Time is running out on a U.S.-Russian agreement that until now has guaranteed American astronauts a seat aboard the Soyuz spacecraft that ferry crews to and from the international space station twice a year and guarantee their safe return in an emergency.

In October, the 11th and final Soyuz that Russia is obligated under a 1996 bilateral agreement to share with NASA is due to launch from Kazakhstan carrying a U.S.-Russian crew to the space station. Six months later, in April 2006, that Soyuz is due to come back to Earth, fulfilling Russia’s commitment to provide crew return services for American astronauts.

NASA officials acknowledge that the United States has no choice but to pay Russia if it wants American astronauts to be allowed to ride aboard Soyuz spacecraft after April 2006. NASA’s 2006 budget request includes $1.7 billion over the next five years to pay for the space station crew and cargo launch services the agency needs if it wants to retire the space shuttle in 2010. Some of that $1.7 billion, NASA officials have said, was put into the budget to buy Soyuz.

U.S. law, however, currently prohibits NASA from making any space station-related payments to Russia so long as the White House remains unable to assure Congress that Russian aerospace entities have stopped helping Iran with its efforts to develop missiles and other advanced weaponry.

With NASA planning to resume space shuttle flights in mid-May, getting astronauts to the space station will not be a problem much longer. But unless NASA changes its policy to permit its astronauts to remain onboard the space station without a way home in an emergency, by this time next year American astronauts could be limited to visiting the station only while a space shuttle remains docked there.

Further complicating matters, the European, Japanese and Canadian space agencies are still counting on the United States to provide a space station lifeboat capability for at least four people once the station is completed.

Because NASA canceled the development of its proposed crew lifeboat several years ago to deal with rampant cost growth on the international space station program, the Soyuz is the only means of getting a space station crew home in an emergency.

If NASA retires the space shuttle fleet by the end of 2010, as called for under the space exploration vision put forward by President George W. Bush last year, NASA would have no means of launching astronauts into space until at least 2014, when it plans to field the Crew Exploration Vehicle, a spacecraft intended primarily to carry astronauts to and from the Moon.

In the months ahead, the White House and Congress will have to choose between accepting at least a temporary end to extended U.S. stays aboard the space station and changing a law designed to discourage Russian assistance to Iranian nuclear and missile programs.

The law, the Iran Nonproliferation Act (INA) of 2000, includes a provision known as Section 6 that bars the U.S. government from making any space station-related payments to the Russian space agency or any entity under its control until the White House can certify to Congress that the Russian aerospace sector has stopped proliferating ballistic missiles and other advanced weapons, and has not done so for at least a year.

House Science Committee Chairman Sherwood Boehlert (R-N.Y.) raised the Soyuz issue during a NASA budget hearing in mid-February, saying he expected the White House would put forward a legislative proposal by the end of March for amending the Iran Nonproliferation Act to permit NASA to buy Soyuz. He said any such proposal would face intense scrutiny from lawmakers loathe to put the space station program ahead of U.S. nonproliferation goals.

Interim NASA Administrator Fred Gregory told lawmakers at the Feb. 17 hearing that NASA and the White House were aware of the restrictions imposed on the international space station program by the Iran Nonproliferation Act, but provided no details on how the administration proposed to resolve the issue.

NASA spokeswoman Debra Rahn said March 14 that an interagency group is still evaluating the needs of the international space station program as they relate to the restrictions imposed by the Iran Nonproliferation Act. She said she knew of no clear timetable for the group to finish its work or put forward recommendations or legislative proposals.

NASA’s predicament elicits no sympathy from proliferation foe Henry Sokolski, executive director of the Nonproliferation Policy Education Center, who said the space agency has had plenty of time to take action to avert a space station crisis.

“There was plenty of warning on this,” he said. “This did not just creep up on them. They chose to let this one go.”

Anticipating the debates that lay ahead, the non-partisan Congressional Research Service — the public policy research arm of the U.S. Congress — prepared for lawmakers the March 2 report “The Iran Nonproliferation Act and the International Space Station: Issues and Options.”

The six-page report traces the roots of the Iran Nonproliferation Act of 2000, analyzes the law’s impacts on Russian behavior and NASA’s use of the space station, and discusses the options the United States has at its disposal.

The report notes that while the U.S. State Department has seen some improvement in Russia’s export control laws in recent years, the Central Intelligence Agency reported in 2003 that Russian entities were still proliferating ballistic missile technology to Iran.

“INA proponents argue that Section 6 has had a positive impact on Russian proliferation behavior because it has created a strong economic incentive for the Russian space agency to become a proponent of Russian nonproliferation compliance,” the Congressional Research Service report states. “Critics, however, maintain that the Russian space agency is just one agency, and that the Ministry of Defense and Ministry of Atomic Energy have committed other proliferation ‘crimes’ related to Iran that are untouched by the [Iran Nonproliferation Act] .”

Iran’s efforts to acquire foreign weapons technology “seem to continue unabated,” according to the report, making it “unlikely that the president would determine that Russia is complying with the [Iran Nonproliferation Act] .”

The report lays out two options for amending the Iran Nonproliferation Act: changing the law to permit NASA to buy crew services from the Russian space agency or changing the law to allow NASA to purchase Russian designs, materials and know-how to build Soyuz in the United States and launch them on U.S. rockets.

The report also said it may be possible, although not necessarily politically prudent, for the Bush Administration to conclude that the restrictions in the Iran Nonproliferation Act do not apply to Energia, the Korolev, Russia-based company that builds Soyuz, and thus open the door to a direct purchase.

Another set of options, according to the report, entails “ensuring that NASA has an independent capability to use the [international space station] ” — either by postponing the shuttle’s retirement and modifying it for extended stays on orbit or accelerating the development of the Crew Exploration Vehicle and making sure it can be used to go to the station.

“The cost and schedule for these options may be prohibitive, however,” the report notes, “and questions remain about the safety of the shuttle (it has not yet returned to flight status following the Columbia tragedy), and how many flights it should make.”

The report also raises the possibility that NASA might not actually need to have astronauts onboard the station other than when a shuttle is there.

“From a space program perspective, the threshold question is the extent to which NASA needs to have U.S. astronauts on the ISS for long duration missions between 2006 and 2010, and to have any astronauts there after 2010,” the report says. “Under the vision, the only U.S. research that will be conducted on [space station] is that needed to support the vision. Questions thus arise as to whether adequate research could be performed on Earth (and, eventually, the Moon), or if NASA could pay astronauts from the non-Russian [space station] partners to conduct the research.”

NASA’s Exploration Systems Mission Directorate has been evaluating the international space station research agenda since November with the goal of weeding out research projects that do not support the goals of the vision. Craig Steidle, NASA’s associate administrator for exploration systems, said March 11 that he completed his assessment of international space station research requirements at the end of February and passed it on to NASA’s Space Operations Mission Directorate to determine the implications for space station assembly and the space shuttle manifest.

A final report is expected around the end of April.

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