NASA Administrator Mike Griffin told an international audience here that the United States can afford to return to the Moon on its own but will need help from other spacefaring nations to ensure “a robust program of lunar surface exploration and exploitation.”

European and Japanese space officials welcomed NASA’s overture, but also said that completion of the international space station is a prerequisite for collaboration on future human space flight activities with the United States.

In an address before the Center for Strategic and International Studies’ Workshop on Space Exploration and International Cooperation here Nov. 1, Griffin said that the United States is alone among today’s spacefaring nations in its ability to afford building the space transportation systems needed for traveling from the Earth to the Moon and points beyond, a project he likened to the creation of America’s interstate highway system more than 50 years ago.

“Today, a half-century after this major commitment of our nation’s resources and energies, we have the modern interstate highway system … that visionary focus on the proper role of government in creating crucial core infrastructure has paid dividends for decade s to America’s well-being,” Griffin said. “And that is the context in which we should view NASA’s new architecture for space exploration and the new generation of spacecraft which comprise that architecture. The Crew Exploration Vehicle, the associated Crew Launch Vehicle, and later the Heavy Lift Vehicle, will be the 21st century equivalent of our interstate highways.”

Griffin said that although the United States has taken the initiative to provide “the essential transportation nodes — the 21st century space highway,” NASA fully intends to work with other national space agencies and the U.S. commercial sector “to figure out what we can collectively accomplish at the exit ramps.”

Taking full advantage of the space transportation infrastructure NASA intends to put in place to conduct by 2018 the first human lunar landing since the Apollo program ended in 1972 will depend on the willingness of other spacefaring nation s to join the United States on the Moon, Griffin said.

“America alone can bring to bear the discretionary financial resources to provide the man-rated, heavy-lift transportation systems required for this task,” Griffin said. “But with this task accomplished, our presently foreseeable fiscal resources will be exhausted. We will not, by ourselves, be able to conduct the robust program of lunar surface exploration and exploitation that a world with a surface area the size of Africa merits. We will not, by ourselves, be able to take advantage of what lies at the exit ramps of the new interstate highway.”

After Griffin’s speech, representatives of the European and Japanese space agencies said their nation’s share many of the same space exploration goals as the United States but consider completion of the 15-nation international space station program a precondition for joining NASA in any new human space flight ventures.

Assembly of the international space station has been on hold since the February 2003 loss of the Space Shuttle Columbia. Although NASA intends to resume space station assembly around mid-2006, questions remain about whether the United States will be able to honor its commitments to launch the European Columbus science laboratory and the Japanese Experiment Module to the station before retiring the space shuttle in 2010.

Jean-Jacques Tortora, Washington representative for the French space agency CNES, said there are a number of challenges to cooperating with the United States on its new space exploration agenda, the chief among them be “to finish what we have already undertaken.”

“A fully satisfying conclusion of the [international space station program] is a prerequisite to move any further,” Tortora said.

Tortora also said CNES must reconcile its own priorities before setting its sights on putting humans on the Moon or Mars.

“Human exploration is of interest but it’s not a first priority,” he said. “Within exploration we are much more focused on robotic missions to Mars.”

Tortora also expressed misgivings about NASA’s intent on going in alone to build the space transportation infrastructure needed to reach the Moon.

“We welcome the U.S. building a highway. We need one,’” he said. “Having one highway is fine, but what if the highway is blocked for any reason?” Tortora’s concerns about completing the space station were seconded by the head of the European Space Agency’s Washington office, Frederic Nordlund.

“[The space station program] is a very, very visible activity in Europe taking a major share of our budgets and the European taxpayers’ euros and we expect a return from a major 20-plus year investment,” Nordlund said.

Kiwao Shibukawa, director of the Japanese Aerospace Exploration Agency’s Washington office, told Space News after the presentation that Japan also considers the launch of the Japanese Experiment Module (JEM) critical for future cooperation with NASA.

“The launch of the JEM module is a must for future space activities,” he said.

Brian Berger is editor in chief of and the SpaceNews magazine. He joined in 1998, spending his first decade with the publication covering NASA. His reporting on the 2003 Space Shuttle Columbia accident was...