Astrodynamics is also called as orbital mechanics. It an application of celestial bodies and ballistics to the practical problems concerning motion of rockets and space crafts etc. It is the term used to explain the Newtonian mechanics in the modern physics to man made objects in space. Newton's law of universal gravitation and Newton's laws of Motion are the fundamental laws of Astrodynamics. Review articles are the summary of current state of understanding on a particular research topic. They analyze or discuss research previously published by scientist and academicians rather than reporting novel research results. Review article comes in the form of systematic reviews and literature reviews and are a form of secondary literature. Systematic reviews determine an objective list of criteria, and find all previously published original research papers that meet the criteria. They then compare the results presented in these papers. Literature reviews, by contrast, provide a summary of what the authors believe are the best and most relevant prior publications. The concept of "review article" is separate from the concept of peer-reviewed literature. It is possible for a review to be peer-reviewed, and it is possible for a review to be non-peer-reviewed.