Cosmos

 1. Spacecraft  The term spacecraft can refer to any vehicle that travels through space. In recent years, the term has become synonymous with man-made objects used to travel into outer space. These vehicles are created from metals, plastics, ceramics, composites and other materials. They have been designed for many purposes including exploration, colonization, scientific research and military operations.  Spacecraft can range in size from tiny satellites to huge interplanetary probes, but regardless of their sizes they all share common characteristics. Most spacecraft are composed of several systems that work together to provide propulsion and control. Propulsion is how a spacecraft moves. Control refers to a mechanism that allows a spacecraft to maintain its position relative to distant points. Some spacecraft use reaction engines while others make use of rockets. Rockets are fueled by chemicals, whereas reaction engines use nuclear fission or fusion processes. A th...