On December 13, 2013, NASA announced that it had selected SpaceX as the new commercial tenant. On April 14, 2014, SpaceX signed a lease agreement that gave it a 20-year exclusive lease on LC-39A. SpaceX planned to launch their launch vehicles from the pad and build a new hangar nearby. Elon Musk, CEO of SpaceX, stated that he wanted to shift most of SpaceX's NASA launches to LC-39A, including commercial cargo and crew missions to the International Space Station. Modifications In 2015, SpaceX built the Horizontal Integration Facility (HIF) just outside the perimeter of the existing launch pad in order to house both the Falcon 9 and the Falcon Heavy rockets, and their associated hardware and payloads, during preparation for flight. Both types of launch vehicles are transported from the HIF to the launch pad aboard a Transporter Erector (TE) which rides on rails up the former crawlerway path. Also in 2015, the launch mount for the Falcon Heavy was constructed on Pad 39A over the existing infrastructure. The work on both the HIF building and the pad was substantially complete by late 2015. A rollout test of the new Transporter Erector was conducted in November 2015. In February 2016, SpaceX indicated that they had "completed and activated Launch Complex 39A", but still had more work yet to do to support crewed flights. SpaceX originally planned to be ready to accomplish the first launch at pad 39A — of a Falcon Heavy — as early as 2015, as they had had architects and engineers working on the new design and modifications since 2013. By late 2014, a preliminary date for a wet dress rehearsal of the Falcon Heavy was set for no earlier than July 1, 2015. Due to a failure in a June 2015 Falcon 9 launch, SpaceX had to delay launching the Falcon Heavy in order to focus on the Falcon 9's failure investigation and its return to flight. In early 2016, considering the busy Falcon 9 launch manifest, it became unclear if the Falcon Heavy would be the first vehicle to launch from Pad 39A, or if one or more Falcon 9 missions would precede a Falcon Heavy launch. In the following months, the Falcon Heavy launch was delayed multiple times and eventually pushed back to February 2018. In 2019, SpaceX began substantial modification to LC 39A in order to begin work on phase 1 of the