Standing 212 feet high—more than 20 stories—the TE moves launch-ready rockets and spacecraft from the processing hangar at the base of the pad up to the pad surface and into a vertical position over the flame trench. The TE is a much larger and stronger version of the erector the company uses at Space Launch Complex 40, and is used for processing and launching Falcon Heavy rockets. The first SpaceX launch from LC-39A was SpaceX's 10th Commercial Resupply Services mission to the International Space Station, known as CRS-10. The launch on Falcon 9 took place on Feb. 19, 2017, and carried supplies and research to the space station. Since then, CRS-11 and CRS-12 have also launched from LC-39A. SpaceX will use LC-39A for its Crew Dragon missions to the International Space Station.
NASA, SpaceX & Boeing | Commercial Crew Program Page 26 Page 28