The Mojave Air and Space Port at Rutan Field is in Mojave, California, United States, at an elevation of . It is the first facility to be licensed in the United States for horizontal launches of reusable spacecraft, being certified as a spaceport by the Federal Aviation Administration on June 17, 2004. The facility covers 2,998 acres (1,213 ha) and has three runways. In 1935, Kern County opened the Mojave Airport east of Mojave, California to serve the gold and silver mining industry in the area. The airport had two dirt runways, one oiled, but no fueling or servicing facilities. In 1941, the Civil Aeronautics Board began improvements to the airport for national defense purposes that included two asphalt runways and a taxiway. Kern County agreed the airport could be taken over by the military in the event of war. After the Japanese attack on Pearl Harbor in December 1941, the United States Marine Corps took over the airport and expanded it into Marine Corps Auxiliary Air Station (MCAAS) Mojave. The two runways were extended and a third one added. Barracks were constructed to house 2,734 male and 376 female military personnel. The expansion of MCAAS Mojave was done by Vinson & Pringle and Del E. Webb Construction Company out of Phoenix, Arizona. Civilian employment at the base would peak at 176. The Marines would eventually spend more than $7 million on the base, which totaled . Many of the Corps' World War II aces received their gunnery training at Mojave. During World War II, Mojave hosted 29 aircraft squadrons, four Carrier Aircraft Service Detachments, and three Air Warning Squadrons. At its peak, the air station had 145 training and other aircraft. Mojave also had a 75 x 156 foot swimming pool that was used to train aviators in emergency water egress and for recreation. The base's 900-seat auditorium hosted several USO shows that featured Bob Hope, Frances Langford and Marilyn Maxwell. With the end of World War II, MCAAS was disestablished on February 7, 1946; a United States Navy Air Station (NAS) was established the same day.