Spacecraft are designed to fly in and explore the upper atmosphere or space. The first successful powered flight into space was on April 12, 1981, when Space Shuttle Columbia launched from Kennedy Space Center in Florida. Since then, many different types of spacecraft have been built and flown by a variety of nations for a variety of purposes.
There are two main types of spacecraft: piloted and unpiloted. Piloted spacecraft carry humans or animals into space, while unpiloted spacecraft do not. Unpiloted spacecraft can be either robotic or remote-controlled.
Piloted spacecraft include orbital vehicles such as the space shuttle and International Space Station (ISS), as well as suborbital craft such as Virgin Galactic’s VSS Unity spaceship. Orbital vehicles remain in space for extended periods of time, typically years, while suborbital craft only stay in space for a few minutes or hours before returning to Earth.
Robotic spacecraft are designed to operate without human intervention and can be either orbiters or landers. Orbiters circle a planet or moon without landing on it, while landers descend to the surface. Robotic orbiters have been sent to all eight planets in the solar system, as well as numerous moons; robotic landers have soft-landed on Mars, Venus, Saturn’s moon Titan, and Comet 67P/Churyumov-Gerasimenko among others.
Remote-controlled spacecraft are operated by ground controllers from mission control centers around the world. These include planetary rovers such as NASA’s Curiosity rover on Mars and the Philae comet lander operated by the European Space Agency (ESA).
Both piloted and unpiloted craft require propulsion systems to provide thrust that overcomes drag and moves them through the vacuum of outer space. Chemical rockets are currently the most common type of propulsion used for this purpose; however other options are being developed including electric propulsion and nuclear thermal rockets.