PMA 1, 2, 3

The PMA (Pressurized Mating Adapter) are elements to connect the 1.3 m US CBM (Common Berthing Mechanism) interface to the russian 0.7m APAS (Androgynous Peripheral Attachment System) docking systems. Three PMAs are untilised at the ISS - one for connecting the russian with the american segment and two to allow dockings of the Shuttle and later Orion spacrafts.

PMA 1 connects permanently the aft hatch of Node 1 with the Zarya module.

PMA 2 was delivered with Node 1 and was located at first at the forward hatch of this module. When STS-98 delivered Destiny, PMA 2 was moved to the forward hatch of Destiny. When STS-120 delivers the Node 2 to its temporary berthing at the port hatch of Node 2, PMA 2 will first be moved to the front hatch of Node 2 and then with this module to the front hatch of Destiny.

PMA 3 was delivered on a Spacelab pallet by STS-92. First docked at the nadir hatch of Node 1, it provided docking for the STS-97 and STS-98. In March 2001 it was moved to the port hatch of Node 1. In Augus 2007 PMA-3 moved to the nadir hatch of Unity to make room for the temporary docking of the Node 2 module delivered by STS-120. For adding Node 3, it will temorary move to the nadir port of Node 2. Finally it will be docked to the nadir hatch of Node 3 when this will be berthed to Node 1 in 2010.