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John B. Charles - One of the best experts on this subject based on the ideXlab platform.
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Medical Implications of Space Radiation Exposure Due to Low-Altitude Polar Orbits.
Aerospace medicine and human performance, 2018Co-Authors: Jeffery C. Chancellor, Serena M. Auñón-chancellor, John B. CharlesAbstract:INTRODUCTION Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and solar particle events (SPEs) may pose a critical health risk to future spaceflight crews and can have a serious impact on all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960s Manned Orbiting Laboratory (MOL) program's space vehicle and the high inclination Polar Orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. METHODS In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-d mission using high performance, multicore computers. RESULTS Projected doses from a historically large SPE (e.g., the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent contingencies. DISCUSSION It is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit (LEO) will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.Chancellor JC, Aunon-Chancellor SM, Charles J. Medical implications of space radiation exposure due to low-altitude Polar Orbits. Aerosp Med Hum Perform. 2018; 89(1):3-8.
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medical implications of space radiation exposure due to low altitude Polar Orbits
arXiv: Medical Physics, 2017Co-Authors: Jeffery C. Chancellor, Serena M Aunonchancellor, John B. CharlesAbstract:Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and Solar Particle Events may pose a critical health risk to future spaceflight crews and can have a serious impact to all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960's Manned Orbiting Laboratory program's space vehicle and the high inclination Polar Orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-day mission using high performance, multi-core computers. Projected doses from a historically large SPE (e.g. the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent this http URL is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.
Jeffery C. Chancellor - One of the best experts on this subject based on the ideXlab platform.
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Medical Implications of Space Radiation Exposure Due to Low-Altitude Polar Orbits.
Aerospace medicine and human performance, 2018Co-Authors: Jeffery C. Chancellor, Serena M. Auñón-chancellor, John B. CharlesAbstract:INTRODUCTION Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and solar particle events (SPEs) may pose a critical health risk to future spaceflight crews and can have a serious impact on all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960s Manned Orbiting Laboratory (MOL) program's space vehicle and the high inclination Polar Orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. METHODS In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-d mission using high performance, multicore computers. RESULTS Projected doses from a historically large SPE (e.g., the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent contingencies. DISCUSSION It is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit (LEO) will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.Chancellor JC, Aunon-Chancellor SM, Charles J. Medical implications of space radiation exposure due to low-altitude Polar Orbits. Aerosp Med Hum Perform. 2018; 89(1):3-8.
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medical implications of space radiation exposure due to low altitude Polar Orbits
arXiv: Medical Physics, 2017Co-Authors: Jeffery C. Chancellor, Serena M Aunonchancellor, John B. CharlesAbstract:Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and Solar Particle Events may pose a critical health risk to future spaceflight crews and can have a serious impact to all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960's Manned Orbiting Laboratory program's space vehicle and the high inclination Polar Orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-day mission using high performance, multi-core computers. Projected doses from a historically large SPE (e.g. the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent this http URL is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.
O C Winter - One of the best experts on this subject based on the ideXlab platform.
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Mars climate engineering using space solar reflectors in Sun-synchronous Polar Orbits
2018Co-Authors: F. J. T. Salazar, O C WinterAbstract:Several space-based climate engineering methods, including shading the Earth with a particle ring for active cooling, or the use of orbital reflectors to increase the total insolation of Mars for climate warming have been proposed to modify planetary climates in a controller manner. In this study, solar reflectors on Sun-synchronous Polar Orbits (frozen Orbits) normal to the ecliptic plane to the Mars are considered to intervene in the Mars’s climate system.The two-body problem is considered, and the Gauss’ form of the variational equations is used to describe the propagation of the Polar orbit, taking into account the effects of solar radiation pressure and Mars’s J2 oblateness perturbation.
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a permanent magnet hall thruster for pulsed orbit control of lunar Polar satellites
Journal of Physics: Conference Series, 2014Co-Authors: Brunno Silva Moraes, O C Winter, Jose Leonardo Ferreira, I S Ferreira, Decio Cardozo MouraoAbstract:Future Moon missions devoted to Lunar surface remote sensing, for example, will require very fine and accurate orbit control. It is well known that Lunar satellites in Polar Orbits will suffer a high increase on the eccentricity due to the gravitational perturbation of the Earth. Without proper orbit correction the satellite lifetime will decrease and end up in a collision with the Moon surface. It is pointed out by many authors that this effect is a natural consequence of the Lidov-Kozai resonance. We studied different arcs of active lunar satellite propulsion, centered on the orbit apoapsis or periapsis, in order to be able to introduce a correction of the eccentricity at each cycle. The proposed method is based on an approach intended to keep the orbital eccentricity of the satellite at low values.
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controlling the eccentricity of Polar lunar Orbits with low thrust propulsion
Mathematical Problems in Engineering, 2009Co-Authors: O C Winter, C F De Melo, Elbert E N Macau, D C Mour, Jose Leonardo Ferreira, J. P. S. CarvalhoAbstract:It is well known that lunar satellites in Polar Orbits suffer a high increase on the eccentricity due to the gravitational perturbation of the Earth. The final fate of such satellites is the collision with the Moon. Therefore, the control of the orbital eccentricity leads to the control of the satellite's lifetime. In the present work we study this problem and introduce an approach in order to keep the orbital eccentricity of the satellite at low values. The whole work was made considering two systems: the 3-body problem, Moon-Earth-satellite, and the 4-body problem, Moon-Earth-Sun-satellite. First, we simulated the systems considering a satellite with initial eccentricity equals to 0.0001 and a range of initial altitudes between 100 km and 5000 km. In such simulations we followed the evolution of the satellite's eccentricity. We also obtained an empirical expression for the length of time needed to occur the collision with the Moon as a function of the initial altitude. The results found for the 3-body model were not significantly different from those found for the 4-body model. Secondly, using low-thrust propulsion, we introduced a correction of the eccentricity every time it reached the value 0.05.
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alternative paths for insertion of probes into high inclination lunar Orbits
Advances in Space Research, 2007Co-Authors: C F De Melo, Elbert E N Macau, O C Winter, Vieira E NetoAbstract:Abstract The dynamics of the restricted three-body Earth–Moon-particle problem predicts the existence of direct periodic Orbits around the Lagrangian equilibrium point L1. From these Orbits, we derive a set of trajectories that form links between the Earth and the Moon and are capable of performing transfers between terrestrial and lunar Orbits, in addition to defining an escape route from the Earth–Moon system. When we consider a more complex and realistic dynamical system – the four-body Sun–Earth–Moon-particle (probe) problem – the trajectories have an expressive gain of inclination when they penetrate in the lunar influence sphere, thus allowing the insertion of probes into low-altitude lunar Orbits with high inclinations, including Polar Orbits. In this study, we present these links and investigate some possibilities for performing an Earth–Moon transfer based on these trajectories.
Serena M Aunonchancellor - One of the best experts on this subject based on the ideXlab platform.
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medical implications of space radiation exposure due to low altitude Polar Orbits
arXiv: Medical Physics, 2017Co-Authors: Jeffery C. Chancellor, Serena M Aunonchancellor, John B. CharlesAbstract:Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and Solar Particle Events may pose a critical health risk to future spaceflight crews and can have a serious impact to all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960's Manned Orbiting Laboratory program's space vehicle and the high inclination Polar Orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-day mission using high performance, multi-core computers. Projected doses from a historically large SPE (e.g. the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent this http URL is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.
W J Burke - One of the best experts on this subject based on the ideXlab platform.
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stormtime coupling of the ring current plasmasphere and topside ionosphere electromagnetic and plasma disturbances
Journal of Geophysical Research, 2005Co-Authors: E V Mishin, W J BurkeAbstract:[1] We compare plasma and field disturbances observed in the ring current/plasmasphere overlap region and in the conjugate ionosphere during the magnetic storm of 5 June 1991. Data come from the Combined Release and Radiation Effects Satellite (CRRES) flying in a geostationary transfer orbit and three satellites of the Defense Meteorological Satellite Program (DMSP) series in Sun-synchronous Polar Orbits. In the region between ring current nose structures and the electron plasma sheet, CRRES detected wave-like features in local electric and magnetic fields, embedded in structured cold plasmas. Mapped to the ionosphere, these fields should reflect structuring within subauroral plasma streams (SAPS). Indeed, during the period of interest, DMSP F8, F9, and F10 satellites observed highly structured SAPS in the evening ionosphere at topside altitudes. They were collocated with precipitating ring current ions, enhanced fluxes of suprathermal electrons and ions, elevated electron temperatures, and irregular plasma density troughs. Overall, these events are similar to electromagnetic structures observed by DMSP satellites within SAPS during recent geomagnetic storms (Mishin et al., 2003, 2004). Their features can be explained in terms of Alfven and fast magnetosonic perturbations. We developed a scenario for the formation of elevated electron temperatures at the equatorward side of the SAPS. It includes a lower-hybrid drift instability driven by diamagnetic currents, consistent with strong lower- and upper-hybrid plasma wave activity and intense fluxes of the low-energy electrons and ions near the ring current's inner edge.
