The systematic application of engineering and scientific disciplines to the exploration and utilization of outer space. Since 1957, space satellites and probes have been launched beyond the Earth's atmosphere to orbit the Earth (velocity of 7 km/s or 4.4 mi/s) or to escape from it (velocity 11 km/s or 6.9 mi/s). Due to the severe environmental conditions in space, such as high vacuum, intense solar radiation, and extremes of temperature, a variety of disciplines are required to design, build, test, and launch a successful spacecraft.