The ATV Integrated Cargo carrier being loaded with dry cargo

The Equipped External Bay of the ICC holds 22 spherical tanks of different sizes and colours. These tanks are used to re-supply the Station with refuelling propellant for the Station's own propulsion system, water and gas (air or oxygen or nitrogen) for the crew. This cylindrical bay and its tanks are not visible from outside the ATV since they are hidden behind the interface linking the Cargo Carrier to the ATV Service Module.

Although noone travels in an ATV, astronauts dressed in regular clothing are able to access the contents of the pressurised part of the ICC during its joint orbital flight with the ISS.

All the dry cargo is stored in the Integrated Cargo Carrier (ICC), the pressurised upper segment which docks with the ISS.

Russian docking system

The 'nose' of the ICC contains the Russian-made docking equipment and various kinds of rendezvous sensors. The Russian docking system enables physical, electrical and propellant connections with the Station; it also provides the ISS crew access to the ICC. The associated Russian made electronics are installed on the side of the front racks in the pressurised module.

With the ATV securely docked, the Station's crew can enter the cargo section and remove the payload: maintenance supplies, science hardware, and parcels of fresh food, mail and family tapes or DVDs. Meanwhile, the ATV's liquid tanks can be connected to the Station's own plumbing to transfer their contents to the ISS.

The fluid tanks of the ATV Integrated Cargo Carrier

Up to two astronauts can work to unload supplies and conduct experiments, while the hatch remains constantly open between ISS and the ATV. The pressurised module is designed to accommodate up to two crewmembers working for eight hours.

The ATV's pressurised cargo section is based on the Italian-built Multi-Purpose Logistics Module (MPLM), which is already in service as a Shuttle-carried 'space barge' transporting equipment to and from the Station.

Air loaded in the ATV can be released manually from the Cargo Carrier into the Station cabin through the hatch.

External appearance

On the outside of the Cargo Carrier, the details of the ATV's structure are covered with an eggshell-coloured insulating foil layer on top of meteorite protection panels.

On the external ICC front cone, avionics and propulsion hardware, critical to the automatic rendezvous with the ISS are visible:

• 2 telegoniometers, which continuously calculate distance and direction from ATV to ISS

• 2 videometers, an image processing system able to compute distance and orientation of the ISS

• 2 star trackers, which are able to recognize constellations in the sky

• 2 visual video targets, used by the ISS crew for visual monitoring of the ATV's final approach

• 8 mini jets for attitude control

The front cone of the Russian-made docking adapter

The front cone of the ICC accommodates the 235 kg Russian docking system with its 80 cm-diameter hatch, its alignment mechanism and its one-metre-long extendible probe. During rendezvous with ISS, the ATV is the active spacecraft and is equipped with an arrow-shaped probe mechanism. The Space Station has receiving-cone mechanisms at the docking ports which are routinely used for Soyuz and Progress dockings.

The Russian docking system, which has been continuously refined since it was originally developed in the late 1960s for the Salyut space station programme, remains the worldwide state-of-the-art in docking mechanisms.