NASA was thinking about a reusable spacecraft even during the Apollo missions to the moon in the 1960’s culminating on July 20, 1969 when the Eagle landed at Tranquility Base on the moon with astronauts Neil Armstrong and Buzz Aldrin aboard Apollo 11. Tests for a reusable vehicle actually began with the ‘X’ series planes in the 1950’s and 1960’s like the X-1 and the X-15 that was able to climb to the very edge of space. While the moon missions continued into the 1970’s testing of lifting bodies, wing configurations and maneuverability continued and Skylab, launched in 1973, also played a role in the research. Development of the engine system needed to get the shuttle into space and figuring out the aerodynamics for returning the shuttle from space continued throughout the 1970’s culminating in the first space shuttle mission, STS-1, on April 12, 1981