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0414

NASA Image and Video Library

2000-03-27

At Cape Canaveral Air Force Station, the first stage of an Atlas II/Centaur rocket begins erection in the launch gantry on pad 36A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0543

NASA Image and Video Library

2000-04-23

The GOES-L satellite is about midway in its journey up the gantry on pad 36A, Cape Canaveral Air Force Station. The Atlas IIA rocket is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

Solar power satellite. System definition study. Part 1, volume 5: SPS transportation. Representative system descriptions

NASA Technical Reports Server (NTRS)

1977-01-01

Both LEO transportation (earth to low earth orbit) and GEO transportation (low earth orbit to geosynchronous orbit) segments were addressed. LEO options include both a 2 stage winged space freighter vehicle and a 2 stage ballistic recoverable vehicle. Both incorporate LO(2)/RP-1/LH(2) engines on the booster and standard SSME's on the upper stage. The orbit transfer vehicle options included chemical for geosynchronous satellite assembly and self powered electric propulsion for low earth orbit satellite assembly. An exhaust products analysis was conducted for the earth to LEO vehicle since atmospheric pollution could be a concern.

Land observation from geosynchronous earth orbit (LOGEO): Mission concept and preliminary engineering analysis

NASA Astrophysics Data System (ADS)

Román-Colón, Miguel O.; Strahler, Alan H.

2007-06-01

We propose an Earth-observation mission Land Observation from Geosynchronous Earth Orbit (LOGEO) to place two spin-scan-stabilized 500-m resolution 9-band VNIR-SWIR imagers in a near-geosynchronous inclined orbit, allowing 15 min observations with a full range of daily sun angles and 30∘ variations in view angle. LOGEO drifts westward at about 4∘ per day, providing geostationary-style coverage for all points on the globe eight times per year. This unique imaging geometry allows accurate retrievals of daily changes in surface bidirectional reflectance, which in turn enhances direct retrieval of biophysical properties, as well as long term and consistent land surface parameters for modeling studies that seek to understand the Earth system and its interactions. For studies of climate and environmental dynamics, LOGEO provides accurate observations of atmospheric aerosols, clouds, as well as other atmospheric constituents across a diverse number of spatial and temporal scales. This collection of land, atmospheric, and climate data products are directly applicable to seven of the nine GEOSS societal benefits areas, providing great opportunities for international collaboration. We also present an overview of LOGEO's systems architecture, as well as top-level design-trade studies and orbital scenarios.

Leveraging Commercial Communication Satellites to support the Space Situational

NASA Astrophysics Data System (ADS)

Deaver, T.

The majority of USSTRATCOM detect and track requirements in the geosynchronous regime could be met via strategic placement of medium grade optical sensors on select geosynchronous satellites at relatively low cost in less than 48 months. An architecture which includes hosting SSA sensors on eight to ten commercial communication satellites could provide for highly accurate, timely and relatively inexpensive detect and track capabilities. The major factors considered when hosting any sensor on a commercial communications satellite are size, weight (mass) and power or SWAP. Additional sensor specific items must also be considered to form a complete feasibility analysis. These include data rate, mounting constraints, thermal balance, timing accuracy, and attitude stability requirements. All of these factors directly impact the cost and flexibility of hosting such a sensor on a geosynchronous communication satellite. By choosing a relatively light weight, low power consumption sensor which requires a small amount of bandwidth to transmit its data, the cost of hosting the sensor is kept to a minimum. Once the type of sensor or sensors is identified, the next step is to identify idea geosynchronous locations for the "hosted" sensors. Once these locations are identified, then one would identify a potential host which needs to be replaced within the desired timeframe. Once the host is identified, then the satellite owner / operator should be approached about hosting a "neighborhood" watch sensor aboard their spacecraft. Commercial satellites are routinely replaced based on age, lack of available station keeping fuel or to allow a service provider to upgrade its capabilities. Each commercial communication satellite operator maintains a plan of replacing spacecraft. Between the two largest commercial SATCOM providers, INTELSAT and SES, six to eight spacecraft will be replaced each year (100 plus spacecraft with 15 year average lifetimes). The satellites are usually procured, designed, built, launched and operational within 36 months. In order for the US Government to adapt to this timeline, a sensor specification would need to be established as well as a sensor procurement pipeline. The sensors would then be provided to the satellite bus manufacturer for integration onto the bus. The spacecraft would then be launched and operated by the commercial SATCOM operator for the life of the spacecraft. Based on this approach, it is highly conceivable that a complete geosynchronous "neighborhood" watch program could be completed within 48 months of initiation.

SHIELDS Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordanova, Vania Koleva

Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure, i.e. “space weather”, remains a big space physics challenge. A new capability was developed at Los Alamos National Laboratory (LANL) to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. This framework simulates the dynamics of the Surface Charging Environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro- and micro-scale. In addition to using physics-based models (like RAM-SCB, BATS-R-US, and iPIC3D), new data assimilation techniques employing data frommore » LANL instruments on the Van Allen Probes and geosynchronous satellites were developed. An order of magnitude improvement in the accuracy in the simulation of the spacecraft surface charging environment was thus obtained. SHIELDS also includes a post-processing tool designed to calculate the surface charging for specific spacecraft geometry using the Curvilinear Particle-In-Cell (CPIC) code and to evaluate anomalies' relation to SCE dynamics. Such diagnostics is critically important when performing forensic analyses of space-system failures.« less

Simulation of the low earth orbital atomic oxygen interaction with materials by means of an oxygen ion beam

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Rutledge, Sharon K.; Paulsen, Phillip E.; Steuber, Thomas J.

1989-01-01

Atomic oxygen is the predominant species in low-Earth orbit between the altitudes of 180 and 650 km. These highly reactive atoms are a result of photodissociation of diatomic oxygen molecules from solar photons having a wavelength less than or equal to 2430A. Spacecraft in low-Earth orbit collide with atomic oxygen in the 3P ground state at impact energies of approximately 4.2 to 4.5 eV. As a consequence, organic materials previously used for high altitude geosynchronous spacecraft are severely oxidized in the low-Earth orbital environment. The evaluation of materials durability to atomic oxygen requires ground simulation of this environment to cost effectively screen materials for durability. Directed broad beam oxygen sources are necessary to evaluate potential spacecraft materials performance before and after exposure to the simulated low-Earth orbital environment. This paper presents a description of a low energy, broad oxygen ion beam source used to simulate the low-Earth orbital atomic oxygen environment. The results of materials interaction with this beam and comparison with actual in-space tests of the same meterials will be discussed. Resulting surface morphologies appear to closely replicate those observed in space tests.

Secondary emission conductivity of high purity silica fabric

NASA Technical Reports Server (NTRS)

Belanger, V. J.; Eagles, A. E.

1977-01-01

High purity silica fabrics were proposed for use as a material to control the effects of electrostatic charging of satellites at synchronous altitudes. These materials exhibited very quiet behavior when placed in simulated charging environments as opposed to other dielectrics used for passive thermal control which exhibit varying degrees of electrical arcing. Secondary emission conductivity is proposed as a mechanism for this superior behavior. Design of experiments to measure this phenomena and data taken on silica fabrics are discussed as they relate to electrostatic discharge (ESD) control on geosynchronous orbit spacecraft. Studies include the apparent change in resistivity of the material as a function of the electron beam energy, flux intensity, and the effect of varying electric fields impressed across the material under test.

Management of the orbital environment

NASA Technical Reports Server (NTRS)

Loftus, Joseph P., Jr.; Kessler, Donald J.; Anz-Meador, Phillip D.

1991-01-01

Data regarding orbital debris are presented to shed light on the requirements of environmental management in space, and strategies are given for active intervention and operational strategies. Debris are generated by inadvertent explosions of upper stages, intentional military explosions, and collisional breakups. Design and operation practices are set forth for minimizing debris generation and removing useless debris from orbit in the low-earth and geosynchronous orbits. Self-disposal options include propulsive maneuvers, drag-augmentation devices, and tether systems, and the drag devices are described as simple and passive. Active retrieval and disposition are considered, and the difficulty is examined of removing small debris. Active intervention techniques are required since pollution prevention is more effective than remediation for the problems of both earth and space.

Laser-driven two-electron quantum dot in plasmas

NASA Astrophysics Data System (ADS)

Bahar, M. K.; Soylu, A.

2018-06-01

We have investigated the energies of two-electron parabolic quantum dots (TEPQdots) embedded in plasmas characterized by more general exponential cosine screened Coulomb (MGECSC) potential under the action of a monochromatic, linearly polarized laser field by solving the corresponding Schrödinger equation numerically via the asymptotic iteration method. The four different cases of the MGECSC potential constituted by various sets of the potential parameters are reckoned in modeling of the interactions in the plasma environments which are Debye and quantum plasmas. The plasma environment is a remarkable experimental argument for the quantum dots and the interactions in plasma environments are different compared to the interactions in an environment without plasma and the screening specifications of the plasmas can be controlled through the plasma parameters. These findings constitute our major motivation in consideration of the plasma environments. An appreciable confinement effect is made up by implementing the laser field on the TEPQdot. The influences of the laser field on the system are included by using the Ehlotzky approximation, and then Kramers-Henneberger transformation is carried out for the corresponding Schrödinger equation. The influences of the ponderomotive force on two-electron quantum dots embedded in plasmas are investigated. The behaviours, the similarities and the functionalities of the laser field, the plasma environment, and the quantum dot confinement are also scrutinized. In addition, the role of the plasma environments in the mentioned analysis is also discussed in detail.

Puncture discharges in surface dielectrics as contaminant sources in spacecraft environments

NASA Technical Reports Server (NTRS)

Yadlowsky, E. J.; Hazelton, R. C.; Churchill, R. J.

1978-01-01

Spacecraft in geosynchronous orbits are known to become charged to large negative potentials during the local midnight region of the satellite orbit. Such discharges have been studied by the electron beam irradiation of dielectric samples in a vacuum environment. In addition to static measurements and photographic examination of the puncture discharges in Teflon samples, the transient characteristics of the electrical discharges are determined from oscillographs of voltage and current and by charged particle measurements employing a biased Faraday cup and a retarding potential analyzer. Using these latter techniques, studies of angular and energy distributions of charged particles have indicated an initial burst of high energy electrons (5 x 10 to the 13th power per discharge at energies greater than 300 eV) followed by a less intense burst of lower energy negative particles. Positive ions are emitted from the discharge site in an initial high velocity burst followed by a lower velocity burst tentatively identified as carbon.

Combined release and radiation effects satellite (CRRES) - Spacecraft and mission

NASA Astrophysics Data System (ADS)

Johnson, M. H.; Kierein, John

1992-08-01

The CRRES mission is a joint NASA and U.S. Department of Defense undertaking to study the near-Earth space environment and the effects of the Earth's radiation environment on state-of-the-art microelectronic components. To perform these studies, CRRES was launched with a complex array of scientific payloads. These included 24 chemical canisters which were released during the first 13 months of the mission at various altitudes over ground observation sites and diagnostic facilities. The CRRES system was launched on July 25, 1990, from Cape Canaveral Air Force Station on an Atlas I expendable launch vehicle into a low-inclination geosynchronous transfer orbit. The specified mission duration was 1 year with a goal of 3 years. The satellite subsystems support the instrument payloads by providing them with electrical power, command and data handling, and thermal control. This review briefly describes the CRRES observatory and mission, and provides an introduction to the CRRES instrumentation technical notes contained within this issue.

Validation of the SWMF Magnetosphere: Fields and Particles

NASA Astrophysics Data System (ADS)

Welling, D. T.; Ridley, A. J.

2009-05-01

The Space Weather Modeling Framework has been developed at the University of Michigan to allow many independent space environment numerical models to be executed simultaneously and coupled together to create a more accurate, all-encompassing system. This work explores the capabilities of the framework when using the BATS-R-US MHD code, Rice Convection Model (RCM), the Ridley Ionosphere Model (RIM), and the Polar Wind Outflow Model (PWOM). Ten space weather events, ranging from quiet to extremely stormy periods, are modeled by the framework. All simulations are executed in a manner that mimics an operational environment where fewer resources are available and predictions are required in a timely manner. The results are compared against in-situ measurements of magnetic fields from GOES, Polar, Geotail, and Cluster satellites as well as MPA particle measurements from the LANL geosynchronous spacecraft. Various metrics are calculated to quantify performance. Results when using only two to all four components are compared to evaluate the increase in performance as new physics are included in the system.

Tuning the Solar Dynamics Observatory Onboard Kalman Filter

NASA Technical Reports Server (NTRS)

Halverson, Julie Kay; Harman, Rick; Carpenter, Russell; Poland, Devin

2017-01-01

The Solar Dynamics Observatory (SDO) was launched in 2010. SDO is a sun pointing semi-autonomous spacecraft in a geosynchronous orbit that allows nearly continuous observations of the sun. SDO is equipped with coarse sun sensors, two star trackers, a digital sun sensor, and three two-axis inertial reference units (IRU). The IRUs are temperature sensitive and were designed to operate in a stable thermal environment. Due to battery degradation concerns the IRU heaters were not used on SDO and the onboard filter was tuned to accommodate the noisier IRU data. Since launch currents have increased on two IRUs, one had to eventually be powered off. Recent ground tests on a battery similar to SDO indicated the heaters would have negligible impact on battery degradation, so in 2016 a decision was made to turn the heaters on. This paper presents the analysis and results of updating the filter tuning parameters onboard SDO with the IRUs now operating in their intended thermal environment.

Voltage gradients in solar array cavities as possible breakdown sites in spacecraft-charging-induced discharges

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Mills, H. E.; Orange, L.

1981-01-01

A possible explanation for environmentally-induced discharges on geosynchronous satellites exists in the electric fields formed in the cavities between solar cells - the small gaps formed by the cover slides, solar cells, metallic interconnects and insulating substrate. When exposed to a substorm environment, the cover slides become less negatively charged than the spacecraft ground. If the resultant electric field becomes large enough, then the interconnect could emit electrons (probably by field emission) which could be accelerated to space by the positive voltage on the covers. An experimental study was conducted using a small solar array segment in which the interconnect potential was controlled by a power supply while the cover slides were irradiated by monoenergetic electrons. It was found that discharges could be triggered when the interconnect potential became at least 500 volts negative with respect to the cover slides. Analytical modeling of satellites exposed to substorm environments indicates that such gradients are possible. Therefore, it appears that this trigger mechanism for discharges is possible.

NASA's Optical Program on Ascension Island: Bringing MCAT to Life as the Eugene Stansbery-Meter Class Autonomous Telescope (ES-MCAT)

NASA Technical Reports Server (NTRS)

Lederer, S. M.; Hickson, P.; Cowardin, H. M.; Buckalew, B.; Frith, J.; Alliss, R.

2017-01-01

In June 2015, the construction of the Meter Class Autonomous Telescope was completed and MCAT saw the light of the stars for the first time. In 2017, MCAT was newly dedicated as the Eugene Stansbery-MCAT telescope by NASA's Orbital Debris Program Office (ODPO), in honor of his inspiration and dedication to this newest optical member of the NASA ODPO. Since that time, MCAT has viewed the skies with one engineering camera and two scientific cameras, and the ODPO optical team has begun the process of vetting the entire system. The full system vetting includes verification and validation of: (1) the hardware comprising the system (e.g. the telescopes and its instruments, the dome, weather systems, all-sky camera, FLIR cloud infrared camera, etc.), (2) the custom-written Observatory Control System (OCS) master software designed to autonomously control this complex system of instruments, each with its own control software, and (3) the custom written Orbital Debris Processing software for post-processing the data. ES-MCAT is now capable of autonomous observing to include Geosynchronous survey, TLE (Two-line element) tracking of individual catalogued debris at all orbital regimes (Low-Earth Orbit all the way to Geosynchronous (GEO) orbit), tracking at specified non-sidereal rates, as well as sidereal rates for proper calibration with standard stars. Ultimately, the data will be used for validation of NASA's Orbital Debris Engineering Model, ORDEM, which aids in engineering designs of spacecraft that require knowledge of the orbital debris environment and long-term risks for collisions with Resident Space Objects (RSOs).

Combined Space Environmental Exposure Tests of Multi-Junction GaAs/Ge Solar Array Coupons

NASA Technical Reports Server (NTRS)

Hoang, Bao; Wong, Frankie; Corey, Ron; Gardiner, George; Funderburk, Victor V.; Gahart, Richard; Wright, Kenneth H.; Schneider, Todd; Vaughn, Jason

2010-01-01

A set of multi-junction GaAs/Ge solar array test coupons were subjected to a sequence of 5-year increments of combined environmental exposure tests. The purpose of this test program is to understand the changes and degradation of the solar array panel components, including its ESD mitigation design features in their integrated form, after multiple years (up to 15) of simulated geosynchronous space environment. These tests consist of: UV radiation, electrostatic discharge (ESD), electron/proton particle radiation, thermal cycling, and ion thruster plume exposures. The solar radiation was produced using a Mercury-Xenon lamp with wavelengths in the UV spectrum ranging from 230 to 400 nm. The ESD test was performed in the inverted-gradient mode using a low-energy electron (2.6 - 6 keV) beam exposure. The ESD test also included a simulated panel coverglass flashover for the primary arc event. The electron/proton radiation exposure included both 1.0 MeV and 100 keV electron beams simultaneous with a 40 keV proton beam. The thermal cycling included simulated transient earth eclipse for satellites in geosynchronous orbit. With the increasing use of ion thruster engines on many satellites, the combined environmental test also included ion thruster exposure to determine whether solar array surface erosion had any impact on its performance. Before and after each increment of environmental exposures, the coupons underwent visual inspection under high power magnification and electrical tests that included characterization by LAPSS, Dark I-V, and electroluminescence. This paper discusses the test objective, test methodologies, and preliminary results after 5 years of simulated exposure.

Materials and techniques for spacecraft static charge control

NASA Technical Reports Server (NTRS)

Amore, L. J.; Eagles, A. E.

1977-01-01

An overview of the design, development, fabrication, and testing of transparent conductive coatings and conductive lattices deposited or formed on high resistivity spacecraft dielectric materials to obtain control static charge buildup on spacecraft external surfaces is presented. Fabrication techniques for the deposition of indium/tin oxide coatings and copper grid networks on Kapton and FEP Teflon films and special frit coatings for OSR and solar cell cover glasses are discussed. The techniques include sputtering, photoetching, silkscreening, and mechanical processes. A facility designed and built to simulate the electron plasma at geosynchronous altitudes is described along with test procedures. The results of material characterizations as well as electron irradiation aging effects in this facility for spacecraft polymers treated to control static charge are presented. The data presents results for electron beam energies up to 30 kV and electron current densities of 30 nA/cm squared. Parameters measured include secondary emission, surface leakage, and through the sample currents as a function of primary beam energy and voltage.

Hall Thruster Plume Measurements On-Board the Russian Express Satellites

NASA Technical Reports Server (NTRS)

Manzella, David; Jankovsky, Robert; Elliott, Frederick; Mikellides, Ioannis; Jongeward, Gary; Allen, Doug

2001-01-01

The operation of North-South and East-West station-keeping Hall thruster propulsion systems on-board two Russian Express-A geosynchronous communication satellites were investigated through a collaborative effort with the manufacturer of the spacecraft. Over 435 firings of 16 different thrusters with a cumulative run time of over 550 hr were reported with no thruster failures. Momentum transfer due to plume impingement was evaluated based on reductions in the effective thrust of the SPT-100 thrusters and induced disturbance torques determined based on attitude control system data and range data. Hall thruster plasma plume effects on the transmission of C-band and Ku-band communication signals were shown to be negligible. On-orbit ion current density measurements were made and subsequently compared to predictions and ground test data. Ion energy, total pressure, and electric field strength measurements were also measured on-orbit. The effect of Hall thruster operation on solar array performance over several months was investigated. A subset of these data is presented.

Radiating dipole model of interference induced in spacecraft circuitry by surface discharges

NASA Technical Reports Server (NTRS)

Metz, R. N.

1984-01-01

Spacecraft in geosynchronous orbit can be charged electrically to high voltages by interaction with the space plasma. Differential charging of spacecraft surfaces leads to arc and blowoff discharging. The discharges are thought to upset interior, computer-level circuitry. In addition to capacitive or electrostatic effects, significant inductive and less significant radiative effects of these discharges exist and can be modeled in a dipole approximation. Flight measurements suggest source frequencies of 5 to 50 MHz. Laboratory tests indicate source current strengths of several amperes. Electrical and magnetic fields at distances of many centimeters from such sources can be as large as tens of volts per meter and meter squared, respectively. Estimates of field attenuation by spacecraft walls and structures suggest that interior fields may be appreciable if electromagnetic shielding is much thinner than about 0.025 mm (1 mil). Pickup of such fields by wires and cables interconnecting circuit components could be a source of interference signals of several volts amplitude.

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 3: Appendices

NASA Technical Reports Server (NTRS)

Caluori, V. A.; Conrad, R. T.; Jenkins, J. C.

1980-01-01

Technological requirements and forecasts of rocket engine parameters and launch vehicles for future Earth to geosynchronous orbit transportation systems are presented. The parametric performance, weight, and envelope data for the LOX/CH4, fuel cooled, staged combustion cycle and the hydrogen cooled, expander bleed cycle engine concepts are discussed. The costing methodology and ground rules used to develop the engine study are summarized. The weight estimating methodology for winged launched vehicles is described and summary data, used to evaluate and compare weight data for dedicated and integrated O2/H2 subsystems for the SSTO, HLLV and POTV are presented. Detail weights, comparisons, and weight scaling equations are provided.

KSC-00pp0422

NASA Image and Video Library

2000-03-29

The second stage of an Atlas II/Centaur rocket is raised to a vertical position in front of the gantry on pad 36-A, Cape Canaveral Air Force Station, for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0422

NASA Image and Video Library

2000-03-29

The second stage of an Atlas II/Centaur rocket is raised to a vertical position in front of the gantry on pad 36-A, Cape Canaveral Air Force Station, for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0413

NASA Image and Video Library

2000-03-27

Workers at Cape Canaveral Air Force Station prepare to erect the first stage of an Atlas II/Centaur rocket in the launch gantry on pad 36A. Shown are the rocket thrusters. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0426

NASA Image and Video Library

2000-03-29

At launch pad 36-A, Cape Canaveral Air Force Station, cables help guide the second stage of an Atlas II/Centaur rocket as it is lifted up the gantry (behind it) for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0424

NASA Image and Video Library

2000-03-29

At launch pad 36-A, Cape Canaveral Air Force Station, workers check over the second stage of an Atlas II/Centaur rocket before it is lifted up the gantry (behind it) for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0413

NASA Image and Video Library

2000-03-27

Workers at Cape Canaveral Air Force Station prepare to erect the first stage of an Atlas II/Centaur rocket in the launch gantry on pad 36A. Shown are the rocket thrusters. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the NASA/Lockheed Martin GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0544

NASA Image and Video Library

2000-04-23

The GOES-L satellite approaches the end of its journey up the gantry on pad 36A, Cape Canaveral Air Force Station, for mating with the Atlas IIA/Centaur rocket. The Atlas IIA is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC00pp0424

NASA Image and Video Library

2000-03-29

At launch pad 36-A, Cape Canaveral Air Force Station, workers check over the second stage of an Atlas II/Centaur rocket before it is lifted up the gantry (behind it) for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC-00pp0542

NASA Image and Video Library

2000-04-21

The GOES-L satellite is ready for mating with the lower stages of the Atlas IIA rocket on pad 36A, Cape Canaveral Air Force Station. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC-00pp0425

NASA Image and Video Library

2000-03-29

At launch pad 36-A, Cape Canaveral Air Force Station, the second stage of an Atlas II/Centaur rocket is lifted up the gantry (behind it) for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0425

NASA Image and Video Library

2000-03-29

At launch pad 36-A, Cape Canaveral Air Force Station, the second stage of an Atlas II/Centaur rocket is lifted up the gantry (behind it) for mating with the first stage. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0423

NASA Image and Video Library

2000-03-29

Workers at Cape Canaveral Air Force Station watch as the second stage of an Atlas II/Centaur rocket is raised to a vertical position in front of the gantry on pad 36-A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

KSC00pp0544

NASA Image and Video Library

2000-04-23

The GOES-L satellite approaches the end of its journey up the gantry on pad 36A, Cape Canaveral Air Force Station, for mating with the Atlas IIA/Centaur rocket. The Atlas IIA is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC00pp0542

NASA Image and Video Library

2000-04-21

The GOES-L satellite is ready for mating with the lower stages of the Atlas IIA rocket on pad 36A, Cape Canaveral Air Force Station. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC-00pp0423

NASA Image and Video Library

2000-03-29

Workers at Cape Canaveral Air Force Station watch as the second stage of an Atlas II/Centaur rocket is raised to a vertical position in front of the gantry on pad 36-A. Atlas II is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing

Need for expanded environmental measurement capabilities in geosynchronous Earth orbit

NASA Technical Reports Server (NTRS)

Mercanti, Enrico P.

1991-01-01

The proliferation of environmental satellites in low altitude earth orbit (LEO) has demonstrated the usefulness of earth remote sensing from space. As use of the technology grows, the limitations of LEO missions become more apparent. Many inadequacies can be met by remote sensing from geosynchronous earth orbits (GEO) that can provide high temporal resolution, consistent viewing of specific earth targets, long sensing dwell times with varying sun angles, stereoscopic coverage, and correlative measurements with ground and LEO observations. An environmental platform in GEO is being studied by NASA. Small research satellite missions in GEO were studied (1990) at GSFC. Some recent independent assessments of NASA Earth Science Programs recommend accelerating the earlier deployment of smaller missions.

Discrimination of Closely-Spaced Geosynchronous Satellites - Phase Curve Analysis & New Small Business Innovative Research (SBIR) Efforts

NASA Astrophysics Data System (ADS)

Levan, P.

2010-09-01

Geosynchronous objects appear as unresolved blurs even when observed with the largest ground-based telescopes. Due to the lack of any spatial detail, two or more objects appearing at similar brightness levels within the spectral bandpass they are observed are difficult to distinguish. Observing a changing pattern of such objects from one time epoch to another showcases the deficiencies in associating individual objects before and after the configuration change. This paper explores solutions to this deficiency in the form of spectral (under small business innovative research) and phase curve analyses. The extension of the technique to phase curves proves to be a powerful new capability.

Initial results from a dynamic coupled magnetosphere-ionosphere-ring current model

NASA Astrophysics Data System (ADS)

Pembroke, Asher; Toffoletto, Frank; Sazykin, Stanislav; Wiltberger, Michael; Lyon, John; Merkin, Viacheslav; Schmitt, Peter

2012-02-01

In this paper we describe a coupled model of Earth's magnetosphere that consists of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamics (MHD) simulation, the MIX ionosphere solver and the Rice Convection Model (RCM) and report some results using idealized inputs and model parameters. The algorithmic and physical components of the model are described, including the transfer of magnetic field information and plasma boundary conditions to the RCM and the return of ring current plasma properties to the LFM. Crucial aspects of the coupling include the restriction of RCM to regions where field-line averaged plasma-β ≤ 1, the use of a plasmasphere model, and the MIX ionosphere model. Compared to stand-alone MHD, the coupled model produces a substantial increase in ring current pressure and reduction of the magnetic field near the Earth. In the ionosphere, stronger region-1 and region-2 Birkeland currents are seen in the coupled model but with no significant change in the cross polar cap potential drop, while the region-2 currents shielded the low-latitude convection potential. In addition, oscillations in the magnetic field are produced at geosynchronous orbit with the coupled code. The diagnostics of entropy and mass content indicate that these oscillations are associated with low-entropy flow channels moving in from the tail and may be related to bursty bulk flows and bubbles seen in observations. As with most complex numerical models, there is the ongoing challenge of untangling numerical artifacts and physics, and we find that while there is still much room for improvement, the results presented here are encouraging.

A Small Postmidnight Substorm During IMF Bz+ and By+ Conditions -- Joint Optical, Radar, Magnetic and Satellite Observations

NASA Astrophysics Data System (ADS)

Liang, J.; Sofko, G.; Donovan, E.; Greenwald, R.

2002-12-01

Multi-instrument observations of a small postmidnight substorm event during a period of IMF dominated by Bz+ and By+ conditions on October 9, 2000, showed the substorm structure with high time resolution. Three optical intensifications and Pi2 bursts occurred. The last and strongest Pi2 burst was associated with an expansive phase (EP) onset, characterized by a 100 nT magnetic bay at Fort Churchill and an auroral breakup in which the 630 nm emissions moved poleward about 2.5 degrees. About 11 minutes after the first EP onset, a second stage of auroral brightening occurred. For each of the three initial optical intensifications, there was an eastward-moving discrete azimuthal structure. SuperDARN HF radar line-of-sight velocity measurements revealed eastward electric fields within each Pi2 wave train. The observations are interpreted as resulting from the drift-Alfven-ballooning (DAB) mode instability at near-geosynchronous orbit (NGO) locations. Within the NGO drift waves, regions of charge separation led to electric fields and field-aligned currents (FACs) of alternating direction. The ionospheric reflection of Alfven wave energy likely generated the Pi2 pulsations observed on the ground. The multi-instrument ground observations agree quite well with the substorm onset scenario based upon CRRES satellite observations by Erickson et al. [2000]. There was a single, relatively confined (~4 hour in MLT) counterclockwise convection cell during the growth phase and EP onset. A clearly defined vortex at its center defined the center of the downward FAC. This vortex, initially northward of the optical aurora, moved eastward and then suddenly southward just prior to the EP onset. At that time, the FAC structure was typical of the substorm current wedge (SCW). Reasons for the convection cell motion and SCW development are discussed. Erickson, G. M., N. C. Maynard, W. J. Burke, G. R. Wilson, and M. A. Heinemann, Electromagnetics of substorm onsets in the near-geosynchronous plasma sheet, J. Geophys. Res., 105, 25265, 2000.

Van Allen Probes observations of outer radiation belt evolution during CME and CIR storms

NASA Astrophysics Data System (ADS)

Hudson, M. K.; Shen, X.; Jaynes, A. N.; Shi, Q.; Tian, A.; Claudepierre, S. G.; Qin, M.; Zong, Q.; Sun, W.

2017-12-01

Storm time outer radiation belt evolutes dramatically. It is still an stuff problem to model and predict the evolutions. The MeV electron flux can loss, no change or increase during different storms. Most of the previous statistical results were made by low altitude polar orbiting satellites, such as SAMPEX and NOAA POES, or geosynchronous orbiting satellites, such as GOES. Although part of the electron flux observed by polar orbiting satellites can be treated as trapped electrons, they are already close to the ionosphere with pitch angles apart from 90 degrees. Geosynchronous orbiting satellites are limited to r=6.6 RE (geocentric radial distance in Earth radii). The Van Allen Probes twin spacecraft, launched on 30 August 2012 with orbit near the equatorial plane, apogee at 5.8 RE and perigee at 620 km, give us a good oppurtuinity to study the storm-time outer radiation belt evolutions. During the time period from the begining of 2013 to the end of 2016, 31 CMEs and 28 CIRs are identified from OMNI-2 dataset. Superposed epoch analysis shows that CIR-storms which increased flux closer to geosynchronous orbit consistent with earlier studies, while CME-storms likely produce deeper penetration of enhanced flux and local heating which is greater at higher energies at lower L*.

Calibration of a system to collect visible-light polarization data for classification of geosynchronous satellites

NASA Astrophysics Data System (ADS)

Speicher, Andy; Matin, Mohammad; Tippets, Roger; Chun, Francis

2014-09-01

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. The objective of this study was to calibrate a system to exploit the optical signature of unresolved geosynchronous satellite images by collecting polarization data in the visible wavelengths for the purpose of revealing discriminating features. These features may lead to positive identification or classification of each satellite. The system was calibrated with an algorithm and process that takes raw observation data from a two-channel polarimeter and converts it to Stokes parameters S0 and S1. This instrumentation is a new asset for the United States Air Force Academy (USAFA) Department of Physics and consists of one 20-inch Ritchey-Chretien telescope and a dual focal plane system fed with a polarizing beam splitter. This study calibrated the system and collected preliminary polarization data on five geosynchronous satellites to validate performance. Preliminary data revealed that each of the five satellites had a different polarization signature that could potentially lead to identification in future studies.

Modeling the entry and trapping of solar energetic particles in the magnetosphere during the November 24-25, 2001 storm

NASA Astrophysics Data System (ADS)

Richard, R. L.; El-Alaoui, M.; Ashour-Abdalla, M.; Walker, R. J.

2009-04-01

We have modeled the entry of solar energetic particles (SEPs) into the magnetosphere during the November 24-25, 2001 magnetic storm and the trapping of particles in the inner magnetosphere. The study used the technique of following many test particles, protons with energies greater than about 100 keV, in the electric and magnetic fields from a global magnetohydrodynamic (MHD) simulation of the magnetosphere during this storm. SEP protons formed a quasi-trapped and trapped population near and within geosynchronous orbit. Preliminary data comparisons show that the simulation does a reasonably good job of predicting the differential flux measured by geosynchronous spacecraft. Particle trapping took place mainly as a result of particles becoming non-adiabatic and crossing onto closed field lines. Particle flux in the inner magnetosphere increased dramatically as an interplanetary shock impacted and compressed the magnetosphere near 0600 UT, but long term trapping (hours) did not become widespread until about an hour later, during a further compression of the magnetosphere. Trapped and quasi-trapped particles were lost during the simulation by motion through the magnetopause and by precipitation, primarily the former. This caused the particle population near and within geosynchronous orbit to gradually decrease later on during the latter part of the interval.

Cycle life status of SAFT VOS nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Goualard, Jacques

1993-01-01

The SAFT prismatic VOS Ni-Cd cells have been flown in geosynchronous orbit since 1977 and in low earth orbit since 1983. Parallel cycling tests are performed by several space agencies in order to determine the cycle life for a wide range of temperature and depth of discharge (DOD). In low Earth orbit (LEO), the ELAN program is conducted on 24 Ah cells by CNES and ESA at the European Battery Test Center at temperatures ranging from 0 to 27 C and DOD from 10 to 40 percent. Data are presented up to 37,000 cycles. One pack (X-80) has achieved 49,000 cycles at 10 C and 23 percent DOD. The geosynchronous orbit simulation of a high DOD test is conducted by ESA on 3 batteries at 10 C and 70, 90, and 100 percent DOD. Thirty-one eclipse seasons are completed, and no signs of degradation have been found. The Air Force test at CRANE on 24 Ah and 40 Ah cells at 20 C and 80 percent DOD has achieved 19 shadow periods. Life expectancy is discussed. The VOS cell technology could be used for the following: (1) in geosynchronous conditions--15 yrs at 10-15 C and 80 percent DOD; and (2) in low earth orbit--10 yrs at 5-15 C and 25-30 percent DOD.

LANL*V2.0: global modeling and validation

NASA Astrophysics Data System (ADS)

Koller, J.; Zaharia, S.

2011-08-01

We describe in this paper the new version of LANL*, an artificial neural network (ANN) for calculating the magnetic drift invariant L*. This quantity is used for modeling radiation belt dynamics and for space weather applications. We have implemented the following enhancements in the new version: (1) we have removed the limitation to geosynchronous orbit and the model can now be used for a much larger region. (2) The new version is based on the improved magnetic field model by Tsyganenko and Sitnov (2005) (TS05) instead of the older model by Tsyganenko et al. (2003). We have validated the model and compared our results to L* calculations with the TS05 model based on ephemerides for CRRES, Polar, GPS, a LANL geosynchronous satellite, and a virtual RBSP type orbit. We find that the neural network performs very well for all these orbits with an error typically ΔL* < 0.2 which corresponds to an error of 3 % at geosynchronous orbit. This new LANL* V2.0 artificial neural network is orders of magnitudes faster than traditional numerical field line integration techniques with the TS05 model. It has applications to real-time radiation belt forecasting, analysis of data sets involving decades of satellite of observations, and other problems in space weather.

Uncovering the nonadiabatic response of geosynchronous electrons to geomagnetic disturbance

USGS Publications Warehouse

Gannon, Jennifer; Elkington, Scot R.; Onsager, Terrance G.

2012-01-01

We describe an energy spectrum method for scaling electron integral flux, which is measured at a constant energy, to phase space density at a constant value of the first adiabatic invariant which removes much of the variation due to reversible adiabatic effects. Applying this method to nearly a solar cycle (1995 - 2006) of geosynchronous electron integral flux (E>2.0MeV) from the GOES satellites, we see that much of the diurnal variation in electron phase space density at constant energy can be removed by the transformation to phase space density at constant μ (4000 MeV/G). This allows us a clearer picture of underlying non-adiabatic electron population changes due to geomagnetic activity. Using scaled phase space density, we calculate the percentage of geomagnetic storms resulting in an increase, decrease or no change in geosynchronous electrons as 38%, 7%, and 55%, respectively. We also show examples of changes in the electron population that may be different than the unscaled fluxes alone suggest. These examples include sudden electron enhancements during storms which appear during the peak of negative Dst for μ-scaled phase space density, contrary to the slow increase seen during the recovery phase for unscaled phase space density for the same event.

A Survey of Geosynchronous Satellite Glints

NASA Astrophysics Data System (ADS)

Vrba, F.; Hutter, D.; Shankland, P.; Armstrong, J.; Schmitt, H.; Hindsley, R.; Divittorio, M.; Benson, J.

Artificial satellites have characteristic diffuse reflected-light signatures as they are illuminated at varying phase angles by the Sun and are viewed at differing orientations by an observer. At times of favorable alignment between the satellite, observer and Sun, specular reflection off of relatively flat surfaces, such as solar panels, can cause brief increases in reflected light of several hundred times that of the nominal diffuse signature. Such events are commonly referred to as "glints". In the case of geosynchronous satellites, favorable glint alignments are due to changes in the Sun-Vehicle-Observer angle which are primarily due to the apparent motion of the Sun as the observer-satellite vector remains nearly stationary. These occur near in time to the vernal and autumnal equinoxes. While the most favorable geosynchronous satellite glint alignments are precluded by the fact that the satellites are at that time most likely to be in Earth shadow, observations of several glints have been reported in the literature. While such studies note the peak brightnesses, durations, and phase angles of individual glints, to our knowledge, no extended study of geosynchronous glint characteristics exists. Beginning with the autumnal equinox glint season of 2007 we have built on our earlier studies using the U.S. Naval Observatory, Flagstaff Station 40-inch Ritchey telescope to provide near-real-time astrometric and photometric information for use by the Navy Prototype Optical Interferometer (NPOI) team in its efforts to obtain interferometric fringes of geosynchronous satellites during a glint episode. The combined observations culminated in successful fringe measurements of DirecTV-9S during the vernal equinox 2008 and 2009 seasons (see Armstrong, et al. 2009, this conference). For our 40-inch telescope observations we used an LN2-cooled 2048x2048 CCD with standard R-band and H-alpha photometric filters, covering an area of the sky of approximately 22x22 arcmin with each integration. Observations typically were initiated well before a predicted potential glint and continued through the glint occurrence (if any) for our secondary goal of estimating peak glint brightnesses. As we were using photometric equipment, took care to obtain photometric calibrations, and were fortunate to have observed on several photometric nights, we have calibrated, time-resolved observations of numerous glint episodes, dominated by the GE2/GE4/DTV4S/DTV9S constellation. In particular, we will discuss systematic differences between glints from different satellites, comparison of glints from the same satellite during different epochs, and the time evolution of glints from DirecTV-9S during the 2009 vernal equinox observing season.

Charged Particle Environment Definition for NGST: L2 Plasma Environment Statistics

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Blackwell, William C.; Neergaard, Linda F.; Evans, Steven W.; Hardage, Donna M.; Owens, Jerry K.

2000-01-01

The plasma environment encountered by the Next Generation Space Telescope satellite in a halo orbit about L2 can include the Earth's magnetotail and magnetosheath in addition to the solar wind depending on the orbital radius chosen for the mission. Analysis of plasma environment impacts on the satellite requires knowledge of the average and extreme plasma characteristics to assess the magnitude of spacecraft charging and materials degradation expected for the mission lifetime. This report describes the analysis of plasma data from instruments onboard the IMP 8 and Geotail spacecraft used to produce the plasma database for the LRAD engineering-level phenomenology code developed to provide the NGST L2 environment definition.

Charging and discharging characteristics of dielectric materials exposed to low- and mid-energy electrons

NASA Technical Reports Server (NTRS)

Coakley, P.; Kitterer, B.; Treadaway, M.

1982-01-01

Charging and discharging characteristics of dielectric samples exposed to 1-25 keV and 25-100 keV electrons in a laboratory environment are reported. The materials examined comprised OSR, Mylar, Kapton, perforated Kapton, and Alphaquartz, serving as models for materials employed on spacecraft in geosynchronous orbit. The tests were performed in a vacuum chamber with electron guns whose beams were rastered over the entire surface of the planar samples. The specimens were examined in low-impedance-grounded, high-impedance-grounded, and isolated configurations. The worst-case and average peak discharge currents were observed to be independent of the incident electron energy, the time-dependent changes in the worst case discharge peak current were independent of the energy, and predischarge surface potentials are negligibly dependent on incident monoenergetic electrons.

Space Station solar water heater

NASA Technical Reports Server (NTRS)

Horan, D. C.; Somers, Richard E.; Haynes, R. D.

1990-01-01

The feasibility of directly converting solar energy for crew water heating on the Space Station Freedom (SSF) and other human-tended missions such as a geosynchronous space station, lunar base, or Mars spacecraft was investigated. Computer codes were developed to model the systems, and a proof-of-concept thermal vacuum test was conducted to evaluate system performance in an environment simulating the SSF. The results indicate that a solar water heater is feasible. It could provide up to 100 percent of the design heating load without a significant configuration change to the SSF or other missions. The solar heater system requires only 15 percent of the electricity that an all-electric system on the SSF would require. This allows a reduction in the solar array or a surplus of electricity for onboard experiments.

Performance Analysis of a Ring Current Model Driven by Global MHD

NASA Astrophysics Data System (ADS)

Falasca, A.; Keller, K. A.; Fok, M.; Hesse, M.; Gombosi, T.

2003-12-01

Effectively modeling the high-energy particles in Earth's inner magnetosphere has the potential to improve safety in both manned and unmanned spacecraft. One model of this environment is the Fok Ring Current Model. This model can utilize as inputs both solar wind data, and empirical ionospheric electric field and magnetic field models. Alternatively, we have a procedure which allows the model to be driven by outputs from the BATS-R-US global MHD model. By using in-situ satellite data we will compare the predictive capability of this model in its original stand-alone form, to that of the model when driven by the BATS-R-US Global Magnetosphere Model. As a basis for comparison we use the April 2002 and May 2003 storms where suitable LANL geosynchronous data are available.

Energy and Mass Transport of Magnetospheric Plasmas during the November 2003 Magnetic Storm

NASA Technical Reports Server (NTRS)

Fok, Mei-Chging; Moore, Thomas

2008-01-01

Intensive energy and mass transport from the solar wind across the magnetosphere boundary is a trigger of magnetic storms. The storm on 20-21 November 2003 was elicited by a high-speed solar wind and strong southward component of interplanetary magnetic field. This storm attained a minimum Dst of -422 nT. During the storm, some of the solar wind particles enter the magnetosphere and eventually become part of the ring current. At the same time, the fierce solar wind powers strong outflow of H+ and O+ from the ionosphere, as well as from the plasmasphere. We examine the contribution of plasmas from the solar wind, ionosphere and plasmasphere to the storm-time ring current. Our simulation shows, for this particular storm, ionospheric O+ and solar wind ions are the major sources of the ring current particles. The polar wind and plasmaspheric H+ have only minor impacts. In the storm main phase, the strong penetration of solar wind electric field pushes ions from the geosynchronous orbit to L shells of 2 and below. Ring current is greatly intensified during the earthward transport and produces a large magnetic depression in the surface field. When the convection subsides, the deep penetrating ions experience strong charge exchange loss, causing rapid decay of the ring current and fast initial storm recovery. Our simulation reproduces very well the storm development indicated by the Dst index.

What Properties of CMEs are Most Important for Space Weather?

NASA Technical Reports Server (NTRS)

Gopalswamy, Nat

2012-01-01

Severe space weather is characterized by intense particle radiation from the Sun and major geomagnetic storm caused by magnetized solar plasmas arriving at Earth. Coronal mass ejections (CMEs) are key players in both these aspects. CMEs traveling at super-Alfv nic speeds drive fast-mode MHD shocks that create the high levels of particle radiation. When a CME arrives at Earth, the CME-associated magnetic fields reconnect with Earth s magnetopause fields resulting in solar plasma entry into the magnetosphere and a geomagnetic storm depending on the magnetic structure of the CME. Particle radiation starts affecting geospace as soon as the CMEs leave the Sun and the geospace may be immersed in the radiation for several days. On the other hand, the geomagnetic storm happens only upon CME arrival at Earth. The requirements for the production of particles and magnetic storms by CMEs are different in a number of respects: solar source location, CME magnetic structure, conditions in the ambient solar wind, and shock-driving ability of CMEs. Intense shocks arriving at Earth have additional space weather effects such as sudden impulse that shrinks the magnetosphere often exposing satellites in geosynchronous orbit to the solar wind and energetic storm particle events. This paper highlights these space weather effects using CME observations space and ground based instruments during of solar cycles 23 and 24.

Understanding Solar Eruptions with SDO/HMI Measuring Photospheric Flows, Testing Models, and Steps Towards Forecasting Solar Eruptions

NASA Technical Reports Server (NTRS)

Schuck, Peter W.; Linton, Mark; Muglach, Karin; Welsch, Brian; Hageman, Jacob

2010-01-01

The imminent launch of Solar Dynamics Observatory (SDO) will carry the first full-disk imaging vector magnetograph, the Helioseismic and Magnetic Imager (HMI), into an inclined geosynchronous orbit. This magnetograph will provide nearly continuous measurements of photospheric vector magnetic fields at cadences of 90 seconds to 12 minutes with I" resolution, precise pointing, and unfettered by atmospheric seeing. The enormous data stream of 1.5 Terabytes per day from SDO will provide an unprecedented opportunity to understand the mysteries of solar eruptions. These ground-breaking observations will permit the application of a new technique, the differential affine velocity estimator for vector magnetograms (DAVE4VM), to measure photospheric plasma flows in active regions. These measurements will permit, for the first time, accurate assessments of the coronal free energy available for driving CMEs and flares. The details of photospheric plasma flows, particularly along magnetic neutral-lines, are critical to testing models for initiating coronal mass ejections (CMEs) and flares. Assimilating flows and fields into state-of-the art 3D MHD simulations that model the highly stratified solar atmosphere from the convection zone to the corona represents the next step towards achieving NASA's Living with a Star forecasting goals of predicting "when a solar eruption leading to a CME will occur." This talk will describe these major science and predictive advances that will be delivered by SDO /HMI.

Understanding Solar Eruptions with SDO/HMI Measuring Photospheric Flows, Testing Models, and Steps Towards Forecasting Solar Eruptions

NASA Technical Reports Server (NTRS)

Schuck, Peter W.; Linton, M.; Muglach, K.; Hoeksema, T.

2010-01-01

The Solar Dynamics Observatory (SDO) is carrying the first full-disk imaging vector magnetograph, the Helioseismic and Magnetic Imager (HMI), into an inclined geosynchronous orbit. This magnetograph will provide nearly continuous measurements of photospheric vector magnetic fields at cadences of 90 seconds to 12 minutes with 1" resolution, precise pointing, and unfettered by atmospheric seeing. The enormous data stream of 1.5 Terabytes per day from SAO will provide an unprecedented opportunity to understand the mysteries of solar eruptions. These ground-breaking observations will permit the application of a new technique, the differential affine velocity estimator for vector magnetograms (DAVE4VM), to measure photospheric plasma flows in active regions. These measurements will permit, for the first time, accurate assessments of the coronal free energy available for driving CMEs and flares. The details of photospheric plasma flows, particularly along magnetic neutral-lines, are critical to testing models for initiating coronal mass ejections (CMEs) and flares. Assimilating flows and fields into state-of-the art 3D MHD simulations that model the highly stratified solar atmosphere from the convection zone to the corona represents the next step towards achieving NASA's Living with a Star forecasting goals of predicting "when a solar eruption leading to a CME will occur." Our presentation will describe these major science and predictive advances that will be delivered by SDO/HMI.

Geotail Measurements Compared with the Motions of High-Latitude Auroral Boundaries during Two Substorms

NASA Technical Reports Server (NTRS)

Maynard, N. C.; Burke, W. J.; Erickson, G. M.; Nakamura, M.; Mukai, T.; Kokubun, S.; Yamamoto, T.; Jacobsen, B.; Egeland, A.; Samson, J. C.;

Reaping the space investment. [Shuttle era geosynchronous satellite based technological trends

NASA Technical Reports Server (NTRS)

Calio, A. J.

1979-01-01

By 1999 operational space systems will be implemented routinely on a worldwide scale in many areas vital to human survival and life quality. Geosynchronous-based monitoring and observation will be extensively used. The Shuttle era will bring in the capability to allow monitoring and identifying pollution sources which fail to stay within required limits. Remotely sensed data over land masses will provide needed facts on renewable and nonrenewable earth resources. New instruments and techniques will have been developed to provide geologists with clues to the declining number of deposits of fuels and minerals. Also, practical methods for predicting earthquakes will have been elaborated by 1999. Communications will see implementation of many of the technological goals of 1978.

KSC00pp0545

NASA Image and Video Library

2000-04-23

The GOES-L satellite, after being lifted up to the top of the gantry on pad 36A, Cape Canaveral Air Force Station, is ready for mating with the Atlas IIA/Centaur rocket. Atlas IIA is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

KSC-00pp0545

NASA Image and Video Library

2000-04-23

The GOES-L satellite, after being lifted up to the top of the gantry on pad 36A, Cape Canaveral Air Force Station, is ready for mating with the Atlas IIA/Centaur rocket. Atlas IIA is designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. The rocket is the launch vehicle for the GOES-L satellite, part of the NOAA National Weather Service system in weather imagery and atmospheric sounding information. The primary objective of the GOES-L is to provide a full capability satellite in an on-orbit storage condition, to assure NOAA continuity in services from a two-satellite constellation. Launch services are being provided by the 45th Space Wing. Launch is scheduled for May 3

Hyper-spectral Atmospheric Sounding. Appendixes 1

NASA Technical Reports Server (NTRS)

Smith, W. L.; Zhou, D. K.; Revercomb, H. E.; Huang, H. L.; Antonelli, P.; Mango, S. A.

2002-01-01

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) is the first hyper-spectral remote sounding system to be orbited aboard a geosynchronous satellite. The GETS is designed to obtain revolutionary observations of the four dimensional atmospheric temperature, moisture, and wind structure as well as the distribution of the atmospheric trace gases, CO and O3. Although GIFTS will not be orbited until 2006-2008, a glimpse at the its measurement capabilities has been obtained by analyzing data from the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Test-bed-Interferometer (NAST-I) and Aqua satellite Atmospheric Infrared Sounder (AIRS). In this paper we review the GIFTS experiment and empirically assess measurement expectations based on meteorological profiles retrieved from the NAST aircraft and Aqua satellite AIRS spectral radiances.

Geosynchronous Microwave Atmospheric Sounding Radiometer (MASR) feasibility studies. Volume 1: Management summary

NASA Technical Reports Server (NTRS)

1978-01-01

The mission of the microwave atmospheric sounding radiometer (MASR) is to collect data to aid in the observation and prediction of severe storms. The geosynchronous orbit allows the continuous atmospheric measurement needed to resolve mesoscale dynamics. The instrument may operate in conjunction with this document, Volume 1 - Management, which summarizes the highlights of final reports on both the radiometer instrument and antenna studies. The radiometer instrument summary includes a synopsis of Volume 2 - Radiometer Receiver Feasibility, including design, recommended configuration, performance estimates, and weight and power estimates. The summary of the antenna study includes a synopsis of Volume 3 - Antenna Feasibility, including preliminary design tradeoffs, performance of selected design, and details of the mechanical/thermal design.

The Los Alamos dynamic radiation environment assimilation model (DREAM) for space weather specification and forecasting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reeves, Geoffrey D; Friedel, Reiner H W; Chen, Yue

2008-01-01

The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at Los Alamos National Laboratory to assess, quantify, and predict the hazards from the natural space environment and the anthropogenic environment produced by high altitude nuclear explosions (HANE). DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's Van Allen radiation belts. It uses Kalman filter techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts. DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity bymore » assigning appropriate uncertainties to the observations. Data from any spacecraft orbit can be assimilated but DREAM was designed to function with as few as two spacecraft inputs: one from geosynchronous orbit and one from GPS orbit. With those inputs, DREAM can be used to predict the environment at any satellite in any orbit whether space environment data are available in those orbits or not. Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy. DREAM has been extensively tested and evaluated as we transition from research to operations. We report here on one set of test results in which we predict the environment in a highly-elliptical polar orbit. We also discuss long-duration reanalysis for spacecraft design, using DREAM for real-time operations, and prospects for 1-week forecasts of the radiation belt environment.« less

NASA Orbital Debris Large-Object Baseline Population in ORDEM 3.0

NASA Technical Reports Server (NTRS)

Krisco, Paula H.; Vavrin, A. B.; Anz-Meador, P. D.

2013-01-01

The NASA Orbital Debris Program Office (ODPO) has created and validated high fidelity populations of the debris environment for the latest Orbital Debris Engineering Model (ORDEM 3.0). Though the model includes fluxes of objects 10 um and larger, this paper considers particle fluxes for 1 cm and larger debris objects from low Earth orbit (LEO) through Geosynchronous Transfer Orbit (GTO). These are validated by several reliable radar observations through the Space Surveillance Network (SSN), Haystack, and HAX radars. ORDEM 3.0 populations were designed for the purpose of assisting, debris researchers and sensor developers in planning and testing. This environment includes a background derived from the LEO-to-GEO ENvironment Debris evolutionary model (LEGEND) with a Bayesian rescaling as well as specific events such as the FY-1C anti-satellite test, the Iridium 33/Cosmos 2251 accidental collision, and the Soviet/Russian Radar Ocean Reconnaissance Satellite (RORSAT) sodium-potassium droplet releases. The environment described in this paper is the most realistic orbital debris population larger than 1 cm, to date. We describe derivations of the background population and added specific populations. We present sample validation charts of our 1 cm and larger LEO population against Space Surveillance Network (SSN), Haystack, and HAX radar measurements.

Charge-exchange plasma environment for an ion drive spacecraft. [a model for describing mercury ion engines and its effect on spacecraft subsystems

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Carruth, M. R., Jr.

1979-01-01

The charge exchange plasma environment around a spacecraft that uses mercury ion thrusters for propulsion is described. The interactions between the plasma environment and the spacecraft are determined and a model which describes the propagation of the mercury charge exchange plasma is discussed. The model is extended to describe the flow of the molybdenum component of the charge exchange plasma. The uncertainties in the models for various conditions are discussed and current drain to the solar array, charge exchange plasma material deposition, and the effects of space plasma on the charge exchange plasma propagation are addressed.

Earth Science

NASA Image and Video Library

1994-09-02

This image depicts a full view of the Earth, taken by the Geostationary Operational Environment Satellite (GOES-8). The red and green charnels represent visible data, while the blue channel represents inverted 11 micron infrared data. The north and south poles were not actually observed by GOES-8. To produce this image, poles were taken from a GOES-7 image. Owned and operated by the National Oceanic and Atmospheric Administration (NOAA), GOES satellites provide the kind of continuous monitoring necessary for intensive data analysis. They circle the Earth in a geosynchronous orbit, which means they orbit the equatorial plane of the Earth at a speed matching the Earth's rotation. This allows them to hover continuously over one position on the surface. The geosynchronous plane is about 35,800 km (22,300 miles) above the Earth, high enough to allow the satellites a full-disc view of the Earth. Because they stay above a fixed spot on the surface, they provide a constant vigil for the atmospheric triggers for severe weather conditions such as tornadoes, flash floods, hail storms, and hurricanes. When these conditions develop, the GOES satellites are able to monitor storm development and track their movements. NASA manages the design and launch of the spacecraft. NASA launched the first GOES for NOAA in 1975 and followed it with another in 1977. Currently, the United States is operating GOES-8, positioned at 75 west longitude and the equator, and GOES-10, which is positioned at 135 west longitude and the equator. (GOES-9, which malfunctioned in 1998, is being stored in orbit as an emergency backup should either GOES-8 or GOES-10 fail. GOES-11 was launched on May 3, 2000 and GOES-12 on July 23, 2001. Both are being stored in orbit as a fully functioning replacement for GOES-8 or GOES-10 on failure.

The Case for GEO Hosted SSA Payloads

NASA Astrophysics Data System (ADS)

Welsch, C.; Armand, B.; Repp, M.; Robinson, A.

2014-09-01

Space situational awareness (SSA) in the geosynchronous earth orbit (GEO) belt presents unique challenges, and given the national importance and high value of GEO satellites, is increasingly critical as space becomes more congested and contested. Space situational awareness capabilities can serve as an effective deterrent against potential adversaries if they provide accurate, timely, and persistent information and are resilient to the threat environment. This paper will demonstrate how simple optical SSA payloads hosted on GEO commercial and government satellites can complement the SSA mission and data provided by Space-Based Space Surveillance (SBSS) and the Geosynchronous Space Situational Awareness Program (GSSAP). GSSAP is built by Orbital Sciences Corporation and launched on July 28, 2014. Analysis performed for this paper will show how GEO hosted SSA payloads, working in combination with SBSS and GSSAP, can increase persistence and timely coverage of high value assets in the GEO belt. The potential to further increase GEO object identification and tracking accuracy by integrating SSA data from multiple sources across different viewing angles including GEO hosted SSA sources will be addressed. Hosting SSA payloads on GEO platforms also increases SSA mission architecture resiliency as the sensors are by distributed across multiple platforms including commercial platforms. This distributed architecture presents a challenging target for an adversary to attempt to degrade or disable. We will present a viable concept of operations to show how data from hosted SSA sensors could be integrated with SBSS and GSSAP data to present a comprehensive and more accurate data set to users. Lastly, we will present an acquisition approach using commercial practices and building on lessons learned from the Commercially Hosted Infra Red Payload CHIRP to demonstrate the affordability of GEO hosted SSA payloads.

Guidance and Navigation for Rendezvous and Proximity Operations with a Non-Cooperative Spacecraft at Geosynchronous Orbit

NASA Technical Reports Server (NTRS)

Barbee, Brent William; Carpenter, J. Russell; Heatwole, Scott; Markley, F. Landis; Moreau, Michael; Naasz, Bo J.; VanEepoel, John

2010-01-01

The feasibility and benefits of various spacecraft servicing concepts are currently being assessed, and all require that the servicer spacecraft perform rendezvous, proximity, and capture operations with the target spacecraft to be serviced. Many high-value spacecraft, which would be logical targets for servicing from an economic point of view, are located in geosynchronous orbit, a regime in which autonomous rendezvous and capture operations are not commonplace. Furthermore, existing GEO spacecraft were not designed to be serviced. Most do not have cooperative relative navigation sensors or docking features, and some servicing applications, such as de-orbiting of a non-functional spacecraft, entail rendezvous and capture with a spacecraft that may be non-functional or un-controlled. Several of these challenges have been explored via the design of a notional mission in which a nonfunctional satellite in geosynchronous orbit is captured by a servicer spacecraft and boosted into super-synchronous orbit for safe disposal. A strategy for autonomous rendezvous, proximity operations, and capture is developed, and the Orbit Determination Toolbox (ODTBX) is used to perform a relative navigation simulation to assess the feasibility of performing the rendezvous using a combination of angles-only and range measurements. Additionally, a method for designing efficient orbital rendezvous sequences for multiple target spacecraft is utilized to examine the capabilities of a servicer spacecraft to service multiple targets during the course of a single mission.

Coordinated Polar Spacecraft, Geosynchronous Spacecraft, and Ground-based Observations of Magnetopause Oscillations and Pc5 Waves in the Magnetosphere

NASA Technical Reports Server (NTRS)

Le, G.; Chen, S.; Zheng, Y.; Russell, C. T.; Slavin, J. A.; Huang, C.-S.; Petrinec, S. S.; Moore, T. E.; Samson, J.; Singer, H. J.

2005-01-01

In this paper, we present in situ observations of surface waves at the magnetopause and oscillatory magnetospheric field lines, and coordinated observations Pc5 waves at geosynchronous orbit by the GOES spacecraft, and on the ground by CANOPUS and 210 Degree Magnetic Meridian (210MMJ magnetometer arrays. On February 7,2002 during a highspeed solar wind stream, the Polar spacecraft was skimming the magnetopause in a post-noon meridian plane for approximately 3 hours. During this interval, it made two short excursions and a few partial crossings into the magnetosheath and observed quasi-periodic cold ion bursts in the region adjacent to the magnetopause current layer. The multiple magnetopause crossings as well as the velocity of the cold ion bursts indicate that the magnetopause was oscillating with about 6 minute period. Simultaneous observations of Pc5 waves at geosynchronous orbit by the GOES spacecraft and on the ground by the CANOPUS magnetometer array reveal that these magnetospheric pulsations were forced oscillations of magnetic field lines directly driven by the magnetopause oscillations. The magnetospheric pulsations occurred only in a limited longitudinal region in the post-noon dayside sector, and were not a global phenomenon as one would expect for global field line resonance. Thus, the magnetopause oscillations at the source were also limited to a localized region spanning about 4 hours in local time.

LANL* V2.0: global modeling and validation

NASA Astrophysics Data System (ADS)

Koller, J.; Zaharia, S.

2011-03-01

We describe in this paper the new version of LANL*. Just like the previous version, this new version V2.0 of LANL* is an artificial neural network (ANN) for calculating the magnetic drift invariant, L*, that is used for modeling radiation belt dynamics and for other space weather applications. We have implemented the following enhancements in the new version: (1) we have removed the limitation to geosynchronous orbit and the model can now be used for any type of orbit. (2) The new version is based on the improved magnetic field model by Tsyganenko and Sitnov (2005) (TS05) instead of the older model by Tsyganenko et al. (2003). We have validated the model and compared our results to L* calculations with the TS05 model based on ephemerides for CRRES, Polar, GPS, a LANL geosynchronous satellite, and a virtual RBSP type orbit. We find that the neural network performs very well for all these orbits with an error typically Δ L* < 0.2 which corresponds to an error of 3% at geosynchronous orbit. This new LANL-V2.0 artificial neural network is orders of magnitudes faster than traditional numerical field line integration techniques with the TS05 model. It has applications to real-time radiation belt forecasting, analysis of data sets involving decades of satellite of observations, and other problems in space weather.

Geosynchronous Patrol Orbit for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Thompson, B.; Kelecy, T.; Kubancik, T.; Flora, T.; Chylla, M.; Rose, D.

Applying eccentricity to a geosynchronous orbit produces both longitudinal and radial motion when viewed in Earth-fixed coordinates. An interesting family of orbits emerges, useful for “neighborhood patrol” space situational awareness and other missions. The basic result is a periodic (daily), quasielliptical, closed path around a fixed region of the geosynchronous (geo) orbit belt, keeping a sensor spacecraft in relatively close vicinity to designated geo objects. The motion is similar, in some regards, to the relative motion that may be encountered during spacecraft proximity operations, but on a much larger scale. The patrol orbit does not occupy a fixed slot in the geo belt, and the east-west motion can be combined with north-south motion caused by orbital inclination, leading to even greater versatility. Some practical uses of the geo patrol orbit include space surveillance (including catalog maintenance), and general space situational awareness. The patrol orbit offers improved, diverse observation geometry for angles-only sensors, resulting in faster, more accurate orbit determination compared to simple inclined geo orbits. In this paper, we analyze the requirements for putting a spacecraft in a patrol orbit, the unique station keeping requirements to compensate for perturbations, repositioning the patrol orbit to a different location along the geo belt, maneuvering into, around, and out of the volume for proximity operations with objects within the volume, and safe end-of-life disposal requirements.

Plasma Sterilization Technology for Spacecraft Applications

NASA Technical Reports Server (NTRS)

Fraser, S. J.; Olson, R. L.; Leavens, W. M.

1975-01-01

The application of plasma gas technology to sterilization and decontamination of spacecraft components is considered. Areas investigated include: effective sterilizing ranges of four separate gases; lethal constituents of a plasma environment; effectiveness of plasma against a diverse group of microorganisms; penetrating efficiency of plasmas for sterilization; and compatibility of spacecraft materials with plasma environments. Results demonstrated that plasma gas, specifically helium plasma, is a highly effective sterilant and is compatible with spacecraft materials.

The Transport of Plasma and Magnetic Flux in Giant Planet Magnetospheres

NASA Astrophysics Data System (ADS)

Russell, C. T.

2013-05-01

Both Jupiter and Saturn have moons that add significant quantities of neutrals and/or dust beyond geosynchronous orbit. This material becomes charged and interacts with the planetary plasma that is "orbiting" the planets at near corotational speeds, driven by the planetary ionospheres. Since this speed is greater than the keplerian orbital speed at these distances, the net force on the newly added charged mass is outward. The charged material is held in place by the magnetic field which stretches to the amount needed to balance centripetal and centrifugal forces. The currents involved in this process close in the ionosphere which is an imperfect conductor and the feet of the field lines hence slip poleward and the material near the equator moves outward. This motion allows the magnetosphere to divest itself of the added mass by transferring it to the magnetotail. The magnetotail in turn can rid itself of the newly added mass by the process of reconnection, interior to the region of added mass, freeing an island of magnetized plasma which then moves down the magnetotail no longer connected to the magnetosphere. This maintains a quasi-stationary conservation of mass in the magnetosphere with roughly constant mass and "periodic" disturbances. However, there is one other steady state the magnetosphere needs to maintain. It needs to replace the mass loaded flux tubes with emptied flux tubes. Thus the "emptied" flux tubes in the tail must move inward against the outgoing mass-loaded flux tubes. That they are buoyant is a help in this regard but it appears also to be helpful if the returning flux separates into thin flux tubes, just like air bubbles rising in a container with a leak in the bottom. In this way the magnetospheres of Jupiter and Saturn maintain their dynamic, steady-state convection patterns.

SAMI3 Simulations of the Persistent May 1994 Plasmasphere Plume

NASA Astrophysics Data System (ADS)

Krall, J.; Huba, J.; Borovsky, J.

2017-12-01

We use the Naval Research Laboratory SAMI3 ionosphere/plasmasphere model[1] to explore the physics of a long-lived plasmasphere plume. A plasmasphere plume is a storm feature that extends the cold plasma that is normally trapped by the geomagnetic field (the plasmasphere) outward towards the bow shock. In the case of the May 1994 storm, the storm and the plume continued for 12 days. For the model storm, we imposed a Kp-driven Volland/Stern-Maynard/Chen potential [2-4]. Results are compared to measurements of the cold ion density from the 1989-046 spacecraft in geosynchronous orbit [5]. We find that many details of the observed plume are reproduced by SAMI3, but only if a background magnetosphere density is included as a boundary condition. We also find that high-speed, field aligned plasma flows contribute significantly to the observed plume density. [1] Huba, J. and J. Krall (2013), Modeling the plasmasphere with SAMI3, Geophys. Res. Lett., 40, 6-10, doi:10.1029/2012GL054300 [2] Volland, H. (1973), A semiempirical model of large-scale magnetospheric electric fields, Journal of Geophysical Research, 78, 171-180, doi:10.1029/JA078i001p00171 [3] Stern, D.P. (1975), The motion of a proton in the equatorial magnetosphere, Journal of Geophysical Research, 80, 595-599, doi:10.1029/JA080i004p00595 [4] Maynard, N.C., and A.J. Chen (1975), Isolated cold plasma regions: Observations and their relation to possible production mechanisms, Journal of Geophysical Research, 80, 1009-1013, doi:10.1029/JA080i007p01009 [5] Borovsky, J.E., D.T. Welling, M.F. Thomsen, and M.H. Denton (2014), Long-lived plasmaspheric drainage plumes: Where does the plasma come from?, Journal of Geophysical Research: Space Physics, 119, 6496-6520, doi:10.1002/2014JA020228 Research supported by NRL base funds.

One-impulse targeting strategy for longitudinal drift control of geosynchronous spacecraft subject to tesseral harmonics and luni-solar gravity perturbations

NASA Technical Reports Server (NTRS)

Kechichian, J. A.

1984-01-01

Kamel's (1973) East-West Stationkeeping Analysis is extended and an algorithm is presented that targets the geosynchronous spacecraft to the ideal initial conditions starting from any given relative longitude deviation within a given tolerance deadband in order to repeat the ideal longitudinal drift cycle that results in the longest possible period of time between maneuvers. The motion description takes into account the perturbations introduced by earth's tesseral harmonics and by the luni-solar gravity, assuming a near-circular orbit that requires only the control of orbital energy to repeat the ideal drift cycle via a single impulsive velocity change. The location of the maneuver along the orbit is such that the post-Delta-V eccentricity is always minimized.

VISSR Atmospheric Sounder (VAS) Research Review

NASA Technical Reports Server (NTRS)

Greaves, J. R. (Editor)

1983-01-01

The VAS, an experimental instrument flown onboard Geostationary Operational Environmental Satellite (GOES), is capable of achieving mutlispectral imagery of atmospheric temperature, water vapor, and cloudiness patterns over short time intervals. In addition, this instrument provides an atmospheric sounding capability from geosynchronous orbit. The VAS demonstration is an effort for evaluating the VAS instrument's performance, and for demonstrating the capabilities of a VAS prototype system to provide useful geosynchronous satellite data for supporting weather forecasts and atmospheric research. The demonstration evaluates the performance of the VAS Instruments on GOES-4-5, and -6, develops research oriented and prototype/operational VAS data processing systems, determines the accuracy of certain basic and derived meteorological parameters that can be obtained from the VAS instrument, and assesses the utility of VAS derived information in analyzing severe weather situations.

Modification of earth-satellite orbits using medium-energy pulsed lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phipps, C.R.

1992-01-01

Laser Impulse Space Propulsion (LISP) has become an attractive concept, due to recent advances in gas laser technology, high-speed segmented mirrors and improved coeffici-ents for momentum coupling to targets in pulsed laser ablation. There are numerous specialized applications of the basic concept to space science-ranging from far-future and high capital cost to the immediate and inexpensive, such as: LEO-LISP (launch of massive objects into low-Earth-Orbit at dramatically improved cost-per-kg relative to present practice); LEGO-LISP (LEO to geosynchronous transfers); LO-LISP) (periodic re-boost of decaying LEO orbits); and LISK (geosynchronous satellite station-keeping). It is unlikely that one type of laser will bemore » best for all scenarios. In this paper, we will focus on the last two applications.« less

Modification of earth-satellite orbits using medium-energy pulsed lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phipps, C.R.

1992-10-01

Laser Impulse Space Propulsion (LISP) has become an attractive concept, due to recent advances in gas laser technology, high-speed segmented mirrors and improved coeffici-ents for momentum coupling to targets in pulsed laser ablation. There are numerous specialized applications of the basic concept to space science-ranging from far-future and high capital cost to the immediate and inexpensive, such as: LEO-LISP (launch of massive objects into low-Earth-Orbit at dramatically improved cost-per-kg relative to present practice); LEGO-LISP (LEO to geosynchronous transfers); LO-LISP) (periodic re-boost of decaying LEO orbits); and LISK (geosynchronous satellite station-keeping). It is unlikely that one type of laser will bemore » best for all scenarios. In this paper, we will focus on the last two applications.« less

Electric Propulsion Performance from Geo-transfer to Geosynchronous Orbits

NASA Technical Reports Server (NTRS)

Dankanich, John W.; Carpenter, Christian B.

2007-01-01

For near-Earth application, solar electric propulsion advocates have focused on Low Earth Orbit (LEO) to Geosynchronous (GEO) low-thrust transfers because of the significant improvement in capability over chemical alternatives. While the performance gain attained from starting with a lower orbit is large, there are also increased transfer times and radiation exposure risk that has hindered the commercial advocacy for electric propulsion stages. An incremental step towards electric propulsion stages is the use of integrated solar electric propulsion systems (SEPS) for GTO to GEO transfer. Thorough analyses of electric propulsion systems options and performance are presented. Results are based on existing or near-term capabilities of Arcjets, Hall thrusters, and Gridded Ion engines. Parametric analyses based on "rubber" thruster and launch site metrics are also provided.

Accelerated and real-time geosynchronous life cycling test performance of nickel-hydrogen batteries

NASA Technical Reports Server (NTRS)

Green, R. S.

1985-01-01

RCA Astro-Electronics currently has four nickel-hydrogen storage battery modules (11 cells each) on test in simulated geosynchronous life cycle regimes. These battery modules are of identical design to those used on the GSTAR (GTE Satellite Corp.) and Spacenet (GTE Spacenet Corp.) communications satellites. The batteries are being tested using an automated test station equipped with computer-controlled environmental chambers and recording equipment. The two battery types, 30 ampere-hours and 40 ampere-hours (GSTAR and Spacenet, respectively), are being electrically cycled using identical 44-day eclipse sequences at 5 C and vary with respect to depth of discharge, recharge ratio, duration of accumulated suntime, and the use of a reconditioning sequence. The test parameters are outlined and the preliminary test data and results are presented.

Conceptual Design of Tail-Research EXperiment (T-REX) on Space Plasma Environment Research Facility

NASA Astrophysics Data System (ADS)

Xiao, Qingmei; Wang, Xiaogang; E, Peng; Shen, Chao; Wang, Zhibin; Mao, Aohua; Xiao, Chijie; Ding, Weixing; Ji, Hantao; Ren, Yang

2016-10-01

Space Environment Simulation Research Infrastructure (SESRI), a scientific project for a major national facility of fundamental researches, has recently been launched at Harbin Institute of Technology (HIT). The Space Plasma Environment Research Facility (SPERF) for simulation of space plasma environment is one of the components of SESRI. It is designed to investigate fundamental issues in space plasma environment, such as energetic particles transportation and the interaction with waves in magnetosphere, magnetic reconnection at magnetopause and magnetotail, etc. Tail-Research Experiment (T-REX) is part of the SPERF for laboratory studies of space physics relevant to tail reconnection and dipolarization process. T-REX is designed to carry out two kinds of experiments: the tail plasmamoid for magnetic reconnection and magnetohydrodynamic waves excited by high speed plasma jet. In this presentation, the scientific goals and experimental plans for T-REX together with the means applied to generate the plasma with desired parameters are reviewed. Two typical scenarios of T-REX with operations of plasma sources and various magnetic configurations to study specific physical processes in space plasmas will also be presented.

Observations from the GOES Space Environment Monitor and Solar X-ray Imager are now available in a whole new way!

NASA Astrophysics Data System (ADS)

Wilkinson, D. C.

2012-12-01

NOAA's Geosynchronous Operational Environmental Satellites (GOES) have been observing the environment in near-earth-space for over 37 years. Those data are down-linked and processed by the Space Weather Prediction Center (SWPC) and form the cornerstone of their alert and forecast services. At the close of each UT day these data are ingested by the National Geophysical Data Center (NGDC) where they are merged into the national archive and made available to the user community in a uniform manner. In 2012 NGDC unveiled a RESTful web service for accessing these data. What does this mean? Users can now build a web-like URL using simple predefined constructs that allows their browser or custom software to directly access the relational archives and bundle the requested data into a variety of popular formats. The user can select precisely the data they need and the results are delivered immediately. NGDC understands that many users are perfectly happy retrieving data via pre-generated files and will continue to provide internally documented NetCDF and CSV files far into the future.

Observations from the GOES Space Environment Monitor and Solar X-ray Imager are now available in a whole new way!

NASA Astrophysics Data System (ADS)

Wilkinson, D. C.

2013-12-01

NOAA's Geosynchronous Operational Environmental Satellites (GOES) have been observing the environment in near-earth-space for over 37 years. Those data are down-linked and processed by the Space Weather Prediction Center (SWPC) and form the cornerstone of their alert and forecast services. At the close of each UT day these data are ingested by the National Geophysical Data Center (NGDC) where they are merged into the national archive and made available to the user community in a uniform manner. In 2012 NGDC unveiled a RESTful web service for accessing these data. What does this mean? Users can now build a web-like URL using simple predefined constructs that allows their browser or custom software to directly access the relational archives and bundle the requested data into a variety of popular formats. The user can select precisely the data they need and the results are delivered immediately. NGDC understands that many users are perfectly happy retrieving data via pre-generated files and will continue to provide internally documented NetCDF and CSV files far into the future.

Thermal-distortion analysis of an antenna strongback for geostationary high-frequency microwave applications

NASA Technical Reports Server (NTRS)

Farmer, Jeffrey T.; Wahls, Deborah M.; Wright, Robert L.

1990-01-01

The global change technology initiative calls for a geostationary platform for Earth science monitoring. One of the major science instruments is the high frequency microwave sounder (HFMS) which uses a large diameter, high resolution, high frequency microwave antenna. This antenna's size and required accuracy dictates the need for a segmented reflector. On-orbit disturbances may be a significant factor in its design. A study was performed to examine the effects of the geosynchronous thermal environment on the performance of the strongback structure for a proposed antenna concept for this application. The study included definition of the strongback and a corresponding numerical model to be used in the thermal and structural analyses definition of the thermal environment, determination of structural element temperature throughout potential orbits, estimation of resulting thermal distortions, and assessment of the structure's capability to meet surface accuracy requirements. Analyses show that shadows produced by the antenna reflector surface play a major role in increasing thermal distortions. Through customization of surface coating and element expansion characteristics, the segmented reflector concept can meet the tight surface accuracy requirements.

Intelligent Observation Strategies for Geosynchronous Remote Sensing for Natural Hazards

NASA Astrophysics Data System (ADS)

Moe, K.; Cappelaere, P. G.; Frye, S. W.; LeMoigne, J.; Mandl, D.; Flatley, T.; Geist, A.

2015-12-01

Geosynchronous satellites offer a unique perspective for monitoring environmental factors important to understanding natural hazards and supporting the disasters management life cycle, namely forecast, detection, response, recovery and mitigation. In the NASA decadal survey for Earth science, the GEO-CAPE mission was proposed to address coastal and air pollution events in geosynchronous orbit, complementing similar initiatives in Asia by the South Koreans and by ESA in Europe, thereby covering the northern hemisphere. In addition to analyzing the challenges of identifying instrument capabilities to meet the science requirements, and the implications of hosting the instrument payloads on commercial geosynchronous satellites, the GEO-CAPE mission design team conducted a short study to explore strategies to optimize the science return for the coastal imaging instrument. The study focused on intelligent scheduling strategies that took into account cloud avoidance techniques as well as onboard processing methods to reduce the data storage and transmission loads. This paper expands the findings of that study to address the use of intelligent scheduling techniques and near-real time data product acquisition of both the coastal water and air pollution events. The topics include the use of onboard processing to refine and execute schedules, to detect cloud contamination in observations, and to reduce data handling operations. Analysis of state of the art flight computing capabilities will be presented, along with an assessment of cloud detection algorithms and their performance characteristics. Tools developed to illustrate operational concepts will be described, including their applicability to environmental monitoring domains with an eye to the future. In the geostationary configuration, the payload becomes a networked "thing" with enough connectivity to exchange data seamlessly with users. This allows the full field of view to be sensed at very high rate under the control of ground infrastructure, resulting in improved efficiencies, accuracy and science benefits. Hence a remote sensing payload and its data may become one of millions of connected objects in the emerging Internet of Things (IoT), and be as easily accessible by a user's smart phone as any other smart appliance.

Intelligent Observation Strategies for Geosynchronous Remote Sensing for Natural Hazards

NASA Technical Reports Server (NTRS)

Moe, Karen; Cappleare, Patrice; Frye, Stuart; LeMoigne, Jacqueline; Mandl, Daniel; Flatley, Thomas; Geist, Alessandro

2015-01-01

Geosynchronous satellites offer a unique perspective for monitoring environmental factors important to understanding natural hazards and supporting the disasters management life cycle, namely forecast, detection, response, recovery and mitigation. In the NASA decadal survey for Earth science, the GEO-CAPE mission was proposed to address coastal and air pollution events in geosynchronous orbit, complementing similar initiatives in Asia by the South Koreans and by ESA in Europe, thereby covering the northern hemisphere. In addition to analyzing the challenges of identifying instrument capabilities to meet the science requirements, and the implications of hosting the instrument payloads on commercial geosynchronous satellites, the GEO-CAPE mission design team conducted a short study to explore strategies to optimize the science return for the coastal imaging instrument. The study focused on intelligent scheduling strategies that took into account cloud avoidance techniques as well as onboard processing methods to reduce the data storage and transmission loads. This paper expands the findings of that study to address the use of intelligent scheduling techniques and near-real time data product acquisition of both the coastal water and air pollution events. The topics include the use of onboard processing to refine and execute schedules, to detect cloud contamination in observations, and to reduce data handling operations. Analysis of state of the art flight computing capabilities will be presented, along with an assessment of cloud detection algorithms and their performance characteristics. Tools developed to illustrate operational concepts will be described, including their applicability to environmental monitoring domains with an eye to the future. In the geostationary configuration, the payload becomes a networked thing with enough connectivity to exchange data seamlessly with users. This allows the full field of view to be sensed at very high rate under the control of ground infrastructure, resulting in improved efficiencies, accuracy and science benefits. Hence a remote sensing payload and its data may become one of millions of connected objects in the emerging Internet of Things (IoT), and be as easily accessible by a users smart phone as any other smart appliance.

The Relationship of Magnetotail Flow Bursts and Ground Onset Signatures

NASA Technical Reports Server (NTRS)

Kepko, Larry; Spanswick, Emma; Angelopoulos, Vassilis; Donovan, Eric

2010-01-01

It has been known for decades that auroral substorm onset occurs on (or at least near) the most equatorward auroral arc, which is thought to map to the near geosynchronous region. The lack of auroral signatures poleward of this arc prior to onset has been a major criticism of flow-burst driven models of substorm onset. The combined THEMIS 5 spacecraft in-situ and ground array measurements provide an unprecedented opportunity to examine the causal relationship between midtail plasma flows, aurora, and ground magnetic signatures. I first present an event from 2008 using multi-spectral all sky imager data from Gillam and in-situ data from THEMIS. The multispectral data indicate an equatorward moving auroral form prior to substorm onset. When this forms reaches the most equatorward arc, the arc brightens and an auroral substorm begins. The THEMIS data show fast Earthward flows prior to onset as well. I discuss further the association of flow bursts and Pi2 pulsations, in the con text of the directly-driven Pi2 model. This model directly links flows and Pi2 pulsations, providing an important constraint on substorm onset theories.

Modes of energy transfer from the solar wind to the inner magnetosphere

NASA Astrophysics Data System (ADS)

Vassiliadis, D.; Tornquist, M.; Koepke, M. E.

2009-12-01

The energy provided by the solar wind to geospace finds its way to the inner magnetosphere and leads to variations in the mid-latitude ground magnetic field. Through measurement of field disturbances and energetic particle fluxes one can show that the inner magnetospheric behavior is organized in large-scale modes of response. Each mode is excited by a different combination of solar wind plasma and field variables which often occur in characteristic geoeffective structures. We compare the wave field and energetic-electron modes of response to solar wind variables as obtained by filter and correlation techniques. Characteristic modes of response are found for low-frequency wave fields measured by mid- and high-latitude meridional arrays such as MEASURE and the geosynchronous field recorded by GOES magnetometers. The modes are similar to those obtained earlier for magnetospheric electron flux such as that measured by the HIST instrument on POLAR, and the similarity is used to determine the parameter range in L, MLT, time, and perpendicular energy for drift-resonant interaction. We present modeling results for the excitation of these wave fields during the passage of the interplanetary structures.

Deep Discharge Reconditioning and Shorted Storage of Batteries. [nickel cadmium batteries

NASA Technical Reports Server (NTRS)

Ritterman, P. F.

1982-01-01

The identification and measurement of hydrogen recombination in sealed nickel-cadium cells makes deep reconditioning on a battery basis safe and feasible. Deep reconditioning improves performance and increases life of nickel-cadium batteries in geosynchronous orbit applications. The hydrogen mechanism and supporting data are presented. Parameter cell design experiments are described which led to the definition of nickel-cadium cells capable of high rate overdischarge without detriment to specific energy. Nickel-cadium calls of identical optimum design were successfully cycled for 7 seasons in simulation of geosynchronous orbit at 75 percent depth-of-discharge with extensive midseason and end-of-season overdischarge at rates varying from C/20 to C/4. Destructive physical analysis and cyclin data indicated no deterioration or the development of dangerous pressures as a result of the cycling with overdischarge.

The aerobraking space transfer vehicle

NASA Technical Reports Server (NTRS)

Andrews, Glen; Carpenter, Brian; Corns, Steve; Harris, Robert; Jun, Brian; Munro, Bruce; Pulling, Eric; Sekhon, Amrit; Welton, Walt; Jakubowski, A.

1990-01-01

With the advent of the Space Station and the proposed Geosynchronous Operation Support Center (GeoShack) in the early 21st century, the need for a cost effective, reusable orbital transport vehicle has arisen. This transport vehicle will be used in conjunction with the Space Shuttle, the Space Station, and GeoShack. The vehicle will transfer mission crew and payloads between low earth and geosynchronous orbits with minimal cost. Recent technological advances in thermal protection systems such as those employed in the Space Shuttle have made it possible to incorporate and aerobrake on the transfer vehicle to further reduce transport costs. The research and final design configuration of the aerospace senior design team from VPISU, working in conjunction with NASA, are presented. The topic of aerobraking and focuses on the evolution of an Aerobraking Space Transfer Vehicle (ASTV), is addressed.

Incorporation of star measurements for the determination of orbit and attitude parameters of a geosynchronous satellite: An iterative application of linear regression

NASA Astrophysics Data System (ADS)

Phillips, D.

1980-10-01

Currently on NOAA/NESS's VIRGS system at the World Weather Building star images are being ingested on a daily basis. The image coordinates of the star locations are measured and stored. Subsequently, the information is used to determine the attitude, the misalignment angles between the spin axis and the principal axis of the satellite, and the precession rate and direction. This is done for both the 'East' and 'West' operational geosynchronous satellites. This orientation information is then combined with image measurements of earth based landmarks to determine the orbit of each satellite. The method for determining the orbit is simple. For each landmark measurement one determines a nominal position vector for the satellite by extending a ray from the landmark's position towards the satellite and intersecting the ray with a sphere with center coinciding with the Earth's center and with radius equal to the nominal height for a geosynchronous satellite. The apparent motion of the satellite around the Earth's center is then approximated with a Keplerian model. In turn the variations of the satellite's height, as a function of time found by using this model, are used to redetermine the successive satellite positions by again using the Earth based landmark measurements and intersecting rays from these landmarks with the newly determined spheres. This process is performed iteratively until convergence is achieved. Only three iterations are required.

Geosynchronous inclined orbits for high-latitude communications

NASA Astrophysics Data System (ADS)

Fantino, E.; Flores, R. M.; Di Carlo, M.; Di Salvo, A.; Cabot, E.

2017-11-01

We present and discuss a solution to the growing demand for satellite telecommunication coverage in the high-latitude geographical regions (beyond 55°N), where the signal from geostationary satellites is limited or unavailable. We focus on the dynamical issues associated to the design, the coverage, the maintenance and the disposal of a set of orbits selected for the purpose. Specifically, we identify a group of highly inclined, moderately eccentric geosynchronous orbits derived from the Tundra orbit (geosynchronous, eccentric and critically inclined). Continuous coverage can be guaranteed by a constellation of three satellites in equally spaced planes and suitably phased. By means of a high-precision model of the terrestrial gravity field and the relevant environmental perturbations, we study the evolution of these orbits. The effects of the different perturbations on the ground track (which is more important for coverage than the orbital elements themselves) are isolated and analyzed. The physical model and the numerical setup are optimized with respect to computing time and accuracy. We show that, in order to maintain the ground track unchanged, the key parameters are the orbital period and the argument of perigee. Furthermore, corrections to the right ascension of the ascending node are needed in order to preserve the relative orientation of the orbital planes. A station-keeping strategy that minimizes propellant consumption is then devised, and comparisons are made between the cost of a solution based on impulsive maneuvers and one with continuous thrust. Finally, the issue of end-of-life disposal is discussed.

Spectrometric Characterization of Active Geosynchronous Satellites

NASA Astrophysics Data System (ADS)

Bedard, D.; Monin, D.; Scott, R.; Wade, G.

2012-09-01

Spectrometric characterization of artificial space objects for the purposes of Space Situational Awareness (SSA) has demonstrated great potential since this technique was first reported at this conference over a decade ago. Yet, much scientific work remains to be done before this tool can be used reliably in an operational context. For example, a detailed study of the impacts of a dynamic illumination-object-sensor geometry during individual spectrometric observations has yet to be described. A thorough understanding of this last problem is considered critical if reflectance spectroscopy will be used to characterize active low Earth orbiting spacecraft, in which the Sun-object-sensor geometry varies considerably over the course of a few seconds, or to study space debris that have uncontrolled and varying attitude. It is with the above questions in mind that two observation campaigns were conducted. The first consisted in using small-aperture telescopes to obtain multi-color photometric light curves of active geosynchronous satellites over a wide range of phase angles. The second observation campaign was conducted at the Dominion Astrophysical Observatory (DAO) using the 1.8-metre Plaskett telescope and its Cassegrain spectrograph. The objective of this experiment was to gather time-resolved spectrometric measurements of active geosynchronous satellites as a function of phase angle. This class of satellites was selected because their attitude is controlled and can be estimated to a high level of confidence. This paper presents the two observation campaigns and provides a summary of the key results of this experiment.

The global context of the 14 November 2012 storm event

DOE PAGES

Hwang, K. -J.; Sibeck, D. G.; Fok, M. -C. H.; ...

2015-03-01

From 2 to 5 UT on 14 November 2012, the Van Allen Probes observed repeated particle flux dropouts during the main phase of a geomagnetic storm as the satellites traversed the post-midnight to dawnside inner magnetosphere. Each flux dropout corresponded to an abrupt change in the magnetic topology, i.e., from a more dipolar configuration to a configuration with magnetic field lines stretched in the dawn-dusk direction. Geosynchronous GOES spacecraft located in the dusk and near-midnight sectors and the LANL constellation with wide local time coverage also observed repeated flux dropouts and stretched field lines with similar occurrence patterns to thosemore » of the Van Allen Probe events. THEMIS recorded multiple transient abrupt expansions of the evening-side magnetopause ~20–30 min prior to the sequential Van Allen Probes observations. Ground-based magnetograms and all sky images demonstrate repeatable features in conjunction with the dropouts. We combine the various in-situ and ground-based measurements to define and understand the global spatiotemporal features associated with the dropouts observed by the Van Allen Probes. We discuss various proposed hypotheses for the mechanism that plausibly caused this storm-time dropout event as well as formulate a new hypothesis that explains the combined in-situ and ground-based observations: the earthward motion of magnetic flux ropes containing lobe plasmas that form along an extended magnetotail reconnection line in the near-Earth plasma sheet.« less

Observations of Human-Made Debris in Earth Orbit

NASA Technical Reports Server (NTRS)

Cowardia, Heather

2011-01-01

Orbital debris is defined as any human-made object in orbit about the Earth that no longer serves a useful purpose. Beginning in 1957 with the launch of Sputnik 1, there have been more than 4,700 launches, with each launch increasing the potential for impacts from orbital debris. Almost 55 years later there are over 16,000 catalogued objects in orbit over 10 cm in size. Agencies world-wide have realized this is a growing issue for all users of the space environment. To address the orbital debris issue, the Inter-Agency Space Debris Coordination Committee (IADC) was established to collaborate on monitoring, characterizing, and modeling orbital debris, as well as formulating policies and procedures to help control the risk of collisions and population growth. One area of fundamental interest is measurements of the space debris environment. NASA has been utilizing radar and optical measurements to survey the different orbital regimes of space debris for over 25 years, as well as using returned surfaces to aid in determining the flux and size of debris that are too small to detect with ground-based sensors. This paper will concentrate on the optical techniques used by NASA to observe the space debris environment, specifically in the Geosynchronous earth Orbit (GEO) region where radar capability is severely limited.

Characterization of Space Environmental Effects on Candidate Solar Sail Material

NASA Technical Reports Server (NTRS)

Edwards, David; Hubbs, Whitney; Stanaland, Tesia; Munafo, Paul M. (Technical Monitor)

2002-01-01

The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) is concentrating research into the utilization of photonic materials for spacecraft propulsion. Spacecraft propulsion, using photonic materials, will be achieved using a solar sail. A solar sail operates on the principle that photons, originating from the sun, impart pressure to the sail and therefore provide a source for spacecraft propulsion. The pressure imparted to a solar sail can be increased, up to a factor of two if the sunfacing surface is perfectly reflective. Therefore, these solar sails are generally composed of a highly reflective metallic sun-facing layer, a thin polymeric substrate and occasionally a highly emissive back surface. The Space Environmental Effects Team, at MSFC, is actively characterizing candidate solar sail material to evaluate the thermo-optical and mechanical properties after exposure to radiation environments simulating orbital environments. This paper describes the results of three candidate materials after exposure to a simulated Geosynchronous Transfer Orbit (GTO). This is the first known characterization of solar sail material exposed to space simulated radiation environments. The technique of radiation dose versus material depth profiling was used to determine the orbital equivalent exposure doses. The solar sail exposure procedures and results of the material characterization will be discussed.

New Space Weather Systems Under Development and Their Contribution to Space Weather Management

NASA Astrophysics Data System (ADS)

Tobiska, W.; Bouwer, D.; Schunk, R.; Garrett, H.; Mertens, C.; Bowman, B.

2008-12-01

There have been notable successes during the past decade in the development of operational space environment systems. Examples include the Magnetospheric Specification Model (MSM) of the Earth's magnetosphere, 2000; SOLAR2000 (S2K) solar spectral irradiances, 2001; High Accuracy Satellite Drag Model (HASDM) neutral atmosphere densities, 2004; Global Assimilation of Ionospheric Measurements (GAIM) ionosphere specification, 2006; Hakamada-Akasofu-Fry (HAF) solar wind parameters, 2007; Communication Alert and Prediction System (CAPS) ionosphere, high frequency radio, and scintillation S4 index prediction, 2008; and GEO Alert and Prediction System (GAPS) geosynchronous environment satellite charging specification and forecast, 2008. Operational systems that are in active operational implementation include the Jacchia-Bowman 2006/2008 (JB2006/2008) neutral atmosphere, 2009, and the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) aviation radiation model using the Radiation Alert and Prediction System (RAPS), 2010. U.S. national agency and commercial assets will soon reach a state where specification and prediction will become ubiquitous and where coordinated management of the space environment and space weather will become a necessity. We describe the status of the CAPS, GAPS, RAPS, and JB2008 operational development. We additionally discuss the conditions that are laying the groundwork for space weather management and estimate the unfilled needs as we move beyond specification and prediction efforts.

Dusty Plasmas in Planetary Magnetospheres Award

NASA Technical Reports Server (NTRS)

Horanyi, Mihaly

2005-01-01

This is my final report for the grant Dusty Plasmas in Planetary Magnetospheres. The funding from this grant supported our research on dusty plasmas to study: a) dust plasma interactions in general plasma environments, and b) dusty plasma processes in planetary magnetospheres (Earth, Jupiter and Saturn). We have developed a general purpose transport code in order to follow the spatial and temporal evolution of dust density distributions in magnetized plasma environments. The code allows the central body to be represented by a multipole expansion of its gravitational and magnetic fields. The density and the temperature of the possibly many-component plasma environment can be pre-defined as a function of coordinates and, if necessary, the time as well. The code simultaneously integrates the equations of motion with the equations describing the charging processes. The charging currents are dependent not only on the instantaneous plasma parameters but on the velocity, as well as on the previous charging history of the dust grains.

Stereo Measurements from Satellites

NASA Technical Reports Server (NTRS)

Adler, R.

1982-01-01

The papers in this presentation include: 1) 'Stereographic Observations from Geosynchronous Satellites: An Important New Tool for the Atmospheric Sciences'; 2) 'Thunderstorm Cloud Top Ascent Rates Determined from Stereoscopic Satellite Observations'; 3) 'Artificial Stereo Presentation of Meteorological Data Fields'.

Influence of O2 or H2O in a plasma jet and its environment on plasma electrical and biochemical performances

NASA Astrophysics Data System (ADS)

Adhikari, Ek R.; Samara, Vladimir; Ptasinska, Sylwia

2018-05-01

Because environmental conditions, such as room temperature and humidity, fluctuate arbitrarily, effects of atmospheric pressure plasma jets (APPJs) used in medical applications operating at various places and time might vary. Therefore, understanding the possible effects of air components in and outside APPJs is essential for clinical use, which requires reproducibility of plasma performance. These air components can influence the formation of reactive species in the APPJ, and the type and amount of these species formed depend on the feed gas inside the APPJ and the plasma jet environment. In this study, we monitored changes in plasma current and power, as well as in the level of DNA damage attributable to plasma irradiation, by adjusting the fraction of oxygen and water vapor in the plasma jet environment and feed gas. Here, DNA was used as a molecular probe to identify chemical changes that occurred in the plasma jet under these various environmental conditions. The damaged and undamaged fractions of DNA were quantified using agarose gel electrophoresis. We obtained an optimal amount of oxygen or water vapor in the plasma jet environment, as well as in the feed gas, which increased the level of DNA damage significantly. This increase can be attributed primarily to the formation of reactive species caused by water and oxygen decomposition in the APPJ detected with mass spectrometry. Moreover, we observed that the plasma power remained the same or decreased when gas was added to the jet environment or the feed gas, respectively, but in both cases, DNA damage increased. This indicates the superiority of plasma chemistry over the electrical power applied for APPJ ignition of the plasma sources used in medical applications.

Monitoring Cyanobacteria Bloom in Taihu Lake by High-Resolution Geostationary Satellite GF4

NASA Astrophysics Data System (ADS)

Liu, J.

2018-04-01

The high-resolution remote-sensing satellite, GF4 PMS, of China's geosynchronous earth orbit was successfully launched on December 29, 2015. Its high spatial resolution and high temporal resolution allow GF4 PMS to play a very important role in water environment monitoring, especially in the dynamic monitoring of lake and reservoir cyanobacteria blooms. As GF4 PMS has just been launched, there is still relatively little related research, and the practical application effect of GF4 PMS in the extraction of cyanobacteria blooms remains to be further tested. Therefore, in this study, the method and effect of GF4 PMS application in cyanobacteria bloom monitoring were studied in Taihu. It turned that GF4 PMS can be applied to the dynamic monitoring of the distribution of cyanobacteria blooms in Taihu, thereby finding the temporal and spatial variation of the distribution of cyanobacteria blooms.

Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes

PubMed Central

Pakhotin, I P; Drozdov, A Y; Shprits, Y Y; Boynton, R J; Subbotin, D A; Balikhin, M A

2014-01-01

This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extended time periods totalling several weeks of observations. The time periods involved periods of quiet, moderate, and strong geomagnetic activity and captured a range of dynamics typical of the radiation belts. The model has successfully simulated energetic electron fluxes for various magnetospheric conditions. Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed. PMID:26167432

A simple model of space radiation damage in GaAs solar cells

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Stith, J. J.; Stock, L. V.

1983-01-01

A simple model is derived for the radiation damage of shallow junction gallium arsenide (GaAs) solar cells. Reasonable agreement is found between the model and specific experimental studies of radiation effects with electron and proton beams. In particular, the extreme sensitivity of the cell to protons stopping near the cell junction is predicted by the model. The equivalent fluence concept is of questionable validity for monoenergetic proton beams. Angular factors are quite important in establishing the cell sensitivity to incident particle types and energies. A fluence of isotropic incidence 1 MeV electrons (assuming infinite backing) is equivalent to four times the fluence of normal incidence 1 MeV electrons. Spectral factors common to the space radiations are considered, and cover glass thickness required to minimize the initial damage for a typical cell configuration is calculated. Rough equivalence between the geosynchronous environment and an equivalent 1 MeV electron fluence (normal incidence) is established.

A three-dimensional spacecraft-charging computer code

NASA Technical Reports Server (NTRS)

Rubin, A. G.; Katz, I.; Mandell, M.; Schnuelle, G.; Steen, P.; Parks, D.; Cassidy, J.; Roche, J.

1980-01-01

A computer code is described which simulates the interaction of the space environment with a satellite at geosynchronous altitude. Employing finite elements, a three-dimensional satellite model has been constructed with more than 1000 surface cells and 15 different surface materials. Free space around the satellite is modeled by nesting grids within grids. Applications of this NASA Spacecraft Charging Analyzer Program (NASCAP) code to the study of a satellite photosheath and the differential charging of the SCATHA (satellite charging at high altitudes) satellite in eclipse and in sunlight are discussed. In order to understand detector response when the satellite is charged, the code is used to trace the trajectories of particles reaching the SCATHA detectors. Particle trajectories from positive and negative emitters on SCATHA also are traced to determine the location of returning particles, to estimate the escaping flux, and to simulate active control of satellite potentials.

Regenerative fuel cell study for satellites in GEO orbit

NASA Technical Reports Server (NTRS)

Vandine, Leslie; Gonzalez-Sanabria, Olga; Levy, Alexander

1987-01-01

The results of a 12 month study to identify high performance regenerative hydrogen-oxygen fuel cell concepts for geosynchronous satellite application are summarized. Emphasis was placed on concepts with the potential for high energy density and passive means for water and heat management to maximize system reliability. Both polymer membrane and alkaline electrolyte fuel cells were considered, with emphasis on the alkaline cell because of its high performance, advanced state of development, and proven ability to operate in a launch and space environment. Three alkaline system concepts were studied. Results indicate that using near term technology energy densities between 46 and 52 watt-hour/lb can be achieved at efficiencies of 55 percent. Using advanced light weight cell construction which was achieved in experimental cells, composite tankage material for the reactant gases and the reversible stack concept, system energy densities of 115 watt-hours/lb can be projected.

Investigation of antenna pattern constraints for passive geosynchronous microwave imaging radiometers

NASA Technical Reports Server (NTRS)

Gasiewski, A. J.; Skofronick, G. M.

1992-01-01

Progress by investigators at Georgia Tech in defining the requirements for large space antennas for passive microwave Earth imaging systems is reviewed. In order to determine antenna constraints (e.g., the aperture size, illumination taper, and gain uncertainty limits) necessary for the retrieval of geophysical parameters (e.g., rain rate) with adequate spatial resolution and accuracy, a numerical simulation of the passive microwave observation and retrieval process is being developed. Due to the small spatial scale of precipitation and the nonlinear relationships between precipitation parameters (e.g., rain rate, water density profile) and observed brightness temperatures, the retrieval of precipitation parameters are of primary interest in the simulation studies. Major components of the simulation are described as well as progress and plans for completion. The overall goal of providing quantitative assessments of the accuracy of candidate geosynchronous and low-Earth orbiting imaging systems will continue under a separate grant.

Detection of severe Midwest thunderstorms using geosynchronous satellite data

NASA Technical Reports Server (NTRS)

Adler, R. F.; Markus, M. J.; Fenn, D. D.

1985-01-01

In the present exploration of the effectiveness of severe thunderstorm detection in the Midwestern region of the U.S. by means of approximately 5-min interval geosynchronous satellite data, thunderstorms are defined in IR data as points of relative minimum in brightness temperature T(B) having good time continuity and exhibiting a period of rapid growth. The four parameters of rate of T(B) decrease in the upper troposphere and stratosphere, isotherm expansion, and storm lifetime minimum T(B), are shown to be statistically related to the occurrence of severe weather on four case study days and are combined into a Thunderstorm Index which varies among values from 1 to 9. Storms rating higher than 6 have a much higher probability of severe weather reports, yielding a warning time lead of 15 min for hail and 30 min for the first tornado report.

High resolution observations of low contrast phenomena from an Advanced Geosynchronous Platform (AGP)

NASA Technical Reports Server (NTRS)

Maxwell, M. S.

1984-01-01

Present technology allows radiometric monitoring of the Earth, ocean and atmosphere from a geosynchronous platform with good spatial, spectral and temporal resolution. The proposed system could provide a capability for multispectral remote sensing with a 50 m nadir spatial resolution in the visible bands, 250 m in the 4 micron band and 1 km in the 11 micron thermal infrared band. The diffraction limited telescope has a 1 m aperture, a 10 m focal length (with a shorter focal length in the infrared) and linear and area arrays of detectors. The diffraction limited resolution applies to scenes of any brightness but for a dark low contrast scenes, the good signal to noise ratio of the system contribute to the observation capability. The capabilities of the AGP system are assessed for quantitative observations of ocean scenes. Instrument and ground system configuration are presented and projected sensor capabilities are analyzed.

A New Look at the GEO and Near-GEO Regimes: Operations, Disposals, and Debris

NASA Technical Reports Server (NTRS)

Johnson, Nicholas

2011-01-01

Since 1963 more than 900 spacecraft and more than 200 launch vehicle upper stages have been inserted into the vicinity of the geosynchronous regime. Equally important, more than 300 spacecraft have been maneuvered into disposal orbits at mission termination to alleviate unnecessary congestion in the finite GEO region. However, the number of GEO satellites continues to grow, and evidence exists of a substantial small debris population. In addition, the operational modes of an increasing number of GEO spacecraft differ from those of their predecessors of several decades ago, including more frequent utilization of inclined and eccentric geosynchronous orbits. Consequently, the nature of the GEO regime and its immediate surroundings is evolving from well-known classical characteristics. This paper takes a fresh look at the GEO satellite population and the near- and far-term environmental implications of the region, including the effects of national and international debris mitigation measures.

Navy Prototype Optical Interferometer observations of geosynchronous satellites.

PubMed

Hindsley, Robert B; Armstrong, J Thomas; Schmitt, Henrique R; Andrews, Jonathan R; Restaino, Sergio R; Wilcox, Christopher C; Vrba, Frederick J; Benson, James A; DiVittorio, Michael E; Hutter, Donald J; Shankland, Paul D; Gregory, Steven A

2011-06-10

Using a 15.9  m baseline at the Navy Prototype Optical Interferometer (NPOI), we have successfully detected interferometric fringes in observations of the geosynchronous satellite (geosat) DirecTV-9S while it glinted on two nights in March 2009. The fringe visibilities can be fitted by a model consisting of two components, one resolved (≳3.7  m) and one unresolved (∼1.1  m). Both the length of the glint and the specular albedos are consistent with the notion that the glinting surfaces are not completely flat and scatter reflected sunlight into an opening angle of roughly 15°. Enhancements to the NPOI that would improve geosat observations include adding an infrared capability, which could extend the glint season, and adding larger, adaptive-optics equipped telescopes. Future work may test the feasibility of observing geosats with aperture-masked large telescopes and of developing an array of six to nine elements.

The rationale and suggested approaches for research geosynchronous satellite measurements for severe storm and mesoscale investigations

NASA Technical Reports Server (NTRS)

Shenk, W. E.; Adler, R. F.; Chesters, D.; Susskind, J.; Uccellini, L.

1984-01-01

The measurements from current and planned geosynchronous satellites provide quantitative estimates of temperature and moisture profiles, surface temperature, wind, cloud properties, and precipitation. A number of significant observation characteristics remain, they include: (1) temperature and moisture profiles in cloudy areas; (2) high vertical profile resolution; (3) definitive precipitation area mapping and precipitation rate estimates on the convective cloud scale; (4) winds from low level cloud motions at night; (5) the determination of convective cloud structure; and (6) high resolution surface temperature determination. Four major new observing capabilities are proposed to overcome these deficiencies: a microwave sounder/imager, a high resolution visible and infrared imager, a high spectral resolution infrared sounder, and a total ozone mapper. It is suggested that the four sensors are flown together and used to support major mesoscale and short range forecasting field experiments.

AMPTE/CCE CHEM observations of the energetic ion population at geosynchronous altitudes

NASA Technical Reports Server (NTRS)

Daglis, Ioannis A.; Sarris, Emmanuel T.; Wilken, Berend

1993-01-01

The paper presents results of a statistical study of average characteristics of the energetic ion population at geosynchronous altitudes, using energetic-ion (1-300 keV/e) measurements from the CHEM spectrometer aboard the AMPTE Charge Composition Explorer between January 1985 and June 1987. Data were sorted into four MLT groups and two extreme geomagnetic activity levels ('very quiet' for AE less than 30 nT and 'very active' for AE greater than 700 nT). A clear quiet-time dayside feature found in the measurements was a dip in H(+) and He(2+) spectra, at 6.6 keV/e in the prenoon sector and at 3.5 keV/e in the postnoon sector. During active times, the ion fluxes increased (except for He(+)), and the O(+) contribution to the total energy density increased dramatically. The pitch angle distributions were normal during quiet times and isotropic or field-aligned during active times.

Satellite orbit considerations for a global change technology architecture trade study

NASA Technical Reports Server (NTRS)

Harrison, Edwin F.; Gibson, Gary G.; Suttles, John T.; Buglia, James J.; Taback, Israel

1991-01-01

A study was conducted to determine satellite orbits for earth observation missions aimed at obtaining data for assessing data global climate change. A multisatellite system is required to meet the scientific requirements for temporal coverage over the globe. The best system consists of four sun-synchronous satellites equally spaced in local time of equatorial crossing. This system can obtain data every three hours for all regions. Several other satellite systems consisting of combinations of sun-synchronous orbits and either the Space Station Freedom or a mid-altitude equatorial satellite can provide three to six hour temporal coverage, which is sufficient for measuring many of the parameters required for the global change monitoring mission. Geosynchronous satellites are required to study atmospheric and surface processes involving variations on the order of a few minutes to an hour. One or two geosynchronous satellites can be relocated in longitude to study processes over selected regions of earth.

Precise interferometric tracking of the DSCS II geosynchronous orbiter

NASA Astrophysics Data System (ADS)

Border, J. S.; Donivan, F. F., Jr.; Shiomi, T.; Kawano, N.

1986-01-01

A demonstration of the precise tracking of a geosynchronous orbiter by radio metric techniques based on very-long-baseline interferometry (VLBI) has been jointly conducted by the Jet Propulsion Laboratory and Japan's Radio Research Laboratory. Simultaneous observations of a U.S. Air Force communications satellite from tracking stations in California, Australia, and Japan have determined the satellite's position with an accuracy of a few meters. Accuracy claims are based on formal statistics, which include the effects of errors in non-estimated parameters and which are supported by a chi-squared of less than one, and on the consistency of orbit solutions from disjoint data sets. A study made to assess the impact of shorter baselines and reduced data noise concludes that with a properly designed system, similar accuracy could be obtained for either a satellite viewed from stations located within the continental U.S. or for a satellite viewed from stations within Japanese territory.

Two-dimensiosnal electron beam charging model for polymer films. M.S. Thesis; [spacecraft charging, geosynchronous satellites

NASA Technical Reports Server (NTRS)

Reeves, R. D.; Balmain, K. G.

1981-01-01

A two dimensional model was developed to describe the charging of thin polymer films exposed to a uniform mon-energetic electron beam. The study was motivated by observed anomalous behavior of geosynchronous satellites which was attributed to electrical discharges associated with the differential charging of satellite surfaces of magnetospheric electrons. Electric fields both internal and external to the irradiated specimen were calculated at steady state in order to identify regions of high electrical stress. Particular emphasis was placed on evaluating the charging characteristics near the material's edge. The model was used to identify and quantify the effects of some of the experimental parameters notably: beam energy; beam angle of incidence; beam current density; material thickness; and material width. Simulations of the following situations were also conducted: positive or negative precharging over part of the surface; a central gap in the material; and a discontinuity in the material's thickness.

Illumination from space with orbiting solar-reflector spacecraft

NASA Technical Reports Server (NTRS)

Canady, J. E., Jr.; Allen, J. L., Jr.

1982-01-01

The feasibility of using orbiting mirrors to reflect sunlight to Earth for several illumination applications is studied. A constellation of sixteen 1 km solar reflector spacecraft in geosynchronous orbit can illuminate a region 333 km in diameter to 8 lux, which is brighter than most existing expressway lighting systems. This constellation can serve one region all night long or can provide illumination during mornings and evenings to five regions across the United States. Preliminary cost estimates indicate such an endeavor is economically feasible. The studies also explain how two solar reflectors can illuminate the in-orbit nighttime operations of Space Shuttle. An unfurlable, 1 km diameter solar reflector spacecraft design concept was derived. This spacecraft can be packaged in the Space, Shuttle, transported to low Earth orbit, unfurled, and solar sailed to operational orbits up to geosynchronous. The necessary technical studies and improvements in technology are described, and potential environmental concerns are discussed.

Characterizing Space Environments with Long-Term Space Plasma Archive Resources

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Miller, J. Scott; Diekmann, Anne M.; Parker, Linda N.

2009-01-01

A significant scientific benefit of establishing and maintaining long-term space plasma data archives is the ready access the archives afford to resources required for characterizing spacecraft design environments. Space systems must be capable of operating in the mean environments driven by climatology as well as the extremes that occur during individual space weather events. Long- term time series are necessary to obtain quantitative information on environment variability and extremes that characterize the mean and worst case environments that may be encountered during a mission. In addition, analysis of large data sets are important to scientific studies of flux limiting processes that provide a basis for establishing upper limits to environment specifications used in radiation or charging analyses. We present applications using data from existing archives and highlight their contributions to space environment models developed at Marshall Space Flight Center including the Chandra Radiation Model, ionospheric plasma variability models, and plasma models of the L2 space environment.

Observational test of empirical magnetopause location models using geosynchronous satellite data

NASA Astrophysics Data System (ADS)

Park, Eunsu; Moon, Y.-J.; Lee, Kangjin

2016-11-01

In this study, we identify 123 geosynchronous magnetopause crossings using geosynchronous satellite observation data from 1996 to 2010 as well as make an observational test of magnetopause location models using the identified events. For this, we consider three models: Petrinec and Russell (1996), Shue et al. (1998), and Lin et al. (2010). To evaluate the models, we estimate a probability of detection (PoD) and a critical success index (CSI) as a function of year. To examine the effect of solar cycle phase, we consider three different time periods: (1) ascending phase (1996-1999), (2) maximum phase (2000-2002), and (3) descending phase (2003-2008). Major results from this study are as follows. First, the PoD values of all models range from 0.4 to 0.8 for the most of years. Second, the PoD values of Lin et al. (2010) are noticeably higher than those of the other models. Third, the CSI values of all models range from 0.1 to 0.3, and those of Shue et al. (1998) are slightly higher than those of the other models. Fourth, the predicted magnetopause radii based on Lin et al.(2010) well match the observed ones within 1 Earth radius, while those on Shue et al. (1998) overestimate the observed ones by about 2 Earth radii. Fifth, the PoD and critical success index (CSI) values of all the models are better for the solar maximum phase than those for the other phases, implying that the models are more optimized for the phase.

New Magnetospheric Substorm Injection Monitor: Image Electron Spectrometer On Board a Chinese Navigation IGSO Satellite

NASA Astrophysics Data System (ADS)

Zong, Qiugang; Wang, Yongfu; Zou, Hong; Wang, Linghua; Rankin, Robert; Zhang, Xiaoxin

2018-02-01

Substorm injections are one of the most dynamic processes in Earth's magnetosphere and have global consequences and broad implications for space weather modeling. They can be monitored using energetic electron detectors on geosynchronous satellites. The Imaging Electron Spectrometer (IES) on board a Chinese navigation satellite, launched on 16 October 2015 into an inclined geosynchronous satellite orbit (IGSO), provides the first energetic electron measurement in IGSO orbit to the best of our knowledge. The IES was developed by Peking University and is named hereafter as BD-IES. Using a pin-hole technique, the BD-IES instrument measures 50-600 keV incident electrons in eight energy channels from nine directions covering a range of 180° in polar angle. Data collection by the BD-IES instrument have recently passed the 1 year mark, which reflects a successful milestone for the mission. The innermost and outermost signatures of substorm injection at L 6 and 12 have been observed by the BD-IES with a high L shell spatial coverage, complementary to the existing missions such as the Van Allen Probes that covers the range below L 6. There are another two BD-IES instruments to be installed in the coming Chinese Sun-synchronous and geosynchronous satellites, respectively. Such a configuration will provide a unique opportunity to investigate inward and outward radial propagation of the substorm injection region simultaneously at high and low L shells. It will further elucidate potential mechanisms for the particle energization and transport, two of the most important topics in magnetospheric dynamics.

The Effects of Solar Wind Dynamic Pressure Changes on the Substorm Auroras and Energetic Electron Injections on 24 August 2005

NASA Astrophysics Data System (ADS)

Li, L. Y.; Wang, Z. Q.

2018-01-01

After the passage of an interplanetary (IP) shock at 06:13 UT on 24 August 2005, the enhancement (>6 nPa) of solar wind dynamic pressure and the southward turning of interplanetary magnetic field (IMF) cause the earthward movement of dayside magnetopause and the drift loss of energetic particles near geosynchronous orbit. The persistent electron drift loss makes the geosynchronous satellites cannot observe the substorm electron injection phenomenon during the two substorm expansion phases (06:57-07:39 UT) on that day. Behind the IP shock, the fluctuations ( 0.5-3 nPa) of solar wind dynamic pressure not only alter the dayside auroral brightness but also cause the entire auroral oval to swing in the day-night direction. However, there is no Pi2 pulsation in the nightside auroral oval during the substorm growth phase from 06:13 to 06:57 UT. During the subsequent two substorm expansion phases, the substorm expansion activities cause the nightside aurora oval brightening from substorm onset site to higher latitudes, and meanwhile, the enhancement (decline) of solar wind dynamic pressure makes the nightside auroral oval move toward the magnetic equator (the magnetic pole). These observations demonstrate that solar wind dynamic pressure changes and substorm expansion activities can jointly control the luminosity and location of the nightside auroral oval when the internal and external disturbances occur simultaneously. During the impact of a strong IP shock, the earthward movement of dayside magnetopause probably causes the disappearance of the substorm electron injections near geosynchronous orbit.

Solar power satellite system definition study, volume 7

NASA Technical Reports Server (NTRS)

1977-01-01

Guidelines and assumptions used in the design of a system of geosynchronous satellites for transmitting solar power to earth were discussed as well as the design evolutions of the principle types of solar power satellites and space support systems.

Effects of weakly coupled and dense quantum plasmas environments on charge exchange and ionization processes in Na+ + Rb(5s) atom collisions

NASA Astrophysics Data System (ADS)

Pandey, Mukesh Kumar; Lin, Yen-Chang; Ho, Yew Kam

2017-02-01

The effects of weakly coupled or classical and dense quantum plasmas environment on charge exchange and ionization processes in Na+ + Rb(5s) atom collision at keV energy range have been investigated using classical trajectory Monte Carlo (CTMC) method. The interaction of three charged particles are described by the Debye-Hückel screen potential for weakly coupled plasma, whereas exponential cosine-screened Coulomb potential have been used for dense quantum plasma environment and the effects of both conditions on the cross sections are compared. It is found that screening effects on cross sections in high Debye length condition is quite small in both plasma environments. However, enhanced screening effects on cross sections are observed in dense quantum plasmas for low Debye length condition, which becomes more effective while decreasing the Debye length. Also, we have found that our calculated results for plasma-free case are comparable with the available theoretical results. These results are analyzed in light of available theoretical data with the choice of model potentials.

Stereoscopic observations from meteorological satellites

NASA Astrophysics Data System (ADS)

Hasler, A. F.; Mack, R.; Negri, A.

The capability of making stereoscopic observations of clouds from meteorological satellites is a new basic analysis tool with a broad spectrum of applications. Stereoscopic observations from satellites were first made using the early vidicon tube weather satellites (e.g., Ondrejka and Conover [1]). However, the only high quality meteorological stereoscopy from low orbit has been done from Apollo and Skylab, (e.g., Shenk et al. [2] and Black [3], [4]). Stereoscopy from geosynchronous satellites was proposed by Shenk [5] and Bristor and Pichel [6] in 1974 which allowed Minzner et al. [7] to demonstrate the first quantitative cloud height analysis. In 1978 Bryson [8] and desJardins [9] independently developed digital processing techniques to remap stereo images which made possible precision height measurement and spectacular display of stereograms (Hasler et al. [10], and Hasler [11]). In 1980 the Japanese Geosynchronous Satellite (GMS) and the U.S. GOES-West satellite were synchronized to obtain stereo over the central Pacific as described by Fujita and Dodge [12] and in this paper. Recently the authors have remapped images from a Low Earth Orbiter (LEO) to the coordinate system of a Geosynchronous Earth Orbiter (GEO) and obtained stereoscopic cloud height measurements which promise to have quality comparable to previous all GEO stereo. It has also been determined that the north-south imaging scan rate of some GEOs can be slowed or reversed. Therefore the feasibility of obtaining stereoscopic observations world wide from combinations of operational GEO and LEO satellites has been demonstrated. Stereoscopy from satellites has many advantages over infrared techniques for the observation of cloud structure because it depends only on basic geometric relationships. Digital remapping of GEO and LEO satellite images is imperative for precision stereo height measurement and high quality displays because of the curvature of the earth and the large angular separation of the two satellites. A general solution for accurate height computation depends on precise navigation of the two satellites. Validation of the geosynchronous satellite stereo using high altitude mountain lakes and vertically pointing aircraft lidar leads to a height accuracy estimate of +/- 500 m for typical clouds which have been studied. Applications of the satellite stereo include: 1) cloud top and base height measurements, 2) cloud-wind height assignment, 3) vertical motion estimates for convective clouds (Mack et al. [13], [14]), 4) temperature vs. height measurements when stereo is used together with infrared observations and 5) cloud emissivity measurements when stereo, infrared and temperature sounding are used together (see Szejwach et al. [15]). When true satellite stereo image pairs are not available, synthetic stereo may be generated. The combination of multispectral satellite data using computer produced stereo image pairs is a dramatic example of synthetic stereoscopic display. The classic case uses the combination of infrared and visible data as first demonstrated by Pichel et al. [16]. Hasler et at. [17], Mosher and Young [18] and Lorenz [19], have expanded this concept to display many channels of data from various radiometers as well as real and simulated data fields. A future system of stereoscopic satellites would be comprised of both low orbiters (as suggested by Lorenz and Schmidt [20], [19]) and a global system of geosynchronous satellites. The low earth orbiters would provide stereo coverage day and night and include the poles. An optimum global system of stereoscopic geosynchronous satellites would require international standarization of scan rate and direction, and scan times (synchronization) and resolution of at least 1 km in all imaging channels. A stereoscopic satellite system as suggested here would make an extremely important contribution to the understanding and prediction of the atmosphere.

NiCd cell reliability in the mission environment

NASA Technical Reports Server (NTRS)

Denson, William K.; Klein, Glenn C.

1993-01-01

This paper summarizes an effort by Gates Aerospace Batteries (GAB) and the Reliability Analysis Center (RAC) to analyze survivability data for both General Electric and GAB NiCd cells utilized in various spacecraft. For simplicity sake, all mission environments are described as either low Earth orbital (LEO) or geosynchronous Earth orbit (GEO). 'Extreme value statistical methods' are applied to this database because of the longevity of the numerous missions while encountering relatively few failures. Every attempt was made to include all known instances of cell-induced-failures of the battery and to exclude battery-induced-failures of the cell. While this distinction may be somewhat limited due to availability of in-flight data, we have accepted the learned opinion of the specific customer contacts to ensure integrity of the common databases. This paper advances the preliminary analysis reported upon at the 1991 NASA Battery Workshop. That prior analysis was concerned with an estimated 278 million cell-hours of operation encompassing 183 satellites. The paper also cited 'no reported failures to date.' This analysis reports on 428 million cell hours of operation emcompassing 212 satellites. This analysis also reports on seven 'cell-induced-failures.'

Radiation and Plasma Environments for Lunar Missions

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Edwards, David L.; Altstatt, Richard L.; Diekmann, Anne M.; Blackwell, William C., Jr.; Harine, Katherine J.

2006-01-01

Space system design for lunar orbit and extended operations on the lunar surface requires analysis of potential system vulnerabilities to plasma and radiation environments to minimize anomalies and assure that environmental failures do not occur during the mission. Individual environments include the trapped particles in Earth s radiation belts, solar energetic particles and galactic cosmic rays, plasma environments encountered in transit to the moon and on the lunar surface (solar wind, terrestrial magnetosheath and magnetotail, and lunar photoelectrons), and solar ultraviolet and extreme ultraviolet photons. These are the plasma and radiation environments which contribute to a variety of effects on space systems including total ionizing dose and dose rate effects in electronics, degradation of materials in the space environment, and charging of spacecraft and lunar dust. This paper provides a survey of the relevant charged particle and photon environments of importance to lunar mission design ranging from the lowest (approx.few 10 s eV) photoelectron energies to the highest (approx.GeV) cosmic ray energies.

Inner Radiation Belt Representation of the Energetic Electron Environment: Model and Data Synthesis Using the Salammbo Radiation Belt Transport Code and Los Alamos Geosynchronous and GPS Energetic Particle Data

NASA Technical Reports Server (NTRS)

Friedel, R. H. W.; Bourdarie, S.; Fennell, J.; Kanekal, S.; Cayton, T. E.

2004-01-01

The highly energetic electron environment in the inner magnetosphere (GEO inward) has received a lot of research attention in resent years, as the dynamics of relativistic electron acceleration and transport are not yet fully understood. These electrons can cause deep dielectric charging in any space hardware in the MEO to GEO region. We use a new and novel approach to obtain a global representation of the inner magnetospheric energetic electron environment, which can reproduce the absolute environment (flux) for any spacecraft orbit in that region to within a factor of 2 for the energy range of 100 KeV to 5 MeV electrons, for any levels of magnetospheric activity. We combine the extensive set of inner magnetospheric energetic electron observations available at Los Alamos with the physics based Salammbo transport code, using the data assimilation technique of "nudging". This in effect input in-situ data into the code and allows the diffusion mechanisms in the code to interpolate the data into regions and times of no data availability. We present here details of the methods used, both in the data assimilation process and in the necessary inter-calibration of the input data used. We will present sample runs of the model/data code and compare the results to test spacecraft data not used in the data assimilation process.

A new path to first light for the Magdalena Ridge Observatory interferometer

NASA Astrophysics Data System (ADS)

Creech-Eakman, M. J.; Romero, V.; Payne, I.; Haniff, C. A.; Buscher, D. F.; Young, J. S.; Cervantes, R.; Dahl, C.; Farris, A.; Fisher, M.; Johnston, P.; Klinglesmith, D.; Love, H.; Ochoa, D.; Olivares, A.; Pino, J.; Salcido, C.; Santoro, F.; Schmidt, L.; Seneta, E. B.; Sun, X.; Jenka, L.; Kelly, R.; Price, J.; Rea, A.; Riker, J.; Rochelle, S.

2016-08-01

The Magdalena Ridge Observatory Interferometer (MROI) was the most ambitious infrared interferometric facility conceived of in 2003 when funding began. Today, despite having suffered some financial short-falls, it is still one of the most ambitious interferometric imaging facilities ever designed. With an innovative approach to attaining the original goal of fringe tracking to H = 14th magnitude via completely redesigned mobile telescopes, and a unique approach to the beam train and delay lines, the MROI will be able to image faint and complex objects with milliarcsecond resolutions for a fraction of the cost of giant telescopes or space-based facilities. The design goals of MROI have been optimized for studying stellar astrophysical processes such as mass loss and mass transfer, the formation and evolution of YSOs and their disks, and the environs of nearby AGN. The global needs for Space Situational Awareness (SSA) have moved to the forefront in many communities as Space becomes a more integral part of a national security portfolio. These needs drive imaging capabilities ultimately to a few tens of centimeter resolution at geosynchronous orbits. Any array capable of producing images on faint and complex geosynchronous objects in just a few hours will be outstanding not only as an astrophysical tool, but also for these types of SSA missions. With the recent infusion of new funding from the Air Force Research Lab (AFRL) in Albuquerque, NM, MROI will be able to attain first light, first fringes, and demonstrate bootstrapping with three telescopes by 2020. MROI's current status along with a sketch of our activities over the coming 5 years will be presented, as well as clear opportunities to collaborate on various aspects of the facility as it comes online. Further funding is actively being sought to accelerate the capability of the array for interferometric imaging on a short time-scale so as to achieve the original goals of this ambitious facility

Strong Solar Wind Dynamic Pressure Pulses during Solar Cycle 23 and Their Impacts on Geosynchronous Magnetic Fields

NASA Astrophysics Data System (ADS)

Zuo, P.

2015-12-01

Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. In this investigation, we first present a statistical study on the properties of strong dynamic pressure pulses in the solar wind during solar cycle 23. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here we found that, a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, being stronger at the noon sector.

Substorm occurrence rates, substorm recurrence times, and solar wind structure

NASA Astrophysics Data System (ADS)

Borovsky, Joseph E.; Yakymenko, Kateryna

2017-03-01

Two collections of substorms are created: 28,464 substorms identified with jumps in the SuperMAG AL index in the years 1979-2015 and 16,025 substorms identified with electron injections into geosynchronous orbit in the years 1989-2007. Substorm occurrence rates and substorm recurrence-time distributions are examined as functions of the phase of the solar cycle, the season of the year, the Russell-McPherron favorability, the type of solar wind plasma at Earth, the geomagnetic-activity level, and as functions of various solar and solar wind properties. Three populations of substorm occurrences are seen: (1) quasiperiodically occurring substorms with recurrence times (waiting times) of 2-4 h, (2) randomly occurring substorms with recurrence times of about 6-15 h, and (3) long intervals wherein no substorms occur. A working model is suggested wherein (1) the period of periodic substorms is set by the magnetosphere with variations in the actual recurrence times caused by the need for a solar wind driving interval to occur, (2) the mesoscale structure of the solar wind magnetic field triggers the occurrence of the random substorms, and (3) the large-scale structure of the solar wind plasma is responsible for the long intervals wherein no substorms occur. Statistically, the recurrence period of periodically occurring substorms is slightly shorter when the ram pressure of the solar wind is high, when the magnetic field strength of the solar wind is strong, when the Mach number of the solar wind is low, and when the polar-cap potential saturation parameter is high.

Opportunities for Utilizing the International Space Station for Studies of F2- Region Plasma Science and High Voltage Solar Array Interactions with the Plasma Environment

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Coffey, Victoria; Wright, Kenneth; Craven, Paul; Koontz, Steven

2010-01-01

The near circular, 51.6deg inclination orbit of the International Space Station (ISS) is maintained within an altitude range of approximately 300 km to 400 km providing an ideal platform for conducting in-situ studies of space weather effects on the mid and low-latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) is a suite of instruments installed on the ISS in August 2006 which includes a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). The primary purpose for deploying the FPMU is to characterize ambient plasma temperatures and densities in which the ISS operates and to obtain measurements of the ISS potential relative to the space plasma environment for use in characterizing and mitigating spacecraft charging hazards to the vehicle and crew. In addition to the engineering goals, data from the FPMU instrument package is available for collaborative multi-satellite and ground based instrument studies of the F-region ionosphere during both quiet and disturbed periods. Finally, the FPMU measurements supported by ISS engineering telemetry data provides a unique opportunity to investigate interactions of the ISS high voltage (160 volt) solar array system with the plasma environment. This presentation will provide examples of FPMU measurements along the ISS orbit including night-time equatorial plasma density depletions sampled near the peak electron density in the F2-region ionosphere, charging phenomenon due to interaction of the ISS solar arrays with the plasma environment, and modification of ISS charging due to visiting vehicles demonstrating the capabilities of the FPMU probes for monitoring mid and low latitude plasma processes as well as vehicle interactions with the plasma environment.

Performance modelling of plasma microthruster nozzles in vacuum

NASA Astrophysics Data System (ADS)

Ho, Teck Seng; Charles, Christine; Boswell, Rod

2018-05-01

Computational fluid dynamics and plasma simulations of three geometrical variations of the Pocket Rocket radiofrequency plasma electrothermal microthruster are conducted, comparing pulsed plasma to steady state cold gas operation. While numerical limitations prevent plasma modelling in a vacuum environment, results may be obtained by extrapolating from plasma simulations performed in a pressurised environment, using the performance delta from cold gas simulations performed in both environments. Slip regime boundary layer effects are significant at these operating conditions. The present investigation targets a power budget of ˜10 W for applications on CubeSats. During plasma operation, the thrust force increases by ˜30% with a power efficiency of ˜30 μNW-1. These performance metrics represent instantaneous or pulsed operation and will increase over time as the discharge chamber attains thermal equilibrium with the heated propellant. Additionally, the sculpted nozzle geometry achieves plasma confinement facilitated by the formation of a plasma sheath at the nozzle throat, and fast recombination ensures a neutral exhaust plume that avoids the contamination of solar panels and interference with externally mounted instruments.

Coagulation of dust particles in a plasma

NASA Technical Reports Server (NTRS)

Horanyi, M.; Goertz, C. K.

1990-01-01

The electrostatic charge of small dust grains in a plasma in which the temperature varies in time is discussed, pointing out that secondary electron emission might introduce charge separation. If the sign of the charge on small grains is opposite to that on big ones, enhanced coagulation can occur which will affect the size distribution of grains in a plasma. Two scenarios where this process might be relevant are considered: a hot plasma environment with temperature fluctuations and a cold plasma environment with transient heating events. The importance of the enhanced coagulation is uncertain, because the plasma parameters in grain-producing environments such as a molecular cloud or a protoplanetary disk are not known. It is possible, however, that this process is the most efficient mechanism for the growth of grains in the size range of 0.1-500 microns.

Active Space Debris Charging for Contactless Electrostatic Disposal Maneuvers

NASA Astrophysics Data System (ADS)

Schaub, H.; Sternovsky, Z.

2013-08-01

We assess the feasibility of removing large space debris from geosynchronous orbit (GEO) by means of a tug spacecraft that uses electrostatic forces to pull the debris without touching. The advantage of this method is that it can operate with a separation distance of multiple craft radii, thus reducing the risk of collision. Further, the debris does not have to be detumbled first to engage the re-orbit maneuver. The charging of the tug-debris system to high potentials is achieved by active charge transfer using a directed electron beam and an auxiliary ion bleeder. Our simple charging model takes into account the primary electron beam current, UV induced photoelectron emission, collection of plasma particles, secondary electron emission and the recapture of emitted particles. The results show that by active charging high potentials can be both achieved and maintained. The resulting mN level electrostatic force is sufficient for the safe re-orbiting of debris objects over an acceptable period of a few months. The capability of debris removal is becoming a pressing need as the increasing population of dysfunctional satellites poses a threat to the future of satellite operations at GEO.

Separator Qualification for Aerospace Nickel-cadmium Cells

NASA Technical Reports Server (NTRS)

Milden, M. J.

1984-01-01

The development plans for a new separator for nickel cadmium (NiCd) cells is described. Research includes acceptance testing, operation in a charge/discharge characterization matrix, and life testing in low earth orbit (LEO) and geosynchronous (GEO) orbit under real time and accelerated conditions.

Electrochemistry and Storage Panel Report

NASA Technical Reports Server (NTRS)

Stedman, J. K.; Halpert, G.

1984-01-01

Design and performance requirements for electrochemical power storage systems are discussed and some of the approaches towards satisfying these constraints are described. Geosynchronous and low Earth orbit applications, radar type load constraints, and high voltage systems requirements are addressed. In addition, flywheel energy storage is discussed.

A Dynamic Coupled Magnetosphere-Ionosphere-Ring Current Model

NASA Astrophysics Data System (ADS)

Pembroke, Asher

In this thesis we describe a coupled model of Earth's magnetosphere that consists of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamics (MHD) simulation, the MIX ionosphere solver and the Rice Convection Model (RCM). We report some results of the coupled model using idealized inputs and model parameters. The algorithmic and physical components of the model are described, including the transfer of magnetic field information and plasma boundary conditions to the RCM and the return of ring current plasma properties to the LFM. Crucial aspects of the coupling include the restriction of RCM to regions where field-line averaged plasma-beta ¡=1, the use of a plasmasphere model, and the MIX ionosphere model. Compared to stand-alone MHD, the coupled model produces a substantial increase in ring current pressure and reduction of the magnetic field near the Earth. In the ionosphere, stronger region-1 and region-2 Birkeland currents are seen in the coupled model but with no significant change in the cross polar cap potential drop, while the region-2 currents shielded the low-latitude convection potential. In addition, oscillations in the magnetic field are produced at geosynchronous orbit with the coupled code. The diagnostics of entropy and mass content indicate that these oscillations are associated with low-entropy flow channels moving in from the tail and may be related to bursty bulk flows and bubbles seen in observations. As with most complex numerical models, there is the ongoing challenge of untangling numerical artifacts and physics, and we find that while there is still much room for improvement, the results presented here are encouraging. Finally, we introduce several new methods for magnetospheric visualization and analysis, including a fluid-spatial volume for RCM and a field-aligned analysis mesh for the LFM. The latter allows us to construct novel visualizations of flux tubes, drift surfaces, topological boundaries, and bursty-bulk flows.

The relationship between diffuse auroral and plasma sheet electron distributions near local midnight

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumaker, T.L.; Gussenhoven, M.S.; Hardy, D.A.

1989-08-01

A study of the relationship between diffuse auroral and plasma sheet electron distributions in the energy range from 50 eV to 20 keV in the midnight region was conducted using data from the P78-1 and SCATHA satellites. From 1 1/2 years of data, 14 events were found where the polar-orbiting P78-1 satellite and the near-geosynchronous SCATHA satellite were approximately on the same magnetic field line simultaneously, with SCATHA in the plasma sheet and P78-1 in the diffuse auroral region. For all cases the spectra from the two satellites are in good quantitative agreement. For 13 of the 14 events themore » pitch angle distribution measured at P78-1 was isotropic for angles mapping into the loss cone at the SCATHA orbit. For one event the P78-1 electron flux decreased with pitch angle toward the field line direction. At SCATHA the distributions outside the loss cone were most commonly butterfly or pancake, although distributions peaked toward the field line were sometimes observed at energies below 1 keV. Electron distributions, as measured where there is isotropy within the loss cone but anisotropy outside the loss cone, are inconsistent with current theories for the scattering of cone for the distribution measured at SCATHA, the electron precipitation lifetimes were calculated for the 14 events. Because the distributions are anisotropic at pitch angles away from the loss cone, the calculated lifetimes significantly exceed the lifetimes in the limit when the flu is isotropic at all pitch angles. The computed precipitation lifetimes are found to be weakly dependent on magnetic activity. The average lifetimes exceed those for the case of isotropy at all pitch angles by a factor between 2 and 3 for {ital Kp}{le}2 and approximately 1.5 for {ital Kp}{gt}2. {copyright} American Geophysical Union 1989« less

Optical Analysis of Transparent Polymeric Material Exposed to Simulated Space Environment

NASA Technical Reports Server (NTRS)

Edwards, David L.; Finckenor, Miria M.

1999-01-01

Transparent polymeric materials are being designed and utilized as solar concentrating lenses for spacecraft power and propulsion systems. These polymeric lenses concentrate solar energy onto energy conversion devices such as solar cells and thermal energy systems. The conversion efficiency is directly related to the transmissivity of the polymeric lens. The Environmental Effects Group of the Marshall Space Flight Center's Materials, Processes, and Manufacturing Department exposed a variety of materials to a simulated space environment and evaluated them for an, change in optical transmission. These materials include Lexan(TM), polyethylene terephthalate (PET). several formulations of Tefzel(TM). and Teflon(TM), and silicone DC 93-500. Samples were exposed to a minimum of 1000 Equivalent Sun Hours (ESH) of near-UV radiation (250 - 400 nm wavelength). Data will be presented on materials exposed to charged particle radiation equivalent to a five-year dose in geosynchronous orbit. These exposures were performed in MSFC's Combined Environmental Effects Test Chamber, a unique facility with the capability to expose materials simultaneously or sequentially to protons, low-energy electrons, high-energy electrons, near UV radiation and vacuum UV radiation.Prolonged exposure to the space environment will decrease the polymer film's transmission and thus reduce the conversion efficiency. A method was developed to normalize the transmission loss and thus rank the materials according to their tolerance to space environmental exposure. Spectral results and the material ranking according to transmission loss are presented.

LEMUR: Large European Module for Solar Ultraviolet Research

NASA Technical Reports Server (NTRS)

Teriaca, Luca; Vincenzo, Andretta; Auchere, Frederic; Brown, Charles M.; Buchlin, Eric; Cauzzi, Gianna; Culhane, J. Len; Curdt, Werner; Davila, Joseph M.; Del Zanna, Giulio;

The Plasma Environment at Enceladus and Europa Compared

NASA Astrophysics Data System (ADS)

Rymer, Abigail; Persoon, Ann; Morooka, Michiko; Heuer, Steven; Westlake, Joseph H.

2017-10-01

The plasma environment near Enceladus is complex, as revealed during 16 encounters of the Cassini spacecraft. The well documented Enceladus plumes create a dusty, asymmetric exosphere in which electrons can attach to small ice particles - forming anions, and negatively charged nanograins and dust - to the extent that cations can be the lightest charged particles present and, as a result, the dominant current carriers. Several instruments on the Cassini spacecraft are able to measure this environment in both expected and unexpected ways. Cassini Plasma Spectrometer (CAPS) is designed and calibrated to measure the thermal plasma ions and electrons and also measures the energy/charge of charged nanograins when present. Cassini Radio Plasma Wave Sensor (RPWS) measures electron density as derived from the ‘upper hybrid frequency’ which is a function of the total free electron density and magnetic field strength and provides a vital ground truth measurement for Cassini calibration when the density is sufficiently high for it to be well measured. Cassini Langmuir Probe (LP) measures the electron density and temperature via direct current measurement, and both CAPS and LP can provide estimates for the spacecraft potential which we compare. The plasma environment near Europa is similarly complex and, although not so comprehensively equipped and hampered by the non-deployment of its high gain antenna, the Galileo spacecraft made similar measurements during 9 Europa flybys and recent observations have suggested that, like Enceladus, Europa might have active plume activity. We present a detailed comparison of data from the Cassini and Galileo sensors in order to assess the plasma environment observed by the different instruments, discuss what is consistent and otherwise, and the implications for the plasma environment at Enceladus and Europa in the context of work to date as well as implications for future studies.

Binding of canonical Wnt ligands to their receptor complexes occurs in ordered plasma membrane environments.

PubMed

Sezgin, Erdinc; Azbazdar, Yagmur; Ng, Xue W; Teh, Cathleen; Simons, Kai; Weidinger, Gilbert; Wohland, Thorsten; Eggeling, Christian; Ozhan, Gunes

2017-08-01

While the cytosolic events of Wnt/β-catenin signaling (canonical Wnt signaling) pathway have been widely studied, only little is known about the molecular mechanisms involved in Wnt binding to its receptors at the plasma membrane. Here, we reveal the influence of the immediate plasma membrane environment on the canonical Wnt-receptor interaction. While the receptors are distributed both in ordered and disordered environments, Wnt binding to its receptors selectively occurs in more ordered membrane environments which appear to cointernalize with the Wnt-receptor complex. Moreover, Wnt/β-catenin signaling is significantly reduced when the membrane order is disturbed by specific inhibitors of certain lipids that prefer to localize at the ordered environments. Similarly, a reduction in Wnt signaling activity is observed in Niemann-Pick Type C disease cells where trafficking of ordered membrane lipid components to the plasma membrane is genetically impaired. We thus conclude that ordered plasma membrane environments are essential for binding of canonical Wnts to their receptor complexes and downstream signaling activity. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

Helium-like magnesium embedded in strongly coupled plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Sukhamoy

2016-05-06

In recent days, with the advent of the x-ray free electron laser (FEL) with Linac coherent light source (LCLS) and the Orion laser, experimental studies on atomic systems within strongly coupled plasma environment with remarkable improvement in accuracy as compared to earlier experiments have become possible. In these kinds of experiments, hydrogen-like and helium-like spectral lines are used for determination of plasma parameters such as temperature, density. Accurate theoretical calculations are, therefore, necessary for such kind of studies within a dense plasma environment. In this work, ab initio calculations are carried out in the framework of the Rayleigh-Ritz variation principlemore » to estimate the ground state energy of helium-like magnesium within strongly coupled plasma environment. Explicitly correlated wave functions in Hylleraas coordinates have been used to incorporate the effect of electron correlation. The ion-sphere model potential that confines the central positive ion in a finite domain filled with plasma electrons has been adopted to mimic the strongly coupled plasma environment. Thermodynamic pressure ’felt’ by the ion in the ground states due to the confinement inside the ion spheres is also estimated.« less

Radiation and Internal Charging Environments for Thin Dielectrics in Interplanetary Space

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Parker, Linda Neergaard; Altstatt, Richard L.

2004-01-01

Spacecraft designs using solar sails for propulsion or thin membranes to shade instruments from the sun to achieve cryogenic operating temperatures are being considered for a number of missions in the next decades. A common feature of these designs are thin dielectric materials that will be exposed to the solar wind, solar energetic particle events, and the distant magnetotail plasma environments encountered by spacecraft in orbit about the Earth-Sun L2 point. This paper will discuss the relevant radiation and internal charging environments developed to support spacecraft design for both total dose radiation effects as well as dose rate dependent phenomenon, such as internal charging in the solar wind and distant magnetotail environments. We will describe the development of radiation and internal charging environment models based on nearly a complete solar cycle of Ulysses solar wind plasma measurements over a complete range of heliocentric latitudes and the early years of the Geotail mission where distant magnetotail plasma environments were sampled beyond X(sub GSE) = -100 Re to nearly L2 (X(sub GSE) -236 Re). Example applications of the environment models are shown to demonstrate the radiation and internal charging environments of thin materials exposed to the interplanetary space plasma environments.

Specification of ISS Plasma Environment Variability

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Neergaard, Linda F.; Bui, Them H.; Mikatarian, Ronald R.; Barsamian, H.; Koontz, Steven L.

2004-01-01

Quantifying spacecraft charging risks and associated hazards for the International Space Station (ISS) requires a plasma environment specification for the natural variability of ionospheric temperature (Te) and density (Ne). Empirical ionospheric specification and forecast models such as the International Reference Ionosphere (IRI) model typically only provide long term (seasonal) mean Te and Ne values for the low Earth orbit environment. This paper describes a statistical analysis of historical ionospheric low Earth orbit plasma measurements from the AE-C, AE-D, and DE-2 satellites used to derive a model of deviations of observed data values from IRI-2001 estimates of Ne, Te parameters for each data point to provide a statistical basis for modeling the deviations of the plasma environment from the IRI model output. Application of the deviation model with the IRI-2001 output yields a method for estimating extreme environments for the ISS spacecraft charging analysis.

Influence of plasma shock wave on the morphology of laser drilling in different environments

NASA Astrophysics Data System (ADS)

Zhai, Zhaoyang; Wang, Wenjun; Mei, Xuesong; Wang, Kedian; Yang, Huizhu

2017-05-01

Nanosecond pulse laser was used to study nickel-based alloy drilling and compare processing results of microholes in air environment and water environment. Through analysis and comparison, it's found that environmental medium had obvious influence on morphology of laser drilling. High-speed camera was used to shoot plasma morphology during laser drilling process, theoretical formula was used to calculate boundary dimension of plasma and shock wave velocity, and finally parameters were substituted into computational fluid dynamics simulation software to obtain solutions. Obtained analysis results could intuitively explain different morphological features and forming reasons between laser drilling in air environment and water environment in the experiment from angle of plasma shock waves. By comparing simulation results and experimental results, it could help to get an understanding of formation mechanism of microhole morphology, thus providing basis for further improving process optimization of laser drilling quality.

Observations and analysis of Alfvén wave phase mixing in the Earth's magnetosphere

NASA Astrophysics Data System (ADS)

Sarris, T. E.; Wright, A. N.; Li, X.

2009-03-01

Signatures of Alfvén wave phase mixing in the Earth's magnetosphere, observed as polarization rotation of a transverse, Pc5 magnetospheric pulsation, are presented and compared to theory. The polarization rotation occurred during a rare event of a dayside narrowband ULF magnetospheric pulsation that lasted for 5 consecutive days, from 24 to 30 November 1997; details of this event were reported by Sarris et al. (2009) through observations at geosynchronous orbit and on the ground. In this paper we investigate the polarization signatures of the pulsation by performing a detailed analysis of its transverse components as observed through hodogram plots. Density measurements from one of the Los Alamos National Laboratory (LANL) spacecraft which had its L shells closest to GOES-8 are used to calculate field line resonance frequencies at geosynchronous orbit; these frequency calculations show good agreement with the observed pulsations but also have a local time offset. For an instance of an observed polarization rotation we estimate the observed poloidal lifetime of the pulsation by the time taken for the poloidal and toroidal amplitudes to become equal, which we compare with the theoretical approximation to the poloidal lifetime, as calculated in a box model magnetosphere by Mann and Wright (1995). Density measurements from different LANL spacecraft at geosynchronous orbit and their varying L shells as derived from their varying local times are used to estimate a local gradient in the local Alfvén speed, which is then used in the calculation of the predicted poloidal lifetime. This is the first time that such polarization rotations are directly observed and compared with theoretical predictions.

Effects of ULF waves on local and global energetic particles: Particle energy and species dependences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, L. Y.; Yu, J.; Cao, J. B.

After 06:13 UT on 24 August 2005, an interplanetary shock triggers large-amplitude ultralow-frequency (ULF) waves (|δB| ≥ 15 nT) in the Pc4–Pc5 wave band (1.6–9 mHz) near the noon geosynchronous orbit (6.6 RE). The local and global effects of ULF waves on energetic particles are observed by five Los Alamos National Laboratory satellites at different magnetic local times. The large-amplitude ULF waves cause the synchronous oscillations of energetic electrons and protons (≥75 keV) at the noon geosynchronous orbit. When the energetic particles have a negative phase space density radial gradient, they undergo rapid outward radial diffusion and loss in themore » wave activity region. In the particle drift paths without strong ULF waves, only the rapidly drifting energetic electrons (≥225 keV) display energy-dispersive oscillations and flux decays, whereas the slowly drifting electrons (<225 keV) and protons (75–400 keV) have no ULF oscillation and loss feature. When the dayside magnetopause is compressed to the geosynchronous orbit, most of energetic electrons and protons are rapidly lost because of open drift trajectories. Furthermore, the global and multicomposition particle measurements demonstrate that the effect of ULF waves on nonlocal particle flux depends on the particle energy and species, whereas magnetopause shadowing effect is independent of the energetic particle species. For the rapidly drifting outer radiation belt particles (≥225 keV), nonlocal particle loss/acceleration processes could also change their fluxes in the entire drift trajectory in the absence of “ Dst effect” and substorm injection.« less

Effects of ULF waves on local and global energetic particles: Particle energy and species dependences

DOE PAGES

Li, L. Y.; Yu, J.; Cao, J. B.; ...

2016-11-05

After 06:13 UT on 24 August 2005, an interplanetary shock triggers large-amplitude ultralow-frequency (ULF) waves (|δB| ≥ 15 nT) in the Pc4–Pc5 wave band (1.6–9 mHz) near the noon geosynchronous orbit (6.6 RE). The local and global effects of ULF waves on energetic particles are observed by five Los Alamos National Laboratory satellites at different magnetic local times. The large-amplitude ULF waves cause the synchronous oscillations of energetic electrons and protons (≥75 keV) at the noon geosynchronous orbit. When the energetic particles have a negative phase space density radial gradient, they undergo rapid outward radial diffusion and loss in themore » wave activity region. In the particle drift paths without strong ULF waves, only the rapidly drifting energetic electrons (≥225 keV) display energy-dispersive oscillations and flux decays, whereas the slowly drifting electrons (<225 keV) and protons (75–400 keV) have no ULF oscillation and loss feature. When the dayside magnetopause is compressed to the geosynchronous orbit, most of energetic electrons and protons are rapidly lost because of open drift trajectories. Furthermore, the global and multicomposition particle measurements demonstrate that the effect of ULF waves on nonlocal particle flux depends on the particle energy and species, whereas magnetopause shadowing effect is independent of the energetic particle species. For the rapidly drifting outer radiation belt particles (≥225 keV), nonlocal particle loss/acceleration processes could also change their fluxes in the entire drift trajectory in the absence of “ Dst effect” and substorm injection.« less

Radial diffusion comparing a THEMIS statistical model with geosynchronous measurements as the outer boundary

NASA Astrophysics Data System (ADS)

Li, Z.; Hudson, M. K.; Chen, Y.

2013-12-01

The outer boundary energetic electron flux is used as a driver in radial diffusion calculations, and its precise determination is critical to the solution. A new model was proposed recently based on THEMIS measurements to express the boundary flux as three fit functions of solar wind parameters in a response window, that depend on energy and which solar parameter is used: speed, density, or both (Shin and Lee, 2013). The Dartmouth radial diffusion model has been run using LANL geosynchronous satellite measurements as the outer boundary for a one-month interval in July to August 2004 and the calculated phase space density (PSD) is compared with GPS measurements at the GPS orbit (L=4.16), at magnetic equatorial plane crossings, as a test of the model. We also used the outer boundary generated from the Shin and Lee model and examined this boundary condition by computing the error relative to the simulation using a LANL geosynchronous spacecraft data-driven outer boundary. The calculation shows that there is overestimation and underestimation at different times, however the new boundary condition can be used to drive the radial diffusion model generally, producing the phase space density increase and dropout during a storm with a relatively small error. Having this new method based on a solar wind parametrized data set, we can run the radial diffusion model for storms when particle measurements are not available at the outer boundary. We chose the Whole Heliosphere Interval (WHI) as an example and compared the result with MHD/test-particle simulations (Hudson et al., 2012), obtaining much better agreement with PSD based on GPS measurements at L=4.16 using the diffusion model, which incorporates atmospheric losses.

Flight Plasma Diagnostics for High-Power, Solar-Electric Deep-Space Spacecraft

NASA Technical Reports Server (NTRS)

Johnson, Lee; De Soria-Santacruz Pich, Maria; Conroy, David; Lobbia, Robert; Huang, Wensheng; Choi, Maria; Sekerak, Michael J.

2018-01-01

NASA's Asteroid Redirect Robotic Mission (ARRM) project plans included a set of plasma and space environment instruments, the Plasma Diagnostic Package (PDP), to fulfill ARRM requirements for technology extensibility to future missions. The PDP objectives were divided into the classes of 1) Plasma thruster dynamics, 2) Solar array-specific environmental effects, 3) Plasma environmental spacecraft effects, and 4) Energetic particle spacecraft environment. A reference design approach and interface requirements for ARRM's PDP was generated by the PDP team at JPL and GRC. The reference design consisted of redundant single-string avionics located on the ARRM spacecraft bus as well as solar array, driving and processing signals from multiple copies of several types of plasma, effects, and environments sensors distributed over the spacecraft and array. The reference design sensor types were derived in part from sensors previously developed for USAF Research Laboratory (AFRL) plasma effects campaigns such as those aboard TacSat-2 in 2007 and AEHF-2 in 2012.

Li-Ion Battery Studies at NASA/Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Lee, Leonine; Rao, Gopalakrishna M.

2006-01-01

This viewgraph presentation reviews NASA and GSFC's interest in Lithium Ion Batteries as power suupplies for space usage, the tests, and results on several commercially available batteries. Severl batteries were tested for Geosynchronous orbit, Low Earth Orbit, and Low Lunar Orbit conditions.

Remote Sensing as a Demonstration of Applied Physics.

ERIC Educational Resources Information Center

Colwell, Robert N.

1980-01-01

Provides information about the field of remote sensing, including discussions of geo-synchronous and sun-synchronous remote-sensing platforms, the actual physical processes and equipment involved in sensing, the analysis of images by humans and machines, and inexpensive, small scale methods, including aerial photography. (CS)

Early Program Development

NASA Image and Video Library

1971-01-01

This 1971 artist's concept shows the Nuclear Shuttle in both its lunar logistics configuraton and geosynchronous station configuration. As envisioned by Marshall Space Flight Center Program Development persornel, the Nuclear Shuttle would deliver payloads to lunar orbits or other destinations then return to Earth orbit for refueling and additional missions.

Geosynchronous platform definition study. Volume 4, Part 2: Traffic analysis and system requirements for the new traffic model

NASA Technical Reports Server (NTRS)

1973-01-01

A condensed summary of the traffic analyses and systems requirements for the new traffic model is presented. The results of each study activity are explained, key analyses are described, and important results are highlighted.

Convective and stratiform components of a Winter Monsoon Cloud Cluster determined from geosynchronous infrared satellite data

NASA Technical Reports Server (NTRS)

Goldenberg, Stanley B.; Houze, Robert A., Jr.; Churchill, Dean D.

1990-01-01

The horizontal precipitation structure of cloud clusters observed over the South China Sea during the Winter Monsoon Experiment (WMONEX) is analyzed using a convective-stratiform technique (CST) developed by Adler and Negri (1988). The technique was modified by altering the method for identifying convective cells in the satellite data, accounting for the extremely cold cloud tops characteristic of the WMONEX region, and modifying the threshold infrared temperature for the boundary of the stratiform rain area. The precipitation analysis was extended to the entire history of the cloud cluster by applying the modified CST to IR imagery from geosynchronous-satellite observations. The ship and aircraft data from the later period of the cluster's lifetime make it possible to check the locations of convective and stratiform precipitation identified by the CST using in situ observations. The extended CST is considered to be effective for determining the climatology of the convective-stratiform structure of tropical cloud clusters.

Trends in mobile satellite communication

NASA Technical Reports Server (NTRS)

Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

1993-01-01

Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

Mass comparisons of electric propulsion systems for NSSK of geosynchronous spacecraft. [North-South Station Keeping

NASA Technical Reports Server (NTRS)

Rawlin, V. K.; Majcher, G. A.

1991-01-01

A model was developed and exercised to allow wet mass comparisons of three-axis stabilized communications satellites delivered to geosynchronous transfer orbit. The mass benefits of using advanced chemical propulsion for apogee injection and north-south stationkeeping (NSSK) functions or electric propulsion (hydrazine arcjets and xenon ion thrusters) for NSSK functions are documented. A large derated ion thruster is proposed which minimizes thruster lifetime concerns and qualification test times when compared to those of smaller ion thrusters planned for NSSK applications. The mass benefits, which depend on the spacecraft mass and mission duration, increase dramatically with arcjet specific impulse in the 500-600 s range, but are nearly constant for the derated ion thruster operated in the 2300-3000 s range. For a given mission, the mass benefits with an ion system are typically double those of the arcjet system; however, the total thrusting time with arcjets is less than one-third that with ion thrusters for the same thruster power.

Forecasting the impact of an 1859-caliber superstorm on geosynchronous Earth-orbiting satellites: Transponder resources

NASA Astrophysics Data System (ADS)

Odenwald, Sten F.; Green, James L.

2007-06-01

We calculate the economic impact on the existing geosynchronous Earth-orbiting satellite population of an 1859-caliber superstorm event were it to occur between 2008 and 2018 during the next solar activity cycle. From a detailed model for transponder capacity and leasing, we have investigated the total revenue loss over the entire solar cycle, as a function of superstorm onset year and intensity. Our Monte Carlo simulations of 1000 possible superstorms, of varying intensity and onset year, suggest that the minimum revenue loss could be of the order of 30 billion. The losses would be larger than this if more that 20 satellites are disabled, if future launch rates do not keep up with the expected rate of retirements, or if the number of spare transponders falls below ˜30%. Consequently, revenue losses can be significantly reduced below 30 billion if the current satellite population undergoes net growth beyond 300 units during Solar Cycle 24 and a larger margin of unused transponders is maintained.

The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present)

NASA Technical Reports Server (NTRS)

Adler, Robert F.; Huffman, George J.; Chang, Alfred; Ferraro, Ralph; Xie, Ping-Ping; Janowiak, John; Rudolf, Bruno; Schneider, Udo; Curtis, Scott; Bolvin, David

2003-01-01

The Global Precipitation Climatology Project (GPCP) Version 2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.5 degrees x 2.5 degrees latitude-longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The data set is extended back into the premicrowave era (before 1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the raingauge analysis. This monthly analysis is the foundation for the GPCP suite of products including those at finer temporal resolution, satellite estimate, and error estimates for each field. The 23-year GPCP climatology is characterized, along with time and space variations of precipitation.

Optical space-to-ground link availability assessment and diversity requirements

NASA Technical Reports Server (NTRS)

Chapman, William; Fitzmaurice, Michael

1991-01-01

The application of optical space-to-ground links (SGLs) for high speed data distribution from geosynchronous and low earth orbiting satellites (e.g., sensor data from the planned Earth Observing System), for lunar and Mars links, and for links from interplanetary probes has been a topic of considerable recent interest. These optical SGLs could conceivably represent the system's operational baseline, or could represent backup links in the event of a GEO relay terminal failure. In this paper the availability of optical SGLs for various system/orbit configurations is considered. Single CONUS sites are assessed for their probability of cloud free line of sight (PCFLOS), and cloud free field of view (PCFFOV). PCFLOS represents an availability metric for geosynchronous platforms, while PCFFOV is a relevant performance metric for non-geostationary platforms (e.g., low earth orbiting satellites). Additionally, the availability of multiple ground terminals utilized in a diversity configuration is considered. Availability statistics vs. the number of diversity sites are derived from climatological data bases for CONUS sites.

Propulsion requirements for communications satellites.

NASA Technical Reports Server (NTRS)

Isley, W. C.; Duck, K. I.

1972-01-01

The concept of characteristics thrust is introduced herein as a means of classifying propulsion system tasks related particularly to geosynchronous communications spacecraft. Approximate analytical models are developed to permit estimation of characteristic thrust for injection error corrections, orbit angle re-location, north-south station keeping, east-west station keeping, spin axis precession control, attitude rate damping, and orbit raising applications. Performance assessment factors are then outlined in terms of characteristic power, characteristic weight, and characteristic volume envelope, which are related to the characteristic thrust. Finally, selected performance curves are shown for power as a function of spacecraft weight, including the influence of duty cycle on north-south station keeping, a 90 degree orbit angle re-location in 14 days, and finally comparison of orbit raising tasks from low and intermediate orbits to a final geosynchronous station. Power requirements range from less than 75 watts for north-south station keeping on small payloads up to greater than 15 KW for a 180 day orbit raising mission including a 28.5 degree plane change.

Radiation Belt and Plasma Model Requirements

NASA Technical Reports Server (NTRS)

Barth, Janet L.

2005-01-01

Contents include the following: Radiation belt and plasma model environment. Environment hazards for systems and humans. Need for new models. How models are used. Model requirements. How can space weather community help?

Four-fluid MHD Simulations of the Plasma and Neutral Gas Environment of Comet 67P/Churyumov-Gerasimenko Near Perihelion

NASA Astrophysics Data System (ADS)

Huang, Zhenguang; Toth, Gabor; Gombosi, Tamas; Jia, Xianzhe; Rubin, Martin; Fougere, Nicolas; Tenishev, Valeriy; Combi, Michael; Bieler, Andre; Hansen, Kenneth; Shou, Yinsi; Altwegg, Kathrin

2016-04-01

The neutral and plasma environment is critical in understanding the interaction of the solar wind and comet 67P/Churyumov-Gerasimenko (CG), the target of the European Space Agency's Rosetta mission. In this study, we have developed a 3-D four-fluid model, which is based on BATS-R-US (Block-Adaptive Tree Solarwind Roe-type Upwind Scheme) within SWMF (Space Weather Modeling Framework) that solves the governing multi-fluid MHD equations and the Euler equations for the neutral gas fluid. These equations describe the behavior and interactions of the cometary heavy ions, the solar wind protons, the electrons, and the neutrals. We simulated the plasma and neutral gas environment of comet CG with SHAP5 model near perihelion and we showed that the plasma environment in the inner coma region have some new features: magnetic reconnection in the tail region, a magnetic pile-up region on the nightside, and nucleus directed plasma flow inside the nightside reconnection region.

Assessment of Capabilities for First-Principles Simulation of Spacecraft Electric Propulsion Systems and Plasma Spacecraft Environment

DTIC Science & Technology

2016-04-29

Simulation of Spacecraft Electric Propulsion Systems and Plasma Spacecraft Environment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...Assessment of Capabilities for First‐ Principles Simulation of Spacecraft Electric  Propulsion   Systems and Plasma Spacecraft Environment” Team leader(s

Plasma in a Pulsed Discharge Environment

NASA Technical Reports Server (NTRS)

Remy, J.; Bienier, L.; Salama, F.

2005-01-01

The plasma generated in a pulsed slit discharge nozzle is used to form molecular ions in an astrophysically relevant environment. The plasma has been characterized as a glow discharge in the abnormal regime. Laboratory studies help understand the formation processes of polycyclic aromatic hydrocarbon (PAH) ions that are thought to be the source of the ubiquitous unidentified infrared bands.

Development of a Double Hemispherical Probe for Improved Space Plasma Measurements

NASA Astrophysics Data System (ADS)

Wang, X.; Samaniego, J. I.; Hsu, H.-W.; Horányi, M.; Wahlund, J.-E.; Ergun, R. E.; Bering, E. A.

2018-04-01

Langmuir probes have been widely used for space plasma measurements for decades. However, there are still challenges in the interpretation of their measurements. Due to the interaction of the ambient plasma with a spacecraft and an onboard probe itself, the local plasma conditions around the probe could be very different from the true ambient plasma of interest. These local plasma conditions are often anisotropic and/or inhomogeneous. Most of the Langmuir probes that are made of a single electrode have difficulties to remove these local plasma effects, introducing errors in the derived plasma characteristics. Directional probes are able to characterize anisotropic and inhomogeneous plasmas. The split Langmuir probe and the Segmented Langmuir Probe have been developed to characterize the plasma flow in the Earth's ionosphere. Here we introduce a new type of a directional Langmuir probe, the Double Hemispherical Probe (DHP), to improve the space plasma measurements in a broad range of scenarios: (a) low-density plasmas, (b) high surface-emission (photo and/or secondary electron emission) environments, (c) flowing plasmas, and (d) dust-rich plasma environments. The DHP consists of two identical hemispheres that are electrically insulated and swept with the same voltages simultaneously. The difference currents between the two hemispheres are used to characterize the anisotropic/inhomogeneous plasma conditions created around the probe, which will be then removed or minimized on the interpretation of their current-voltage curves. This paper describes the basic concept and design of the DHP sensor, as well as its initial results tested in the laboratory plasma environments.

Nuclear Shuttle Logistics Configuration

NASA Technical Reports Server (NTRS)

1971-01-01

This 1971 artist's concept shows the Nuclear Shuttle in both its lunar logistics configuraton and geosynchronous station configuration. As envisioned by Marshall Space Flight Center Program Development persornel, the Nuclear Shuttle would deliver payloads to lunar orbits or other destinations then return to Earth orbit for refueling and additional missions.

Laboratory Investigation of Space and Planetary Dust Grains

NASA Technical Reports Server (NTRS)

Spann, James

2005-01-01

Dust in space is ubiquitous and impacts diverse observed phenomena in various ways. Understanding the dominant mechanisms that control dust grain properties and its impact on surrounding environments is basic to improving our understanding observed processes at work in space. There is a substantial body of work on the theory and modeling of dust in space and dusty plasmas. To substantiate and validate theory and models, laboratory investigations and space borne observations have been conducted. Laboratory investigations are largely confined to an assembly of dust grains immersed in a plasma environment. Frequently the behaviors of these complex dusty plasmas in the laboratory have raised more questions than verified theories. Space borne observations have helped us characterize planetary environments. The complex behavior of dust grains in space indicates the need to understand the microphysics of individual grains immersed in a plasma or space environment.

Orbital debris and near-Earth environmental management: A chronology

NASA Technical Reports Server (NTRS)

Portree, David S. F.; Loftus, Joseph P., Jr.

1993-01-01

This chronology covers the 32-year history of orbital debris and near-Earth environmental concerns. It tracks near-Earth environmental hazard creation, research, observation, experimentation, management, mitigation, protection, and policy-making, with emphasis on the orbital debris problem. Included are the Project West Ford experiments; Soviet ASAT tests and U.S. Delta upper stage explosions; the Ariane V16 explosion, U.N. treaties pertinent to near-Earth environmental problems, the PARCS tests; space nuclear power issues, the SPS/orbital debris link; Space Shuttle and space station orbital debris issues; the Solwind ASAT test; milestones in theory and modeling the Cosmos 954, Salyut 7, and Skylab reentries; the orbital debris/meteoroid research link; detection system development; orbital debris shielding development; popular culture and orbital debris; Solar Max results; LDEF results; orbital debris issues peculiar to geosynchronous orbit, including reboost policies and the stable plane; seminal papers, reports, and studies; the increasing effects of space activities on astronomy; and growing international awareness of the near-Earth environment.

Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

NASA Astrophysics Data System (ADS)

TayyebTaher, M.; Esmaeilzadeh, S. Majid

2017-07-01

This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

Radiation and temperature effects on the time-dependent response of T300/934 graphite/epoxy

NASA Technical Reports Server (NTRS)

Yancey, Robert N.; Pindera, Marek-Jerzy

1988-01-01

A time-dependent characterization study was performed on T300/934 graphite/epoxy in a simulated space environment. Creep tests on irradiated and nonirradiated graphite/epoxy and bulk resin specimens were carried out at temperatures of 72 and 250 F. Irradiated specimens were exposed to dosages of penetrating electron radiation equal to 30 years exposure at GEO-synchronous orbit. Radiation was shown to have little effect on the creep response of both the composite and bulk resin specimens at 72 F while radiation had a significant effect at 250 F. A healing process was shown to be present in the irradiated specimens where broken bonds in the epoxy due to radiation recombined over time to form cross-links in the 934 resin structure. An analytical micromechanical model was also developed to predict the viscoelastic response of fiber reinforced composite materials. The model was shown to correlate well with experimental results for linearly viscoelastic materials with relatively small creep strains.

Characterization of Space Environmental Effects on Candidate Solar Sail Material

NASA Technical Reports Server (NTRS)

Edwards, David; Hubbs, Whitney; Stanaland, Tesia; Altstatt, Richard

2002-01-01

The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) is concentrating research into the utilization of photonic materials for spacecraft propulsion. Spacecraft propulsion, using photonic materials, will be achieved using a solar sail. A sail operates on the principle that photons, originating from the sun, impart pressure and provide a source of spacecraft propulsion. The pressure can be increased, by a factor of two if the sun-facing surface is perfectly reflective. Solar sails are generally composed of a highly reflective metallic front layer, a thin polymeric substrate, and occasionally a highly emissive back surface. The Space Environmental Effects Team at MSFC is actively characterizing candidate solar sail materials to evaluate the thermo-optical and mechanical properties after exposure to a simulated Geosynchronous Transfer Orbit (GTO) radiation environment. The technique of radiation dose verses material depth profiling was used to determine the orbital equivalent exposure doses. The solar sail exposure procedures and results of the material characterization will be discussed.

Toward large space systems. [Space Construction Base development from shuttles

NASA Technical Reports Server (NTRS)

Daros, C. J.; Freitag, R. F.; Kline, R. L.

1977-01-01

The design of the Space Transportation System, consisting of the Space Shuttle, Spacelab, and upper stages, provides experience for the development of more advanced space systems. The next stage will involve space stations in low earth orbit with limited self-sufficiency, characterized by closed ecological environments, space-generated power, and perhaps the first use of space materials. The third phase would include manned geosynchronous space-station activity and a return to lunar operations. Easier access to space will encourage the use of more complex, maintenance-requiring satellites than those currently used. More advanced space systems could perform a wide range of public services such as electronic mail, personal and police communication, disaster control, earthquake detection/prediction, water availability indication, vehicle speed control, and burglar alarm/intrusion detection. Certain products, including integrated-circuit chips and some enzymes, can be processed to a higher degree of purity in space and might eventually be manufactured there. Hardware including dishes, booms, and planar surfaces necessary for advanced space systems and their development are discussed.

Partially Ionized Plasmas in Astrophysics

NASA Astrophysics Data System (ADS)

Ballester, José Luis; Alexeev, Igor; Collados, Manuel; Downes, Turlough; Pfaff, Robert F.; Gilbert, Holly; Khodachenko, Maxim; Khomenko, Elena; Shaikhislamov, Ildar F.; Soler, Roberto; Vázquez-Semadeni, Enrique; Zaqarashvili, Teimuraz

2018-03-01

Partially ionized plasmas are found across the Universe in many different astrophysical environments. They constitute an essential ingredient of the solar atmosphere, molecular clouds, planetary ionospheres and protoplanetary disks, among other environments, and display a richness of physical effects which are not present in fully ionized plasmas. This review provides an overview of the physics of partially ionized plasmas, including recent advances in different astrophysical areas in which partial ionization plays a fundamental role. We outline outstanding observational and theoretical questions and discuss possible directions for future progress.

ISS Local Environment Spectrometers (ISLES)

NASA Technical Reports Server (NTRS)

Krause, Linda Habash; Gilchrist, Brian E.

2014-01-01

In order to study the complex interactions between the space environment surrounding the ISS and the ISS surface materials, we propose to use lowcost, high-TRL plasma sensors on the ISS robotic arm to probe the ISS space environment. During many years of ISS operation, we have been able to condut effective (but not perfect) extravehicular activities (both human and robotic) within the perturbed local ISS space environment. Because of the complexity of the interaction between the ISS and the LEO space environment, there remain important questions, such as differential charging at solar panel junctions (the so-called "triple point" between conductor, dielectric, and space plasma), increased chemical contamination due to ISS surface charging and/or thruster activation, water dumps, etc, and "bootstrap" charging of insulating surfaces. Some compelling questions could synergistically draw upon a common sensor suite, which also leverages previous and current MSFC investments. Specific questions address ISS surface charging, plasma contactor plume expansion in a magnetized drifting plasma, and possible localized contamination effects across the ISS.

Radial diffusion with outer boundary determined by geosynchronous measurements: Storm and post-storm intervals

NASA Astrophysics Data System (ADS)

Chu, F.; Haines, P.; Hudson, M.; Kress, B.; Freidel, R.; Kanekal, S.

2007-12-01

Work is underway by several groups to quantify diffusive radial transport of radiation belt electrons, including a model for pitch angle scattering losses to the atmosphere. The radial diffusion model conserves the first and second adiabatic invariants and breaks the third invariant. We have developed a radial diffusion code which uses the Crank Nicholson method with a variable outer boundary condition. For the radial diffusion coefficient, DLL, we have several choices, including the Brautigam and Albert (JGR, 2000) diffusion coefficient parameterized by Kp, which provides an ad hoc measure of the power level at ULF wave frequencies in the range of electron drift (mHz), breaking the third invariant. Other diffusion coefficient models are Kp-independent, fixed in time but explicitly dependent on the first invariant, or energy at a fixed L, such as calculated by Elkington et al. (JGR, 2003) and Perry et al. (JGR, 2006) based on ULF wave model fields. We analyzed three periods of electron flux and phase space density (PSD) enhancements inside of geosynchronous orbit: March 31 - May 31, 1991, and July 2004 and Nov 2004 storm intervals. The radial diffusion calculation is initialized with a computed phase space density profile for the 1991 interval using differential flux values from the CRRES High Energy Electron Fluxmeter instrument, covering 0.65 - 7.5 MeV. To calculate the initial phase space density, we convert Roederer L* to McIlwain's L- parameter using the ONERA-DESP program. A time averaged model developed by Vampola1 from the entire 14 month CRRES data set is applied to the July 2004 and Nov 2004 storms. The online CRESS data for specific orbits and the Vampola-model flux are both expressed in McIlwain L-shell, while conversion to L* conserves phase space density in a distorted non-dipolar magnetic field model. A Tsyganenko (T04) magnetic field model is used for conversion between L* and L. The outer boundary PSD is updated using LANL GEO satellite fluxes. After calculating the phase space density time evolution for the two storms and post-injection interval (March 31 - May 31, 1991), we compare results with SAMPEX measurements. A better match with SAMPEX measurements is obtained with a variable outer boundary, also with a Kp-dependent diffusion coefficient, and finally with an energy and L-dependent loss term (Summers et al., JGR, 2004), than with a time-independent diffusion coefficient and a simple Kp-parametrized loss rate and location of the plasmapause. Addition of a varying outer boundary which incorporates measured fluxes at geosynchronous orbit using L* has the biggest effect of the three parametrized variations studied. 1Vampola, A.L., 1996, The ESA Outer Zone Electron Model Update, Environment Modelling for Spaced-based Applications, ESA SP-392, ESTEC, Nordwijk, NL, pp. 151-158, W. Burke and T.-D. Guyenne, eds.

The Near-Earth Plasma Environment

NASA Technical Reports Server (NTRS)

Pfaff, Robert F., Jr.

2012-01-01

An overview of the plasma environment near the earth is provided. We describe how the near-earth plasma is formed, including photo-ionization from solar photons and impact ionization at high latitudes from energetic particles. We review the fundamental characteristics of the earth's plasma environment, with emphasis on the ionosphere and its interactions with the extended neutral atmosphere. Important processes that control ionospheric physics at low, middle, and high latitudes are discussed. The general dynamics and morphology of the ionized gas at mid- and low-latitudes are described including electrodynamic contributions from wind-driven dynamos, tides, and planetary-scale waves. The unique properties of the near-earth plasma and its associated currents at high latitudes are shown to depend on precipitating auroral charged particles and strong electric fields which map earthward from the magnetosphere. The upper atmosphere is shown to have profound effects on the transfer of energy and momentum between the high-latitude plasma and the neutral constituents. The article concludes with a discussion of how the near-earth plasma responds to magnetic storms associated with solar disturbances.

The Predicted Growth of the Low Earth Orbit Space Debris Environment: An Assessment of Future Risk for Spacecraft

NASA Technical Reports Server (NTRS)

Krisko, Paula H.

2007-01-01

Space debris is a worldwide-recognized issue concerning the safety of commercial, military, and exploration spacecraft. The space debris environment includes both naturally occuring meteoroids and objects in Earth orbit that are generated by human activity, termed orbital debris. Space agencies around the world are addressing the dangers of debris collisions to both crewed and robotic spacecraft. In the United States, the Orbital Debris Program Office at the NASA Johnson Space Center leads the effort to categorize debris, predict its growth, and formulate mitigation policy for the environment from low Earth orbit (LEO) through geosynchronous orbit (GEO). This paper presents recent results derived from the NASA long-term debris environment model, LEGEND. It includes the revised NASA sodium potassium droplet model, newly corrected for a factor of two over-estimation of the droplet population. The study indicates a LEO environment that is already highly collisionally active among orbital debris larger than 1 cm in size. Most of the modeled collision events are non-catastrophic (i.e., They lead to a cratering of the target, but no large scale fragmentation.). But they are potentially mission-ending, and take place between impactors smaller than 10 cm and targets larger than 10 cm. Given the small size of the impactor these events would likely be undetectable by present-day measurement means. The activity continues into the future as would be expected. Impact rates of about four per year are predicted by the current study within the next 30 years, with the majority of targets being abandoned intacts (spent upper stages and spacecraft). Still, operational spacecraft do show a small collisional activity, one that increases over time as the small fragment population increases.

Proceedings of the 2nd Annual Conference on NASA/University Advanced Space Design Program

NASA Technical Reports Server (NTRS)

1986-01-01

Topics discussed include: lunar transportation system, Mars rover, lunar fiberglass production, geosynchronous space stations, regenerative system for growing plants, lunar mining devices, lunar oxygen transporation system, mobile remote manipulator system, Mars exploration, launch/landing facility for a lunar base, and multi-megawatt nuclear power system.

Study of Energy Loss Mechanisms in the BPT-4000 Hall Thruster

DTIC Science & Technology

2003-06-30

Aerojet has developed a high performance multi-mode flightweight Hall thruster for orbit raising and stationkeeping on geo-synchronous satellites. In...order to further understand and improve upon the performance of this state of the art Hall thruster and other next generation thrusters being planned

Special Report: High-Speed Data Races Home.

ERIC Educational Resources Information Center

Clark, David D.

1999-01-01

Describes the worldwide use of Internet services and the changing technology to fill consumer requirements. Explains the technology that is used to provide Internet access. Focuses on the cable TV, telephone, and satellite-based communications industries. Sees satellites, which are mostly geosynchronous, as a broadband option, which is risky from…

Wide-field high-performance geosynchronous imaging

NASA Astrophysics Data System (ADS)

Wood, H. John; Jenstrom, Del; Wilson, Mark; Hinkal, Sanford; Kirchman, Frank

1998-01-01

The NASA Mission to Planet Earth (MTPE) Program and the National Oceanographic and Atmospheric Administration (NOAA) are sponsoring the Advanced Geosynchronous Studies (AGS) to develop technologies and system concepts for Earth observation from geosynchronous orbit. This series of studies is intended to benefit both MTPE science and the NOAA GOES Program. Within the AGS program, advanced imager trade studies have investigated two candidate concepts for near-term advanced geosynchronous imagers. One concept uses a scan mirror to direct the line of sight from a 3-axis stabilized platform. Another eliminates the need for a scan mirror by using an agile spacecraft bus to scan the entire instrument. The purpose of this paper is to discuss the optical design trades and system issues encountered in evaluating the two scanning approaches. The imager design started with a look at first principles: what is the most efficient way to image the Earth in those numerous spectral bands of interest to MTPE scientists and NOAA weather forecasters. Optical design trades included rotating filter wheels and dispersive grating instruments. The design converged on a bandpass filter instrument using four focal planes to cover the spectral range 0.45 to 13.0 micrometers. The first imager design uses a small agile spacecraft supporting an afocal optical telescope. Dichroic beamsplitters feed refractive objectives to four focal planes. The detectors are a series of long linear and rectangular arrays which are scanned in a raster fashion over the 17 degree Earth image. The use of the spacecraft attitude control system to raster the imager field-of-view (FOV) back and forth over the Earth eliminates the need for a scan mirror. However, the price paid is significant energy and time required to reverse the spacecraft slew motions at the end of each scan line. Hence, it is desired to minimize the number of scan lines needed to cover the full Earth disk. This desire, coupled with the ground coverage requirements, drives the telescope design to a 1.6 degree square FOV to provide full Earth disk coverage in less than 12 swaths. The telescope design to accommodate the FOV and image quality requirements is a 30 cm aperture three-element off-axis anastigmat. The size and mass of the imager instrument that result from this optical configuration are larger than desired. But spacecraft reaction wheel torque and power requirements to raster the imager FOV are achievable using existing spacecraft technology. However, launch mass and cost are higher than desired. In the second high-level trade study, the AGS imager team is looking at incorporating a scan mirror and having the satellite three-axis stabilized. The use of the scan mirror eliminates the long turn-around times of the spacecraft scanning approach, allowing for faster Earth coverage. Thus the field of view of the afocal telescope can be reduced by half while still satisfying ground coverage requirements. The optical design of the reduced field afocal telescope is being studied to shrink its size and improve its performance. Both a three-mirror Cassegrain afocal and a two-mirror pair of confocal paraboloids are being considered. With either telescope, the size, mass, and power requirements of this imager are significantly less than those of the first imager design. Both imager designs appear to be feasible and both meet envisioned MTPE and NOAA geosynchronous imaging needs. The AGS imager team is continuing to explore the optical trade space to further optimize imager designs.

Micromachined probes for laboratory plasmas

NASA Astrophysics Data System (ADS)

Chiang, Franklin Changta

As we begin to find more applications for plasmas in our everyday lives, the ability to characterize and understand their inner workings becomes increasingly important. Much of our current understanding of plasma physics comes from investigations conducted in diffuse, outer space plasmas where experimenters have no control over the environment or experimental conditions and one measures interesting phenomena only by chance when the spacecraft or satellite passes through them. Ideally, experiments should be performed in a controlled environment, where plasma events can be deliberately and reliably created when wanted and probes placed precisely within the plasma. Unfortunately, often due to their size, probes used in outer space are unsuitable for use in high-density laboratory plasmas, and constructing probes that can be used in terrestrial plasmas is a considerable challenge. This dissertation presents the development, implementation, and experimental results of three micromachined probes capable of measuring voltage and electric field, ion energies, and changing magnetic fields (B-dot) in laboratory plasmas.

Characterizing ISS Charging Environments with On-Board Ionospheric Plasma Measurements

NASA Technical Reports Server (NTRS)

Minow, Jospeh I.; Craven, Paul D.; Coffey, Victoria N.; Schneider, Todd A.; Vaughn, Jason A.; Wright Jr, Kenneth; Parker, Paul D.; Mikatarian, Ronald R.; Kramer, Leonard; Hartman, William A.;

Contaminant ions and waves in the space station environment

NASA Technical Reports Server (NTRS)

Murphy, G. B.

1988-01-01

The probable plasma (ions and electrons) and plasma wave environment that will exist in the vicinity of the Space Station and how this environment may affect the operation of proposed experiments are discussed. Differences between quiescent operational periods and non-operational periods are also addressed. Areas which need further work are identified and a course of action suggested.

Transparent, Conductive Coatings Developed for Arc-Proof Solar Arrays

NASA Technical Reports Server (NTRS)

1996-01-01

Transparent, conductive thin-film coatings have many potential applications where a surface must be able to dissipate electrical charges without sacrificing its optical properties. Such applications include automotive and aircraft windows, heat mirrors, optoelectronic devices, gas sensors, and solar cell array surfaces for space applications. Many spacecraft missions require that solar cell array surfaces dissipate charges in order to avoid damage such as electronic upsets, formation of pinholes in the protective coatings on solar array blankets, and contamination due to deposition of sputtered products. In tests at the NASA Lewis Research Center, mixed thin-films of sputter-deposited indium tin oxide (ITO) and magnesium fluoride (MgF2) that could be tailored to the desired sheet resistivity, showed transmittance values of greater than 90 percent. The samples evaluated were composed of mixed, thin-film ITO/MgF2 coatings, with a nominal thickness of 650 angstroms, deposited onto glass substrates. Preliminary results indicated that these coatings were durable to vacuum ultraviolet radiation and atomic oxygen. These coatings show promise for use on solar array surfaces in polar low-Earth-orbit environments, where a sheet resistivity of less than 10(exp 8)/square is required, and in geosynchronous orbit environments, where a resistivity of less than 10(exp 9)/square is required.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, S.; Saha, J. K.; Chandra, R.

The Rayleigh-Ritz variational technique with a Hylleraas basis set is being tested for the first time to estimate the structural modifications of a lithium atom embedded in a weakly coupled plasma environment. The Debye-Huckel potential is used to mimic the weakly coupled plasma environment. The wave functions for both the helium-like lithium ion and the lithium atom are expanded in the explicitly correlated Hylleraas type basis set which fully takes care of the electron-electron correlation effect. Due to the continuum lowering under plasma environment, the ionization potential of the system gradually decreases leading to the destabilization of the atom. Themore » excited states destabilize at a lower value of the plasma density. The estimated ionization potential agrees fairly well with the few available theoretical estimates. The variation of one and two particle moments, dielectric susceptibility and magnetic shielding constant, with respect to plasma density is also been discussed in detail.« less

Investigation of Orbital Debris: Mitigation, Removal, and Modeling the Debris Population

NASA Astrophysics Data System (ADS)

Slotten, Joel

The population of objects in orbit around Earth has grown since the late 1950s. Today there are over 21,000 objects over 10 cm in length in orbit, and an estimated 500,000 more between 1 and 10 cm. Only a small fraction of these objects are operational satellites. The rest are debris: old derelict spacecraft or rocket bodies, fragments created as the result of explosions or collisions, discarded objects, slag from solid rockets, or even flaked off paint. Traveling at up to 7 km/s, a collision with even a 1 cm piece of debris could severely damage or destroy a satellite. This dissertation examines three aspects of orbital debris. First, the concept of a self-consuming satellite is explored. This nanosatellite would use its own external structure as propellant to execute a deorbit maneuver at the end of its operational life, thus allowing it to meet current debris mitigation standards. Results from lab experiments examining potential materials for this concept have shown favorable results. Second, Particle in Cell techniques are modified and used to model the plasma plume from a micro-cathode arc thruster. This model is then applied to the concept of an ion beam shepherd satellite. This satellite would use its plasma plume to deorbit another derelict satellite. Results from these simulations indicate the micro-cathode arc thruster could potentially deorbit a derelict CubeSat in a matter of a few weeks. Finally, the orbital debris population at geosynchronous orbit is examined, focusing on variations in the density of the population as a function of longitude. New insights are revealed demonstrating that the variation in population density is slightly less than previously reported.

The INAF/IAPS Plasma Chamber for ionospheric simulation experiment

NASA Astrophysics Data System (ADS)

Diego, Piero

2016-04-01

The plasma chamber is particularly suitable to perform studies for the following applications: - plasma compatibility and functional tests on payloads envisioned to operate in the ionosphere (e.g. sensors onboard satellites, exposed to the external plasma environment); - calibration/testing of plasma diagnostic sensors; - characterization and compatibility tests on components for space applications (e.g. optical elements, harness, satellite paints, photo-voltaic cells, etc.); - experiments on satellite charging in a space plasma environment; - tests on active experiments which use ion, electron or plasma sources (ion thrusters, hollow cathodes, field effect emitters, plasma contactors, etc.); - possible studies relevant to fundamental space plasma physics. The facility consists of a large volume vacuum tank (a cylinder of length 4.5 m and diameter 1.7 m) equipped with a Kaufman type plasma source, operating with Argon gas, capable to generate a plasma beam with parameters (i.e. density and electron temperature) close to the values encountered in the ionosphere at F layer altitudes. The plasma beam (A+ ions and electrons) is accelerated into the chamber at a velocity that reproduces the relative motion between an orbiting satellite and the ionosphere (≈ 8 km/s). This feature, in particular, allows laboratory simulations of the actual compression and depletion phenomena which take place in the ram and wake regions around satellites moving through the ionosphere. The reproduced plasma environment is monitored using Langmuir Probes (LP) and Retarding Potential Analyzers (RPA). These sensors can be automatically moved within the experimental space using a sled mechanism. Such a feature allows the acquisition of the plasma parameters all around the space payload installed into the chamber for testing. The facility is currently in use to test the payloads of CSES satellite (Chinese Seismic Electromagnetic Satellite) devoted to plasma parameters and electric field measurements in a polar orbit at 500 km altitude.

Atmospheric Plasma Blade for Surgical Purposes

NASA Astrophysics Data System (ADS)

Oksuz, Lutfi; Yurdabak Karaca, Gozde; Özkaptan, Emir; Uygun, Emre; Uygun Oksuz, Aysegul

2017-10-01

Atmospheric plasma cut is a process at the minimum level due to the ions, radicals and free electrons generated by the active electrode and target tissue. Atmospheric plasma cutting devices provide significant advantages as a non-contact electrocautery system that can operate in isotonic environment. During operations where plasma cutting is applied, bleeding is controlled and the side effects that would create the isotonic environment are eliminated. In this study in vivo and in vitro studies will be carried out by producing and optimizing the atmospheric plasma blade. Once the optimum parameters of the instrument are determined, in vivo studies will be performed and the pathology results will be evaluated.

Survey of the plasma electron environment of Jupiter: A view from Voyager

NASA Technical Reports Server (NTRS)

Scudder, J. D.; Sittler, E. C., Jr.; Bridge, H. S.

1980-01-01

The plasma environment within Jupiter's bow shock is considered in terms of the in situ, calibrated electron plasma measurements made between 10 eV and 5.95 keV by the Voyager plasma science experiment (PLS). Measurements were analyzed and corrected for spacecraft potential variations; the data were reduced to nearly model independent macroscopic parameters of the local electron density and temperature. It is tentatively concluded that the radial temperature profile within the plasma sheet is caused by the intermixing of two different electron populations that probably have different temporal histories and spatial paths to their local observation. The cool plasma source of the plasma sheet and spikes is probably the Io plasma torus and arrives in the plasma sheet as a result of flux tube interchange motions or other generalized transport which can be accomplished without diverting the plasma from the centrifugal equator. The hot suprathermal populations in the plasma sheet have most recently come from the sparse, hot mid-latitude "bath" of electrons which were directly observed juxtaposed to the plasma sheet.

The Plasma Interaction Experiment (PIX) description and test program. [electrometers

NASA Technical Reports Server (NTRS)

Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

1978-01-01

The plasma interaction experiment (PIX) is a battery powered preprogrammed auxiliary payload on the LANDSAT-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

The effects of RF plasma ashing on zinc orthotitanate/potassium silicate thermal control coatings

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Bruckner, Eric J.

1992-01-01

Samples of YB-71, a white thermal control coating composed of zinc orthotitanate pigment in a potassium silicate binder, were exposed in air plasma and in oxygen plasma to determine optical property and surface chemistry changes. Results show that YB-71 undergoes a significant reflectance decrease upon exposure to the simulated LEO atomic oxygen environment provided by an air plasma asher. YB-71 samples exposed to the same effective fluence in oxygen plasma, or in a UV screening Faraday cage in air or oxygen, do not undergo as severe reflectance decreases as the samples exposed in the air plasma asher environment. The UV and VUV radiation present in the plasma ashers affects the YB-71 degradation. It is noted that, when using plasma ashers to determine LEO degradation, it is necessary to take into account the sensitivity of the material to the synergistic effects of atomic oxygen and accelerated UV radiation.

The interaction between Saturn's moons and their plasma environments

NASA Astrophysics Data System (ADS)

Simon, Sven; Roussos, Elias; Paty, Carol S.

2015-11-01

Since the arrival of the Cassini spacecraft at Saturn in July 2004, newly collected plasma and magnetic field data have greatly expanded our knowledge on the interaction between the giant planet's multifaceted family of moons and its magnetospheric environment. Cassini has already accomplished more than 200 orbits around Saturn, encompassing 111 flybys of the giant planet's largest moon Titan and 20 encounters of Enceladus. This small icy moon had been identified as the major source of magnetospheric plasma and neutral particles during the first year of Cassini's tour in the Saturnian system. In addition, the spacecraft has paid visits to several other icy satellites in the inner and middle magnetosphere: Rhea, Dione and Tethys. Depending on the ambient magnetospheric flow parameters as well as the properties of its atmosphere/ionosphere and surface, each of these moons generates a characteristic and unique set of perturbation signatures in the magnetospheric plasma incident upon it. Therefore, observations made during close flybys of Saturn's moons by the Cassini plasma and magnetic field detectors contain valuable diagnostic information on the properties of the moons' atmospheres, surfaces and even their interiors. However, the spacecraft can measure these plasma and magnetic field perturbations only along its trajectory, whereas the interaction between the moons and their plasma environments constitutes a complex three-dimensional process. Therefore, sophisticated models are required in order to place the data collected along Cassini's flyby trajectories within the context of the full three-dimensional moon-plasma interaction scenarios. In this review, we combine observations from the Cassini mission with sophisticated modeling results to draw a comprehensive picture of the interaction between Saturn's largest moons and their highly dynamic plasma environments.

Federal Communications Commission (FCC) Transponder Loading Data Conversion Software. User's guide and software maintenance manual, version 1.2

NASA Technical Reports Server (NTRS)

Mallasch, Paul G.

1993-01-01

This volume contains the complete software system documentation for the Federal Communications Commission (FCC) Transponder Loading Data Conversion Software (FIX-FCC). This software was written to facilitate the formatting and conversion of FCC Transponder Occupancy (Loading) Data before it is loaded into the NASA Geosynchronous Satellite Orbital Statistics Database System (GSOSTATS). The information that FCC supplies NASA is in report form and must be converted into a form readable by the database management software used in the GSOSTATS application. Both the User's Guide and Software Maintenance Manual are contained in this document. This volume of documentation passed an independent quality assurance review and certification by the Product Assurance and Security Office of the Planning Research Corporation (PRC). The manuals were reviewed for format, content, and readability. The Software Management and Assurance Program (SMAP) life cycle and documentation standards were used in the development of this document. Accordingly, these standards were used in the review. Refer to the System/Software Test/Product Assurance Report for the Geosynchronous Satellite Orbital Statistics Database System (GSOSTATS) for additional information.

Estimating the spin axis orientation of the Echostar-2 box-wing geosynchronous satellite

NASA Astrophysics Data System (ADS)

Earl, Michael A.; Somers, Philip W.; Kabin, Konstantin; Bédard, Donald; Wade, Gregg A.

2018-04-01

For the first time, the spin axis orientation of an inactive box-wing geosynchronous satellite has been estimated from ground-based optical photometric observations of Echostar-2's specular reflections. Recent photometric light curves obtained of Echostar-2 over four years suggest that unusually bright and brief specular reflections were occurring twice within an observed spin period. These bright and brief specular reflections suggested two satellite surfaces with surface normals separated by approximately 180°. The geometry between the satellite, the Sun, and the observing location at the time of each of the brightest observed reflections, was used to estimate Echostar-2's equatorial spin axis orientation coordinates. When considering prograde and retrograde rotation, Echostar-2's spin axis orientation was estimated to have been located within 30° of either equatorial coordinate pole. Echostar-2's spin axis was observed to have moved approximately 180° in right ascension, within a time span of six months, suggesting a roughly one year spin axis precession period about the satellite's angular momentum vector.

A new modem for microwave time synchronisation via geosynchronous telecommunication satellites

NASA Astrophysics Data System (ADS)

Dienert, Michael

1992-06-01

A study illustrating the two way time transfer technique and describing the use of this technique with the MITREX (Microwave Time and Range Experiment) SATRE (Satellite Time and Range Experiment) modems is presented. The two way time transfer technique via geosynchronous telecom satellites is one of the most accurate methods for synchronization and comparison of remote clocks. Most of the unknown propagation delays can be eliminated by the two way principle. The use of a coherent spread spectrum technique with a truncated pseudonoise code offers a resolution better than 30 ps of the measured time interval. The receiver is built around a Delay Locked Loop (DLL), which correlates the received signal with the known PN sequence to derive the control signal of the loop. In the locked state both PN sequences are synchronous and tracking errors of less than 30 ps are possible. Results showing the accuracy of the modem depending on signal to noise ratio and variation of total input power levels are presented and show that the expected improvement of the jitter of the internal delay by an increase of the chip rate is possible.

Mass comparisons of electric propulsion systems for NSSK of geosynchronous spacecraft

NASA Technical Reports Server (NTRS)

Rawlin, Vincent K.; Majcher, Gregory A.

1991-01-01

A model was developed and exercised to allow wet mass comparisons of three axis stabilized communication satellites delivered to geosynchronous transfer orbit. The mass benefits of using advanced chemical propulsion for apogee injection and north-south stationkeeping (NSSK) functions or electric propulsion (hydrazine arcjets and xenon ion thrusters) for NSSK functions are documented. A large derated ion thrusters is proposed which minimizes thruster lifetime concerns and qualification test times when compared to those of smaller ion thrusters planned for NSSK applications. The mass benefits, which depend on the spacecraft mass and mission duration, increase dramatically with arcjet specific impulse in the 500 to 600 s range, but are nearly constant for the derated ion thruster operated in the 2300 to 3000 s range. For a given mission, the mass benefits with an ion system are typically double those of the arcjet system; however, the total thrusting time with arcjets is less than 1/3 that with ion thrusters for the same thruster power. The mass benefits may permit increases in revenue producing payload or reduce launch costs by allowing a move to a smaller launch vehicle.

Tracking in a ground-to-satellite optical link: effects due to lead-ahead and aperture mismatch, including temporal tracking response.

PubMed

Basu, Santasri; Voelz, David

2008-07-01

Establishing a link between a ground station and a geosynchronous orbiting satellite can be aided greatly with the use of a beacon on the satellite. A tracker, or even an adaptive optics system, can use the beacon during communication or tracking activities to correct beam pointing for atmospheric turbulence and mount jitter effects. However, the pointing lead-ahead required to illuminate the moving object and an aperture mismatch between the tracking and the pointing apertures can limit the effectiveness of the correction, as the sensed tilt will not be the same as the tilt required for optimal transmission to the satellite. We have developed an analytical model that addresses the combined impact of these tracking issues in a ground-to-satellite optical link. We present these results for different tracker/pointer configurations. By setting the low-pass cutoff frequency of the tracking servo properly, the tracking errors can be minimized. The analysis considers geosynchronous Earth orbit satellites as well as low Earth orbit satellites.

Space-Based Solar Power Conversion and Delivery Systems Study. Volume 3: Microwave Power Transmission Studies

NASA Technical Reports Server (NTRS)

1977-01-01

The Microwave Fower Beam Ionosphere effects and critical interfaces between th Microwave Power Transmission System (MPTS) and the Satellite were studied as part of the NASA/MSFC continuing research on the feasibility of power transmission from geosynchronous orbit. Theoretical predications of ionospheric modifications produced by the direct interaction of the MPTS on the earth's upper atmosphere are used to determine their impact on the performance of the Microwave Power Beam and Pilot Beam System as well as on other RF systems effected by the ionosphere. A technology program to quantitatively define these interactions is developed. Critical interface areas between the MPTS and the satellite which could have a major impact on cost and performance of the power system are idenfified and analyzed. The areas selected include: use of either a 20 kV versus 40 kV Amplitron, thermal blockage effects of Amplitron heat radiation by the satellite structure, effect of dielectric carry-through structure on power beam, and effect of material sublimation on performance of the Amplitron in Geosynchronous Orbit.

Remote Acoustic Imaging of Geosynchronous Satellites

NASA Astrophysics Data System (ADS)

Watson, Z.; Hart, M.

Identification and characterization of orbiting objects that are not spatially resolved are challenging problems for traditional remote sensing methods. Hyper temporal imaging, enabled by fast, low-noise electro-optical detectors is a new sensing modality which may allow the direct detection of acoustic resonances on satellites enabling a new regime of signature and state detection. Detectable signatures may be caused by the oscillations of solar panels, high-gain antennae, or other on-board subsystems driven by thermal gradients, fluctuations in solar radiation pressure, worn reaction wheels, or orbit maneuvers. Herein we present the first hyper-temporal observations of geosynchronous satellites. Data were collected at the Kuiper 1.54-meter telescope in Arizona using an experimental dual-channel imaging instrument that simultaneously measures light in two orthogonally polarized beams at sampling rates extending up to 1 kHz. In these observations, we see evidence of acoustic resonances in the polarization state of satellites. The technique is expected to support object identification and characterization of on-board components and to act as a discriminant between active satellites, debris, and passive bodies.

Time-series analysis of energetic electron fluxes (1. 2 - 16 MeV) at geosynchronous altitude. Master's thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halpin, M.P.

This project used a Box and Jenkins time-series analysis of energetic electron fluxes measured at geosynchronous orbit in an effort to derive prediction models for the flux in each of five energy channels. In addition, the technique of transfer function modeling described by Box and Jenkins was used in an attempt to derive input-output relationships between the flux channels (viewed as the output) and the solar-wind speed or interplanetary magnetic field (IMF) north-south component, Bz, (viewed as the input). The transfer function modeling was done in order to investigate the theoretical dynamic relationship which is believed to exist between themore » solar wind, the IMF Bz, and the energetic electron flux in the magnetosphere. The models derived from the transfer-function techniques employed were also intended to be used in the prediction of flux values. The results from this study indicate that the energetic electron flux changes in the various channels are dependent on more than simply the solar-wind speed or the IMF Bz.« less

Dusty Plasmas on the Lunar Surface

NASA Astrophysics Data System (ADS)

Horanyi, M.; Andersson, L.; Colwell, J.; Ergun, R.; Gruen, E.; McClintock, B.; Peterson, W. K.; Robertson, S.; Sternovsky, Z.; Wang, X.

2006-12-01

The electrostatic levitation and transport of lunar dust remains one of the most interesting and controversial science issues from the Apollo era. This issue is also of great engineering importance in designing human habitats and protecting optical and mechanical devices. As function of time and location, the lunar surface is exposed to solar wind plasma, UV radiation, and/or the plasma environment of our magnetosphere. Dust grains on the lunar surface collect an electrostatic charge; alter the large-scale surface charge density distribution, ?and subsequently develop an interface region to the background plasma and radiation. There are several in situ and remote sensing observations that indicate that dusty plasma processes are likely to be responsible for the mobilization and transport of lunar soil. These processes are relevant to: a) understanding the lunar surface environment; b) develop dust mitigation strategies; c) to understand the basic physical processes involved in the birth and collapse of dust loaded plasma sheaths. This talk will focus on the dusty plasma processes on the lunar surface. We will review the existing body of observations, and will also consider future opportunities for the combination of in situ and remote sensing observations. Our goals are to characterize: a) the temporal variation of the spatial and size distributions of the levitated/transported dust; and b) the surface plasma environment

Specification of the ISS Plasma Environment Variability

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Neergaard, Linda F.; Bui, Them H.; Mikatarian, Ronald R.; Barsamian, H.; Koontz, Steven L.

2002-01-01

Quantifying the spacecraft charging risks and corresponding hazards for the International Space Station (ISS) requires a plasma environment specification describing the natural variability of ionospheric temperature (Te) and density (Ne). Empirical ionospheric specification and forecast models such as the International Reference Ionosphere (IRI) model typically only provide estimates of long term (seasonal) mean Te and Ne values for the low Earth orbit environment. Knowledge of the Te and Ne variability as well as the likelihood of extreme deviations from the mean values are required to estimate both the magnitude and frequency of occurrence of potentially hazardous spacecraft charging environments for a given ISS construction stage and flight configuration. This paper describes the statistical analysis of historical ionospheric low Earth orbit plasma measurements used to estimate Ne, Te variability in the ISS flight environment. The statistical variability analysis of Ne and Te enables calculation of the expected frequency of Occurrence of any particular values of Ne and Te, especially those that correspond to possibly hazardous spacecraft charging environments. The database used in the original analysis included measurements from the AE-C, AE-D, and DE-2 satellites. Recent work on the database has added additional satellites to the database and ground based incoherent scatter radar observations as well. Deviations of the data values from the IRI estimated Ne, Te parameters for each data point provide a statistical basis for modeling the deviations of the plasma environment from the IRI model output. This technique, while developed specifically for the Space Station analysis, can also be generalized to provide ionospheric plasma environment risk specification models for low Earth orbit over an altitude range of 200 km through approximately 1000 km.

Comparison of Magnetospheric Magnetic Field Variations at Quasi-Zenith Orbit Based on Michibiki Observation and REPPU Global MHD Simulation

NASA Astrophysics Data System (ADS)

Kubota, Y.; Nagatsuma, T.; Den, M.; Nakamizo, A.; Matsumoto, H.; Tanaka, T.

2017-12-01

We are developing a numerical simulator for future space weather forecast using magnetosphere-ionosphere coupling global MHD simulation called REPPU (REProduce Plasma Universe) code. We investigate the validity of the MHD simulation result as compared with observation. In this study we simulate some events including both quiet and disturbed geomagnetic conditions using OMNIWeb solar wind data. The simulation results are compared with magnetic field observations from Michibiki satellite, which is on the quasi-zenith orbit (QZO). In quiet geomagnetic condition, magnetic field variations at QZO obtained from simulation results have good consistency as compared correspondence with those from Michibiki observation. In disturbed geomagnetic condition in which the Dst < -20 nT, however, V component of magnetic field variations from simulation results tend to deviate from observations especially at the night side. We consider that this deviation during disturbed geomagnetic condition might be due to tail and/or ring current enhancement which is already suggested by many other MHD simulation studies as compared with the magnetic field observation at geosynchronous orbit. In this presentation, we will discuss the cause of this discrepancy in more detail with studying the relationship between the magnetic field deviation and some parameters such as Dst and solar wind.

Xenon ion propulsion for orbit transfer

NASA Technical Reports Server (NTRS)

Rawlin, V. K.; Patterson, M. J.; Gruber, R. P.

1990-01-01

For more than 30 years, NASA has conducted an ion propulsion program which has resulted in several experimental space flight demonstrations and the development of many supporting technologies. Technologies appropriate for geosynchronous stationkeeping, earth-orbit transfer missions, and interplanetary missions are defined and evaluated. The status of critical ion propulsion system elements is reviewed. Electron bombardment ion thrusters for primary propulsion have evolved to operate on xenon in the 5 to 10 kW power range. Thruster efficiencies of 0.7 and specific impulse values of 4000 s were documented. The baseline thruster currently under development by NASA LeRC includes ring-cusp magnetic field plasma containment and dished two-grid ion optics. Based on past experience and demonstrated simplifications, power processors for these thrusters should have approximately 500 parts, a mass of 40 kg, and an efficiency near 0.94. Thrust vector control, via individual thruster gimbals, is a mature technology. High pressure, gaseous xenon propellant storage and control schemes, using flight qualified hardware, result in propellant tankage fractions between 0.1 and 0.2. In-space and ground integration testing has demonstrated that ion propulsion systems can be successfully integrated with their host spacecraft. Ion propulsion system technologies are mature and can significantly enhance and/or enable a variety of missions in the nation's space propulsion program.

Charged dust phenomena in the near-Earth space environment.

PubMed

Scales, W A; Mahmoudian, A

2016-10-01

Dusty (or complex) plasmas in the Earth's middle and upper atmosphere ultimately result in exotic phenomena that are currently forefront research issues in the space science community. This paper presents some of the basic criteria and fundamental physical processes associated with the creation, evolution and dynamics of dusty plasmas in the near-Earth space environment. Recent remote sensing techniques to probe naturally created dusty plasma regions are also discussed. These include ground-based experiments employing high-power radio wave interaction. Some characteristics of the dusty plasmas that are actively produced by space-borne aerosol release experiments are discussed. Basic models that may be used to investigate the characteristics of such dusty plasma regions are presented.

The Lunar dusty plasmas -levitation and transport.

NASA Astrophysics Data System (ADS)

Atamaniuk, Barbara; Rothkaehl, Hanna

Lunar dust can exhibit unusual behavior -due to electron photoemission via solar-UV radiation the lunar surface represents a complex plasma -"dusty plasma". The dust grains and lunar surface are electrostatically charged by the Moon's interaction with the local plasma environ-ment and the photoemission of electrons due to solar UV and X-rays. This effect causes the like-charged surface and dust particles to repel each other, and creates a near-surface electric field. Lunar dust must be treated as a dusty plasma. Using analytic (kinetic (Vlasov) and magnetohydrodynamic theory ) and numerical modeling we show physical processes related to levitation and transport dusty plasma on the Moon. These dust grains could affect the lunar environment for radio wave and plasma diagnostics and interfere with exploration activities. References: 1. Wilson T.L. (1992), in Analysis of Interplanetary Dust, M. Zolensky et al. AIP Conf.Proc. 310, 33-44 (AIP, NY), 2.Wilson T.L."LUNAR DUST AND DUSTY PLASMA PHYSICS".40th Lunar and Planetary Science Conference (2009), 3. Grün E., et al.(1993),Nature 363, 144. 4. Morfill G. and Grün E.(1979), Planet. Space Sci.. 27, 1269, 1283, 5. Manka R. and Michel F. (1971), Proc. 2nd Lun. Sci. Conf. 2, 1717 (MIT Press, Cambridge). 6. Manka R. et al.(1973), Lun. Sci.-III, 504. 7. Barbara Atamaniuk "Kinetic Description of Localized Plasma Structure in Dusty Plasmas". Czechoslovak Journal of Physics Vol.54 C 2004

Horizon: A Proposal for Large Aperture, Active Optics in Geosynchronous Orbit

NASA Technical Reports Server (NTRS)

Chesters, Dennis; Jenstrom, Del

2000-01-01

In 1999, NASA's New Millennium Program called for proposals to validate new technology in high-earth orbit for the Earth Observing-3 (NMP EO3) mission to fly in 2003. In response, we proposed to test a large aperture, active optics telescope in geosynchronous orbit. This would flight-qualify new technologies for both Earth and Space science: 1) a future instrument with LANDSAT image resolution and radiometric quality watching continuously from geosynchronous station, and 2) the Next Generation Space Telescope (NGST) for deep space imaging. Six enabling technologies were to be flight-qualified: 1) a 3-meter, lightweight segmented primary mirror, 2) mirror actuators and mechanisms, 3) a deformable mirror, 4) coarse phasing techniques, 5) phase retrieval for wavefront control during stellar viewing, and 6) phase diversity for wavefront control during Earth viewing. Three enhancing technologies were to be flight- validated: 1) mirror deployment and latching mechanisms, 2) an advanced microcontroller, and 3) GPS at GEO. In particular, two wavefront sensing algorithms, phase retrieval by JPL and phase diversity by ERIM International, were to sense optical system alignment and focus errors, and to correct them using high-precision mirror mechanisms. Active corrections based on Earth scenes are challenging because phase diversity images must be collected from extended, dynamically changing scenes. In addition, an Earth-facing telescope in GEO orbit is subject to a powerful diurnal thermal and radiometric cycle not experienced by deep-space astronomy. The Horizon proposal was a bare-bones design for a lightweight large-aperture, active optical system that is a practical blend of science requirements, emerging technologies, budget constraints, launch vehicle considerations, orbital mechanics, optical hardware, phase-determination algorithms, communication strategy, computational burdens, and first-rate cooperation among earth and space scientists, engineers and managers. This manuscript presents excerpts from the Horizon proposal's sections that describe the Earth science requirements, the structural -thermal-optical design, the wavefront sensing and control, and the on-orbit validation.

Elastic-plastic adhesive impacts of tungsten dust with metal surfaces in plasma environments

NASA Astrophysics Data System (ADS)

Ratynskaia, S.; Tolias, P.; Shalpegin, A.; Vignitchouk, L.; De Angeli, M.; Bykov, I.; Bystrov, K.; Bardin, S.; Brochard, F.; Ripamonti, D.; den Harder, N.; De Temmerman, G.

2015-08-01

Dust-surface collisions impose size selectivity on the ability of dust grains to migrate in scrape-off layer and divertor plasmas and to adhere to plasma-facing components. Here, we report first experimental evidence of dust impact phenomena in plasma environments concerning low-speed collisions of tungsten dust with tungsten surfaces: re-bouncing, adhesion, sliding and rolling. The results comply with the predictions of the model of elastic-perfectly plastic adhesive spheres employed in the dust dynamics code MIGRAINe for sub- to several meters per second impacts of micrometer-range metal dust.

The effect of environmental plasma interactions on the performance of the solar sail system

NASA Technical Reports Server (NTRS)

Douglas, M.; Laquey, R.; Deforest, S. E.

1977-01-01

Interaction between the solar sail and the natural plasma environment were examined for deleterious impacts upon the operation of the sail and its associated payload. Electrostatic charging of the sail in the solar wind and in near earth environment were examined. Deployment problems were studied. An analysis of electromechanical oscillations coupling the sail to the natural plasma was performed. As a result of these studies, it was concluded that none of these effects will have a significant negative impact upon the sail operation. The natural environment will be significantly perturbed and this will preclude measurements of electric and magnetic fields from an attached payload.

8th Spacecraft Charging Technology Conference

NASA Technical Reports Server (NTRS)

Minor, J. L. (Compiler)

2004-01-01

The 8th Spacecraft Charging Technology Conference was held in Huntsville, Alabama, October 20-24, 2003. Hosted by NASA s Space Environments and Effects (SEE) Program and co-sponsored by the Air Force Research Laboratory (AFRL) and the European Space Agency (ESA), the 2003 conference saw attendance from eleven countries with over 65 oral papers and 18 poster papers. Presentation topics highlighted the latest in spacecraft charging mitigation techniques and on-orbit investigations, including: Plasma Propulsion and Tethers; Ground Testing Techniques; Interactions of Spacecraft and Systems With the Natural and Induced Plasma Environment; Materials Characterizations; Models and Computer Simulations; Environment Specifications; Current Collection and Plasma Probes in Space Plasmas; On-Orbit Investigations. A round-table discussion of international standards regarding electrostatic discharge (ESD) testing was also held with the promise of continued discussions in the off years and an official continuation at the next conference.

Cold air plasma to decontaminate inanimate surfaces of the hospital environment.

PubMed

Cahill, Orla J; Claro, Tânia; O'Connor, Niall; Cafolla, Anthony A; Stevens, Niall T; Daniels, Stephen; Humphreys, Hilary

2014-03-01

The hospital environment harbors bacteria that may cause health care-associated infections. Microorganisms, such as multiresistant bacteria, can spread around the patient's inanimate environment. Some recently introduced biodecontamination approaches in hospitals have significant limitations due to the toxic nature of the gases and the length of time required for aeration. This study evaluated the in vitro use of cold air plasma as an efficient alternative to traditional methods of biodecontamination of hospital surfaces. Cultures of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli, and Acinetobacter baumannii were applied to different materials similar to those found in the hospital environment. Artificially contaminated sections of marmoleum, mattress, polypropylene, powder-coated mild steel, and stainless steel were then exposed to a cold air pressure plasma single jet for 30 s, 60 s, and 90 s, operating at approximately 25 W and 12 liters/min flow rate. Direct plasma exposure successfully reduced the bacterial load by log 3 for MRSA, log 2.7 for VRE, log 2 for ESBL-producing E. coli, and log 1.7 for A. baumannii. The present report confirms the efficient antibacterial activity of a cold air plasma single-jet plume on nosocomial bacterially contaminated surfaces over a short period of time and highlights its potential for routine biodecontamination in the clinical environment.

Specifying the ISS Plasma Environment

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Diekmann, Anne; Neergaard, Linda; Bui, Them; Mikatarian, Ronald; Barsamian, Hagop; Koontz, Steven

2002-01-01

Quantifying the spacecraft charging risks and corresponding hazards for the International Space Station (ISS) requires a plasma environment specification describing the natural variability of ionospheric temperature (Te) and density (Ne). Empirical ionospheric specification and forecast models such as the International Reference Ionosphere (IN) model typically only provide estimates of long term (seasonal) mean Te and Ne values for the low Earth orbit environment. Knowledge of the Te and Ne variability as well as the likelihood of extreme deviations from the mean values are required to estimate both the magnitude and frequency of occurrence of potentially hazardous spacecraft charging environments for a given ISS construction stage and flight configuration. This paper describes the statistical analysis of historical ionospheric low Earth orbit plasma measurements used to estimate Ne, Te variability in the ISS flight environment. The statistical variability analysis of Ne and Te enables calculation of the expected frequency of occurrence of any particular values of Ne and Te, especially those that correspond to possibly hazardous spacecraft charging environments. The database used in the original analysis included measurements from the AE-C, AE-D, and DE-2 satellites. Recent work on the database has added additional satellites to the database and ground based incoherent scatter radar observations as well. Deviations of the data values from the IRI estimated Ne, Te parameters for each data point provide a statistical basis for modeling the deviations of the plasma environment from the IRI model output.

78 FR 31444 - Amendment to the International Traffic in Arms Regulations: Revision of U.S. Munitions List...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-24

...) 150 meters from geosynchronous orbit (GEO); or (iv) 225 meters from high earth orbit (HEO); (11) Space... operating frequencies above 10 GHz; (15) ``Space-qualified'' oscillator for radar in paragraph (a) of this... Fiscal Year 1999, required that space-related items, including all satellites, were to be controlled as...

Implications of Gun Launch to Space for Nanosatellite Architectures

NASA Technical Reports Server (NTRS)

Palmer, Miles R.

1995-01-01

Engineering and economic scaling factors for gun launch to space (GLTS) systems are compared to conventional rocket launch systems. It is argued that GLTS might reduce the cost of small satellite development and launch in the mid to far term, thereby inducing a shift away from large centralized geosynchronous communications satellites to small proliferated low earth orbit systems.

Threats to U.S. National Security Interests in Space: Orbital Debris Mitigation and Removal

DTIC Science & Technology

2014-01-08

objects larger than the size of a softball and hundreds of thousands of smaller fragments. This population of space debris potentially threatens U.S...catalogues objects as small as about 10 cm ( softball size) in LEO and as small as 1 meter in Geosynchronous Orbit.12 Today, the Space Surveillance

Survey of United States Commercial Satellites in Geosynchronous Earth Orbit

DTIC Science & Technology

1994-09-01

248 a. Imaging Sensors ...... ............ 248 (1) Return Beam Vidicon Camera . ... 249 (2) Scanners. ...... ............ 249 b. Nonimaging ...251 a. Imaging Microwave Sensors ......... .. 251 (1) Synthetic Aperture Radar . ... 251 b. Nonimaging Microwave Sensors ..... .. 252 (1) Radar...The stream of electrons travels alonq the axis oa the tube, constrained by focusing magnets, until it reaches the collector . Surrounding this electron

Space station systems analysis study. Part 3: Documentation. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1977-01-01

The space stations systems analysis study is summarized. A cost efffective system concept capable of meeting a broad spectrum of mission requirements was developed. Candidate objectives were reviewed and implementation requirements were defined. Program options for both low earth and geosynchronous orbits were examined. Space construction concepts were analyzed and defined in detail.

Spectral Measurements of Geosynchronous Satellites During Glint Season

DTIC Science & Technology

2015-10-18

mechanical structures. 1. INTRODUCTION Man-made satellites serve a plethora of purposes from navigation to remote sensing. Geostationary orbits...in effect causing these satellites to appear fixed above the same point on earth. These geostationary satellites (GEOs) facilitate communications... Geostationary satellites are used for communication and navigation, among other purposes as mentioned above. By observing and characterizing the

An Improved Model for Operational Specification of the Electron Density Structure up to Geosynchronous Heights

DTIC Science & Technology

2010-07-01

http://www.iono.noa.gr/ElectronDensity/EDProfile.php The web service has been developed with the following open source tools: a) PHP , for the... MySQL for the database, which was based on the enhancement of the DIAS database. Below we present some screen shots to demonstrate the functionality

Effects of environmental novelty on fear-related behavior and stress responses of rats to emotionally relevant odors.

PubMed

Nikaido, Y; Nakashima, T

2009-05-16

Although various emotional behaviors and activation of the hypothalamic-pituitary-adrenal (HPA) axis of rats are induced by the exposure of 2,5-dihydro-2,4,5-trimethylthiazoline: TMT, a component of fox odor, these odor-induced responses are influenced by the external environment. Our previous study demonstrated that exposure to green odor, a mixture of cis-3-hexenol and trans-2-hexenal, attenuated stress-induced elevation of the plasma ACTH level in rats. The present study investigated the effect of TMT or green odor on emotional behavior and the HPA axis stress response with or without the influence of environmental novelty. We exposed rats to TMT or green odor in "familiar" or "unfamiliar" environments and compared the various responses, including fear-related behaviors, non-defensive behaviors and plasma ACTH concentrations. TMT induced enhanced freezing behavior, reduced exploration behavior and elevations in plasma ACTH concentrations in two environmental conditions. Comparing TMT-induced responses in an unfamiliar environment with the familiar environment showed that environmental novelty enhanced TMT-induced fear-related behaviors and elevations of plasma ACTH concentrations. These results revealed that TMT causes fear and stress responses in both familiar and unfamiliar environments, although the novelty of an unfamiliar environment enhances these TMT-induced responses. On the other hand, green odor did not induce any responses in either environment. These findings indicate that odor-induced responses are influenced by the surrounding environment.

Microwave plasma enabled synthesis of free standing carbon nanostructures at atmospheric pressure conditions.

PubMed

Bundaleska, N; Tsyganov, D; Dias, A; Felizardo, E; Henriques, J; Dias, F M; Abrashev, M; Kissovski, J; Tatarova, E

2018-05-23

An experimental and theoretical study on microwave (2.45 GHz) plasma enabled assembly of carbon nanostructures, such as multilayer graphene sheets and nanoparticles, was performed. The carbon nanostructures were fabricated at different Ar-CH4 gas mixture composition and flows at atmospheric pressure conditions. The synthesis method is based on decomposition of the carbon-containing precursor (CH4) in the "hot" microwave plasma environment into carbon atoms and molecules, which are further converted into solid carbon nuclei in the "colder" plasma zones. By tailoring of the plasma environment, a controlled synthesis of graphene sheets and diamond-like nanoparticles was achieved. Selective synthesis of graphene flakes was achieved at a microwave power of 1 kW, Ar and methane flow rates of 600 sccm and 2 sccm respectively, while the predominant synthesis of diamond-like nanoparticles was obtained at the same power, but with higher flow rates, i.e. 1000 and 7.5 sccm, respectively. Optical emission spectroscopy was applied to detect the plasma emission related to carbon species from the 'hot' plasma zone and to determine the main plasma parameters. Raman spectroscopy and scanning electron microscopy have been applied to characterize the synthesized nanostructures. A previously developed theoretical model was further updated and employed to understand the mechanism of CH4 decomposition and formation of the main building units, i.e. C and C2, of the carbon nanostructures. An insight into the physical chemistry of carbon nanostructure formation in a high energy density microwave plasma environment is presented.

Van Allen Probes observations of intense parallel Poynting flux associated with magnetic dipolarization, conjugate discrete auroral arcs, and energetic particle injection

NASA Astrophysics Data System (ADS)

Wygant, J. R.; Thaller, S. A.; Breneman, A. W.; Tian, S.; Cattell, C. A.; Chaston, C. C.; Mozer, F.; Bonnell, J. W.; Kistler, L. M.; Mouikis, C.; Hudson, M. K.; Claudepierre, S. G.; Fennell, J. F.; Reeves, G. D.; Baker, D. N.; Donovan, E.; Spanswick, E.; Kletzing, C.

2015-12-01

We present measurements from the Van Allen Probes, in the near Earth tail, at the outer boundary of the plasma sheet, of a magnetic dipolarization/injection event characterized by unusually strong earthward poynting flux flowing along magnetic field lines with amplitudes of 200 mW/m2 lasting ~ 1 minute. The Poynting flux was conjugate to a 30 km wide discrete auroral arc observed by the THEMIS auroral array. The observations were obtained at 5.8 Re in the pre-midnight sector during the main phase of a geomagnetic storm on 5/01/2013. This brief interval transferred more electromagnetic energy (at the spacecraft position) than that transferred during entire remainder of the main phase of the storm. The parallel Poynting flux coincided with a local section of the "cross tail current sheet" which generated the dipolarization signature. The latitudinal width of the arc, mapped along magnetic field lines, provides an estimate of the spatial scale of the Poynting flux, the electric fields, and the current sheets (parallel and perpendicular). It is estimated that the latitudinal width of the Poynting flux "sheet" was ~600 km or ~1-2 H+ inertial lengths. An estimate of the ∫E·dl across the current sheet along the direction normal to the plasma sheet is ~20-40 kilovolts. The "normal" to the plasma sheet component of the electric field (~70 mV/m) strongly dominated the azimuthal component(which is reponsible for drift energetization). The dipolarization event resulted in the local dispersion-less injection of electrons between 50 keV and ~2 MeV at the Van Allen Probe position. The injection event involved brief (factor of two) local spike in ~2 MeV electron fluxes. Measurements from the Los Alamos geosynchronous spacecraft, displaced eastward from the Van Allen probes, provided evidence for dispersive energy-time electron signatures consistent with injection and energization at the RBSP position. The Poynting flux also coincided with the energy peak in the up-flowing dispersive ion energy-time profile and the onset of earthward ExB convection. A similar injection event during the storm on 6/1/2013 will be discussed.

Profile control simulations and experiments on TCV: a controller test environment and results using a model-based predictive controller

NASA Astrophysics Data System (ADS)

Maljaars, E.; Felici, F.; Blanken, T. C.; Galperti, C.; Sauter, O.; de Baar, M. R.; Carpanese, F.; Goodman, T. P.; Kim, D.; Kim, S. H.; Kong, M.; Mavkov, B.; Merle, A.; Moret, J. M.; Nouailletas, R.; Scheffer, M.; Teplukhina, A. A.; Vu, N. M. T.; The EUROfusion MST1-team; The TCV-team

2017-12-01

The successful performance of a model predictive profile controller is demonstrated in simulations and experiments on the TCV tokamak, employing a profile controller test environment. Stable high-performance tokamak operation in hybrid and advanced plasma scenarios requires control over the safety factor profile (q-profile) and kinetic plasma parameters such as the plasma beta. This demands to establish reliable profile control routines in presently operational tokamaks. We present a model predictive profile controller that controls the q-profile and plasma beta using power requests to two clusters of gyrotrons and the plasma current request. The performance of the controller is analyzed in both simulation and TCV L-mode discharges where successful tracking of the estimated inverse q-profile as well as plasma beta is demonstrated under uncertain plasma conditions and the presence of disturbances. The controller exploits the knowledge of the time-varying actuator limits in the actuator input calculation itself such that fast transitions between targets are achieved without overshoot. A software environment is employed to prepare and test this and three other profile controllers in parallel in simulations and experiments on TCV. This set of tools includes the rapid plasma transport simulator RAPTOR and various algorithms to reconstruct the plasma equilibrium and plasma profiles by merging the available measurements with model-based predictions. In this work the estimated q-profile is merely based on RAPTOR model predictions due to the absence of internal current density measurements in TCV. These results encourage to further exploit model predictive profile control in experiments on TCV and other (future) tokamaks.

plasmatis Center for Innovation Competence: Controlling reactive component output of atmospheric pressure plasmas in plasma medicine

NASA Astrophysics Data System (ADS)

Reuter, Stephan

2012-10-01

The novel approach of using plasmas in order to alter the local chemistry of cells and cell environment presents a significant development in biomedical applications. The plasmatis center for innovation competence at the INP Greifswald e.V. performs fundamental research in plasma medicine in two interdisciplinary research groups. The aim of our plasma physics research group ``Extracellular Effects'' is (a) quantitative space and time resolved diagnostics and modelling of plasmas and liquids to determine distribution and composition of reactive species (b) to control the plasma and apply differing plasma source concepts in order to produce a tailored output of reactive components and design the chemical composition of the liquids/cellular environment and (c) to identify and understand the interaction mechanisms of plasmas with liquids and biological systems. Methods to characterize the plasma generated reactive species from plasma-, gas- and liquid phase and their biological effects will be presented. The diagnostic spectrum ranges from absorption/emission/laser spectroscopy and molecular beam mass spectrometry to electron paramagnetic resonance spectroscopy and cell biological diagnostic techniques. Concluding, a presentation will be given of the comprehensive approach to plasma medicine in Greifswald where the applied and clinical research of the Campus PlasmaMed association is combined with the fundamental research at plasmatis center.

Study of plasma environments for the integrated Space Station electromagnetic analysis system

NASA Technical Reports Server (NTRS)

Singh, Nagendra

1992-01-01

The final report includes an analysis of various plasma effects on the electromagnetic environment of the Space Station Freedom. Effects of arcing are presented. Concerns of control of arcing by a plasma contactor are highlighted. Generation of waves by contaminant ions are studied and amplitude levels of the waves are estimated. Generation of electromagnetic waves by currents in the structure of the space station, driven by motional EMF, is analyzed and the radiation level is estimated.

Characterization of Magnetospheric Spacecraft Charging Environments Using the LANL Magnetospheric Plasma Analyzer Data Set

NASA Technical Reports Server (NTRS)

Hardage, Donna (Technical Monitor); Davis, V. A.; Mandell, M. J.; Thomsen, M. F.

2003-01-01

An improved specification of the plasma environment has been developed for use in modeling spacecraft charging. It was developed by statistically analyzing a large part of the LANL Magnetospheric Plasma Analyzer (MPA) data set for ion and electron spectral signature correlation with spacecraft charging, including anisotropies. The objective is to identify a relatively simple characterization of the full particle distributions that yield an accurate predication of the observed charging under a wide variety of conditions.

Micro- to macroscale perspectives on space plasmas

NASA Technical Reports Server (NTRS)

Eastman, Timothy E.

1993-01-01

The Earth's magnetosphere is the most accessible of natural collisionless plasma environments; an astrophysical plasma 'laboratory'. Magnetospheric physics has been in an exploration phase since its origin 35 years ago but new coordinated, multipoint observations, theory, modeling, and simulations are moving this highly interdisciplinary field of plasma science into a new phase of synthesis and understanding. Plasma systems are ones in which binary collisions are relatively negligible and collective behavior beyond the microscale emerges. Most readily accessible natural plasma systems are collisional and nearest-neighbor classical interactions compete with longer-range plasma effects. Except for stars, most space plasmas are collisionless, however, and the effects of electrodynamic coupling dominate. Basic physical processes in such collisionless plasmas occur at micro-, meso-, and macroscales that are not merely reducible to each other in certain crucial ways as illustrated for the global coupling of the Earth's magnetosphere and for the nonlinear dynamics of charged particle motion in the magnetotail. Such global coupling and coherence makes the geospace environment, the domain of solar-terrestrial science, the most highly coupled of all physical geospheres.

Review of biased solar arraay. Plasma interaction studies

NASA Technical Reports Server (NTRS)

Stevens, N. J.

1981-01-01

The Solar Electric Propulsion System (SEPS) is proposed for a variety of space missions. Power for operating SEPS is obtained from large solar array wings capable of generating tens of kilowatts of power. To minimize resistive losses in the solar array bus lines, the array is designed to operate at voltages up to 400 volts. This use of high voltage can increase interactions between the biased solar cell interconnects and plasma environments. With thrusters operating, the system ground is maintained at space plasma potential which exposes large areas of the arrays at the operating voltages. This can increase interactions with both the natural and enhanced charged particle environments. Available data on interactions between biased solar array surfaces and plasma environments are summarized. The apparent relationship between collection phenomena and solar cell size and effects of array size on interactions are discussed. The impact of these interactions on SEPS performance is presented.

A Comparison of Atomic Oxygen Degradation in Low Earth Orbit and in a Plasma Etcher

NASA Technical Reports Server (NTRS)

Townsend, Jacqueline A.; Park, Gloria

1997-01-01

In low Earth orbit (LEO) significant degradation of certain materials occurs from exposure to atomic oxygen (AO). Orbital opportunities to study this degradation for specific materials are limited and expensive. While plasma etchers are commonly used in ground-based studies because of their low cost and convenience, the environment produced in an etcher chamber differs greatly from the LEO environment. Because of the differences in environment, the validity of using etcher data has remained an open question. In this paper, degradation data for 22 materials from the orbital experiment Evaluation of Oxygen Interaction with Materials (EOIM-3) are compared with data from EOIM-3 control specimens exposed in a typical plasma etcher. This comparison indicates that, when carefully considered, plasma etcher results can produce order-of-magnitude estimates of orbital degradation. This allows the etcher to be used to screen unacceptable materials from further, more expensive tests.

Interpretation of STS-3/plasma diagnostics package results in terms of large space structure plasma interactions

NASA Technical Reports Server (NTRS)

Kurth, W. S.

1984-01-01

The Plasma Diagnostics Package, which was flown aboard STS-3 recorded various chemical releases from the Orbiter. Changes in the plasma environment were observed to occur during Flash Evaporator System (FES) releases, water dumps and maneuvering thruster operations. During flash evaporator operations, broadband Orbiter-generated electro-static noise is enhanced and plasma density irregularity (delta n/N) is observed to increase by as much as 4 times and is strongly peaked below 6 Hz. In the case of water dumps, background electrostatic noise is enhanced or suppressed depending on frequency and Delta N/N is also seen to increase by as much as 4 times. Various changes in the plasma environment are effected by primary and vernier thruster operations. In addition, thruster activity stimulates electrostatic noise with a spectrum which is most intense at frequencies below 10 kHz.

Electron and proton absorption calculations for a graphite/epoxy composite model. [large space structures

NASA Technical Reports Server (NTRS)

Long, E. R., Jr.

1979-01-01

The Bethe-Bloch stopping power relations for inelastic collisions were used to determine the absorption of electron and proton energy in cured neat epoxy resin and the absorption of electron energy in a graphite/epoxy composite. Absorption of electron energy due to bremsstrahlung was determined. Electron energies from 0.2 to 4.0 MeV and proton energies from 0.3 to 1.75 MeV were used. Monoenergetic electron energy absorption profiles for models of pure graphite, cured neat epoxy resin, and graphite/epoxy composites are reported. A relation is determined for depth of uniform energy absorption in a composite as a function of fiber volume fraction and initial electron energy. Monoenergetic proton energy absorption profiles are reported for the neat resin model. A relation for total proton penetration in the epoxy resin as a function of initial proton energy is determined. Electron energy absorption in the composite due to bremsstrahlung is reported. Electron and proton energy absorption profiles in cured neat epoxy resin are reported for environments approximating geosynchronous earth orbit.

COOP 3D ARPA Experiment 109 National Center for Atmospheric Research

NASA Technical Reports Server (NTRS)

1998-01-01

Coupled atmospheric and hydrodynamic forecast models were executed on the supercomputing resources of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado and the Ohio Supercomputing Center (OSC)in Columbus, Ohio. respectively. The interoperation of the forecast models on these geographically diverse, high performance Cray platforms required the transfer of large three dimensional data sets at very high information rates. High capacity, terrestrial fiber optic transmission system technologies were integrated with those of an experimental high speed communications satellite in Geosynchronous Earth Orbit (GEO) to test the integration of the two systems. Operation over a spacecraft in GEO orbit required modification of the standard configuration of legacy data communications protocols to facilitate their ability to perform efficiently in the changing environment characteristic of a hybrid network. The success of this performance tuning enabled the use of such an architecture to facilitate high data rate, fiber optic quality data communications between high performance systems not accessible to standard terrestrial fiber transmission systems. Thus obviating the performance degradation often found in contemporary earth/satellite hybrids.

Space solar cell research: Problems and potential

NASA Technical Reports Server (NTRS)

Flood, D. J.

1986-01-01

The value of a passive, maintenance-free, renewable energy source was apparent in the early days of the space program, and the silicon solar cell was pressed into service. Efficiencies of those early space solar arrays were low, and lifetimes shorter than hoped for, but within a decade significant advances had been made in both areas. Better performance was achieved through improvements in silicon single crystal material, better device designs, and a better understanding of the factors that affect the performance of a solar cell in space. Chief among the latter, particularly for the mid-to-high altitude (HEO) and geosynchronous (GEO) orbits, are the effects of the naturally occurring particulate radiation environment. Although not as broadly important to the photovoltaic community at large as increased efficiency, the topic of radiation damage is critically important to use of solar cells in space, and is a major component of the NASA research program in space photovoltaics. A brief overview of some of the opportunities and challenges for space photovoltaic applications is given, and some of the current research directed at achieving high efficiency and controlling radiation damage in space solar cells is discussed.

Analysis and verification of a prediction model of solar energetic proton events

NASA Astrophysics Data System (ADS)

Wang, J.; Zhong, Q.

2017-12-01

The solar energetic particle event can cause severe radiation damages near Earth. The alerts and summary products of the solar energetic proton events were provided by the Space Environment Prediction Center (SEPC) according to the flux of the greater than 10 MeV protons taken by GOES satellite in geosynchronous orbit. The start of a solar energetic proton event is defined as the time when the flux of the greater than 10 MeV protons equals or exceeds 10 proton flux units (pfu). In this study, a model was developed to predict the solar energetic proton events, provide the warning for the solar energetic proton events at least minutes in advance, based on both the soft X-ray flux and integral proton flux taken by GOES. The quality of the forecast model was measured against verifications of accuracy, reliability, discrimination capability, and forecast skills. The peak flux and rise time of the solar energetic proton events in the six channels, >1MeV, >5 MeV, >10 MeV, >30 MeV, >50 MeV, >100 MeV, were also simulated and analyzed.

The impact of solar cell technology on planar solar array performance

NASA Technical Reports Server (NTRS)

Mills, Michael W.; Kurland, Richard M.

1989-01-01

The results of a study into the potential impact of advanced solar cell technologies on the characteristics (weight, cost, area) of typical planar solar arrays designed for low, medium and geosynchronous altitude earth orbits are discussed. The study considered planar solar array substrate designs of lightweight, rigid-panel graphite epoxy and ultra-lightweight Kapton. The study proposed to answer the following questions: Do improved cell characteristics translate into array-level weight, size and cost improvements; What is the relative importance of cell efficiency, weight and cost with respect to array-level performance; How does mission orbital environment affect array-level performance. Comparisons were made at the array level including all mechanisms, hinges, booms, and harnesses. Array designs were sized to provide 5kW of array power (not spacecraft bus power, which is system dependent but can be scaled from given values). The study used important grass roots issues such as use of the GaAs radiation damage coefficients as determined by Anspaugh. Detailed costing was prepared, including cell and cover costs, and manufacturing attrition rates for the various cell types.

Characterizing GEO Titan Transtage Fragmentations using Ground-based Measurements

NASA Technical Reports Server (NTRS)

Cowardin, H.; Anz-Meador, P.

2016-01-01

In a continued effort to better characterize the Geosynchronous Orbit (GEO) environment, NASA's Orbital Debris Program Office (ODPO) utilizes various ground-based optical assets to acquire photometric and spectral data of known debris associated with fragmentations in or near GEO. The Titan IIIC Transtage upper stage is known to have fragmented four times. Two of the four fragmentations were in GEO while a third Transtage fragmented in GEO transfer orbit. The forth fragmentation occurred in Low Earth Orbit. In order to better assess what may be causing these fragmentations, the NASA ODPO recently acquired a Titan Transtage test and display article that was previously in the custody of the 309th Aerospace Maintenance and Regeneration Group (AMARG) in Tucson, Arizona. After initial inspections at AMARG demonstrated that the test article was of sufficient fidelity to be of interest, the test article was brought to JSC to continue material analysis and historical documentation of the Titan Transtage. The Transtage will be a subject of forensic analysis using spectral measurements to compare with telescopic data; as well, a scale model will be created to use in the Optical Measurement Center for photometric analysis of an intact Transtage, including a BRDF. The following presentation will provide a review of the Titan Transtage, the current analysis that has been done to date, and the future work to be completed in support of characterizing the GEO and near GEO orbital debris environment.

Electrostatic Discharge Test of Multi-Junction Solar Array Coupons After Combined Space Environmental Exposures

NASA Technical Reports Server (NTRS)

Wright, Kenneth H.; Schneider, Todd; Vaughn, Jason; Hoang, Bao; Funderburk, Victor V.; Wong, Frankie; Gardiner, George

2010-01-01

A set of multi-junction GaAs/Ge solar array test coupons were subjected to a sequence of 5-year increments of combined environmental exposure tests. The test coupons capture an integrated design intended for use in a geosynchronous (GEO) space environment. A key component of this test campaign is conducting electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO/CD 11221, the ISO standard for ESD testing on solar array panels. This standard is currently in its final review with expected approval in 2010. The test schematic in the ISO reference has been modified with Space System/Loral designed circuitry to better simulate the on-orbit operational conditions of its solar array design. Part of the modified circuitry is to simulate a solar array panel coverglass flashover discharge. All solar array coupons used in the test campaign consist of 4 cells. The ESD tests are performed at the beginning of life (BOL) and at each 5-year environment exposure point. The environmental exposure sequence consists of UV radiation, electron/proton particle radiation, thermal cycling, and ion thruster plume. This paper discusses the coverglass flashover simulation, ESD test setup, and the importance of the electrical test design in simulating the on-orbit operational conditions. Results from 5th-year testing are compared to the baseline ESD characteristics determined at the BOL condition.

Current and Near-Term Future Measurements of the Orbital Debris Environment at NASA

NASA Technical Reports Server (NTRS)

Stansbery, Gene; Liou, J.-C.; Mulrooney, M.; Horstman, M

2010-01-01

The NASA Orbital Debris Program Office places great emphasis on obtaining and understanding direct measurements of the orbital debris environment. The Orbital Debris Program Office's environmental models are all based on these measurements. Because OD measurements must cover a very wide range of sizes and altitudes, one technique realistically cannot be used for all measurements. In general, radar measurements have been used for lower altitudes and optical measurements for higher altitude orbits. For very small debris, in situ measurements such as returned spacecraft surfaces are utilized. In addition to receiving information from large debris (> 5-10 cm diameter) from the U.S. Space Surveillance Network, NASA conducts statistical measurements of the debris population for smaller sizes. NASA collects data from the Haystack and Goldstone radars for debris in low Earth orbit as small as 2- 4 mm diameter and from the Michigan Orbital DEbris Survey Telescope for debris near geosynchronous orbit altitude for sizes as small as 30-60 cm diameter. NASA is also currently examining the radiator panel of the Hubble Space Telescope Wide Field Planetary Camera 2 which was exposed to space for 16 years and was recently returned to Earth during the STS- 125 Space Shuttle mission. This paper will give an overview of these on-going measurement programs at NASA as well as discuss progress and plans for new instruments and techniques in the near future.

A comprehensive picture of Callisto's magnetic and cold plasma environment during the Galileo era and implications for JUICE

NASA Astrophysics Data System (ADS)

Liuzzo, L.; Simon, S.; Feyerabend, M.; Motschmann, U. M.

2017-12-01

We apply data analysis techniques and hybrid modeling to study Callisto's interaction with Jupiter's magnetosphere. Magnetometer data from the C3 and C9 Galileo flybys had been explained with a pure induction model, as the plasma interaction was weak. We expand this analysis to include the remaining five flybys (C10, C21, C22, C23, C30) where the plasma interaction was non-negligible. We therefore consider contributions to Callisto's magnetic environment generated by induction as well as the plasma interaction. We have identified a quasi-dipolar "core region" near Callisto's wakeside surface, dominated by induction and partially shielded from the plasma interaction. Outside of this region, Callisto's magnetic environment is characterized by field line draping. Future flybys during the upcoming JUICE mission may sample the wakeside "core region" to better constrain the conductivity, thickness, and depth of Callisto's subsurface ocean. Our analysis also shows that even during a single flyby, various non-stationarities in the upstream environment may be present near Callisto, which may partially obscure the magnetic signature of the moon's subsurface ocean. Overall, our study provides a complete three-dimensional picture of Callisto's magnetic environment during the Galileo era, based on all available magnetometer data from the Galileo flybys. We apply our understanding to the future JUICE flybys of Callisto to determine which encounters will be best to identify Callisto's inductive response in magnetometer data.

Protein diffusion in plant cell plasma membranes: the cell-wall corral.

PubMed

Martinière, Alexandre; Runions, John

2013-01-01

Studying protein diffusion informs us about how proteins interact with their environment. Work on protein diffusion over the last several decades has illustrated the complex nature of biological lipid bilayers. The plasma membrane contains an array of membrane-spanning proteins or proteins with peripheral membrane associations. Maintenance of plasma membrane microstructure can be via physical features that provide intrinsic ordering such as lipid microdomains, or from membrane-associated structures such as the cytoskeleton. Recent evidence indicates, that in the case of plant cells, the cell wall seems to be a major player in maintaining plasma membrane microstructure. This interconnection / interaction between cell-wall and plasma membrane proteins most likely plays an important role in signal transduction, cell growth, and cell physiological responses to the environment.

A fluorogenic probe for SNAP-tagged plasma membrane proteins based on the solvatochromic molecule Nile Red.

PubMed

Prifti, Efthymia; Reymond, Luc; Umebayashi, Miwa; Hovius, Ruud; Riezman, Howard; Johnsson, Kai

2014-03-21

A fluorogenic probe for plasma membrane proteins based on the dye Nile Red and SNAP-tag is introduced. It takes advantage of Nile Red, a solvatochromic molecule highly fluorescent in an apolar environment, such as cellular membranes, but almost dark in a polar aqueous environment. The probe possesses a tuned affinity for membranes allowing its Nile Red moiety to insert into the lipid bilayer of the plasma membrane, becoming fluorescent, only after its conjugation to a SNAP-tagged plasma membrane protein. The fluorogenic character of the probe was demonstrated for different SNAP-tag fusion proteins, including the human insulin receptor. This work introduces a new approach for generating a powerful turn-on probe for "no-wash" labeling of plasma membrane proteins with numerous applications in bioimaging.

Method for determining the effects of oxygen plasma on a specimen

NASA Technical Reports Server (NTRS)

Whitaker, Ann F. (Inventor)

1991-01-01

A method for determining the effects of exposure of oxygen plasma on a specimen such as a thin film polymer or thin metals. The method includes providing an apparatus with a chamber having a holder supporting the polymer specimen in a plasma environment provided in the chamber. The chamber is regulated to a predetermined pressure and set temperature prior to the introduction of oxygen plasma therein. The specimen is then subjected to the plasma environment for a predetermined time during which time the temperature of the specimen is sensed and regulated to be maintained at the set temperature. Temperature sensing is accomplished by a probe which senses any changes in bulk sample temperature. Temperature regulation is provided by a thermoelectric module and by a coolant flow tube.

The Plasma Environment at Enceladus

NASA Astrophysics Data System (ADS)

Rymer, Abigail; Morooka, Michiko; Persoon, Ann

2016-10-01

The plasma environment near Enceladus is complex. The well documented Enceladus plumes create a dusty, asymmetric exosphere in which electrons can attach to small ice particles - forming anions, and negatively charged nanograins and dust - to the extent that cations can be the lightest charged particles present and, as a result, the dominant current carriers. Several instruments on the Cassini spacecraft are able to measure this environment in both expected and unexpected ways. Cassini Plasma Spectrometer (CAPS) is designed and calibrated to measure the thermal plasma ions and electrons and also measures the energy/charge of charged nanograins when present. Cassini Radio Plasma Wave Sensor (RPWS) measures electron density as derived from the 'upper hybrid frequency' which is a function of the total free electron density and magnetic field strength and provides a vital ground truth measurement for Cassini calibration when the density is sufficiently high for it to be well measured. Cassini Langmuir Probe (LP) measures the electron density and temperature via direct current measurement, and both CAPS and LP can provide estimates for the spacecraft potential which we compare. Cassini Magnetospheric Imaging Instrument (MIMI) directly measures energetic particles that are manifest in the CAPS measurements as penetrating background in this region and, while not particularly efficient ionisers, create sputtering and surface weathering of Enceladus surface, MIMI also measures energetic neutral atoms produced during the charge exchange interactions in and near the plumes.In this presentation we exploit two almost identical Cassini-Enceladus flybys 'E17' and 'E18' which took place in March/April 2012. We present a detailed comparison of data from these Cassini sensors in order to assess the plasma environment observed by the different instruments, discuss what is consistent and otherwise, and the implications for the plasma environment at Enceladus in the context of work to date as well as implications for future studies.

Organizational Changes to Thyroid Regulation in Alligator mississippiensis: Evidence for Predictive Adaptive Responses

PubMed Central

Boggs, Ashley S. P.; Lowers, Russell H.; Cloy-McCoy, Jessica A.; Guillette, Louis J.

2013-01-01

During embryonic development, organisms are sensitive to changes in thyroid hormone signaling which can reset the hypothalamic-pituitary-thyroid axis. It has been hypothesized that this developmental programming is a ‘predictive adaptive response’, a physiological adjustment in accordance with the embryonic environment that will best aid an individual's survival in a similar postnatal environment. When the embryonic environment is a poor predictor of the external environment, the developmental changes are no longer adaptive and can result in disease states. We predicted that endocrine disrupting chemicals (EDCs) and environmentally-based iodide imbalance could lead to developmental changes to the thyroid axis. To explore whether iodide or EDCs could alter developmental programming, we collected American alligator eggs from an estuarine environment with high iodide availability and elevated thyroid-specific EDCs, a freshwater environment contaminated with elevated agriculturally derived EDCs, and a reference freshwater environment. We then incubated them under identical conditions. We examined plasma thyroxine and triiodothyronine concentrations, thyroid gland histology, plasma inorganic iodide, and somatic growth at one week (before external nutrition) and ten months after hatching (on identical diets). Neonates from the estuarine environment were thyrotoxic, expressing follicular cell hyperplasia (p = 0.01) and elevated plasma triiodothyronine concentrations (p = 0.0006) closely tied to plasma iodide concentrations (p = 0.003). Neonates from the freshwater contaminated site were hypothyroid, expressing thyroid follicular cell hyperplasia (p = 0.01) and depressed plasma thyroxine concentrations (p = 0.008). Following a ten month growth period under identical conditions, thyroid histology (hyperplasia p = 0.04; colloid depletion p = 0.01) and somatic growth (body mass p<0.0001; length p = 0.02) remained altered among the contaminated sites. This work supports the hypothesis that embryonic EDC exposure or iodide imbalance could induce adult metabolic disease states, thereby stressing the need to consider the multiple environmental variables present during development. PMID:23383213

A socio-economic evaluation of the lunar environment and resources. I. Principles and overall system strategy

NASA Astrophysics Data System (ADS)

Ehricke, Krafft A.

This first of several study papers, based on a fundamental paper presented in 1972, provides an independent conceptual analysis and evaluation of the lunar environment as industrial base and habitat. A selenosphere system strategy is outlined. The underlying concept is that of one or several lunar industrial zones for resource extraction and on-surface processing, integrated with a circumlunar zero-g processing capability, serving markets in geolunar space. A classification of lunar elements by utilization category is presented. Lunar oxygen is a prime candidate for being an initial economic "drawing card", because of its value for fast transportation in geolunar space, requiring significantly fewer ships for equal transfer capability per unit time than electric transports which, however, have value, especially between geosynchronous and lunar orbit. The reduced development difficulties of controlled fusion outside the atmosphere and its advantages for extracting oxygen and other elements in quantity are summarized. Examples of lunar cycle management as fundamental exoindustrial requirement for economic resource enhancement are presented. The principal initial socio-economic value of lunar industry lies in the use of lunar resources for exoindustrial products and operations designed to accelerate, intensify and diversify Earth-related benefits. In the longer run, lunar settlements are a highly suitable proving ground for studying and testing the complex matrix of technological, biological, cultural, social and psychological aspects that must be understood and manageable before large settlements beyond Earth can have a realistic basis for viability. The lunar environment is more suitable for experimentation and comparatively more "forgiving" in case of failures than is orbital space.

Progress in Development of the ITER Plasma Control System Simulation Platform

NASA Astrophysics Data System (ADS)

Walker, Michael; Humphreys, David; Sammuli, Brian; Ambrosino, Giuseppe; de Tommasi, Gianmaria; Mattei, Massimiliano; Raupp, Gerhard; Treutterer, Wolfgang; Winter, Axel

2017-10-01

We report on progress made and expected uses of the Plasma Control System Simulation Platform (PCSSP), the primary test environment for development of the ITER Plasma Control System (PCS). PCSSP will be used for verification and validation of the ITER PCS Final Design for First Plasma, to be completed in 2020. We discuss the objectives of PCSSP, its overall structure, selected features, application to existing devices, and expected evolution over the lifetime of the ITER PCS. We describe an archiving solution for simulation results, methods for incorporating physics models of the plasma and physical plant (tokamak, actuator, and diagnostic systems) into PCSSP, and defining characteristics of models suitable for a plasma control development environment such as PCSSP. Applications of PCSSP simulation models including resistive plasma equilibrium evolution are demonstrated. PCSSP development supported by ITER Organization under ITER/CTS/6000000037. Resistive evolution code developed under General Atomics' Internal funding. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

Canadian radiation belt science in the ILWS era

NASA Astrophysics Data System (ADS)

Mann, I. R.

The Outer Radiation Belt Injection, Transport, Acceleration, and Loss Satellite (ORBITALS) is a Canadian Space Agency small satellite mission proposed as a Canadian contribution to the satellite infrastructure for the International Living With a Star (ILWS) program. Planned to operate contemporaneously with the NASA Radiation Belt Storm Probes (RBSP), the ORBITALS will monitor the energetic electron and ion populations in the inner magnetosphere across a wide range of energies (keV to tens of MeV) as well as the dynamic electric and magnetic fields, waves, and cold plasma environment which govern the injection, transport, acceleration and loss of these energetic and space weather critical particle populations in the inner magnetosphere. Currently in Phase A Design Study, the ORBITALS will be launched into a low-inclination GTO-like orbit which every second orbit maximizes the long lasting apogee-pass conjunctions with both the ground-based instruments of the Canadian Geospace Monitoring (CGSM) array as well as with the GOES East and West and geosynchronous communications satellites in the North American sector. In a twelve-hour orbit, every second apogee will conjunct with instrumentation 180 degree in longitude away in the Asian sector. Specifically, the ORBITALS will make the measurements necessary to reach reveal fundamental new understanding of the relative importance of different physical processes (for example VLF verses ULF waves) which shape the energetic particle populations in the inner magnetosphere, as well as providing the raw radiation measurements at MEO altitudes necessary for the development of the next-generation of radiation belt specification models. On-board experiments will also monitor the dose, single event upset, and deep-dielectric charging responses of electronic components on-orbit. Supporting ground-based measurements of ULF and higher frequency wave fields from the Canadian CARISMA (www.carisma.ca) magnetometer array, as well as from other distributed networks of ground-based instrumentation will also be critical for reaching science closure. This paper outlines the radiation belt science targets for the ORBITALS mission, and describe how the ORBITALS can provide an essential complement to other proposed inner magnetospheric missions in the ILWS era.

A prototype Knowledge-Based System to Aid Space System Restoration Management.

DTIC Science & Technology

1986-12-01

Systems. ......... 122 Appendix B: Computation of Weights With AHP . . .. 132 Appendix C: ART Code .. ............... 138 Appendix D: Test Outputs...45 5.1 Earth Coverage With Geosynchronous Satellites 49 5.2 Space System Configurations ... ........... . 50 5.3 AHP Hierarchy...67 5.4 AHP Hierarchy With Weights .... ............ 68 6.1 TALK Schema Structure ..... .............. 75 6.2 ART Code for TALK Satellite C

Geosynchronous Orbit Determination Using Space Surveillance Network Observations and Improved Radiative Force Modeling

DTIC Science & Technology

2004-06-01

equinoctial elements , because both sets of orbital elements reference the equinoctial coordinate system. In fact, to...spacecraft position and velocity vectors, or an element set , which represents the orbit using scalar quantities and angle measurements called orbital ...common element sets used to describe elliptical orbits (including circular orbits ) are Keplerian elements , also called classical orbital

Constellation Design of Geosynchronous Navigation Satellites Which Maximizes Availability and Accuracy Over a Specified Region of the Earth

DTIC Science & Technology

2008-03-01

Society, Washington DC, 1999. 11. Ferringer, Matthew P. and David B. Spencer . “Satellite Constellation Design Optimization Via Multiple-Objective...5 GA Genetic Algorithms . . . . . . . . . . . . . . . . . . . . . . 5 HEO Highly Elliptical Orbit...and their phasing relationship. He analyzed different combinations of GEO, Highly Elliptical Orbit (HEO)1 and Tundra2 orbits to create a global

Orbit decay analysis of STS upper stage boosters

NASA Technical Reports Server (NTRS)

Graf, O. F., Jr.; Mueller, A. C.

1979-01-01

An orbit decay analysis of the space transportation system upper stage boosters is presented. An overview of the computer trajectory programs, DSTROB, algorithm is presented. Atmospheric drag and perturbation models are described. The development of launch windows, such that the transfer orbit will decay within two years, is discussed. A study of the lifetimes of geosynchronous transfer orbits is presented.

Plots of ground coverage achieveable by global change monitoring instruments and spacecraft

NASA Technical Reports Server (NTRS)

Knight, Heather R.; Foernsler, Lynda

1991-01-01

Low Earth Orbit (LEO) and Geosynchronous Earth Orbit (GEO) satellite plots are given. All satellites are in an 800 km circular orbit at an inclination of 98.6 deg (sun synchronous). Specifics of the instrument package are given. Additionally, the time period of the plot and the percentage of the Earth covered during the time period are listed.

Solar power satellite system definition study. Part 2, volume 5: Space operations (construction and transportation)

NASA Technical Reports Server (NTRS)

Miller, K.; Davis, E. E.

1977-01-01

Construction and transportation systems and operations are described for the following combinations: (1) silicon photovoltaic CR=1 satellite constructed primarily in low earth orbit (LEO); (2) silicon photovoltaic CR=1 satellite constructed in geosynchronous earth orbit (GEO); (3) Rankine thermal engine satellite constructed primarily in LEO; and (4) Rankine thermal engine satellite constructed in GEO.

Early Program Development

NASA Image and Video Library

1970-01-01

In this 1970 artist's concept, the Nuclear Shuttle is shown in its lunar and geosynchronous orbit configuration and in its planetary mission configuration. As envisioned by Marshall Space Flight Center Program Development plarners, the Nuclear Shuttle would deliver payloads to lunar orbit or other destinations then return to Earth orbit for refueling. A cluster of Nuclear Shuttle units could form the basis for planetary missions.

Early Program Development

NASA Image and Video Library

1989-01-01

In June 1989 the Marshall Space Flight Center initiated studies of Space Transfer Vehicle (STV) concepts. A successor to the Orbital Transfer Vehicle (OTV) concept, the STV would be a high-performance space vehicle capable of transferring automated payloads from a Space Station to geosynchronous orbits, the Moon, or planets. Illustrated in this artist's concept are two STV's undergoing aerobraking maneuvers as they approach a Space Station.

Full-Particle Simulations on Electrostatic Plasma Environment near Lunar Vertical Holes

NASA Astrophysics Data System (ADS)

Miyake, Y.; Nishino, M. N.

2015-12-01

The Kaguya satellite and the Lunar Reconnaissance Orbiter have observed a number of vertical holes on the terrestrial Moon [Haruyama et al., GRL, 2009; Robinson et al., PSS, 2012], which have spatial scales of tens of meters and are possible lava tube skylights. The hole structure has recently received particular attention, because the structure gives an important clue to the complex volcanic history of the Moon. The holes also have high potential as locations for constructing future lunar bases, because of fewer extra-lunar rays/particles and micrometeorites reaching the hole bottoms. In this sense, these holes are not only interesting in selenology, but are also significant from the viewpoint of electrostatic environments. The subject can also be an interesting resource of research in comparative planetary science, because hole structures have been found in other solar system bodies such as the Mars. The lunar dayside electrostatic environment is governed by electrodynamic interactions among the solar wind plasma, photoelectrons, and the charged lunar surface, providing topologically complex boundaries to the plasma. We use the three-dimensional, massively-parallelized, particle-in-cell simulation code EMSES [Miyake and Usui, POP, 2009] to simulate the near-hole plasma environment on the Moon [Miyake and Nishino, Icarus, 2015]. We took into account the solar wind plasma downflow, photoelectron emission from the sunlit part of the lunar surface, and plasma charge deposition on the surface. The simulation domain consists of 400×400×2000 grid points and contains about 25 billion plasma macro-particles. Thus, we need to use supercomputers for the simulations. The vertical wall of the hole introduces a new boundary for both photo and solar wind electrons. The current balance condition established at a hole bottom is altered by the limited solar wind electron penetration into the hole and complex photoelectron current paths inside the hole. The self-consistent modeling not only reproduces intense differential charging between sunlit and shadowed surfaces, but also reveals the potential difference between sunlit surfaces inside and outside the hole. The results demonstrate the uniqueness of the near-hole plasma environment as well as provide useful knowledge for future landing missions.

Gravitational force and torque on a solar power satellite considering the structural flexibility

NASA Astrophysics Data System (ADS)

Zhao, Yi; Zhang, Jingrui; Zhang, Yao; Zhang, Jun; Hu, Quan

2017-11-01

The solar power satellites (SPS) are designed to collect the constant solar energy and beam it to Earth. They are traditionally large in scale and flexible in structure. In order to obtain an accurate model of such system, the analytical expressions of the gravitational force, gravity gradient torque and modal force are investigated. They are expanded to the fourth order in a Taylor series with the elastic displacements considered. It is assumed that the deformation of the structure is relatively small compared with its characteristic length, so that the assumed mode method is applicable. The high-order moments of inertia and flexibility coefficients are presented. The comprehensive dynamics of a large flexible SPS and its orbital, attitude and vibration evolutions with different order gravitational forces, gravity gradient torques and modal forces in geosynchronous Earth orbit are performed. Numerical simulations show that an accurate representation of the SPS‧ dynamic characteristics requires the retention of the higher moments of inertia and flexibility. Perturbations of orbit, attitude and vibration can be retained to the 1-2nd order gravitational forces, the 1-2nd order gravity gradient torques and the 1-2nd order modal forces for a large flexible SPS in geosynchronous Earth orbit.

Numerical Analysis of Orbital Perturbation Effects on Inclined Geosynchronous SAR

PubMed Central

Dong, Xichao; Hu, Cheng; Long, Teng; Li, Yuanhao

2016-01-01

The geosynchronous synthetic aperture radar (GEO SAR) is susceptible to orbit perturbations, leading to orbit drifts and variations. The influences behave very differently from those in low Earth orbit (LEO) SAR. In this paper, the impacts of perturbations on GEO SAR orbital elements are modelled based on the perturbed dynamic equations, and then, the focusing is analyzed theoretically and numerically by using the Systems Tool Kit (STK) software. The accurate GEO SAR slant range histories can be calculated according to the perturbed orbit positions in STK. The perturbed slant range errors are mainly the first and second derivatives, leading to image drifts and defocusing. Simulations of the point target imaging are performed to validate the aforementioned analysis. In the GEO SAR with an inclination of 53° and an argument of perigee of 90°, the Doppler parameters and the integration time are different and dependent on the geometry configurations. Thus, the influences are varying at different orbit positions: at the equator, the first-order phase errors should be mainly considered; at the perigee and apogee, the second-order phase errors should be mainly considered; at other positions, first-order and second-order exist simultaneously. PMID:27598168

Empirical analysis of storm-time energetic electron enhancements

NASA Astrophysics Data System (ADS)

O'Brien, Thomas Paul, III

This Ph.D. thesis documents a program for studying the appearance of energetic electrons in the Earth's outer radiation belts that is associated with many geomagnetic storms. The dynamic evolution of the electron radiation belts is an outstanding empirical problem in both theoretical space physics and its applied sibling, space weather. The project emphasizes the development of empirical tools and their use in testing several theoretical models of the energization of the electron belts. First, I develop the Statistical Asynchronous Regression technique to provide proxy electron fluxes throughout the parts of the radiation belts explored by geosynchronous and GPS spacecraft. Next, I show that a theoretical adiabatic model can relate the local time asymmetry of the proxy geosynchronous fluxes to the asymmetry of the geomagnetic field. Then, I perform a superposed epoch analysis on the proxy fluxes at local noon to identify magnetospheric and interplanetary precursors of relativistic electron enhancements. Finally, I use statistical and neural network phase space analyses to determine the hourly evolution of flux at a virtual stationary monitor. The dynamic equation quantitatively identifies the importance of different drivers of the electron belts. This project provides empirical constraints on theoretical models of electron acceleration.

Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes

DOE PAGES

Sarno-Smith, Lois K.; Larsen, Brian A.; Skoug, Ruth M.; ...

2016-02-27

Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H+ charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV.more » It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. Furthermore, we also show noneclipse significant negative charging events on the Van Allen Probes.« less

Spacecraft design project: High latitude communications satellite

NASA Technical Reports Server (NTRS)

Josefson, Carl; Myers, Jack; Cloutier, Mike; Paluszek, Steve; Michael, Gerry; Hunter, Dan; Sakoda, Dan; Walters, Wes; Johnson, Dennis; Bauer, Terry

1989-01-01

The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage.

Method of processing materials using an inductively coupled plasma

DOEpatents

Hull, Donald E.; Bieniewski, Thomas M.

1990-01-01

A method for making fine power using an inductively coupled plasma. The method provides a gas-free environment, since the plasma is formed without using a gas. The starting material used in the method is in solid form.

Current leakage for low altitude satellites - Modeling applications. [simulation of high voltage solar cell array in ionospheric plasma environment

NASA Technical Reports Server (NTRS)

Konradi, A.; Mccoy, J. E.; Garriott, O. K.

1979-01-01

To simulate the behavior of a high voltage solar cell array in the ionospheric plasma environment, the large (90 ft x 55 ft diameter) vacuum chamber was used to measure the high-voltage plasma interactions of a 3 ft x 30 ft conductive panel. The chamber was filled with Nitrogen and Argon plasma at electron densities of up to 1,000,000 per cu cm. Measurements of current flow to the plasma were made in three configurations: (a) with one end of the panel grounded, (b) with the whole panel floating while a high bias was applied between the ends of the panel, and (c) with the whole panel at high negative voltage with respect to the chamber walls. The results indicate that a simple model with a constant panel conductivity and plasma resistance can adequately describe the voltage distribution along the panel and the plasma current flow. As expected, when a high potential difference is applied to the panel ends more than 95% of the panel floats negative with respect to the plasma.

Comprehensive Study of Plasma-Wall Sheath Transport Phenomena

DTIC Science & Technology

2012-09-10

environment, a Langmuir probe and a Retarding Potential Analyzer (RPA). The Langmuir probe could be considered the seminal plasma diagnostic, and a large...plasma-sheath interface. Electric field is normalized by Te/LD (LD is the Debye length) and velocity is normalized by the Bohm speed. Figure 14...studying the interaction of the near-wall plasma sheath with a magnetic field , and modeled the plasma sheath of the GT thick-sheath (~10mm) plasma

Particle-In-Cell Simulations on Electric Field Antenna Characteristics in the Spacecraft Environment

NASA Astrophysics Data System (ADS)

Miyake, Y.; Usui, H.; Kojima, H.; Omura, Y.; Matsumoto, H.

2006-12-01

The Solar Terrestrial Physics (STP) group in Japan has organized a new magnetospheric mission named SCOPE whose objective is to investigate the scale-coupling process of plasma dynamics in the Terrestrial magnetosphere. For the sophisticated electric field measurements planned in the SCOPE mission, we have to investigate the antenna characteristics which are essential for the precise calibration of observed data. Particularly, (1) realistic antenna geometries including spacecraft body and (2) inhomogeneous plasma environment created by plasma-spacecraft interactions should be taken into consideration in the antenna analysis for application to the scientific mission. However, the analysis of the antenna impedance is very complex because the plasma is a dispersive and anisotropic medium, and thus it is too difficult to consider the realistic plasma environment near the spacecraft by the theoretical approaches. In the present study, we apply the Particle-In-Cell simulations to the antenna analysis, which enables us to treat the antenna model including a spacecraft body and analyze the effects of photoelectron emission on antenna characteristics. The present antenna model consists of perfect conducting antennas and spacecraft body, and the photoelectron emission from the sunlit surfaces is also modeled. Using these models, we first performed the electrostatic simulations and examined the photoelectron environment around the spacecraft. Next, the antenna impedance under the obtained photoelectron environment was examined by the electromagnetic simulations. Impedance values obtained in photoelectron environment were much different from those in free space, and they were analogous to the impedance characteristics of an equivalent electric circuit consisting of a resistance and capacitance connected in parallel. The validity of the obtained values has been examined by the comparison with the measurements by the scientific spacecraft.

Multifluid MHD Simulations of the Plasma Environment of Comet Churyumov-Gerasimenko at Different Heliocentric Distances

NASA Astrophysics Data System (ADS)

Huang, Z.; Jia, X.; Rubin, M.; Fougere, N.; Gombosi, T. I.; Tenishev, V.; Combi, M. R.; Bieler, A. M.; Toth, G.; Hansen, K. C.; Shou, Y.

2014-12-01

We study the plasma environment of the comet Churyumov-Gerasimenko, which is the target of the Rosetta mission, by performing large scale numerical simulations. Our model is based on BATS-R-US within the Space Weather Modeling Framework that solves the governing multifluid MHD equations, which describe the behavior of the cometary heavy ions, the solar wind protons, and electrons. The model includes various mass loading processes, including ionization, charge exchange, dissociative ion-electron recombination, as well as collisional interactions between different fluids. The neutral background used in our MHD simulations is provided by a kinetic Direct Simulation Monte Carlo (DSMC) model. We will simulate how the cometary plasma environment changes at different heliocentric distances.

Artificial plasma experiments. Chemical release observations associated with the CRRES program

NASA Technical Reports Server (NTRS)

Mende, Stephen B.

1994-01-01

This report submitted is the final report and covers work performed under the contract for the period Apr. 12, 1985 - Dec. 23, 1993. The CRRES program investigated earth plasma environment by active experiments in which metal vapors were injected into the upper atmosphere and magnetosphere. The vapor clouds perturb the ambient ionospheric / magnetospheric environment and the effects could be monitored by passive observing instruments. Our part of the CRRES program, the Artificial Plasma Experiment program, was a ground based and aircraft based investigation to observe artificial chemical releases by optical techniques.

Plasma Diagnostics: Use and Justification in an Industrial Environment

NASA Astrophysics Data System (ADS)

Loewenhardt, Peter

1998-10-01

The usefulness and importance of plasma diagnostics have played a major role in the development of plasma processing tools in the semiconductor industry. As can be seen through marketing materials from semiconductor equipment manufacturers, results from plasma diagnostic equipment can be a powerful tool in selling the technological leadership of tool design. Some diagnostics have long been used for simple process control such as optical emission for endpoint determination, but in recent years more sophisticated and involved diagnostic tools have been utilized in chamber and plasma source development and optimization. It is now common to find an assortment of tools at semiconductor equipment companies such as Langmuir probes, mass spectrometers, spatial optical emission probes, impedance, ion energy and ion flux probes. An outline of how the importance of plasma diagnostics has grown at an equipment manufacturer over the last decade will be given, with examples of significant and useful results obtained. Examples will include the development and optimization of an inductive plasma source, trends and hardware effects on ion energy distributions, mass spectrometry influences on process development and investigations of plasma-wall interactions. Plasma diagnostic focus, in-house development and proliferation in an environment where financial justification requirements are both strong and necessary will be discussed.

Preliminary results on the plasma environment of saturn from the pioneer 11 plasma analyzer experiment.

PubMed

Wolfe, J H; Mihalov, J D; Collard, H R; McKibbin, D D; Frank, L A; Intriligator, D S

1980-01-25

The Ames Research Center Pioneer 11 plasma analyzer experiment provided measurements of the solar wind interaction with Saturn and the character of the plasma environment within Saturn's magnetosphere. It is shown that Saturn has a detached bow shock wave and magnetopause quite similar to those at Earth and Jupiter. The scale size of the interaction region for Saturn is roughly one-third that at Jupiter, but Saturn's magnetosphere is equally responsive to changes in the solar wind dynamic pressure. Saturn's outer magnetosphere is inflated, as evidenced by the observation of large fluxes of corotating plasma. It is postulated that Saturn's magnetosphere may undergo a large expansion when the solar wind pressure is greatly diminished by the presence of Jupiter's extended magnetospheric tail when the two planets are approximately aligned along the same solar radial vector.

Cold atmospheric plasma activity on microorganisms. A study on the influence of the treatment time and surface

NASA Astrophysics Data System (ADS)

Xaplanteris, C. L.; Filippaki, E. D.; Christodoulakis, J. K.; Kazantzaki, M. A.; Tsakalos, E. P.; Xaplanteris, L. C.

2015-08-01

The second half of the 20th century can be characterized and named as the `plasma era', as the plasma gathered scientific interest because of its special physical behaviour. Thus, it was considered as the fourth material state and the plasma physics began to form consequently. In addition to this, many important applications of plasma were discovered and put to use. Especially, in last few decades, there has been an increased interest in the use of cold atmospheric plasma in bio-chemical applications. Until now, thermal plasma has been commonly used in many bio-medical and other applications; however, more recent efforts have shown that plasma can also be produced at lower temperature (close to the environment temperature) by using ambient air in an open space (in atmospheric pressure). However, two aspects remain neglected: firstly, low-temperature plasma production with a large area, and secondly, acquiring the necessary knowledge and understanding the relevant interaction mechanisms of plasma species with microorganisms. These aspects are currently being investigated at the `Demokritos' Plasma Laboratory in Athens, Greece with radio frequency (27.12 MHz and it integer harmonics)-driven sub-atmospheric pressure plasma (100 Pa). The first aspect was achieved with atmospheric plasma being produced at a low temperature (close to the environment temperature) and in a large closed space systems. Regarding the plasma effect on living microorganisms, preliminary experiments and findings have already been carried out and many more have been planned for the near future.