If the Vehicle Assembly Building is the heart of Launch Complex 39, then the Launch Control Center is its brain. The Center is a four-story building connected to the east side of the Vehicle Assembly Building by an elevated, enclosed bridge.

The Launch Control Center contains two primary and two backup firing rooms. Each is equipped with the Launch Processing System -- an automated computer-operated system -- which monitors and controls Shuttle assembly, checkout and launch operations.

Largely because of the Launch Processing System, the countdown for a Space Shuttle launch (excluding built-in holds) takes only about 43 hours, compared to more than 80 hours needed for the earlier Apollo/Saturn flights.

Also, use of the Launch Processing System requires only approximately 225-230 persons in the firing room as compared to some 450 people needed for Apollo manned missions.

Mission responsibility transfers to Mission Control Center at Johnson Space Center, Houston, Texas, when the solid rocket boosters ignite at liftoff.