PARIS — Astrium GmbH of Germany will begin design work on an unmanned vehicle to shuttle cargo to and from the international space station under a contract signed July 7 and valued at 21 million euros ($29.2 million), Astrium and the German space agency, DLR, announced.

Under the 18-month contract, Astrium will perform studies on ways to modify the existing Automated Transfer Vehicle (ATV), Europe’s current cargo-carrying vehicle, to extend its mission beyond today’s one-way trips to the international space station.

The ATV made its inaugural flight in March 2008 and a second, nearly identical model is scheduled for flight in November 2010. The current ATV version is an unmanned canister that, when loaded with fuel, water and other supplies, weighs nearly 20,000 kilograms.

The current design is limited to delivering supplies to the space station and to regularly reboosting the station into a higher orbit. It docks at the station for up to six months, is filled with garbage and then sent on a destructive re-entry over the south Pacific Ocean. Most of it burns up on atmospheric re-entry. The remaining pieces fall into an area of the ocean that has been cleared of traffic for the re-entry period.

European Space Agency governments in November 2008 agreed to take the first small steps toward adding a cargo-return capability to the ATV.

Under current planning, these governments will decide in 2011 whether to pursue the work to full development of what is being called an Advanced Re-entry Vehicle, or ARV. Astrium, which is already prime contractor for ATV development, says the first cargo-return flight of an ARV could occur as soon as 2016, assuming full development funding is approved in 2011.

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