ATV cargo capacity
An ATV can carry more than 6.6 tonnes of wet and dry cargo. In addition, ATV carries about 2.5 tonnes of fuel for its own use, for rendezvous and docking with the International Space Station, performing manoeuvres on the way, and deorbiting at the end of the mission.
The cargo is calculated for each mission depending on the Station's need, but in general the total ATV cargo capacity can be allocated as follows :
Propulsive support propellant (up to 4.0 tonnes)
This takes up the largest proportion of the ATV cargo. This propellant is used by ATV to reboost the International Space Station to a higher orbiting altitude in order to counter the effects of atmospheric drag, for attitude control and for debris avoidance if needed. The propellant consists of two different types: monomethylhydrazine (MMH) and mixed oxides of nitrogen (MON3).
Refuelling propellant (up to 860 kg)
Once attached to the Station, up to 860 kg of refuelling propellant can be transferred from ATV to the Space Station. This consists of two different fluids: the fuel unsymmetrical dimethylhydrazine (UDMH) and the oxidiser, nitrogen tetroxide (N2O4), which provides a source of oxygen so the fuel can ignite and burn in orbit. This is used by the Station for orbit and attitude control with its own engines.
Water (up to 855 kg)
This is what is known as potable water for use by the crew for drinking, food rehydration and oral hygiene.
Gases (up to 102 kg)
Two gases can be transported at a time to resupply the atmosphere on the International Space Station made up of oxygen, nitrogen and air.
Up to 3.2 tonnes of dry cargo can be transported to the ISS inside the Integrated Cargo Carrier of the ATV. This may include food for the crew, spare parts, clothing, and a number of additional items.
Late cargo loading
From ATV-2 onwards it is possible to add dry cargo just weeks before launch through the same hatch astronauts will use to access the spacecraft in space. In the run-up to launch ATVs are placed vertically on their Ariane 5 launcher meaning that late cargo has to be loaded by an operator that is lowered in through the top of the vehicle.
This addition to the mission allows for more flexibility in the cargo and last-minute requests from ESA's international partners.
Last update: 3 June 2013