The US Space Shuttle flew 135 times from 1981 to 2011, supporting Spacelab, Mir, the Hubble Space Telescope, and the ISS. (Columbia's maiden launch, which had a white external tank, shown)

百度 也难怪战士们心情忐忑，因为上世纪60年代，美国王牌核潜艇“长尾鲨号”在深潜试验时失事，160多人葬身海底。

A spacecraft is a vehicle that can carry people and cargo beyond the Earth's atmosphere, through space to other planets, space stations, or orbits and back home again. Spacecraft which are launched from the surface of a planet are called launch vehicles and usually take-off from launch pads at spaceports.

Most spacecraft today are propelled by rocket engines, which shoot hot gases opposite to the direction of travel. Other forms of propulsion are used when appropriate. Spacecraft which do not need to escape from strong gravity may use ion thrusters or other more efficient methods.

Because of the very large amount of energy needed to leave the Earth's gravity, spacecraft are usually very expensive to build, launch, and operate. Plans for future spacecraft often focus on reducing these costs so more people can participate in space. But today, costs are still very high, and until recently all spacecraft were operated by national governments. Now, some companies operate spacecraft.

Human spaceflight vehicles

It is very expensive to send people to space, because they need food, water, air, and living space. People going to space have special names: Americans call themselves astronauts, Russians call themselves cosmonauts, and Chinese call themselves taikonauts.

• The American agency NASA once used a launch vehicle called the Space Shuttle. Currently, they fly on the Russian Soyuz or SpaceX's Falcon 9.
• The Russian agency RFSA uses a launch vehicle called Soyuz.
• The Ukrainian agency UASA uses a launch vehicle called Zenit.
• The Chinese agency CNSA uses a launch vehicle called Shenzhou.
• A space company SpaceX uses a launch vehicle called Falcon 9. The first part of that rocket lands back on Earth, making it cheaper to fly. They are currently building a larger rocket called Starship.
• A space company Blue Origin uses a launch vehicle called New Shepard. It can only send people to space for a few minutes.

Satellites

Some of the most important spacecraft today are artificial satellites. Artificial satellites are smaller, unmanned spacecraft. Some go into Low Earth orbit to look at the Earth or for other purposes. Others are sent to geostationary orbit to relay radio signals from one part of Earth to another, or to watch events on Earth from a high point of view. Communications satellites are important for television and other communications, and other satellites help with weather prediction and other jobs.

Related pages

• Spaceflight
• Space probe