A Spaceplane is any vehicle that operates as a spacecraft in space and as an aircraft within Earth’s atmosphere. The experimental X-15 was the first operational spaceplane after its flight in 1963 when pilot Joseph Walker exceeded 100km in altitude. Another notable group of spaceplanes are the space shuttles, both the American space shuttle program which flew 135 mission over 30 years and the Soviet Buran shuttle program which flew one unmanned test flight in 1988 before being cancelled in 1993. Both the X-15 and the 2004 SpaceShipOne, the first commercial spaceplane, took off horizontally from a “mother ship” which took them high into Earth’s atmosphere. The Space Shuttle, Buran shuttle, and the 2010 Boeing X-37 took off vertically with rocket assistance, reentering by gliding through the atmosphere.