Ariane 5 Lofts European Cargo Tug Toward Space Station

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PARIS —  Europe’s Ariane 5 rocket on June 5 placed its heaviest-ever payload, the 20,190-kilogram Automated Transfer Vehicle (ATV), into low Earth orbit, where it deployed its solar arrays and prepared for an eight-day voyage to dock with the international space station. Docking is scheduled on June 15.

Operating from Europe’s Guiana Space Center on the northeast coast of South America, the Ariane 5 used its ES configuration, with a storable-propellant upper stage, to complete its 55th consecutive launch since 2002. It was the fourth Ariane 5 ES-version campaign, the others having placed the three previous ATV vehicles into orbit for the space station in 2008, 2011 and 2012.

Weighing 20,190 kilograms at launch, ATV-4 is the heaviest to date, exceeding the previous ATV’s liftoff mass by 150 kilograms.

ATV-4 will deliver 2,400 kilograms of dry goods to the station, including 620 kilograms of “last-minute” items that were placed into the vehicle while it was mated to the Ariane rocket.

ATV-4 is also carrying 2,580 kilograms of propellant that it will use to boost the 418,000-kilogram space station into a higher orbit. Atmospheric drag regularly pulls the station into lower altitudes, below its nominal 400-kilometer-altitude operating orbit. Another 860 kilograms of propellant will be pumped into the station’s Russian-built Zvezda module, for use when the station must perform in-orbit maneuvers on its own.

Some 570 kilograms of water and 100 kilograms of oxygen and air will be transferred to the station during its 4.5-month stay at the orbital complex. During that period, station garbage will be loaded onto the ATV before it undocks Oct. 28 and burns up on re-entry into the atmosphere over the southern Pacific Ocean.

The 20-nation European Space Agency (ESA) is providing five ATVs to the station as part of a barter arrangement with NASA to pay ESA’s 8.3 percent share of the station’s operating costs. ESA operates its own habitable module at the station. The final ATV is scheduled for launch in 2014.

ESA and NASA have agreed that Europe’s station obligations between 2017 and 2020 — the tentative station retirement date — will be met by ESA’s provision of the service module for NASA’s Orion Multi-Purpose Crew Vehicle for at least one of the Orion missions. ESA expects to use much of the technology developed for ATV for the Orion service module.