The 20-ton spacecraft is being loaded with Russian propellant destined for the International Space Station. The launch and maiden voyage of the first European resupply spaceship is scheduled for the second half of February, the ESA said.

Through the end of the month, the largest quantity of propellant will be fueled on board -- approximately 4,885 pounds of monomethylhydrazine and mixed nitrogen oxides -- to be used by the ATV's propulsion system.

"The monthlong fueling campaign is a result of having to load four different propellants, some in large quantities, and also some oxygen," said Nicolas Chamussy, the ATV program manager. "Since each propellant is complex and dangerous to handle, the preparatory operations -- the safety rules and the decontamination -- takes much more time than the actual pressurized transfer of each product into the vehicle."

By the time ATV is mated to its Ariane 5 launcher, it will hold four different types of propellant and 44 pounds of oxygen, giving it a total propellant mass of about 6.5 tons.