Artist's impression of the Automated Transfer Vehicle approaching the International Space Station. In combination with ESA's new Ariane 5, the 20.5 tonne, 8.5 m-long Automated Transfer Vehicle (ATV) allows Europe to transport cargo to the International Space Station. This vehicle can carry 9 tonnes of scientific equipment, supplies, water, oxygen and propellant. Up to 4 tonnes of propellant are included for ATV's own engines to reboost the Station at regular intervals as atmospheric drag reduces the orbit. An ATV is launched on average every year contributing to the Station's operating costs. It can remain docked for up to six months, during which time it will is loaded with Station waste before undocking and entering Earth's atmosphere to burn up.