Space: Mankind's Fourth Environment focuses on the emerging trends in astronomy, taking into consideration space transportation and exploration. Along with this topic are various technological developments that are widely used and considered with space, referred to in this book as humankind's ""fourth environment"", as another potential destination of man. Divided into four parts, the book points at different challenges and problems related to the consideration of space as another environment for humankind, which is observed in the manned space flight programs of the United States and Russia. The book gives emphasis on the improvement of space technology, particularly the use of satellites in communication, emphasizing the use of Intelsat 5 and European L-sat in broadcast system. Studies on active and passive microwave sensors are discussed and a discussion on the medical results of a manned space flight is also presented. The book will surely boost the interest of astronomers and those interested in space technology and exploration.