PARIS (AP) -- NASA encouraged Europe on Thursday to develop its own manned spaceship, which would give the world - and particularly the U.S. - another way of reaching the international space station.
Europe became "a full-fledged space power," the agency's administrator said, when flight controllers at a European Space Agency center guided an unmanned cargo ship to the international space station in April, successfully delivering food, water and clothes.
"It would be a small step" to develop that technology into "an independent European human spaceflight capability," NASA Administrator Michael Griffin said.
"We welcome the development of independent European capabilities in space to provide redundant systems in the event of failure of any one partner's capabilities," he told a gathering of European researchers and space executives at the French parliament.
The space station will rely on these unmanned spacecraft for supplies, tools and science experiments when NASA's space shuttles stop flying in 2010. The next-generation U.S. spacecraft, the Orion capsule, won't be ready for manned flight until 2015.
In the interim, NASA will have to pay hundreds of millions of dollars to Russia for a lift to the space station.
While Griffin has long asked the Europeans to join NASA's space exploration program, his latest comments mark a ratcheting up of that encouragement, said John Logsdon, director of space policy at George Washington University.
"Having more capability to get to orbit and having the second capability by an ally rather than the tense relationship with China or Russia would be a positive thing," Logsdon said.
Philippe Berterottiere, marketing director for Arianespace, whose rocket launched the unmanned cargo ship Jules Verne in April, told The Associated Press it would be "quite easy" to develop a manned capsule, with development costs of around $3-4.5 billion.
But Logsdon said it was highly unlikely that the Europeans would be able to get a human-rated ship to space "in time to be much of a help" for the 5-year gap without a U.S. ship.
Griffin told journalists he is "very concerned" about the upcoming period without a U.S. shuttle. He said the situation differs from the six-year gap between the last Apollo flight in 1975 and the first shuttle flight in 1981 because "the advanced nations of the world now have a substantial space asset" to maintain and protect: the international space station.
Griffin, as he has in the past, also encouraged Europe to join the U.S. in its Mars exploration plans. French President Nicolas Sarkozy said in February he wants Europe to work with the United States on the project.
NASA has been working since 2005 on President Bush's plan to return to the moon by 2020 and then travel on to Mars, though public response has been tepid.
"Exploring the Moon, and eventually Mars, will be a challenging task, one that NASA has neither the resources nor the desire to do alone," Griffin said.
"I am personally committed to the idea that this enterprise should be international in scope."
French Prime Minister Francois Fillon, in a note to the space conference, said France will use its presidency of the European Union, starting next month, to move the European space project forward, but he was short on details.
The cost of such a mission could be a sticking point for European nations struggling to tame their budget deficits.
Yannick d'Escatha, head of the French space agency CNES, said the combined European budgets for space amount to around $9.24 billion a year. That compares with NASA's annual $17 billion budget.