WASHINGTON — The White House’s Jan. 8 announcement of its intent to extend international space station operations from 2020 to 2024 marked the official start of a public lobbying campaign to persuade the station’s international partners, some of which are facing financial difficulties, to come along for the ride.

“We hope that [this] announcement now, allowing time for full and careful consideration by our partners, will contribute to an eventual agreement by all to proceed in extending this unprecedented international effort,” John Holdren, chief science adviser to U.S. President Barack Obama, told an audience of international space agency leaders and diplomats Jan. 9 at the State Department’s International Space Exploration Forum.

It has been little more than a year since one key partner, the European Space Agency, committed to participating through 2020, a decision widely viewed as a compromise between ESA’s two biggest contributors, France and Germany. Jean-Yves Le Gall, president of the French space agency, CNES, which contributes more than half of its annual budget to ESA, said the first order of business is securing funding from some of ESA’s cash-strapped member states to fulfill the 2020 commitment.

France, which has long been less enthusiastic than Germany about station participation, “will find a consensus with its European partners” on ESA’s role beyond 2020, Le Gall said.

The head of Italy’s space agency praised the White House’s extension endorsement, saying it provides Italian industry with a long enough time horizon to contemplate some return on the investment an extended mission would require.

“Knowing the station is there and will remain there at least until 2024 … for us, is a major positive message,” Enrico Saggese, president of Agenzia Spaziale Italiana, said here Jan. 10 during an International Academy of Astronautics panel discussion.

A Japanese official said his country must debate what role it might play in a longer mission, adding that having a clearer idea of how the space station supports deep-space exploration would be helpful.

“It would be premature to say anything definitive at this stage,” Hakubun Shimomura, Japan’s minister of education, culture, sports, science and technology, said at the State Department event.

Meanwhile, NASA’s top human spaceflight official made it clear that the agency would keep the $3 billion-a-year orbital outpost flying even if every participating country but Russia deserted the project. Key components of the space station, including its core module, were built and are controlled by the Russian space agency, Roscosmos.

“We’re prepared to do what we have to do if the partners choose to take a different path,” William Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate, said during a Jan. 8 conference call with reporters.

While NASA is prepared to continue with help only from Russia, Gerstenmaier said NASA has “talked to our partners about this [and] they want to go forward with this; it’s just working through the government approval … to get where they need to be.”

NASA has its own financial difficulties, but extending space station operations to 2024 does not have any immediate U.S. budgetary implications, in part because the orbital outpost already has sufficient hardware supplies onboard to last through 2028, government officials say.

“[T]hrough 2020 there’s no additional funds required for this activity,” Gerstenmaier said. “We had reserved funds to deorbit station in the outyears. Those funds … will [now] be applied for the extension of life.”

The White House’s approval of a four-year mission extension — four years fewer than what NASA and space station prime contractor Boeing Space Exploration of Houston have been pushing — was first reported by the Orlando Sentinel late Jan. 7.

The White House announcement was greeted warmly by some of station’s supporters on Capitol Hill.

“I applaud the decision to extend the operations of the International Space Station,” U.S. Senate Appropriations Committee Chairwoman Barbara Mikulski (D-Md.) said in a Jan. 8  statement.

Sen. Bill Nelson (D-Fla.), who chairs the Senate’s Commerce, Science and Transportation science and space subcommittee, was similarly enthusiastic. “This means more jobs at the Kennedy Space Center as we rebuild our entire space program,” Nelson said in recorded remarks that were distributed to media.

On the other side of Capitol Hill, House Science Committee Chairman Rep. Lamar Smith (R-Texas) greeted the White House’s announcement cautiously.

“It is important that we understand costs and are able to clearly define success if we plan to extend the life of the ISS,” Smith wrote in a Jan. 8 email to SpaceNews. “Americans can only reap the benefits from their investment if we fully utilize the ISS for innovative one-of-a-kind research.”

Some space observers have argued that NASA cannot get serious about sending astronauts to a deep-space destination so long as it is spending $3 billion annually on the space station.

NASA is looking for ways to trim that budget, about half of which is dedicated to transporting cargo and crew to the outpost, Gerstenmaier said. Complicating that effort is the need to decide, by this spring, whether to pay Russia to continue ferrying U.S. astronauts to the space station beyond 2016.

The going rate for a single astronaut to fly Soyuz round trip is roughly $70 million and must be booked three years in advance.

NASA is paying three U.S. companies to develop crew transportation systems the agency could use for this purpose as soon as late 2017.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.

Warren Ferster is the Editor-in-Chief of SpaceNews and is responsible for all the news and editorial coverage in the weekly newspaper, the spacenews.com Web site and variety of specialty publications such as show dailies. He manages a staff of seven reporters...