The online edition of the Encyclopedia of Space Science and Technology, representing an ambitious collection of the underlying physical principles of rockets, satellites, and space stations. This state-of-the-art reference outlines what astronomers know about the sun, planets, galaxy, and universe as well as the effect of the space environment on human and other biological systems. The Encyclopedia also provides an in-depth summary of the engineering involved in launching a rocket or satellite and the control systems involved on the ground, in orbit, or in deep space. Manufacturing in space from planetary and other resources is also discussed.