Pressurized Mating Adapters
Artist's rendering (Credit: NASA)
The three PMA's are conical docking adapters which allow the docking systems of the space shuttle and Russian modules to attachy to a node's berthing mechanism. PMA-1 links the U.S. and Russian segments of the ISS. The other two served as docking ports for the space shuttle and may be employed by commercial vehicles and the Orion Multi-Purpose Crew Vehicle (MPCV).
Length: 1.86 m (6.1 ft)
Narrow end: 1.37 m (4.5 ft)
Wide end: 1.9m (6.25 ft)