Space Launch Complex 37, previously Launch Complex 37, is a launch complex on Cape Canaveral Space Force Station, Florida. Construction began in 1959 and the site was accepted by NASA to support the Saturn I program in 1963. The complex consists of two launch pads. LC-37A has never been used, but LC-37B launched uncrewed Saturn I flights and was modified and launched Saturn IB flights, including the first test of the Apollo Lunar Module in space. It was deactivated in 1972. In 2001 it was modified as the launch site for Delta IV, a launch system operated by United Launch Alliance.
The original layout of the launch complex featured one Mobile Service Structure which could be used to service or mate a rocket on either LC-37A or 37B, but not on both simultaneously. The Delta IV Mobile Service Tower is 330 ft tall, and fitted to service all Delta IV configurations, including the Delta IV Heavy.