This work (originally published in 1925) contributes to recognition of the feasibility of space travel. Treated are problems associated with leaving the earth, return to earth, free-space flight, circumnavigation of celestial objects, and landing on other celestial objects.

Explores the history and significance of interplanetary space missions. Features detailed explanations and mathematical methods for trajectory optimization. Includes detailed explanations and mathematical methods for mission analysis for interplanetary missions. Covers the introduction, mathematical methods, and applications of the N-body problem (N>2). Discusses navigation and targeting for interplanetary mission.

Fundamentals of Astrodynamics and Applications is rapidly becoming the standard astrodynamics reference for those involved in the business of spaceflight. What sets this book apart is that nearly all of the theoretical mathematics is followed by discussions of practical applications implemented in tested software routines. For example, the book includes a compendium of algorithms that allow students and professionals to determine orbits with high precision using a PC. Without a doubt, when an astrodynamics problem arises in the future, it will become standard practice for engineers to keep this volume close at hand and `look it up in Vallado'. While the first edition was an exceptionally useful and popular book throughout the community, there are a number of reasons why the second edition will be even more so. There are many reworked examples and derivations. Newly introduced topics include ground illumination calculations, Moon rise and set, and a listing of relevant Internet sites. There is an improved and expanded discussion of coordinate systems, orbit determination, and differential correction. Perhaps most important is that all of the software routines described in the book are now available for free in FORTRAN, PASCAL, and C. This makes the second edition an even more valuable text and superb reference.

Nestled 300 km north of Oslo lies the quaint valley of Hessdalen, home to unique sightings that have puzzled residents and scientists alike. Regular phenomena light up the skies – but are these mysterious lights a portal for communicating with inhabited worlds beyond Earth? For over 30 years, research teams have studied the phenomena yet the secrets of Hessdalen persist. This book explores deeper questions sparked by the valley’s unexplained occurrences. Is Earth an ordinary cosmic body among millions, or somehow unique? We know life emerged nearly four billion years ago but still do not fully grasp the physical and chemical processes enabling this. With expanding resources to study space, might we someday soon detect signatures of extraterrestrial life, whether in our solar system or on distant exoplanets? The final part invites philosophical reflection on the acute fragility of our biosphere and humanity’s place in the vast Universe. As an astrophysicist at the University of Picardie Jules Verne in France, the author weaves empirical science and speculative inquiry to probe Hessdalen’s confounding lights, the exceptional nature of Earth, and the environmental precariousness of this rare life-sustaining planet.