Space planes, also known as reusable spacecraft or aerospace planes, are vehicles designed to fly into outer space and then return to Earth for reuse. They combine features of both rockets and traditional airplanes, allowing for increased efficiency and cost-effectiveness in space travel. This works because a spaceplane can act like a spacecraft once it reaches outer space, but can act like an aircraft on Earth and planets with a thick enough atmosphere.
When spaceplanes take off, rocket engines blast off from the ground, overcoming Earth's gravity. As they ascend into the atmosphere, they transition from rocket propulsion to using air-breathing engines to take advantage of the oxygen in the atmosphere for combustion. This helps conserve fuel and increase their range.
An example of a space plane is the NASA Space Shuttle, operational from 1981 to 2011. The Space Shuttle used solid rocket boosters for the initial launch, transitioning to a combination of rocket engines and air-breathing engines during different phases of flight. It demonstrated the potential for reusable spacecraft by completing multiple missions to space and returning to Earth, significantly reducing the cost of space exploration. The Space Shuttle Discovery is one of those space planes and it is even pictured as the main picture for this particular article.
Another example of a functional version of this type of spacecraft is the Russian Buran which is considered to be the first spaceplane to be made by the Soviet Union, which completed its first spaceflight in 1988, three years before the fall of the USSR.