A spacecraft is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and space tourism. Spacecraft and space travel are common themes in works of science fiction.
On a sub-orbital spaceflight, a spacecraft enters space and then returns to the surface, without having gone into an orbit. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers, while those used for robotic space missions operate either autonomously or telerobotically. Robotic spacecraft used to support scientific research are space probes. Robotic spacecraft that remain in orbit around a planetary body are artificial satellites. Only a handful of interstellar probes, such as Pioneer 10 and 11, Voyager 1 and 2 , and New Horizons, are currently on trajectories that leave our Solar System.
l (TCS), propulsion, and structures. Attached to the bus are typically payloads.
The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963. The first partially reusable orbital spacecraft, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarin's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. The Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California. The first Space Shuttle to fly into space was the Columbia, followed by the Challenger, Discovery, Atlantis, and Endeavour. The Endeavour was built to replace the Challenger when it was lost in January 1986. The Columbia broke up during reentry in February 2003.
The first automatic partially reusable spacecraft was the Buran (Snowstorm), launched by the USSR on November 15, 1988, although it made only one flight. This spaceplane was designed for a crew and strongly resembled the U.S. Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolution of the USSR, prevented any further flights of Buran. The Space Shuttle has since been modified to allow for autonomous re-entry via the addition of a control cable running from the control cabin to the mid-deck which would allow for the automated deployment of the landing gear in the event a un-crewed re-entry was required following abandonment due to damage at the ISS.
Per the Vision for Space Exploration, the Space Shuttle is due to be retired in 2010 due mainly to its old age and high cost of program reaching over a billion dollars per flight. The Shuttle's human transport role is to be replaced by the partially reusable Crew Exploration Vehicle (CEV) no later than 2014. The Shuttle's heavy cargo transport role is to be replaced by expendable rockets such as the Evolved Expendable Launch Vehicle (EELV) or a Shuttle Derived Launch Vehicle.
Scaled Composites' SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. The Spaceship Company will build its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic should begin reusable private spaceflight carrying paying passengers in 2009.
A spacecraft is a vessel that can safely move people and cargo outside the Earth's atmosphere, through space to other planetary bodies, space stations, or orbits. 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 motors, which shoot hot gases and fire 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 most spacecraft were sponsored by wealthy national governments.
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: Americans call themselves astronauts; Russians call themselves cosmonauts; Chinese call themselves taikonauts.
Some of the most important spacecraft today are artificial satellites. Artificial satellites are smaller, unmanned spacecraft which are mostly sent to geostationary orbit to act as points to reflect radio signals from one part of Earth to another, or to watch events on Earth from a high point of view. Without such spacecraft, people on Earth would not be able to communicate as well with each other, accurately predict the weather, or confidently ensure the security of their countries.