But the Hollywood producer behind the deal said a first slice of the reported $20 million fee would be handed over by Friday or next Monday, and said Bass "is not going to leave town."
Bass, 23, who is bidding to become the youngest person in space, was told to leave the Star City training center outside Moscow where he was preparing to join a mission to the International Space Station (ISS).
"After failing to fulfill the conditions of his contract, Lance Bass has been told that his training at the Cosmonaut Training Center has ended and that his flight to the ISS is impossible," Russian space agency spokesman Sergei Gorbunov told Reuters. "It's over."
Bass's trip is being financed by a consortium of U.S. companies and corporate sponsors led by Hollywood producer David Krieff. Krieff told Reuters Tuesday he was confident the complex deal would go through.
"My feeling is we'll have our first big payment this week and that will silence everybody."
"The money is all there. It was never a question of money, ever. The question is delivery of the money ... so that everybody is happy and that just in case, God forbid, the thing (rocket) blew up, what happens?" he said.
Krieff is planning to build a TV mini-series around Bass's adventure and said he has lined up six U.S. sponsors who have agreed to put up about $22 million collectively.
He said he also has a deal with a U.S. TV network he declined to name and broadcasting and sponsorship pacts in about 40 other countries. Bass is expected to sing during the trip.
Cash-strapped Russia says it needs payment to service its fleet of Soyuz craft. The fee for a single tourist is enough to cover the entire cost of launching a manned craft.
Krieff said negotiations had proved complex because of the ambitious entertainment aspects of the project. The two previous paying space tourists -- U.S. millionaire Dennis Tito and South African entrepreneur Mark Shuttleworth were merely fulfilling their own personal dreams.
"Nobody has ever created a model for media in outer space ... We are sitting on top of a goldmine for Russia and for the commercialization of space."
"My hope is that by next Monday, possibly by this Friday, everything will be in satisfactory order for the Russians and they will reopen their doors to the best publicity they have ever received," Krieff said.
Gorbunov, however, said the Russian space agency was now preparing to send a cargo container to the ISS instead of a third crew member. He said Bass was at Star City, "gathering his stuff and preparing to leave."
But both Krieff and Bass's publicist, Jill Fritzo, said Bass would remain in Russia while negotiations continued.
We are still in negotiations," Fritzo said. "We feel very confident that there will be a resolution soon and the trip will go on as planned."
"Lance is not stepping down by any means," said Jeff Manber, president of MirCorp, a company that helps arrange space-related adventures and is partly owned by Russia's Energia Space Corp., which built part of the International Space Station.
Manber said he met with Russian space officials Tuesday.
"It is a little dramatic to say he was kicked out," Manber said. "He will be back there (at Star City) probably tomorrow or the day after."
Bass began preparing for the October Soyuz flight in the spring, allowing himself training time just short of the six months demanded by the ISS protocol.
Bass, who attended a U.S. space camp in Florida 10 years ago, would have been the youngest person ever in space if he went on his trip.
Bass returned to Russia Sunday after spending a week at NASA's Johnson Space Center in Houston with the other two crew members for the Oct. 28 flight aboard a Russian Soyuz rocket - Russian cosmonaut Sergei Zaletin and Belgian astronaut Frank de Winne.
During his training in Star City, Bass participated in a zero-gravity flight, practiced basic safety and learned some Russian. He kept his composure throughout the zero-gravity flight, unlike many experienced astronauts, space officials said.
James Oberg, a Houston-based space industry expert, said Bass emerged as "as a viable candidate for some future mission."
"He impressed everyone with his sincerity and his intelligence," said Oberg, a paid consultant on a separate bid to film a television production from space.
Bass, whose group hits include "Bye Bye Bye," is not the first pop star to nurture space dreams, after Russian pop group Na-Na bid to become the first to give a concert from orbit last year. Na-Na also underwent training, but never made it into space.