For astronauts aboard the International Space Station, the arrival of any new visitor - manned or robotic - is cause for celebration. While manned arrivals dock with the promise of a crew change, unmanned spacecraft bring with them the most precious of cargo; food, fuel, air and tools.

This artistic rendition depicts the arrival of an Automated Transfer Vehicle (ATV) at the space station's Zvezda service module. Under development by the European Space Agency (ESA), the robotic supply ship is designed to ferry more than 7.5 tons of cargo the space station, three times more than the current Russian-built Progress vehicles.

Weighing in at 21 tons, the ATV supply ship is roughly the same size of NASA's Apollo spacecraft though a bit lighter, and is launched via an Ariane 5 rocket. It runs about 32 feet (10 meters) long by 14 feet (4.5 meters) wide.

Today, the crew of ISS Expedition 9 - commander Gennady Padalka and flight engineer Michael Fincke - is expected to conduct the second of two spacewalks aimed at preparing the space station for the arrival of ATVs. The first ATV, dubbed Jules Verne by ESA officials, is expected to make its first shipment to the ISS in the latter half of 2005, possibly as early as July.

-- SPACE.com Staff

Credit: ESA/D.Ducros