Marshall Space Flight Center (NASA), Alabama

The Marshall Center is NASA's primary facility for transportation, propulsion, life support, and microgravity research. The site also hosts research centers for materials, biotechnology, global hydrology and climate studies, astrophysics, payload utilization, propulsion, avionics, space environment and optics technologies. It once housed one of NASA's largest underwater training centers known as the Neutral Buoyancy Simulator (which was used to simulate the weightlessness of space) until its decommissioning in 1997. The Marshall Center is also home to the Payload Operations Center (POC), which serves as the command post for all research, experimental design, and communication pertaining to the International Space Station.