Delta 9: Cultural Landscape Inventory, Minuteman Missile National Historic Site, National Park Service

Delta-09 Launch Facility occupies part of an open, grassy tract of land straddling Pennington County Road about 0.6 miles west and south of Interstate 90. The facility is part of Minuteman Missile National Historic Site in South Dakota, which consists of two separate but associated landscapes. The Delta-01 Launch Control Facility is located about ten miles away from Delta-09. When Minuteman Missile was an active U.S. Air Force facility, the sites were connected by a buried cable network and collectively known as Delta Flight, headquartered at Ellsworth Air Force Base. Currently, Delta-09 is surrounded on three sides by the open prairie of the Buffalo Gap National Grassland, under ownership of the United States Forest Service. Although Interstate 90 is visible in the distance, the rural area contains no other nearby development. Under Air Force ownership, Delta-09 occupied 90 acres: 80 acres of concurrent use and ten acres of exclusive use, with one acre located within the security fence. The launch structures are clustered inside a rectangular area surrounded by the chain-link security fence. A double gate is located on the east side, and a gravel access road leads from the gate to the nearby county road. The area inside the enclosure has been graded to form a level, earthen platform elevated a few feet above the surrounding terrain. The platform, with its gravel surface, was planned specifically to provide maneuvering space for the transporter-erector vehicles that hauled and emplaced Minuteman missiles. The missile launcher and launch facility support building are located near the southern end of the maneuver space platform, with most of their structural elements underground. A smaller rectangular area outlined by four low, yellow concrete corner pylons served as a helicopter landing pad. Floodlights mounted on two wooden utility poles at opposite corners of the maneuver space provided light for nighttime maintenance activities. Two remnants of the concrete-base pad from earlier outer zone security system antennas remain at the site: a square concrete pad with four reflector mount pedestals is located to the southwest (rear) of the missile launcher, and a clutter monument and footing of the antenna pedestal are located to the south of the launch support building. Delta-09 is nationally significant for its military associations, particularly related to the Cold War and missile technology. The period of significance includes the site’s use by the U.S. Air Force from 1963 to 1993, beginning with the activation of the missiles and ending when the site was deactivated. The missile launcher itself consists of an underground launch tube (silo) surrounded by a cylindrical equipment room and covered by a hardened, ballistically actuated closure door. The tube and equipment room are covered by a massive, reinforced concrete roof slab. The top of the slab is level with the maneuver area. Modifications were made to the Delta-09 landscape to prepare it for interpretation as a static display. The launcher closure has been permanently fixed in a partially-open position, and a glass and aluminum viewing enclosure was installed over the opening in 2001. A deactivated training missile was installed in the launch tube that same year. The viewing enclosure allows visitors to see into the launcher to view the training missile. The launch facility support building is located adjacent to the launcher on the southeast. This box-like underground structure has its roof positioned about one foot above ground level. Other associated structures at the site include the IMPSS antenna, a hardened UHF antenna, a cathodic protection rectifier, two azimuth markers, two HICS markers, and the security fencing. Public access is only permitted by reservation and as part of National Park Service tours.

Delta 9: Cultural Landscape Inventory, Minuteman Missile National Historic Site, National Park Service

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