The module has three redundant berthing ports that were not scheduled to be used prior to the end of the Space Shuttle program, although there is a Power Data Grapple Fixture reserved for the Special Purpose Dexterous Manipulator (Dextre), which is located on the zenith berthing location. In the current ISS configuration "Tranquility" is docked to the port berthing location of "Unity". As such, the three unused berthing locations of "Tranquility" were disabled as the node's close proximity to other segments would prohibit the port's direct use for cargo spacecraft or using the docking module PMA-3, which was relocated from "Harmony" to the port berthing location of "Tranquility" for storage. At the time, the move of PMA-3 to the port location of "Tranquility" was required because NASA decided to leave the Multi-Purpose Logistics Module (MPLM) "Leonardo" permanently attached to the ISS, which will be located at the nadir side of "Unity".