Download or read book Plasma Production and Radiation from Meteoroid Impacts on Spacecraft written by Alex Fletcher and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Spacecraft are routinely bombarded with both human-made and naturally occurring dust particles, which we will collectively refer to as hypervelocity particles. Hypervelocity particles possess enough energy to ionize and vaporize themselves as well as a significant portion of the spacecraft material upon impact, forming a plasma that rapidly expands into the surrounding vacuum. The associated electrical effects and potential for damage to satellite electronics through these processes remains largely unknown, but it has been proposed that under certain conditions this plasma can produce an electromagnetic pulse (EMP) which can threaten spacecraft electronics. This area of spacecraft engineering requires a deeper understanding of the underlying physics of the impact-generated plasma plume. This dissertation describes multi-physics simulations of hypervelocity impact plasmas. The simulations utilize a combination of smoothed particle hydrodynamics (SPH) and discontinuous Galerkin (DG) particle-in-cell (PIC) techniques running on graphical processing units (GPU). The results show a minimum velocity threshold of approximately 18 km/s for fully ionized plasma production, which matches the velocity threshold for EMP measurements from impact experiments. The fully ionized plasma produces electrostatic oscillations that can couple to an electromagnetic wave that propagates away from the plasma. Near the impact site, this wave has a field strength that far exceeds the specification to which spacecraft are currently designed. Understanding key parameters of impact plasmas, as well as any EMP mechanisms, will aid in designing more robust and reliable spacecraft that are well protected in the space environment.

Download or read book Understanding Spacecraft Electrical Anomalies written by Nicolas Nik Lee and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Small meteoroids, with masses less than a microgram, are common within the solar system and routinely impact spacecraft. In Earth orbit, human-made debris also presents a risk of impact. This thesis provides the first characterization of the threat of electrical damage from these hypervelocity impacts. When an impactor encounters a spacecraft (typically at 60 km/s for meteoroids or 10 km/s for debris), its kinetic energy is converted over a very short timescale into energy of vaporization and ionization, resulting in a small, dense plasma. This plasma can produce radio frequency (RF) emission, causing electrical anomalies within the spacecraft. The behavior of hypervelocity impact plasmas was studied through ground-based experiments and a corresponding plasma expansion model to interpret the data. The experiments were conducted using a Van de Graaff dust accelerator at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Impacts of iron projectiles ranging from 0.1 fg to 10 pg at speeds of up to 70 km/s were studied using a variety of target materials. Novel plasma sensors were designed and built to characterize the plasma expansion from impacts on these targets under a range of surface charging conditions representative of space environment effects. Impact plasmas associated with bare metal targets as well as spacecraft materials were studied. The expansion behavior of the impact plasma was found to depend strongly on the surface charge of the target. From a correlation of experimental measurements with theoretical models, the dependence of plasma composition and temperature on target material, impact speed, and surface charge was analyzed. This work includes three major results. First, the initial temperature of the impact plasma is at least an order of magnitude lower than previously reported, providing conditions more favorable for sustained RF emission. Second, the composition of impact plasmas from glass targets, unlike that of impact plasmas from tungsten, has low dependence on impact speed, indicating a charge production mechanism that is significant down to orbital debris speeds. Finally, negative ion formation has a strong dependence on target material. These new results can inform the design and operation of satellites in order to prevent impact-related electrical anomalies. Since spacecraft charging is strongly dependent on orientation and surface material, deleterious electrical effects of hypervelocity impacts can be mitigated through design and operational practices that account for the influence of spacecraft geometry and the space environment on the behavior of impact plasmas.

Download or read book Limiting Future Collision Risk to Spacecraft written by National Research Council and published by National Academies Press. This book was released on 2011-12-16 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Derelict satellites, equipment and other debris orbiting Earth (aka space junk) have been accumulating for many decades and could damage or even possibly destroy satellites and human spacecraft if they collide. During the past 50 years, various National Aeronautics and Space Administration (NASA) communities have contributed significantly to maturing meteoroid and orbital debris (MMOD) programs to their current state. Satellites have been redesigned to protect critical components from MMOD damage by moving critical components from exterior surfaces to deep inside a satellite's structure. Orbits are monitored and altered to minimize the risk of collision with tracked orbital debris. MMOD shielding added to the International Space Station (ISS) protects critical components and astronauts from potentially catastrophic damage that might result from smaller, untracked debris and meteoroid impacts. Limiting Future Collision Risk to Spacecraft: An Assessment of NASA's Meteoroid and Orbital Debris Program examines NASA's efforts to understand the meteoroid and orbital debris environment, identifies what NASA is and is not doing to mitigate the risks posed by this threat, and makes recommendations as to how they can improve their programs. While the report identified many positive aspects of NASA's MMOD programs and efforts including responsible use of resources, it recommends that the agency develop a formal strategic plan that provides the basis for prioritizing the allocation of funds and effort over various MMOD program needs. Other necessary steps include improvements in long-term modeling, better measurements, more regular updates of the debris environmental models, and other actions to better characterize the long-term evolution of the debris environment.

Download or read book Detection and Analysis of the Electromagnetic Pulse from Hypervelocity Impact Plasma Expansion written by Theresa Lynn Johnson and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypervelocity dust particles, including meteoroids and space debris, routinely impact spacecraft and produce plasmas that are initially dense (10^25/m^3), but rapidly expand into the surrounding vacuum. This research was the first to detect radio frequency (RF) emission associated with electromagnetic pulses (EMPs) from hypervelocity dust particle impacts in ground-based experiments. These micro particles that produced RF are 15 orders of magnitude less massive than previously observed. We find that one mechanism for EMP production is the result of the growth of the unstable Weibel mode in the plasma and that the EMP detection rate is strongly dependent on impact speed and on the electrical charge conditions at the impact surface. This mode grows from a plasma temperature anisotropy driven by the impact ionization process combined with the external electric field. Upon expansion, the Weibel mode grows, producing RF emission within nanoseconds. In particular, impacts of the fastest particles (speed> 15 km/s) occurring under spacecraft charging conditions representative of high geomagnetic activity are the most likely to produce RF emission. The sensor design and analysis that led to this discovery is discussed. This phenomenon may provide a source for unexplained RF measurements and satellite electrical anomalies.

Download or read book Plasma Physics and Magnetohydrodynamics in Space Exploration written by NASA-University Conference on the Science and Technology of Space Exploration and published by . This book was released on 1963 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dusty Plasma Effects in Hypervelocity Impacts written by Gil Shohet and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Meteoroids routinely impact bodies in space, such as spacecraft and small planetary bodies. Orbital debris also threaten spacecraft near Earth. These hypervelocity impacts occur at velocities of a few to tens of km/s, and the rapid conversion of kinetic energy to internal and thermal energy upon impact leads to fracturing, melting, vaporization, and ionization, producing a dense plasma. As the plasma expands from the impact crater, oscillations and instabilities can generate electromagnetic emissions in the radio frequency (RF) range and a broadband electromagnetic pulse (EMP). Moreover, condensed phase (solid and liquid) ejecta, referred to as dust, may acquire a surface charge due to interactions with the plasma, resulting in a dusty plasma. Hypervelocity impact plasmas generated by ground-based light gas gun impacts, which overlap the mass and velocity range of orbital debris, have been described as dusty for decades. Experimental plasma data and hydrodynamic simulations suggest dust charging as a possible explanation for anomalous plasma measurements. The degree of charge attachment and effect on plasma observations, however, remains unquantified. This thesis makes the first quantitative estimate of charge attachment in light gas gun impacts. We use thin-film witness plates to produce the first measurements of microscopic ejecta 1-50 microns in diameter generated by light gas gun impacts on aluminum and powdered regolith simulant targets, which serve as analogues for spacecraft and small solar system bodies, respectively. We then extend dust charging models based on orbital motion limited (OML) theory to the impact environment and build a novel semi-analytic model for dust charging and dynamics across the many orders of magnitude of space, time, and density spanned by the expanding plasma. Combining ejecta measurements, empirical and analytic models for the expanding plasma, and the dust evolution model enables predictions of the charge state of impact debris throughout the expansion. We quantify and propagate experimental and model uncertainties and use stochastic methods to produce bounded estimates of quantities of interest. This work led to a number of key findings. First, extrapolations from measurements of macroscopic ejecta poorly predict the flux of microscopic debris, and the computed particle size distribution predicts a flux of dust to the co-located plasma sensors that agrees in order of magnitude with the number of impulses, indicative of dust, in the plasma signals. Second, the dust charging model suggests that enough electrons attach to ejecta that dusty plasma phenomena are likely. These may affect electromagnetic emissions generated by hypervelocity impacts, especially on granular bodies, such as asteroids and comets. Third, the evolution model, with reasonable inputs, predicts similar arrival times and a surface charge that agrees in sign with experimental plasma measurements. Thermionic emission by hot debris can explain the observation of positively charged dust in impacts on granular regolith analogues. Finally, the ambient environment plays an important role in the charging and evolution of ejecta, and the neutral background present in many light gas gun facilities augments the tendency of debris to charge positively.

Download or read book Test and Analysis Capabilities of the Space Environment Effects Team at Marshall Space Flight Center written by M. M. Finckenor and published by . This book was released on 2002 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Characterization Methods for Hypervelocity Impact Generated Plasma written by Ya-Yu Hew and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid advancement of technology and ease of accessibility to space have introduced a fundamental change in space, allowing globalization of space programs and commercialization of space activities. Consequently, a more congested and competitive space environment introduces new challenges and threats to spacecraft designers, operators, and users in protecting their space assets. Among these threats includes hypervelocity impacts from microparticles in the form of meteoroids and space debris. These microparticles travel at speeds between 11.2 and 72.8 km/s with respect to the Earth and can impact spacecraft forming a small and dense plasma. This plasma can generate a strong optical emission, known as an impact flash, and an electromagnetic pulse (EMP). The impact flash and EMP can lead to spacecraft electrical anomalies when the impacted spacecraft surface (target) carries high electrical potential due to various space weather effects. Two parameters of the impact plasma that strongly determine its behavior and electrical anomaly risk are its temperature and density. To understand the microparticle hypervelocity impact plasma and its associated threat to spacecraft electronics, we need to determine the impact plasma temperature and density under a range of space operating conditions, such as different spacecraft charging conditions. The understanding of hypervelocity impact flash phenomenon and its connection to the impact plasma under these conditions is critical for our knowledge of hypervelocity impact effects and the development of a reliable optical characterization method in predicting impact plasma properties, impact conditions and risks. We establish three objectives to achieve this overarching goal. First, we create an optical method that enables the characterization of the impact plasma using impact flash measurements. Second, we investigate the generation mechanism of the impact flash from the impact plasma. Third, we examine the correlation between the impact flash and impact conditions, such as the impactor mass, impact velocity, target electrical condition, and spacecraft damage risk. In this dissertation, we develop a non-intrusive optical method to study the impact plasma via its continuum optical emission spectrum. This optical method includes a theoretical model and calibrated sensors to characterize the impact plasma. Our theoretical model (Impact Plasma Generated Flash model) is the first of its kind to qualitatively define the temporal stages of the behavior of the impact flash and plasma. This model evaluates the approximate temperature and density of the plasma where the continuum radiation dominates and theorizes the process by which the plasma generates the impact flash. The photometry sensor suite developed in this dissertation consists of three spectral photomultiplier tubes (450, 550, and 600 nm), which enable intensity, spectrum, and geometry measurements of the impact flash. This sensor suite was deployed at a ground-based 3 MV electrostatic dust accelerator and a light gas gun facility. Using this optical characterization method, we demonstrate new results on hypervelocity impacts with various target electrical conditions as a control variable to study the relationship between the impact plasma and impact flash. Our result suggests that the impact flash continuum spectrum was produced by a combination of the following mechanisms: Bremsstrahlung radiation (a more general form of blackbody radiation) due to the acceleration of charged particles via spacecraft surface electrical conditions or thermal motion; Bremsstrahlung radiation due to the oscillating internal electric field; and recombination radiation from the plasma particles. The impact flash was found to emit blackbody radiation in the early time after impact (~800 ns) and evolve from an optically thick continuum emission to an optically thin continuum emission during this time window. Using blackbody and Bremsstrahlung spectra to estimate the plasma density and temperature, we found that an impact velocity range of 15 to 40 km/s yielded average plasma temperatures at signal intensity peaks between 3500 and 8000 K depending on the surface electrical conditions. The initial plasma density and temperature (0.5 - 2 eV) from optical measurements are in good agreement with previous experimental and simulation results of the impact plasma. Thus, these new results are consistent with the existing literature. The strong resemblance between the impact plasma and impact flash expansion geometry, the consistent plasma diffusion process measured by the optical method, and the strong connections between the target electrical condition and the impact flash temperature all suggest that the impact flash originates from the impact plasma. Therefore, this dissertation enables the future use of the impact flash measurements as an assessment tool for impact conditions, impact plasma properties and the risk of spacecraft electrical anomalies.

Download or read book From Plasma to Planet written by Aina Elvius and published by Coronet Books. This book was released on 1972 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Meteor Showers and their Parent Comets written by Peter Jenniskens and published by Cambridge University Press. This book was released on 2006-09-14 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meteor Showers and their Parent Comets is a unique handbook for astronomers interested in observing meteor storms and outbursts. Spectacular displays of 'shooting stars' are created when the Earth's orbit crosses a meteoroid stream, as each meteoroid causes a bright light when it enters our atmosphere at high speed. Jenniskens, an active meteor storm chaser, explains how meteoroid streams originate from the decay of meteoroids, comets and asteroids, and how they cause meteor showers on Earth. He includes the findings of recent space missions to comets and asteroids, the risk of meteor impacts on Earth, and how meteor showers may have seeded the Earth with ingredients that made life possible. All known meteor showers are identified, accompanied by fascinating details on the most important showers and their parent comets. The book predicts when exceptional meteor showers will occur over the next fifty years, making it a valuable resource for both amateur and professional astronomers.

Download or read book Orbital Debris written by National Research Council and published by National Academies Press. This book was released on 1995-07-07 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the beginning of space flight, the collision hazard in Earth orbit has increased as the number of artificial objects orbiting the Earth has grown. Spacecraft performing communications, navigation, scientific, and other missions now share Earth orbit with spent rocket bodies, nonfunctional spacecraft, fragments from spacecraft breakups, and other debris created as a byproduct of space operations. Orbital Debris examines the methods we can use to characterize orbital debris, estimates the magnitude of the debris population, and assesses the hazard that this population poses to spacecraft. Potential methods to protect spacecraft are explored. The report also takes a close look at the projected future growth in the debris population and evaluates approaches to reducing that growth. Orbital Debris offers clear recommendations for targeted research on the debris population, for methods to improve the protection of spacecraft, on methods to reduce the creation of debris in the future, and much more.

Download or read book A Study of Space Station Contamination Effects written by Marsha R. Torr and published by . This book was released on 1988 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In space Technology Development Atomic Oxygen and Orbital Debris Effects written by James T. Visentine and published by . This book was released on 1989 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lunar Sourcebook written by Grant Heiken and published by CUP Archive. This book was released on 1991-04-26 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only work to date to collect data gathered during the American and Soviet missions in an accessible and complete reference of current scientific and technical information about the Moon.

Download or read book Fundamentals of Electric Propulsion written by Dan M. Goebel and published by John Wiley & Sons. This book was released on 2008-12-22 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout most of the twentieth century, electric propulsion was considered the technology of the future. Now, the future has arrived. This important new book explains the fundamentals of electric propulsion for spacecraft and describes in detail the physics and characteristics of the two major electric thrusters in use today, ion and Hall thrusters. The authors provide an introduction to plasma physics in order to allow readers to understand the models and derivations used in determining electric thruster performance. They then go on to present detailed explanations of: Thruster principles Ion thruster plasma generators and accelerator grids Hollow cathodes Hall thrusters Ion and Hall thruster plumes Flight ion and Hall thrusters Based largely on research and development performed at the Jet Propulsion Laboratory (JPL) and complemented with scores of tables, figures, homework problems, and references, Fundamentals of Electric Propulsion: Ion and Hall Thrusters is an indispensable textbook for advanced undergraduate and graduate students who are preparing to enter the aerospace industry. It also serves as an equally valuable resource for professional engineers already at work in the field.

Download or read book Electromagnetic Properties of Impact Generated Plasma Vapor and Debris written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma, vapor and debris associated with an impact or explosive event have been demonstrated in the laboratory to produce radiofrequency and optical electromagnetic emissions that can be diagnostic of the event. Such effects could potentially interfere with communications or remote sensing equipment if an impact occurred, for example, on a satellite. More seriously, impact generated plasma could end the life of a satellite by mechanisms that are not well understood and not normally taken into account in satellite design. For example, arc/discharge phenomena resulting from highly conductive plasma acting as a current path across normally shielded circuits may have contributed to the loss of the Olympus experimental communications satellite on August 11, 1993. The possibility of significant storm activity during the Leonid meteor showers of November 1998, 1999 and 2000 (impact velocity, 72 km/s) has heightened awareness of potential vulnerabilities from hypervelocity electromagnetic effects to orbital assets. The concern is justified. The amount of plasma, electrostatic charge and the magnitude of the resulting currents and electric fields scale nearly as the cube of the impact velocity. Even for microscopic Leonid impacts, the amount of plasma approaches levels that could be dangerous to spacecraft electronics. The degree of charge separation that occurs during hypervelocity impacts scales linearly with impactor mass. The resulting magnetic fields increase linearly with impactor radius and could play a significant role in our understanding of the paleomagnetism of planetary surfaces. The electromagnetic properties of plasma produced by hypervelocity impact have been exploited by researchers as a diagnostic tool, invoked to potentially explain the magnetically jumbled state of the lunar surface and blamed for the loss of the Olympus experimental communications satellite. The production of plasma in and around an impact event can lead to several effects: (1) the plasma provides a significant perturbation to the ambient magnetic field via the electromagnetic pulse; (2) it supports the production of transient radiofrequency electromagnetic fields; (3) it charges ejected debris which, because of inertial separation, leads to significant electrostatic and magnetostatic field production; and (4) its high electrical conductivity provides a convenient path for discharge of the resulting high electrostatic fields. Effects (1) and (2) have been discussed by the authors elsewhere. Effects (3) and (4) will be discussed here. Typical studies of kinetic energy warheads focus on lethality as a function of impactor momentum or energy as they couple mechanically to the target. At high enough energies, however, additional physical processes come into play. Vaporization plays an important role and a partially ionized plasma can form. Impact-generated plasma, charged debris and magnetic fields have been characterized by laboratory hypervelocity impact experiments and are shown to be more abundant when certain easily ionized materials (such as alkali metals) are used in either projectile or target.

Download or read book Plasma Physics of the Local Cosmos written by National Research Council and published by National Academies Press. This book was released on 2004-06-06 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar and space physics is the study of solar system phenomena that occur in the plasma state. Examples include sunspots, the solar wind, planetary magnetospheres, radiation belts, and the aurora. While each is a distinct phenomenon, there are commonalities among them. To help define and systematize these universal aspects of the field of space physics, the National Research Council was asked by NASA's Office of Space Science to provide a scientific assessment and strategy for the study of magnetized plasmas in the solar system. This report presents that assessment. It covers a number of important research goals for solar and space physics. The report is complementary to the NRC report, The Sun to the Earthâ€"and Beyond: A Decadal Research Strategy for Solar and Space Physics, which presents priorities and strategies for future program activities.