The European and Japanese space agencies are considering upgrades to outfit their robotic space station servicing spacecraft to return cargo to Earth, potentially laying the groundwork for crewed capsules by the 2020s.

Artist's concept of the Advanced Re-entry Vehicle. Credit: ESA

Officials expect decisions on the new spacecraft by next year.

Neither space agency has started development of a piloted spaceship, but both organizations have started designing re-entry vehicles that would bring supplies back to Earth. The ability to return cargo from the space station -- down-mass in space-speak -- will be severely curtailed once the space shuttle is retired next year.

The organizations are studying concepts to update the Automated Transfer Vehicle and H-2 Transfer Vehicle for roundtrip journeys to the International Space Station.

Both re-entry vehicles could debut by the end of this decade, giving the agencies a roundtrip transportation system capable of shepherding pressurized cargo, possibly including plants and small animals.

After delivering supplies and precious consumables, station residents currently load the ATV and HTV with trash for disposal as the craft burns up during re-entry.

The European Space Agency awarded a contract to EADS Astrium in July 2009 for an 18-month study of an Advanced Re-entry Vehicle. Worth 21 million euros, or $27 million at contemporary exchange rates, the contract covers Astrium analysis and studies of a beefed up capsule with a heat shield that could survive a fiery return to Earth and land in the ocean.

Astrium is the lead contractor on the ATV.

Engineers are scheduled to finish the 18-month Phase A study near the end of 2010, according to Simonetta Di Pippo, the director of ESA's human spaceflight programs.

"What I would like to do is to put on the table the Phase B approval at the end of this year," Di Pippo told Spaceflight Now.

The next phase of the project would fund a more detailed definition of the spacecraft's requirements and capabilities, building the foundation for formal design work to begin in about 2012.

The timetable hinges on the continued support of ESA member states at the next Ministerial Council meeting in late 2011, when the agency plans to propose full development of the ARV, Di Pippo said Thursday.

Member states approved the ARV studies in the last Ministerial Council in 2008. A severe financial and currency crisis has since forced many European governments to apply austerity measures, although space spending has not yet been significantly curtailed.

Di Pippo said the first launch of the ARV cargo carrier is planned for 2017 or 2018, slightly later than last year's announced target of 2016.

Artist's concept of Japan's proposed HTV-R spacecraft. Credit: JAXA

The Japan Aerospace Exploration Agency is refining concepts for a recoverable HTV that could be launched as soon as 2016.

In a presentation to the Japanese government's Space Activities Commission earlier this month, officials outlined three designs for the HTV-R spacecraft.

Japan has studied the development of a modest capsule to return a small cache of cargo to Earth. But officials favor more ambitious concepts of larger re-entry vehicles with broad applications.

One alternative is based on a 8.5-foot-diameter capsule to demonstrate a more substantial return capacity of more than 600 pounds. Engineers have also sketched a 13.1-foot-wide, 12.5-foot-tall cone-shaped craft that could transport more than 3,500 pounds back to Earth, plus it is better equipped to eventually carry astronauts.

JAXA says it need to start more advanced development of the HTV-R system in 2011 to launch the first spacecraft in the mid-2010s.

If approved, the international re-entry vehicles would join the SpaceX Dragon capsule to assume a slice of the cargo return capacity of the space shuttle. SpaceX says the Dragon spacecraft will start roundtrip space station flights next year.