A5014429371- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- solar cell performance optimization
- Geomagnetism and Paleomagnetism Studies
- Spacecraft Design and Technology
- Plasma Diagnostics and Applications
- Radiation Effects in Electronics
- Laser-induced spectroscopy and plasma
- Space Satellite Systems and Control
- Dust and Plasma Wave Phenomena
- Earthquake Detection and Analysis
- Forest Insect Ecology and Management
- Planetary Science and Exploration
- GNSS positioning and interference
- Photovoltaic System Optimization Techniques
- Spacecraft and Cryogenic Technologies
- Spacecraft Dynamics and Control
- Stellar, planetary, and galactic studies
- Electrical Fault Detection and Protection
- Solar Radiation and Photovoltaics
- Photovoltaic Systems and Sustainability
- Fire effects on ecosystems
- Atomic and Subatomic Physics Research
- Solar Thermal and Photovoltaic Systems
Universities Space Research Association
2017-2022
Marshall Space Flight Center
1978-2018
University of Alabama in Huntsville
2003-2016
University of Alabama
1983-2013
Universidad Alejandro de Humboldt
2009
University of Wales
2004
Southwest Research Institute
1998
Weyerhaeuser (United States)
1990
Pacific Northwest Research Station
1990
US Forest Service
1990
The Solar Probe Cup (SPC) is a Faraday instrument onboard NASA's Parker (PSP) spacecraft designed to make rapid measurements of thermal coronal and solar wind plasma. in heliocentric orbit that takes it closer the Sun than any previous spacecraft, allowing be made where plasma being heated accelerated. SPC was pointed directly at all times, (which flowing primarily radially away from Sun) measured throughout orbit. capable measuring ions with an energy/charge between 100 V 6000 (protons...
In this review we call attention to basic phenomena and physical processes involved in the expansion of a plasma into vacuum, or more tenuous plasma, particular fact that upon expansion, ions are accelerated reach energies well above their thermal energy. Also, process rarefaction wave propagates ambient an ion front moves volume, discontinuities parameters occur. We discuss which cause point toward possible application for case distribution electrons (hence potential electric fields) wake...
We present data from the Floating Potential Measurement Unit (FPMU) that is deployed on starboard truss of International Space Station. The FPMU a suite instruments capable redundant measurements various plasma parameters. instrument consists floating potential probe, wide-sweeping spherical Langmuir narrow-sweeping cylindrical and impedance probe. This paper gives brief overview instrumentation received quality, then presents algorithm used to reduce I-V curves Several hours are presented...
The plasma expansion into the wake of a large rectangular plate immersed in single-ion, collisionless, streaming has been investigated laboratory. Several characteristics process involved ‘plasma vacuum’ that have predicted theoretically were observed, including creation and motion rarefaction wave disturbance; an front; acceleration ions at speeds above ion-acoustic speed. was limited to early times; i.e. few ion periods, by combination drift speed vacuum chamber size. This prevented...
A set of multijunction GaAs/Ge solar array test coupons provided by Space Systems/Loral was subjected to a sequence five-year increments combined space environmental exposure tests. The capture an integrated design intended for use in geosynchronous (GEO) environment. key component this campaign is performing electrostatic discharge (ESD) tests the inverted gradient mode. protocol ESD based on ISO standard testing panels [ISO-11221]. schematic reference has been modified with System/Loral...
The balsam woolly aphid, Adelges piceae (Ratzeburg), an import from Europe, causes major damage to true fir forests in North America. A program has been underway since 1957 control the pest Oregon and Washington by introducing insect predators. Twenty-three species have introduced 7 countries throughout world. They include 15 of beetles, 4 flies, 3 lacewings, 1 bug. Three Aphidoletes thompsoni Möhn, Cremifania nigrocellulata Czerny, Leucopis obscura Haliday 2 Laricobius erichsonii Rosenhauer...
Measurements of the current collected by Tethered Satellite System (TSS) satellite as a function voltage and ambient plasma parameters are presented. The is found to vary approximately with square root potential from below 10 nearly 1200 V. exceeded premission expectations, based on Parker Murphy [1967] collection model, factors two three. Possible reasons for discrepancies between measurements model briefly discussed.
The purpose of this test program is to understand the changes and degradation space solar array panel components, including its electrostatic discharge (ESD) mitigation design features in their integrated form, after multiple years (up 15) simulated Earth geosynchronous (GEO) environment. A set multijunction GaAs/Ge coupons was subjected five-year increments combined environmental exposure tests. These tests consisted following: ultraviolet (UV) radiation, ESD, electron/proton particle...
Differential measurements of ion flow direction and energy during the third Space Shuttle mission (STS‐3) have revealed existence streams in near vicinity Orbiter at angles attack as great 50° with respect to ram typically 10% current intensity. Neither source nor mechanism by which these secondary were created are known present; however, it is reasonably certain that they not geophysical origin, but result from interaction its environmental ionospheric plasma. The was observed be very close...
The floating potential measurement unit (FPMU) is a multiprobe package designed to measure the of International Space Station (ISS) as well density and temperature local ionospheric plasma environment. purpose FPMU provide direct measurements ISS spacecraft charging continuing construction leads dramatic changes in size configuration. data are used for refinement validation models evaluate severity frequency occurrence hazards. also effectiveness proposed hazard controls. consists four...
Recent results regarding the interactions between a body and its environmental space plasma, made by charged particle probes mounted in bay of shuttle Orbiter Columbia (STS 3 mission), are compared with earlier results, obtained from small ionospheric satellites, an attempt to widen our scope knowledge understanding such interactions. The objective is work toward unified model body‐space plasma solar system covering variety conditions. comparisons focus mainly on (1) (wake/ram) current...
The validation of the floating potential measurement unit (FPMU) plasma density and temperature measurements is an important step in process evaluating International Space Station (ISS) spacecraft charging issues including vehicle arcing hazards to crew during extravehicular activities. highest potentials observed on are due combined V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sp</sub> times B effects a large collection ionospheric...
With the negative grounding of 160V Photovoltaic (PV) arrays, International Space Station (ISS) can experience varied and interesting charging events. Since August 2006, there has been a multi-probe p ackage, called Floating Potential Measurement Unit (FPMU), availa ble to provide redundant measurements floating potential th e ISS as well density temperature local plasma environment. The FPMU operated during intermittent data campaigns since 2006 collected over 160 days information reg...
A numerical simulation was performed in an attempt to explain the enhancement of electron temperature wake ionospheric satellite terms counterstreaming plasma expansions. The conducted using full kinetic treatments (Vlasov‐Poisson code) for both electrons and ions. calculations indicate that at a distance few Debye lengths from surface body ratio [ T e (wake)/ (ambient)] reaches value ∼2. This result is good agreement with some situ laboratory experimental results.
The Floating Potential Measurement Unit (FPMU) has detected high negative amplitude rapid charging events (RCEs) on the International Space Station (ISS) at morning terminator. These are larger and more than ISS first seen by Probe (FPP) in 2001. In this paper, we describe a theory for RCEs that further elucidates nature of spacecraft low Earth orbit (LEO) non-equilibrium situation. model accounts all essential aspects newly discovered phenomenon, is amenable to testing on-orbit. Predictions...
A potentiometer is described for the measurement of d.c. potentials order 50 kV with an accuracy 0.01%. The effect leakage currents eliminated partly by use a comprehensive system guard circuits supplied subsidiary networks connected across h.t. supply, and Wheatstone bridge circuit which enables ratio to be measured under operating conditions while high potential applied.
During the Spacelab 2 mission, while Plasma Diagnostics Package was attached to Remote Manipulator System, differential ion vector measurements were obtained in near wake at a distance of 4‐5 Shuttle radii. The Orbiter's found fill much faster rate than can be explained by simple thermal motion. strongly suggest that filling is produced process "collisionless plasma expansion into vacuum" and that, for oblique angles magnetic field velocity vectors, depletion few radii downstream not...
Solar array wire coupons have successfully completed an environmental life test that simulates 15 years at geosynchronous orbit. The environments included: ultraviolet (UV), electron, and proton irradiation; thermal cycling; electrostatic discharge (ESD); ion thruster plume exposure on electrostatically charged coupon. articles consisted of two coupons: one simulated the sun-facing side other shade side. UV irradiation was performed only Tests were beginning-of-life, 7.5 years, end-of-life....
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation A. W. Case, J. C. Kasper, P. S. Daigneau, D. Caldwell, M. Freeman, T. Gauron, B. Maruca, Bookbinder, K. E. Korreck, Cirtain, Effinger, Halekas, Larson, Lazarus, L. Stevens, R. Taylor, H. Wright Jr.; Designing a sun-pointing Faraday cup for solar probe plus. AIP Conf. Proc. 13 June 2013; 1539 (1): 458–461....
To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of environment. It is critical understand environment interactions not only on PV components, but also substrate materials, wiring harnesses, connectors, protection circuitry (e.g. blocking diodes). Key elements which must be accounted design include: Solar Photon Radiation, Charged Particle Plasma, Thermal Cycling. While solar photon radiation central generating power...
A theoretical model is developed to determine the structure of wake behind a large object moving with mesosonic speeds through rarefied plasma. The takes account electric field that develops as result separation between electrons and ions. Calculated experimental results are in good agreement.
Recent laboratory measurements of plasma expansion in a wake experiment are compared with analytical expressions which approximate the model Crow, Auer & Allen. Good quantitative agreement was found between data and theory for velocity position ion front. These results provide an important insight into behaviour early its development.