- Email: [email protected]
Theory of satellite orbits in an atmosphere
ABSTRACTS
268
G. P. PARFENOV: Origin of crossing-over in Drosophifa males under the intluence of vibration, acceleration and gamma-radiation (pp. 648-653). Consideration is given to the influence of vibration, acceleration and gamma-radiation on the crossingover rate in male Drosophila. It is assumed that this class of hereditary changes is due to the readjustments of homologous chromosomes in meiotic stages. This test has also been used in flights of artificial Earth satellites to indicate the biological effect of cosmic radiation, where non-uniform results were obtained. For an analysis of the differences, the experiments were carried out into the influence on Drosophila of acceleration, vibration, gamma-radiation and combinations of these factors. The results are discussed.
Planet. Spaa Sci. 1965. Vol. 13. pp. 268 to 270. Pcrgsmon Press Ltd. Printed in Northern Ireland
BOOK REVIEWS
R. M. GOODY: Atmospheric Radiation: I. Theoretical Basis. Clarendon Press, Oxford: Oxford University Press, London, 1964. xi + 436 pp. 75s Tms book is an attempt to provide a theoretical background to problems concerning atmospheric radiation. It is the first of a two volume set; the second will deal with instruments, observations and application to the Earth’s atmosphere. The earlier chapters of the book present the basic physics needed for the later developments. In an introduction, the thermal structure and chemicalcompositionof theEarth’sloweratmospherearesummarized. Chapter 2 deals with the theory of radiative transfer and discusses in a concise fashion the important results to be found in the standard works on the subject. In Chapter 3 the theory of gaseous absorption is described ; before going on to discuss in detail the various forms and theories of line broadening, the basic theory of atomic and molecular absorption is presented. Chapter 4 discusses the need for models of band structure and describes in detail several models. Chapter 5 presents a judicious choice of absorption data on various atmospheric constituents. Approximate methods for calculating fluxes and heating rates, including a discussion of radiation charts are presented in Chapter 6. The theory of extinction by molecules and droplets is outlined in Chapter 7 and is a useful commentary on the standard reference work. The final two chapters are complementary, discussing respectively atmospheres in radiative equilibrium and radiative transfer and fluid motions. The book also contains fourteen very useful appendices and has good subject and author indexes. Each chapter ends with an extensive list of references to books and journals put together in a useful form which essentially summarizes the content of the chapter. The author states that he has attempted to make a deductive presentation based on the fundamental laws of physics rather than on higher level hypotheses. He appears to have been successful. This approach unfortunately does not make the book easy reading for the student, The book forms a helpful addition to the literature, gathering together much useful information. It will be valuable to any physicist interested in the lower atmosphere. T. N. L. PATTERSON
DESMOND KING-HELE:
Texts, London,
Theory of Satelfite Orbits in an Atmosphere. 1964. vi + 165 pp. 30s
Butterworths
Mathematical
THE orbits of close Earth satellites are subject to types of perturbations which have previously been of only minor or negligible importance in the well-established subject of celestial mechanics. It is therefore scarcely remarkable that during the years since the first satellite launching in 1957 a great revival of interest has taken place in orbital theory and its development towards interpreting Earth satellite motion. The chief perturbations to satellite orbits arise from the Earth’s oblateness and from atmospheric drag: perturbations due to the Sun and Moon are less important for close satellites, and the effect of radiation pressure is very small unless the satellite is of the balloon type. The two major perturbations however have recognizably different effects on a satellite orbit: the Earth’s gravitational field affects its orientation
BOOK REVIEWS
269
whereas the air drag affects its shape. The theoretical treatment of the atmospheric perturbation can there fore be isolated from that of the gravitational perturbation, apart from a small-order effect which arises when account is taken of the oblate shape of the atmosphere as air drag then depends on orbital orientation. The above book expounds, from first principles, the mathematical theory of satellite orbits subjected to air drag. The 6rst three chapters deal with introductory topics such as orbital elements, the evaluation of drag on a satellite, the density of the upper atmosphere, elliptic orbits and Lagrange’s planetary equations. The next three chapters deal with the contraction of orbits under the inSuence of drag, one chapter dealing with a spherically symmetrical atmosphere, and the following two chapters with an oblate atmosphere and an atmosphere in which the scale height varies with altitude. The material of these three chapters, which fills nearly one half of the book, is based on a series of papers published in the Proceedings of the Royal Society jointly by the author, G. E. Cook and D. M. C. Walker. Expressions are obtained for the functional relationships between such quantities as perigee distance, eccentricity, orbital period, rate of change of period, time in orbit and lifetime, separate developments being needed for large eccentricity and small eccentricity. One interesting result is that the square of eccentricity decreases approximately linearly with time. This result, like others that contain time explicitly, depends on the assumption that air density and the satellite’s drag parameter do not vary with time, conditions that are only approximately true in practice. On the other hand, relationships which do not contain time explicitly, such as that between orbital period and eccentricity do not suffer from this limitation. The theory presented has three major practical applications: to determine orbits over intervals of time for which either observations or data processing are lacking; to estimate satellite lifetimes; and to derive properties of the upper atmosphere. Formulae for deriving air density are concisely presented in a separate chapter and would enable the individual researcher with access to satellite orbit data but only modest calculating facilities to investigate the density structure of the upper atmosphere. Another chapter deals with a small but interesting effect, namely that of the atmosphere’s diurnal rotation on the orientation of the orbital plane. The theory satisfactorily accounts for the observed decreases in orbital inclinations of a few Oslo. The theory for predicting satellite lifetimes can be most successfully applied to low orbiting satellites for which the assumption of a time-independent air density structure is most nearly true. For higher orbits the day-to-night variation becomes increasingly significant and when lifetimes extend over many years the uncertainty associated with future solar-activity cycles seriously influences the accuracy of the lifetime calculation. The book is well-written achieving both thoroughness and conciseness: lengthy mathematical reductions are passed over as they are available in the original papers. The presentation is nevertheless intentionally mathematical, but the author’s experience with the observational as well as the theoretical aspects of satellite orbits ensures that the former is not overlooked, as indeed it should not be, having provided the stimulus for the theoretical work in the first place. For the serious student of satellite orbit theory, this is a unique presentation, which is essential reading: for others concerned with satellite observing, the geophysical use of satellite orbits, the evolution of satellite orbits or with space research in general the book is sure to hold many points of interest and to provide a handy source of reference for results and formulae. 0. V. GROVES
EARL W. MCDANIEL: CollisionPhenomena in Ionized Gases. John Wiley, New York, 1964.
xxii + 775 pp. 132F Tns author of this book has himself contributed directly to the study of collision phenomena in ionized gases and can rightly be regarded as an expert in the field. Nevertheless he has, modestly enough, circulated the early drafts of the manuscript to a number of independent experts for comment and criticism. The result is an authoritative and scholarly work, which will be. prescribed reading for young experimentalists and theorists intending to do research in atomic collisions and which the experts, earlier consulted, will be pleased to have available. The first few chapters are devoted to collision and kinetic theory and are followed by chapters on the measurement of elastic scattering cross sections and the cross sections for excitation and ionization by electron impact. Heavy particle and charge exchange cross section measurements are described together with the relevant quantum theory in chapter 6. The topics of photo-absorption, negative ions, ion mobilities, diffusion, energy distributions, recombination and surface phenomena are also reviewed. The many diagrams illustrating the theory and the experimental apparatus are carefully drawn and annotated and concisely captioned. This can also be said of the fund of graphs which in many cases compare experimental and theoretical results. Comprehensive references are given at the end of each chapter to exhaust the period up to the end of 1963. It would be surprising, in a book of this size, to find no errors and indeed there are some. For example on page 373 a ‘S state is ascribed to N-. In defence of the author, however, this table was essentially taken
268
G. P. PARFENOV: Origin of crossing-over in Drosophifa males under the intluence of vibration, acceleration and gamma-radiation (pp. 648-653). Consideration is given to the influence of vibration, acceleration and gamma-radiation on the crossingover rate in male Drosophila. It is assumed that this class of hereditary changes is due to the readjustments of homologous chromosomes in meiotic stages. This test has also been used in flights of artificial Earth satellites to indicate the biological effect of cosmic radiation, where non-uniform results were obtained. For an analysis of the differences, the experiments were carried out into the influence on Drosophila of acceleration, vibration, gamma-radiation and combinations of these factors. The results are discussed.
Planet. Spaa Sci. 1965. Vol. 13. pp. 268 to 270. Pcrgsmon Press Ltd. Printed in Northern Ireland
BOOK REVIEWS
R. M. GOODY: Atmospheric Radiation: I. Theoretical Basis. Clarendon Press, Oxford: Oxford University Press, London, 1964. xi + 436 pp. 75s Tms book is an attempt to provide a theoretical background to problems concerning atmospheric radiation. It is the first of a two volume set; the second will deal with instruments, observations and application to the Earth’s atmosphere. The earlier chapters of the book present the basic physics needed for the later developments. In an introduction, the thermal structure and chemicalcompositionof theEarth’sloweratmospherearesummarized. Chapter 2 deals with the theory of radiative transfer and discusses in a concise fashion the important results to be found in the standard works on the subject. In Chapter 3 the theory of gaseous absorption is described ; before going on to discuss in detail the various forms and theories of line broadening, the basic theory of atomic and molecular absorption is presented. Chapter 4 discusses the need for models of band structure and describes in detail several models. Chapter 5 presents a judicious choice of absorption data on various atmospheric constituents. Approximate methods for calculating fluxes and heating rates, including a discussion of radiation charts are presented in Chapter 6. The theory of extinction by molecules and droplets is outlined in Chapter 7 and is a useful commentary on the standard reference work. The final two chapters are complementary, discussing respectively atmospheres in radiative equilibrium and radiative transfer and fluid motions. The book also contains fourteen very useful appendices and has good subject and author indexes. Each chapter ends with an extensive list of references to books and journals put together in a useful form which essentially summarizes the content of the chapter. The author states that he has attempted to make a deductive presentation based on the fundamental laws of physics rather than on higher level hypotheses. He appears to have been successful. This approach unfortunately does not make the book easy reading for the student, The book forms a helpful addition to the literature, gathering together much useful information. It will be valuable to any physicist interested in the lower atmosphere. T. N. L. PATTERSON
DESMOND KING-HELE:
Texts, London,
Theory of Satelfite Orbits in an Atmosphere. 1964. vi + 165 pp. 30s
Butterworths
Mathematical
THE orbits of close Earth satellites are subject to types of perturbations which have previously been of only minor or negligible importance in the well-established subject of celestial mechanics. It is therefore scarcely remarkable that during the years since the first satellite launching in 1957 a great revival of interest has taken place in orbital theory and its development towards interpreting Earth satellite motion. The chief perturbations to satellite orbits arise from the Earth’s oblateness and from atmospheric drag: perturbations due to the Sun and Moon are less important for close satellites, and the effect of radiation pressure is very small unless the satellite is of the balloon type. The two major perturbations however have recognizably different effects on a satellite orbit: the Earth’s gravitational field affects its orientation
BOOK REVIEWS
269
whereas the air drag affects its shape. The theoretical treatment of the atmospheric perturbation can there fore be isolated from that of the gravitational perturbation, apart from a small-order effect which arises when account is taken of the oblate shape of the atmosphere as air drag then depends on orbital orientation. The above book expounds, from first principles, the mathematical theory of satellite orbits subjected to air drag. The 6rst three chapters deal with introductory topics such as orbital elements, the evaluation of drag on a satellite, the density of the upper atmosphere, elliptic orbits and Lagrange’s planetary equations. The next three chapters deal with the contraction of orbits under the inSuence of drag, one chapter dealing with a spherically symmetrical atmosphere, and the following two chapters with an oblate atmosphere and an atmosphere in which the scale height varies with altitude. The material of these three chapters, which fills nearly one half of the book, is based on a series of papers published in the Proceedings of the Royal Society jointly by the author, G. E. Cook and D. M. C. Walker. Expressions are obtained for the functional relationships between such quantities as perigee distance, eccentricity, orbital period, rate of change of period, time in orbit and lifetime, separate developments being needed for large eccentricity and small eccentricity. One interesting result is that the square of eccentricity decreases approximately linearly with time. This result, like others that contain time explicitly, depends on the assumption that air density and the satellite’s drag parameter do not vary with time, conditions that are only approximately true in practice. On the other hand, relationships which do not contain time explicitly, such as that between orbital period and eccentricity do not suffer from this limitation. The theory presented has three major practical applications: to determine orbits over intervals of time for which either observations or data processing are lacking; to estimate satellite lifetimes; and to derive properties of the upper atmosphere. Formulae for deriving air density are concisely presented in a separate chapter and would enable the individual researcher with access to satellite orbit data but only modest calculating facilities to investigate the density structure of the upper atmosphere. Another chapter deals with a small but interesting effect, namely that of the atmosphere’s diurnal rotation on the orientation of the orbital plane. The theory satisfactorily accounts for the observed decreases in orbital inclinations of a few Oslo. The theory for predicting satellite lifetimes can be most successfully applied to low orbiting satellites for which the assumption of a time-independent air density structure is most nearly true. For higher orbits the day-to-night variation becomes increasingly significant and when lifetimes extend over many years the uncertainty associated with future solar-activity cycles seriously influences the accuracy of the lifetime calculation. The book is well-written achieving both thoroughness and conciseness: lengthy mathematical reductions are passed over as they are available in the original papers. The presentation is nevertheless intentionally mathematical, but the author’s experience with the observational as well as the theoretical aspects of satellite orbits ensures that the former is not overlooked, as indeed it should not be, having provided the stimulus for the theoretical work in the first place. For the serious student of satellite orbit theory, this is a unique presentation, which is essential reading: for others concerned with satellite observing, the geophysical use of satellite orbits, the evolution of satellite orbits or with space research in general the book is sure to hold many points of interest and to provide a handy source of reference for results and formulae. 0. V. GROVES
EARL W. MCDANIEL: CollisionPhenomena in Ionized Gases. John Wiley, New York, 1964.
xxii + 775 pp. 132F Tns author of this book has himself contributed directly to the study of collision phenomena in ionized gases and can rightly be regarded as an expert in the field. Nevertheless he has, modestly enough, circulated the early drafts of the manuscript to a number of independent experts for comment and criticism. The result is an authoritative and scholarly work, which will be. prescribed reading for young experimentalists and theorists intending to do research in atomic collisions and which the experts, earlier consulted, will be pleased to have available. The first few chapters are devoted to collision and kinetic theory and are followed by chapters on the measurement of elastic scattering cross sections and the cross sections for excitation and ionization by electron impact. Heavy particle and charge exchange cross section measurements are described together with the relevant quantum theory in chapter 6. The topics of photo-absorption, negative ions, ion mobilities, diffusion, energy distributions, recombination and surface phenomena are also reviewed. The many diagrams illustrating the theory and the experimental apparatus are carefully drawn and annotated and concisely captioned. This can also be said of the fund of graphs which in many cases compare experimental and theoretical results. Comprehensive references are given at the end of each chapter to exhaust the period up to the end of 1963. It would be surprising, in a book of this size, to find no errors and indeed there are some. For example on page 373 a ‘S state is ascribed to N-. In defence of the author, however, this table was essentially taken