MOSCOW — At a time when American manned missions have been suspended because of design flaws in the space shuttle, Russian authorities want to spin past the moon with a humble vehicle now serving as NASA's space taxi.

Not only are Russian officials planning their nation's first lunar fly-by, according to Russian media reports, but they hope to make the mission at least partly self-financing by selling a seat aboard the venerable Soyuz spacecraft for $100 million.

Where the shuttle is like a winged, spacious space SUV, Russia's Soyuz is an insect-like three-seater compact based on a 1960s design. The American craft can alight delicately on a runway, while Soyuz plunks to Earth tethered to parachutes.

But the Russian spacecraft is cheap, lightweight and adaptable. It has been used in recent years as the International Space Station's lifeboat, and, for more than two years after the Columbia disaster in February 2003, it has ferried skeleton crews to the station to keep it operating.

The idea of retooling the Soviet-era vehicle for a simple moon mission, some European and American space experts say, is more than just pie in the sky.

"It is an interesting and clever scenario," wrote Dr. Roger M. Bonnet, former chief scientist for the European Space Agency and executive director of the International Space Science Institute in Bern, Switzerland.

"I think that the mission would not need a drastic modification of the present (Soyuz) hardware," he wrote in an e-mail interview. Even if some design changes are needed, he said, "This is not insurmountable given the rapidity (with which) the Russians develop new things."

The newspaper Izvestia first broke news of the planned Russian moon mission Tuesday, the day of the shuttle Discovery's launch. The news came before scientists realized that Discovery's external fuel tank had shed a piece of foam -- in a grim reminder of the incident that led to the fiery breakup of Columbia on its return from orbit in February 2003.

The National Aeronautics and Space Administration says it will suspend future shuttle flights until the problem is fixed. Once again, the U.S. space agency will be forced to rely on the Soyuz to shuttle astronauts to the space station -- and it's not clear how this might affect the Russian effort to swing past the moon.

Efforts to reach officials with the Russian Space Agency or Energia, the state-owned Russian space construction company, were unsuccessful Friday.

Space Agency deputy chief Nikolai Moiseyev told the RIA Novosti wire service earlier this week that he saw no technical obstacles to the two-week mission. Plans call for two rockets, one to loft the Soyuz and another to place a booster rocket in orbit.

Soyuz would dock for eight days with the space station, then rendezvous and couple with its booster. The combined spacecraft -- using the Earth's gravity as a slingshot -- would speed around the moon in a figure-eight-shaped pass.

The biggest challenge, Moiseyev said, would be to beef up Soyuz's heat shields. Because the vehicle would accelerate to tremendous speeds during the long trip to the moon and back, it would need to brake before re-entry.

Soyuz could accomplish this without expensive retro-rockets, he told RIA Novosti, by plowing through Earth's upper atmosphere twice -- the first time temporarily to slow itself down, and the second time for good in order to land.

Russia also might have to consider shielding the Soyuz from cosmic rays, scientists said, because the craft would leave the protection of the Earth's magnetic fields during the flight. That could add weight, and cost.

A Soyuz moon fly-by could cost as little as $2 billion, said the space science institute's Bonnet. "But," he warned, "it is impossible to estimate the cost of this scenario unless you have more details on what (Russian space officials) propose to do."