track near SpaceX's headquarters for the competitive events. The company has held the annual competition since 2017. In collaboration with doctors and academic researchers, SpaceX invited all employees to participate in the creation of a COVID-19 antibody-testing program in 2020. As such, 4300 employees volunteered to provide blood-samples resulting in a peer-reviewed scientific paper crediting eight SpaceX employees as coauthors and suggesting that a certain level of COVID-19 antibodies may provide lasting protection against the virus. In July 2018, Musk arranged for his employees to build a mini-submarine to assist the rescue of children stuck in a flooded cavern in Thailand. Richard Stanton, leader of the international rescue diving team, urged Musk to facilitate the construction of the vehicle as a back-up, in case flooding worsened. Engineers at SpaceX and The Boring Company built the mini-submarine from a Falcon 9 liquid oxygen transfer tube in eight hours and personally delivered it to Thailand. By this time, however, eight of the 12 children had already been rescued using full face masks and oxygen under anesthesia; consequently Thai authorities declined to use the submarine. Facilities SpaceX is headquartered in Hawthorne, California, which also serves as its primary manufacturing plant. The company operates a research and major operation in Redmond, Washington, owns a test site in Texas and operates three launch sites, with another under development. SpaceX also operates regional offices in Texas, Virginia, and Washington, D.C. SpaceX was incorporated in the state of Delaware. Headquarters, manufacturing, and refurbishment facilities SpaceX Headquarters is located in the Los Angeles suburb of Hawthorne, California. The large three-story facility, originally built by Northrop Corporation to build Boeing 747 fuselages, houses SpaceX's office space, mission control, and Falcon 9 manufacturing facilities. The area has one of the largest concentrations of space sector headquarters, facilities, and/or subsidiaries in the U.S., including Boeing/McDonnell Douglas main satellite building campuses, Aerospace Corp., Raytheon, NASA's Jet Propulsion Laboratory, United States Space Force's Space Systems Command at Los Angeles Air Force Base, Lockheed Martin, BAE Systems, Northrop Grumman, and AECOM, etc., with a large pool of aerospace engineers and recent college engineering graduates. SpaceX uses a high degree of vertical integration in the production of its rockets and rocket engines. SpaceX builds its rocket engines, rocket stages, spacecraft, principal avionics and all software in-house in their Hawthorne facility, which is unusual for the space industry. In January 2015, SpaceX announced it would be