The docking compartment has two primary functions: provide a docking port for visiting Soyuz and Progress spacecraft and serve as an airlock for Russian EVAs.

The docking port can accommodate one Soyuz-TMA or one Progress-M spacecraft.
Visiting spacecraft can deliver people and cargo to and from to the space station.
In addition, the Docking Compartment can transfer fuel from the fuel tanks of a docked Progress resupply vehicle to either the Zvezda Service Module Integrated Propulsion System or the Zarya Functional Cargo Block.
It can also transfer propellant from Zvezda and Zarya to the propulsion system of docked vehicles—Soyuz and Progress.

The two airlocks are used for spacewalks by cosmonauts wearing Russian Orlan-M spacesuits.

The Pirs docking compartment was manufactured by RKK Energia.
The Docking Compartment is similar to the Mir Docking Module used on the Mir space station.
The docking compartment's planned lifetime as part of the station was five years.
The docking compartment has two primary functions: provide a docking port for visiting Soyuz and Progress spacecraft and serve as an airlock for Russian EVAs.
The docking port can accommodate one Soyuz-TMA or one Progress-M spacecraft. Visiting spacecraft can deliver people and cargo to and from to the space station. In addition, the Docking Compartment can transfer fuel from the fuel tanks of a docked Progress resupply vehicle to either the Zvezda Service Module Integrated Propulsion System or the Zarya Functional Cargo Block. It can also transfer propellant from Zvezda and Zarya to the propulsion system of docked vehicles—Soyuz and Progress.
The two airlocks are used for spacewalks by cosmonauts wearing Russian Orlan-M spacesuits.
The Pirs docking compartment was manufactured by RKK Energia. The Docking Compartment is similar to the Mir Docking Module used on the Mir space station. The docking compartment's planned lifetime as part of the station was five years.
Pirs (ISS module)