Swing arms
Launch pad 37B has three swing arms that extend from the Fixed Umbilical Tower to the Delta 4 rocket. The top arm feeds conditioned air to payload inside the rocket's nose cone. The middle arm will provide the liquid hydrogen and liquid oxygen cryogenic propellants to the rocket's second stage. The bottom arm provides a hydrogen vent line for the first stage, and is long enough to connect to all three cores when a Delta 4 Heavy is used.
Photo: Justin Ray