This has been done a dozen times, from DC-X to JAXA's RTV to Armadillo's Stig. What makes the SpaceX effort different is it's part of a practical launch system

This has been done a dozen times, from DC-X to JAXA's RTV to Armadillo's Stig. What makes the SpaceX effort different is it's part of a practical launch system and not an SSTO concept prototype like the others.