PARIS — Europe’s Automated Transfer Vehicle (ATV) cargo tug will remain docked to the international space station until September, a month longer than originally planned. The extended stay will be used to allow the ATV to use its extra fuel to perform a fifth station-reboost maneuver, European Space Agency (ESA) officials said.

The decision

also will give the station’s astronauts more time to fill ATV with garbage and prepare for the vehicle’s separation. Once detached from the station, the ATV will be guided to a destructive atmospheric re-entry over the South Pacific.

The inaugural ATV model, called Jules Verne, docked to the station April 3. Its arrival in automatic mode

went so smoothly that the ATV has about

870 kilograms of fuel that is

not needed to complete its mission. This fuel would have been used if ATV had been forced to perform several docking attempts that would have featured approach-and-retreat sequences.

One of the ATV’s missions is to push the station into a higher orbit on a regular basis. The orbital outpost’s altitude drops under the steady pressure of atmospheric drag. In a June 17 interview, Alberto Novelli, ESA’s mission manager at the ATV Control Center in Toulouse, said a late-August reboost

had been added to ATV’s schedule after it was clear the extra fuel was available for the maneuver.

ATV’s other principal mission is to deliver supplies, including fuel and water, to the station.

About 811 kilograms of

propellant was

transferred to the station June 18.

The maneuver, which did not involve the station’s astronauts, was performed using pipes on the exterior of the ATV and the international space station to connect the vehicle to the station’s plumbing system. The station’s mission control center in Moscow oversaw the procedure. ATV is docked to Russia’s end of the station and uses Russian propellant.

ATV has triple the cargo-carrying ability of Russia’s unmanned Progress space tug but also has the same refueling capacity – 850 kilograms – as Progress. Handling the Russian fuel –

transferring it from Russia to Europe’s Guiana Space Center spaceport, loading it onto the ATV and then

transferring it to the station – has been a major focus of attention for ESA and the ATV contracting team, including Astrium Space Transportation of Europe, which is ATV’s prime contractor; RSC Energia of Moscow; and ThalesAlenia Space’s Italian division.

One of ATV’s empty tanks has been used to store 110 liters of unneeded water. Capturing water from the station’s humidity collector – enough to fill five 22-liter bags – is a feature that was not planned when ATV was designed.

Another unplanned use of ATV is as a sleeping and bathing area for astronauts.

Astronauts who have spent time at the station say the living and working quarters are tightly packed with functioning equipment and gear that has been taken out of service but

not yet


ATV is expected to carry 6,300 kilograms of garbage when it leaves the station. In the meantime, it provides 48 cubic

meters of pressurized living space that astronauts have used as bathing and sleeping quarters. “The ATV’s pressurized cabin offers the crew a large space, a lot of privacy and also helps keep the station air humidity lower,” Herve Come, ESA’s ATV mission director

said in a June 16 statement. Novelli said using ATV as a regular living and occasional work space – South Korea’s Yi So-yeon performed some of her experiments in Jules Verne in April – helps distribute the humidity produced by the astronauts more evenly throughout the station and reduces the formation of water droplets in areas of heavier astronaut use.

Under a barter arrangement with NASA, ESA has agreed to provide four more ATV vehicles to the station, with the second scheduled for launch aboard a European Ariane 5 rocket in 2010.