The Earth Moon System As A Dynamical Laboratory

The Earth-Moon neighborhood is the scene of a large variety of applications that concern asteroids, lunar exploration and space debris in Earth orbit. In particular, recent efforts by the scientific community have focused on the possibility of extending the human operations beyond the radiation belts; of exploiting in-situ resources, either on the lunar surface or on asteroids retrieved to the vicinity of the Earth; and of mitigating the space debris concern by taking advantage of the lunar perturbation. The characteristic dynamics in the cislunar space represents an opportunity for the mission designer, but also a challenge in terms of theoretical understanding and operational control. This Research Topic covers the Earth-Moon dynamics in its complexity and allure, considering the most relevant aspects for both natural and artificial objects, in order to get a new comprehension of the dynamics at stake along with the operational procedures that can handle it.

On January 20-21, 1964, the Institute for Space Studies of the Goddard Space Flight Center, National Aeronautics and Space Administration, was host to an international group of astronomers, physicists, and Earth scientists, gathered to discuss the Earth-Moon system. This was the sixth in a continuing series of interdisciplinary meetings on topics in space physics held at the Institute. The conference was organ ized by G.J.F. MacDonald, of the University of California at Los Angeles, and by R.H. Dicke, of Princeton University. The working title of the conference was "The Dynamics of the Earth-Moon System," and indeed much of the contents of this proceedings volume is concerned with dynamical problems, but the conference dealt with many other topics concerning the Earth-Moon system, and hence we have adopted the shorter title for this volume. The conference proceedings have been somewhat rear·· ranged from the order in which the papers were actually presented. In doing this the editors are exercising hindsight to bring together closely related discussions. The first paper, by D. Brouwer, discusses the motions and moments of inertia of the Moon and their relation to the lunar figure and composition. From this discussion it emerges there remain many uncertainties in the motion of the Moon associated with the lunar composition and the distribution of its mass.

Contains 250 questions and answers about astronomy, particular for the amateur astronomer.

Based on years of research conducted at the NASA Jet Propulsion Laboratory, Low-Energy Lunar Trajectory Design provides high-level information to mission managers and detailed information to mission designers about low-energy transfers between Earth and the moon. The book answers high-level questions about the availability and performance of such transfers in any given month and year. Low-energy lunar transfers are compared with various other types of transfers, and placed within the context of historical missions. Using this book, designers may reconstruct any transfer described therein, as well as design similar transfers with particular design parameters. An Appendix, “Locating the Lagrange Points,” and a useful list of terms and constants completes this technical reference. Surveys thousands of possible trajectories that may be used to transfer spacecraft between Earth and the moon, including transfers to lunar libration orbits, low lunar orbits, and the lunar surface Provides information about the methods, models, and tools used to design low-energy lunar transfers Includes discussion about the variations of these transfers from one month to the next, and the important operational aspects of implementing a low-energy lunar transfer Additional discussions address navigation, station-keeping, and spacecraft systems issues

Contents: Basic facts: Distance, size, and mass; The motion of the moon in space; Rotation of the moon; optical librations; Motion of the moon about its center of gravity; physical librations; Photometric consequences of the moon's motion: Phases and eclipses; Dynamics of the earth-moon system.