Delta IV - Launch Sites

Launch Sites

Delta IV launches occur from either of two rocket launch sites. On the East coast of the United States, Space Launch Complex 37 (SLC-37) at the Cape Canaveral Air Force Station. On the West coast, polar-orbit and high-inclination launches use Vandenberg Air Force Base's Space Launch Complex 6 (SLC-6) pad.

Launch facilities at both sites are similar. At the pad is a Mobile Service Tower (MST), which provides service access to the rocket and protection from the weather. There is a crane at the top of the MST, which allows the payload and GEM-60 solid motors to be attached to the vehicle. The MST is rolled away from the rocket several hours before launch. At Vandenberg, the launch pad also has a Mobile Assembly Shelter (MAS), which completely encloses the vehicle; at CCAFS, the vehicle is partly exposed near its bottom.

Beside the vehicle is a Fixed Umbilical Tower (FUT), which has two (VAFB) or three (CCAFS) swing arms. These arms carry electrical, hydraulic, environmental control, and other support functions to the vehicle through umbilical lines. The swing arms retract at T-0 seconds to prevent them from hitting the vehicle.

Under the vehicle is a Launch Table, with six Tail Service Masts (TSMs), two for each CBC. The Launch Table supports the vehicle on the pad, and the TSMs provide further support and fueling functions for the CBCs. The vehicle is mounted to the Launch Table by a Launch Mate Unit (LMU), which is attached to the vehicle by bolts that sever at launch. Behind the Launch Table is a Fixed Pad Erector (FPE), which uses two long-stroke hydraulic pistons to raise the vehicle to the vertical position after being rolled to the pad from the Horizontal Integration Facility (HIF). Beneath the Launch Table is a flame duct, which deflects the rocket's exhaust away from the rocket or facilities.

The Horizontal Integration Facility (HIF) is situated some distance from the pad. It is a large building that allows the Delta IV CBCs and second stages to be mated and tested before they are moved to the pad. The horizontal rocket assembly of the Delta IV are similar to the ones with the assembly of Soyuz launch vehicles; they are also assembled horizontally, unlike the current Space Shuttles, the past Saturn launch vehicles and the upcoming Ares I and Ares V, where they are assembled and rolled out to the launch pad entirely vertically.

Movement of the Delta IVs among the various facilities at the pad is facilitated by Elevating Platform Transporters (EPTs). These rubber-tired vehicles can be powered by either diesel engines or electric power. Diesel EPTs are used for moving the vehicles from the HIF to the pad, while electric EPTs are used in the HIF, where precision of movement is important.