JSC is NASA's center for human space flight and was orinally named Manned Spacecraft Center. It was given the name Johnson Space Center in 1973 in honor of president Lyndon B, Johnson.

Five building areas can distinguished. The main area (marked in red) contains all the buildings for mission design, mission support, flight crew training, all kinds of spacecraft testing facilities, project and administration facoilities.

The flight simulation facility ASCATS was temporarily housed in building 422. ASCATS was used to train the crew of mission control. For an integrated simulation flight crew and remote site personnel were involved. It contained the GSSC (Ground Support Simulation Computer) and the APCU (Apollo Process Control Unit). The GSSC simulates the data streams between MCC and remote sites. The APCU generates telmetry and comnmand response data simulating the launch vehicle and the spacecraft.

JSC is the Center for mission design, mission planning, mission management & control and mission training.
The Mission Control Center (MCC) is located in the center (building 30). The MCC had three wings: an Operations Wing, an Administration Wing and a Lobby Wing in the center. The Operations Wing had two Mission Operations Control Rooms (MOCRs) on the second and third floor respectively. The elaborate systems for mission support: the Real Time Computer Complex (RTCC) and the Communication, Command And Telemetry Center (CCATS); were located on the first floor.