The Docking and Internal Transfer Mechanism connects the Service Module with the Functional Cargo Block, or Zarya. This internal transfer system allows the passage of crew and cargo between the two modules. Attached to the Docking and Internal Transfer Mechanism are three ports. The Forward Port is actually attached to Zarya. The Nadir Port will connect to the Universal Docking Module on Assembly Flight 3R. The Zenith Port will connect to the Science Power Platform on Assembly Flight 9A.1.