Spacecraft

Aspacecraftis avehiclethat can carrypeopleandcargobeyond theEarth'satmosphere,throughspaceto otherplanetarybodies,space stations,ororbitsand back home again. Spacecraft which are launched from the surface of a planet are calledlaunch vehiclesand usually take-off fromlaunch padsatspaceports.

Most spacecraft today are propelled byrocket engines,which shoot hot gases opposite to the direction of travel. Other forms ofpropulsionare used when appropriate. Spacecraft which do not need to escape from stronggravitymay useion thrustersor other moreefficientmethods.

Because of the very large amount ofenergyneeded 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 sponsored by nationalgovernments.

Human spaceflight vehicles

Most expensive of all is to send people in to space, due to their needs for food, water, air, living space, safety, and control. People participating in this way have special names:Americanscall themselvesastronauts;Russianscall themselvescosmonauts;Chinesecall themselvestaikonauts.

The American agencyNASAused a launch vehicle called theSpace Shuttle.Currently, they go on Soyuz with the cosmonauts.
The Russian agencyRFSAuses a launch vehicle calledSoyuz.
The Ukrainian agencyUASAuses a launch vehicle calledZenit.
The Chinese agencyCNSAuses a launch vehicle calledShenzhou.
A private firmVirgin Galacticis building a launch vehicle calledSpaceShipTwo.
A space companySpaceXis building a launch vehicle calledStarship.

Satellites

Some of the most important spacecraft today are artificialsatellites.Artificial satellites are smaller, unmanned spacecraft. Some go intoLow Earth orbitto look at the Earth or for other purposes. Others are sent togeostationary orbitto relayradiosignals from one part of Earth to another, or to watch events on Earth from a high point of view. Communications satellites are important fortelevisionand other communications, and other satellites help withweatherprediction and other jobs.

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