In a move to free up an Earth facing docking port for future commercial docking missions to the International Space Station (ISS), on 28 May 2014 the Permanent Multi-purpose Module (PMM) was moved from the Unity module to a port on the Tranquility module. The movement was achieved using the space station’s robot arm controlled remotely from Earth, with the astronauts on board the ISS monitoring proceedings. They installed the final locking bolts, before opening the hatch to the newly docked PMM.