BREMEN, Germany — Managers of Europe’s unmanned space station Automated Transfer Vehicle (ATV) cargo-delivery spacecraft are expected to decide this year whether to order a sixth and seventh ATV as they position the program to take on greater importance with the retirement of the U.S. space shuttle.

The ATV-2 is scheduled to leave its assembly facility here in May for transport to Europe’s Guiana Space Center in French Guiana to prepare for launch aboard an Ariane 5 rocket in December.

The inaugural ATV flight in mid-2008 was considered a success. ATV-2 nonetheless has been subjected to about 30 modifications to reinforce weaknesses that were noticed during that flight, and to increase its payload-carrying power.

ATV upgrades that increase its payload without increasing its total launch weight, coupled with a lighter, welded-joint enhancement to the Ariane 5 rocket’s strap-on solid-rocket boosters that allow the rocket to lift heavier loads, will permit ATV-2 to deliver 6,600 kilograms of fuel, air and dry cargo to the space station — 40 percent more than the first ATV carried.

Nico Dettmann, ATV-2 program manager at the 18-nation European Space Agency (ESA), said the experience of the first ATV also will enable ESA to reduce the time needed to prepare ATV-2 for launch and to dock it to the space station once it separates from the Ariane 5 rocket.

ATV teams needed eight months of preparation once the first vehicle arrived at the launch site. ATV-2 will need just six months. To ease the concerns of NASA and the other space station partners about the safety of the 20,000-kilogram ATV as it moved toward the station, the inaugural mission was put through a monthlong series of collision-avoidance and start-and-stop maneuvers before the successful docking.

ATV-2 will need no more than eight to 11 days in orbit before attaching itself to the Russian end of the orbital complex.

Ten ESA governments, led by Germany, France and Italy, paid about 1.1 billion euros ($1.5 billion) to manufacture and launch the first ATV in a multiyear development program that encountered numerous delays and cost overruns. The agency has ordered four other ATVs so far, with each mission budgeted at around 425 million euros including launch and operations.

The development of the first ATV was led by Astrium Space Transportation of Les Mureaux, France, because France paid nearly 50 percent of the program’s development budget. But Germany is financing nearly 50 percent of the cost of the serial production of ATV, so the integration and test of the vehicles are done at Astrium’s facility here. Several major French manufacturers of ATV parts have been replaced by German manufacturers.

The transfer of control from France to Germany has added to the normal program personnel turnover that has also occurred at ESA. In a presentation at Astrium’s ATV integration facility here April 13, Dettmann said about 60 percent of ESA’s current ATV-2 team is new to the program.

The proposal by the five space station partners — the United States, Russia, Europe, Japan and Canada — that the orbital complex’s life be extended to 2020 from 2015 opens new possibilities for ATV that ESA governments will be asked to consider this year. The first is whether to purchase a sixth and seventh ATV for launch starting in 2014 or 2015.

With the U.S. space shuttle scheduled for retirement late this year, the ATV will be the most powerful delivery vehicle visiting the station. It also is the only vehicle in operation with enough power to de-orbit the station when its retirement date arrives, whether in 2020 or later.

ESA has ordered five ATVs so far, and the contracting team led by Astrium Space Transportation up to now has made good on its promise to be able to produce about one ATV per year. ATV-2 was originally scheduled for launch in mid-2010 but was delayed for six months because of defects found in its latch valves. There are 48 of them on each ATV, and they had to be redesigned and then requalified for flight.

Aside from this delay, ATV-3 is on track for delivery in late 2011, with ATV-4 and ATV-5 to follow at one-year intervals.

ESA is providing ATV services to the station in lieu of paying cash to NASA for Europe’s 8.3 percent use of the station’s common resources for the European Columbus laboratory attached to the station.

The ATV upgrades, and its annual launch rate, will mean it can carry more fuel and other supplies to the station than what is needed to fulfill Europe’s obligations to NASA as the station’s general contractor. European officials have invited NASA to consider whether it wants to avail itself of this capacity, but no agreement has yet been made. NASA has contracted with two commercial suppliers in the United States, who are building ATV-type vehicles of their own, for station resupply starting in 2012.

Olivier de la Bourdonnaye, ATV program manager at Astrium, said April 13 that the company and its subcontractors will be submitting a contract proposal for ATV-6 and ATV-7 later this month.


Peter B. de Selding was the Paris bureau chief for SpaceNews.