Space mechanics

Book Reviews ology of the nervous system. Much of this material is potentially relevant to the principal arguments of the book, but it is not very meaningfully related to the issue of the brain as a computer in the text. In this book Dr. George has set himself the difficult task of making meaningful contact between concepts and facts in psychology and neurophysiology and the world of computers. This is accomplished at times only at the expense of over-simplifying things on the behavioral side; by reducing the behavior of living organisms to simple response "outputs." It is accomplished also by failing to define key terms precisely (which permits changes in meaning) and by much metaphorical license. Thus the author imputes machines with psychological traits and models are said to "think," "perceive," and have "insight." In spite of these failings, this volume represents a real contribution to an important and difficult area of research. Much literature relating to the physical model approach to understanding behavior is summarized in its pages, along with cogent discussions of the philosophical and logical precepts upon which such attempts are based. JOtIN PAUL BRADY

Department of Psychiatry University of Pennsylvania SPACE MECHANICS,by Walter C. Nelson and Ernest E. Loft. 245 pages, diagrams, 6 X 9 in. Englewood Cliffs, N. J., Prentice-Hall, Inc., 1962. This volume is one of the publications in the Prentice=Hall Space Technology Series. The first four chapters, which constitute approximately one-third of the text, are out of proportion to the main aim of the book which is "the study of the motion of rockets, satellites and bodies in space." Chapter 2, entitled "Mathematical Introduction," should not be necessary in a college text. As a reference for the practicing engineer, this chapter serves a more useful purpose, but not at the expense of material more directly related to space mechanics in a book of this limited size. The chapter on "The Solar System" develops the shape and gravity of the earth to a degree which is out of keeping with applications thereof in the remainder of the text. The

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tabular data on the planets and their natural satellites, which are useful, could well have been included as a portion of the Appendix on "Physical and Astrophysical Constants," in the interest of arrangement and conservation of space. The "Space Mechanics" portion of the book begins with Chapter 5 in the development of two-body motion in vector notation. After a digression of seven pages on the geometrical development of conic sections, the dynamics of two=body orbits (which follows immediately from Equation 5.20-18) is given. Following this, is an extensive summary of equations in terms of various parameters which is handy for quick reference purposes. The section on "Orbit Perturbations" is disappointingly short and non-technical for a book which is supposed to serve as a text or reference. This is misleading to the beginner in space mechanics. For example, atmospheric drag is described as a planar effect when actually there is a component normal to the orbit plane for non-equatorial orbits. Also, the precession of the line of apsides of an elliptical orbit due to oblateness in omitted. Chapter 8, on "Lunar Traiectories," begins with a description of the earth-moon system and its motion. The first paragraph of Section 8.30, on Transfer Techniques, is both poorly written and poorly proof-read. Velocities, quoted by themselves, have no significance because the radial distance from the appropriate body must be quoted at the same time. One of the statements on page 177 says " . . . that its residual velocity will cancel the moon's orbit speed" taken at face value this would result in a straight radial trajectory to the earth. The final section of Chapter 8, "Circumlunar Flight," is an extremely short, undetailed discussion which presents no analysis or results useful for either a college text or a working reference book. The final chapter of the book, concerning "Interplanetary Trajectories," starts with Hohmann transfers to Mars and Venus, assuming coplanar, circular planet orbits. The trajectories are then generalized for transfer angles other than 180 degrees. The "corridor and ring" approach, which was derived in the previous chapter, is applied to planetary approaches. No serious discussion of the transfer trajectory modifications, necessitated by the

Journal of The Franklin Institute

Book Reviews actual inclined, eccentric planetary orbits, is included. As it stands, the discussion of the velocity of the launch site, by virtue of the earth's orbital and rotational motions, is misleading to the beginner. The launch azimuth and resulting parking orbit inclination were completely ignored in this derivation. The numerical examples given on pages 208 and 209 are incorrect. The sentence ending in " . . . the vehicle velocity must be increased by 2.78 km/sec for the soft landing,, is incorrect both conceptually and numerically. I t should read " . . . to match the orbital velocity of M a r s . . . " and the numerical value should correctly be 3.16 km/see. There would be no reason to match the orbital velocity of the planet prior to landing. The sentence following, quoting a retro-velocity increment of 5.93 km/sec, is correct. The example for a Venus mission is also incorrect. The equation at the top of page 309, using the given heliocentric velocities and the Venus escape speed from Table 4.110-2, should give a value of 10.66 km./see. I t is unfortunate that the authors were not abIe to include more analytical developments and typical numerical results in the three prime areas of earth satellites, lunar, trajectories, and interplanetary traiectories which have become available in the Space Flight Handbooks, Volumes I and II, produced by the Martin Company for NASA, and in the general published literature, including papers presented at ARS, AAS, IAS, and AIAA meetings during the past several years. As an example, one valuable early paper which was omitted from the list of references

is "Cergain Problems of Moon Flight Dynamics," by V. A. Egerov in Russian Literature of Satellites, Part I, International Physical Index (New York), 1958. A relatively large number of typographical errors, such as incorrect symbols and missing portions of equations, have been found. This book is described in the Preface as being "intended for use as both an undergraduate or graduate text and reference for the practicing engineer." In the opinion of this reviewer, the book unfortunately does not quite reach either of these objectives. H. A. LIESKE

General Electric Company Valley Forge, Pennsylvania

Vol. 277, No. 6, June 1964

CRYOGENIC TECmqOLOGY, edited by R. W. Vance. 585 pages, diagrams, illustrations, 6 X 9 in. New York, John Wiley & Sons, Inc., 1963. Price, $19.50. "Cryogenic Technology" is a compendium of lectures given in the University of California Engineering and Physical Sciences Extension Series, but the emphasis has been changed since an earlier series led to the publication of "Applied Cryogenic Engineering." In the present volume, greater space is devoted to the presentation of fundamental information and theory and less to the presentation of engineering design data, although there are extensive discussions of engineering problems. While it is quite clear that this is another "Space Age" textbook (e.g., the chapter on "Optical Masers" has little to do with cryogenics although, inferentially, it is concerned with communications techniques that may be used in space), the subject matter is less diffuse than in its predecessor. Nevertheless, it appears to this reviewer that it still suffers, although perhaps to a lesser degree, from the same fault of attempting to cover too much ground. Although the lecture course is described as being at graduate level, the material presented is qualitative and descriptive. Little previous knowledge is assumed. It would be more appropriate to describe the lectures as providing an advanced undergraduate introduction to a variety of interesting new topics. If accepted as this, the book is successful. Since it is well documented with references, the suggested additional reading offers access to more detailed material for further study. The above comments are not intended to imply criticism of the individual chapters. In general, the material is clearly presented and well-written by the sixteen contributing authors, each of whom is well qualified to discuss his subject. The chapters fall into two types : those providing a theoretical review and those discussing existing or proposed engineering applications. Typical of these classes are the two chapters, "Fundamentals of Superconductivity" (J. K. Huhn) and "Applications of Superconductivity" (T. A. Buchhold). Within the former group there is a fair diversity of approach. For example, "Phase Equilibria" (C. McKinley) is representative of those chapters that provide a detailed discussion of a fairly narrow field. By eonstrast, the ex-

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